staticperl/perl/perlio.c

/*
 * perlio.c Copyright (c) 1996-2005, Nick Ing-Simmons You may distribute
 * under the terms of either the GNU General Public License or the
 * Artistic License, as specified in the README file.
 */

/*
 * Hour after hour for nearly three weary days he had jogged up and down,
 * over passes, and through long dales, and across many streams.
 */

/* This file contains the functions needed to implement PerlIO, which
 * is Perl's private replacement for the C stdio library. This is used
 * by default unless you compile with -Uuseperlio or run with
 * PERLIO=:stdio (but don't do this unless you know what you're doing)
 */

/*
 * If we have ActivePerl-like PERL_IMPLICIT_SYS then we need a dTHX to get
 * at the dispatch tables, even when we do not need it for other reasons.
 * Invent a dSYS macro to abstract this out
 */
#ifdef PERL_IMPLICIT_SYS
#define dSYS dTHX
#else
#define dSYS dNOOP
#endif

#define VOIDUSED 1
#ifdef PERL_MICRO
#   include "uconfig.h"
#else
#   include "config.h"
#endif

#define PERLIO_NOT_STDIO 0
#if !defined(PERLIO_IS_STDIO) && !defined(USE_SFIO)
/*
 * #define PerlIO FILE
 */
#endif
/*
 * This file provides those parts of PerlIO abstraction
 * which are not #defined in perlio.h.
 * Which these are depends on various Configure #ifdef's
 */

#include "EXTERN.h"
#define PERL_IN_PERLIO_C
#include "perl.h"

#ifdef PERL_IMPLICIT_CONTEXT
#undef dSYS
#define dSYS dTHX
#endif

#include "XSUB.h"

#ifdef __Lynx__
/* Missing proto on LynxOS */
int mkstemp(char*);
#endif

/* Call the callback or PerlIOBase, and return failure. */
#define Perl_PerlIO_or_Base(f, callback, base, failure, args)   \
        if (PerlIOValid(f)) {                                   \
                PerlIO_funcs *tab = PerlIOBase(f)->tab;         \
                if (tab && tab->callback)                       \
                        return (*tab->callback) args;           \
                else                                            \
                        return PerlIOBase_ ## base args;        \
        }                                                       \
        else                                                    \
                SETERRNO(EBADF, SS_IVCHAN);                     \
        return failure

/* Call the callback or fail, and return failure. */
#define Perl_PerlIO_or_fail(f, callback, failure, args)         \
        if (PerlIOValid(f)) {                                   \
                PerlIO_funcs *tab = PerlIOBase(f)->tab;         \
                if (tab && tab->callback)                       \
                        return (*tab->callback) args;           \
                SETERRNO(EINVAL, LIB_INVARG);                   \
        }                                                       \
        else                                                    \
                SETERRNO(EBADF, SS_IVCHAN);                     \
        return failure

/* Call the callback or PerlIOBase, and be void. */
#define Perl_PerlIO_or_Base_void(f, callback, base, args)       \
        if (PerlIOValid(f)) {                                   \
                PerlIO_funcs *tab = PerlIOBase(f)->tab;         \
                if (tab && tab->callback)                       \
                        (*tab->callback) args;                  \
                else                                            \
                        PerlIOBase_ ## base args;               \
        }                                                       \
        else                                                    \
                SETERRNO(EBADF, SS_IVCHAN)

/* Call the callback or fail, and be void. */
#define Perl_PerlIO_or_fail_void(f, callback, args)             \
        if (PerlIOValid(f)) {                                   \
                PerlIO_funcs *tab = PerlIOBase(f)->tab;         \
                if (tab && tab->callback)                       \
                        (*tab->callback) args;                  \
                else                                            \
                        SETERRNO(EINVAL, LIB_INVARG);           \
        }                                                       \
        else                                                    \
                SETERRNO(EBADF, SS_IVCHAN)

int
perlsio_binmode(FILE *fp, int iotype, int mode)
{
    /*
     * This used to be contents of do_binmode in doio.c
     */
#ifdef DOSISH
#  if defined(atarist) || defined(__MINT__)
    if (!fflush(fp)) {
        if (mode & O_BINARY)
            ((FILE *) fp)->_flag |= _IOBIN;
        else
            ((FILE *) fp)->_flag &= ~_IOBIN;
        return 1;
    }
    return 0;
#  else
    dTHX;
#ifdef NETWARE
    if (PerlLIO_setmode(fp, mode) != -1) {
#else
    if (PerlLIO_setmode(fileno(fp), mode) != -1) {
#endif
#    if defined(WIN32) && defined(__BORLANDC__)
        /*
         * The translation mode of the stream is maintained independent of
         * the translation mode of the fd in the Borland RTL (heavy
         * digging through their runtime sources reveal).  User has to set
         * the mode explicitly for the stream (though they don't document
         * this anywhere). GSAR 97-5-24
         */
        fseek(fp, 0L, 0);
        if (mode & O_BINARY)
            fp->flags |= _F_BIN;
        else
            fp->flags &= ~_F_BIN;
#    endif
        return 1;
    }
    else
        return 0;
#  endif
#else
#  if defined(USEMYBINMODE)
    dTHX;
    if (my_binmode(fp, iotype, mode) != FALSE)
        return 1;
    else
        return 0;
#  else
    return 1;
#  endif
#endif
}

#ifndef O_ACCMODE
#define O_ACCMODE 3             /* Assume traditional implementation */
#endif

int
PerlIO_intmode2str(int rawmode, char *mode, int *writing)
{
    int result = rawmode & O_ACCMODE;
    int ix = 0;
    int ptype;
    switch (result) {
    case O_RDONLY:
        ptype = IoTYPE_RDONLY;
        break;
    case O_WRONLY:
        ptype = IoTYPE_WRONLY;
        break;
    case O_RDWR:
    default:
        ptype = IoTYPE_RDWR;
        break;
    }
    if (writing)
        *writing = (result != O_RDONLY);

    if (result == O_RDONLY) {
        mode[ix++] = 'r';
    }
#ifdef O_APPEND
    else if (rawmode & O_APPEND) {
        mode[ix++] = 'a';
        if (result != O_WRONLY)
            mode[ix++] = '+';
    }
#endif
    else {
        if (result == O_WRONLY)
            mode[ix++] = 'w';
        else {
            mode[ix++] = 'r';
            mode[ix++] = '+';
        }
    }
    if (rawmode & O_BINARY)
        mode[ix++] = 'b';
    mode[ix] = '\0';
    return ptype;
}

#ifndef PERLIO_LAYERS
int
PerlIO_apply_layers(pTHX_ PerlIO *f, const char *mode, const char *names)
{
    if (!names || !*names
        || strEQ(names, ":crlf")
        || strEQ(names, ":raw")
        || strEQ(names, ":bytes")
       ) {
        return 0;
    }
    Perl_croak(aTHX_ "Cannot apply \"%s\" in non-PerlIO perl", names);
    /*
     * NOTREACHED
     */
    return -1;
}

void
PerlIO_destruct(pTHX)
{
}

int
PerlIO_binmode(pTHX_ PerlIO *fp, int iotype, int mode, const char *names)
{
#ifdef USE_SFIO
    return 1;
#else
    return perlsio_binmode(fp, iotype, mode);
#endif
}

PerlIO *
PerlIO_fdupopen(pTHX_ PerlIO *f, CLONE_PARAMS *param, int flags)
{
#ifdef PERL_MICRO
    return NULL;
#else
#ifdef PERL_IMPLICIT_SYS
    return PerlSIO_fdupopen(f);
#else
#ifdef WIN32
    return win32_fdupopen(f);
#else
    if (f) {
        int fd = PerlLIO_dup(PerlIO_fileno(f));
        if (fd >= 0) {
            char mode[8];
            int omode = fcntl(fd, F_GETFL);
#ifdef DJGPP
            omode = djgpp_get_stream_mode(f);
#endif
            PerlIO_intmode2str(omode,mode,NULL);
            /* the r+ is a hack */
            return PerlIO_fdopen(fd, mode);
        }
        return NULL;
    }
    else {
        SETERRNO(EBADF, SS_IVCHAN);
    }
#endif
    return NULL;
#endif
#endif
}


/*
 * De-mux PerlIO_openn() into fdopen, freopen and fopen type entries
 */

PerlIO *
PerlIO_openn(pTHX_ const char *layers, const char *mode, int fd,
             int imode, int perm, PerlIO *old, int narg, SV **args)
{
    if (narg) {
        if (narg > 1) {
            Perl_croak(aTHX_ "More than one argument to open");
        }
        if (*args == &PL_sv_undef)
            return PerlIO_tmpfile();
        else {
            char *name = SvPV_nolen(*args);
            if (*mode == IoTYPE_NUMERIC) {
                fd = PerlLIO_open3(name, imode, perm);
                if (fd >= 0)
                    return PerlIO_fdopen(fd, (char *) mode + 1);
            }
            else if (old) {
                return PerlIO_reopen(name, mode, old);
            }
            else {
                return PerlIO_open(name, mode);
            }
        }
    }
    else {
        return PerlIO_fdopen(fd, (char *) mode);
    }
    return NULL;
}

XS(XS_PerlIO__Layer__find)
{
    dXSARGS;
    if (items < 2)
        Perl_croak(aTHX_ "Usage class->find(name[,load])");
    else {
        char *name = SvPV_nolen(ST(1));
        ST(0) = (strEQ(name, "crlf")
                 || strEQ(name, "raw")) ? &PL_sv_yes : &PL_sv_undef;
        XSRETURN(1);
    }
}


void
Perl_boot_core_PerlIO(pTHX)
{
    newXS("PerlIO::Layer::find", XS_PerlIO__Layer__find, __FILE__);
}

#endif


#ifdef PERLIO_IS_STDIO

void
PerlIO_init(pTHX)
{
    /*
     * Does nothing (yet) except force this file to be included in perl
     * binary. That allows this file to force inclusion of other functions
     * that may be required by loadable extensions e.g. for
     * FileHandle::tmpfile
     */
}

#undef PerlIO_tmpfile
PerlIO *
PerlIO_tmpfile(void)
{
    return tmpfile();
}

#else                           /* PERLIO_IS_STDIO */

#ifdef USE_SFIO

#undef HAS_FSETPOS
#undef HAS_FGETPOS

/*
 * This section is just to make sure these functions get pulled in from
 * libsfio.a
 */

#undef PerlIO_tmpfile
PerlIO *
PerlIO_tmpfile(void)
{
    return sftmp(0);
}

void
PerlIO_init(pTHX)
{
    /*
     * Force this file to be included in perl binary. Which allows this
     * file to force inclusion of other functions that may be required by
     * loadable extensions e.g. for FileHandle::tmpfile
     */

    /*
     * Hack sfio does its own 'autoflush' on stdout in common cases. Flush
     * results in a lot of lseek()s to regular files and lot of small
     * writes to pipes.
     */
    sfset(sfstdout, SF_SHARE, 0);
}

/* This is not the reverse of PerlIO_exportFILE(), PerlIO_releaseFILE() is. */
PerlIO *
PerlIO_importFILE(FILE *stdio, const char *mode)
{
    int fd = fileno(stdio);
    if (!mode || !*mode) {
        mode = "r+";
    }
    return PerlIO_fdopen(fd, mode);
}

FILE *
PerlIO_findFILE(PerlIO *pio)
{
    int fd = PerlIO_fileno(pio);
    FILE *f = fdopen(fd, "r+");
    PerlIO_flush(pio);
    if (!f && errno == EINVAL)
        f = fdopen(fd, "w");
    if (!f && errno == EINVAL)
        f = fdopen(fd, "r");
    return f;
}


#else                           /* USE_SFIO */
/*======================================================================================*/
/*
 * Implement all the PerlIO interface ourselves.
 */

#include "perliol.h"

/*
 * We _MUST_ have <unistd.h> if we are using lseek() and may have large
 * files
 */
#ifdef I_UNISTD
#include <unistd.h>
#endif
#ifdef HAS_MMAP
#include <sys/mman.h>
#endif

/*
 * Why is this here - not in perlio.h?  RMB
 */
void PerlIO_debug(const char *fmt, ...)
    __attribute__format__(__printf__, 1, 2);

void
PerlIO_debug(const char *fmt, ...)
{
    static int dbg = 0;
    va_list ap;
    dSYS;
    va_start(ap, fmt);
    if (!dbg && !PL_tainting && PL_uid == PL_euid && PL_gid == PL_egid) {
        char *s = PerlEnv_getenv("PERLIO_DEBUG");
        if (s && *s)
            dbg = PerlLIO_open3(s, O_WRONLY | O_CREAT | O_APPEND, 0666);
        else
            dbg = -1;
    }
    if (dbg > 0) {
        dTHX;
#ifdef USE_ITHREADS
        /* Use fixed buffer as sv_catpvf etc. needs SVs */
        char buffer[1024];
        char *s;
        STRLEN len;
        s = CopFILE(PL_curcop);
        if (!s)
            s = "(none)";
        sprintf(buffer, "%.40s:%" IVdf " ", s, (IV) CopLINE(PL_curcop));
        len = strlen(buffer);
        vsprintf(buffer+len, fmt, ap);
        PerlLIO_write(dbg, buffer, strlen(buffer));
#else
        SV *sv = newSVpvn("", 0);
        char *s;
        STRLEN len;
        s = CopFILE(PL_curcop);
        if (!s)
            s = "(none)";
        Perl_sv_catpvf(aTHX_ sv, "%s:%" IVdf " ", s,
                       (IV) CopLINE(PL_curcop));
        Perl_sv_vcatpvf(aTHX_ sv, fmt, &ap);

        s = SvPV(sv, len);
        PerlLIO_write(dbg, s, len);
        SvREFCNT_dec(sv);
#endif
    }
    va_end(ap);
}

/*--------------------------------------------------------------------------------------*/

/*
 * Inner level routines
 */

/*
 * Table of pointers to the PerlIO structs (malloc'ed)
 */
#define PERLIO_TABLE_SIZE 64

PerlIO *
PerlIO_allocate(pTHX)
{
    /*
     * Find a free slot in the table, allocating new table as necessary
     */
    PerlIO **last;
    PerlIO *f;
    last = &PL_perlio;
    while ((f = *last)) {
        int i;
        last = (PerlIO **) (f);
        for (i = 1; i < PERLIO_TABLE_SIZE; i++) {
            if (!*++f) {
                return f;
            }
        }
    }
    Newz('I',f,PERLIO_TABLE_SIZE,PerlIO);
    if (!f) {
        return NULL;
    }
    *last = f;
    return f + 1;
}

#undef PerlIO_fdupopen
PerlIO *
PerlIO_fdupopen(pTHX_ PerlIO *f, CLONE_PARAMS *param, int flags)
{
    if (PerlIOValid(f)) {
        PerlIO_funcs *tab = PerlIOBase(f)->tab;
        PerlIO_debug("fdupopen f=%p param=%p\n",(void*)f,(void*)param);
        if (tab && tab->Dup)
             return (*tab->Dup)(aTHX_ PerlIO_allocate(aTHX), f, param, flags);
        else {
             return PerlIOBase_dup(aTHX_ PerlIO_allocate(aTHX), f, param, flags);
        }
    }
    else
         SETERRNO(EBADF, SS_IVCHAN);

    return NULL;
}

void
PerlIO_cleantable(pTHX_ PerlIO **tablep)
{
    PerlIO *table = *tablep;
    if (table) {
        int i;
        PerlIO_cleantable(aTHX_(PerlIO **) & (table[0]));
        for (i = PERLIO_TABLE_SIZE - 1; i > 0; i--) {
            PerlIO *f = table + i;
            if (*f) {
                PerlIO_close(f);
            }
        }
        Safefree(table);
        *tablep = NULL;
    }
}


PerlIO_list_t *
PerlIO_list_alloc(pTHX)
{
    PerlIO_list_t *list;
    Newz('L', list, 1, PerlIO_list_t);
    list->refcnt = 1;
    return list;
}

void
PerlIO_list_free(pTHX_ PerlIO_list_t *list)
{
    if (list) {
        if (--list->refcnt == 0) {
            if (list->array) {
                IV i;
                for (i = 0; i < list->cur; i++) {
                    if (list->array[i].arg)
                        SvREFCNT_dec(list->array[i].arg);
                }
                Safefree(list->array);
            }
            Safefree(list);
        }
    }
}

void
PerlIO_list_push(pTHX_ PerlIO_list_t *list, PerlIO_funcs *funcs, SV *arg)
{
    PerlIO_pair_t *p;
    if (list->cur >= list->len) {
        list->len += 8;
        if (list->array)
            Renew(list->array, list->len, PerlIO_pair_t);
        else
            New('l', list->array, list->len, PerlIO_pair_t);
    }
    p = &(list->array[list->cur++]);
    p->funcs = funcs;
    if ((p->arg = arg)) {
        SvREFCNT_inc(arg);
    }
}

PerlIO_list_t *
PerlIO_clone_list(pTHX_ PerlIO_list_t *proto, CLONE_PARAMS *param)
{
    PerlIO_list_t *list = (PerlIO_list_t *) NULL;
    if (proto) {
        int i;
        list = PerlIO_list_alloc(aTHX);
        for (i=0; i < proto->cur; i++) {
            SV *arg = Nullsv;
            if (proto->array[i].arg)
                arg = PerlIO_sv_dup(aTHX_ proto->array[i].arg,param);
            PerlIO_list_push(aTHX_ list, proto->array[i].funcs, arg);
        }
    }
    return list;
}

void
PerlIO_clone(pTHX_ PerlInterpreter *proto, CLONE_PARAMS *param)
{
#ifdef USE_ITHREADS
    PerlIO **table = &proto->Iperlio;
    PerlIO *f;
    PL_perlio = NULL;
    PL_known_layers = PerlIO_clone_list(aTHX_ proto->Iknown_layers, param);
    PL_def_layerlist = PerlIO_clone_list(aTHX_ proto->Idef_layerlist, param);
    PerlIO_allocate(aTHX); /* root slot is never used */
    PerlIO_debug("Clone %p from %p\n",aTHX,proto);
    while ((f = *table)) {
            int i;
            table = (PerlIO **) (f++);
            for (i = 1; i < PERLIO_TABLE_SIZE; i++) {
                if (*f) {
                    (void) fp_dup(f, 0, param);
                }
                f++;
            }
        }
#endif
}

void
PerlIO_destruct(pTHX)
{
    PerlIO **table = &PL_perlio;
    PerlIO *f;
#ifdef USE_ITHREADS
    PerlIO_debug("Destruct %p\n",aTHX);
#endif
    while ((f = *table)) {
        int i;
        table = (PerlIO **) (f++);
        for (i = 1; i < PERLIO_TABLE_SIZE; i++) {
            PerlIO *x = f;
            PerlIOl *l;
            while ((l = *x)) {
                if (l->tab->kind & PERLIO_K_DESTRUCT) {
                    PerlIO_debug("Destruct popping %s\n", l->tab->name);
                    PerlIO_flush(x);
                    PerlIO_pop(aTHX_ x);
                }
                else {
                    x = PerlIONext(x);
                }
            }
            f++;
        }
    }
}

void
PerlIO_pop(pTHX_ PerlIO *f)
{
    PerlIOl *l = *f;
    if (l) {
        PerlIO_debug("PerlIO_pop f=%p %s\n", (void*)f, l->tab->name);
        if (l->tab->Popped) {
            /*
             * If popped returns non-zero do not free its layer structure
             * it has either done so itself, or it is shared and still in
             * use
             */
            if ((*l->tab->Popped) (aTHX_ f) != 0)
                return;
        }
        *f = l->next;
        Safefree(l);
    }
}

/* Return as an array the stack of layers on a filehandle.  Note that
 * the stack is returned top-first in the array, and there are three
 * times as many array elements as there are layers in the stack: the
 * first element of a layer triplet is the name, the second one is the
 * arguments, and the third one is the flags. */

AV *
PerlIO_get_layers(pTHX_ PerlIO *f)
{
     AV *av = newAV();

     if (PerlIOValid(f)) {
          PerlIOl *l = PerlIOBase(f);

          while (l) {
               SV *name = l->tab && l->tab->name ?
                    newSVpv(l->tab->name, 0) : &PL_sv_undef;
               SV *arg = l->tab && l->tab->Getarg ?
                    (*l->tab->Getarg)(aTHX_ &l, 0, 0) : &PL_sv_undef;
               av_push(av, name);
               av_push(av, arg);
               av_push(av, newSViv((IV)l->flags));
               l = l->next;
          }
     }

     return av;
}

/*--------------------------------------------------------------------------------------*/
/*
 * XS Interface for perl code
 */

PerlIO_funcs *
PerlIO_find_layer(pTHX_ const char *name, STRLEN len, int load)
{
    IV i;
    if ((SSize_t) len <= 0)
        len = strlen(name);
    for (i = 0; i < PL_known_layers->cur; i++) {
        PerlIO_funcs *f = PL_known_layers->array[i].funcs;
        if (memEQ(f->name, name, len) && f->name[len] == 0) {
            PerlIO_debug("%.*s => %p\n", (int) len, name, (void*)f);
            return f;
        }
    }
    if (load && PL_subname && PL_def_layerlist
        && PL_def_layerlist->cur >= 2) {
        if (PL_in_load_module) {
            Perl_croak(aTHX_ "Recursive call to Perl_load_module in PerlIO_find_layer");
            return NULL;
        } else {
            SV *pkgsv = newSVpvn("PerlIO", 6);
            SV *layer = newSVpvn(name, len);
            CV *cv  = get_cv("PerlIO::Layer::NoWarnings", FALSE);
            ENTER;
            SAVEINT(PL_in_load_module);
            if (cv) {
                SAVESPTR(PL_warnhook);
                PL_warnhook = (SV *) cv;
            }
            PL_in_load_module++;
            /*
             * The two SVs are magically freed by load_module
             */
            Perl_load_module(aTHX_ 0, pkgsv, Nullsv, layer, Nullsv);
            PL_in_load_module--;
            LEAVE;
            return PerlIO_find_layer(aTHX_ name, len, 0);
        }
    }
    PerlIO_debug("Cannot find %.*s\n", (int) len, name);
    return NULL;
}

#ifdef USE_ATTRIBUTES_FOR_PERLIO

static int
perlio_mg_set(pTHX_ SV *sv, MAGIC *mg)
{
    if (SvROK(sv)) {
        IO *io = GvIOn((GV *) SvRV(sv));
        PerlIO *ifp = IoIFP(io);
        PerlIO *ofp = IoOFP(io);
        Perl_warn(aTHX_ "set %" SVf " %p %p %p", sv, io, ifp, ofp);
    }
    return 0;
}

static int
perlio_mg_get(pTHX_ SV *sv, MAGIC *mg)
{
    if (SvROK(sv)) {
        IO *io = GvIOn((GV *) SvRV(sv));
        PerlIO *ifp = IoIFP(io);
        PerlIO *ofp = IoOFP(io);
        Perl_warn(aTHX_ "get %" SVf " %p %p %p", sv, io, ifp, ofp);
    }
    return 0;
}

static int
perlio_mg_clear(pTHX_ SV *sv, MAGIC *mg)
{
    Perl_warn(aTHX_ "clear %" SVf, sv);
    return 0;
}

static int
perlio_mg_free(pTHX_ SV *sv, MAGIC *mg)
{
    Perl_warn(aTHX_ "free %" SVf, sv);
    return 0;
}

MGVTBL perlio_vtab = {
    perlio_mg_get,
    perlio_mg_set,
    NULL,                       /* len */
    perlio_mg_clear,
    perlio_mg_free
};

XS(XS_io_MODIFY_SCALAR_ATTRIBUTES)
{
    dXSARGS;
    SV *sv = SvRV(ST(1));
    AV *av = newAV();
    MAGIC *mg;
    int count = 0;
    int i;
    sv_magic(sv, (SV *) av, PERL_MAGIC_ext, NULL, 0);
    SvRMAGICAL_off(sv);
    mg = mg_find(sv, PERL_MAGIC_ext);
    mg->mg_virtual = &perlio_vtab;
    mg_magical(sv);
    Perl_warn(aTHX_ "attrib %" SVf, sv);
    for (i = 2; i < items; i++) {
        STRLEN len;
        const char *name = SvPV(ST(i), len);
        SV *layer = PerlIO_find_layer(aTHX_ name, len, 1);
        if (layer) {
            av_push(av, SvREFCNT_inc(layer));
        }
        else {
            ST(count) = ST(i);
            count++;
        }
    }
    SvREFCNT_dec(av);
    XSRETURN(count);
}

#endif                          /* USE_ATTIBUTES_FOR_PERLIO */

SV *
PerlIO_tab_sv(pTHX_ PerlIO_funcs *tab)
{
    HV *stash = gv_stashpv("PerlIO::Layer", TRUE);
    SV *sv = sv_bless(newRV_noinc(newSViv(PTR2IV(tab))), stash);
    return sv;
}

XS(XS_PerlIO__Layer__NoWarnings)
{
    /* This is used as a %SIG{__WARN__} handler to supress warnings
       during loading of layers.
     */
    dXSARGS;
    if (items)
        PerlIO_debug("warning:%s\n",SvPV_nolen(ST(0)));
    XSRETURN(0);
}

XS(XS_PerlIO__Layer__find)
{
    dXSARGS;
    if (items < 2)
        Perl_croak(aTHX_ "Usage class->find(name[,load])");
    else {
        STRLEN len = 0;
        char *name = SvPV(ST(1), len);
        bool load = (items > 2) ? SvTRUE(ST(2)) : 0;
        PerlIO_funcs *layer = PerlIO_find_layer(aTHX_ name, len, load);
        ST(0) =
            (layer) ? sv_2mortal(PerlIO_tab_sv(aTHX_ layer)) :
            &PL_sv_undef;
        XSRETURN(1);
    }
}

void
PerlIO_define_layer(pTHX_ PerlIO_funcs *tab)
{
    if (!PL_known_layers)
        PL_known_layers = PerlIO_list_alloc(aTHX);
    PerlIO_list_push(aTHX_ PL_known_layers, tab, Nullsv);
    PerlIO_debug("define %s %p\n", tab->name, (void*)tab);
}

int
PerlIO_parse_layers(pTHX_ PerlIO_list_t *av, const char *names)
{
    if (names) {
        const char *s = names;
        while (*s) {
            while (isSPACE(*s) || *s == ':')
                s++;
            if (*s) {
                STRLEN llen = 0;
                const char *e = s;
                const char *as = Nullch;
                STRLEN alen = 0;
                if (!isIDFIRST(*s)) {
                    /*
                     * Message is consistent with how attribute lists are
                     * passed. Even though this means "foo : : bar" is
                     * seen as an invalid separator character.
                     */
                    char q = ((*s == '\'') ? '"' : '\'');
                    if (ckWARN(WARN_LAYER))
                        Perl_warner(aTHX_ packWARN(WARN_LAYER),
                              "Invalid separator character %c%c%c in PerlIO layer specification %s",
                              q, *s, q, s);
                    SETERRNO(EINVAL, LIB_INVARG);
                    return -1;
                }
                do {
                    e++;
                } while (isALNUM(*e));
                llen = e - s;
                if (*e == '(') {
                    int nesting = 1;
                    as = ++e;
                    while (nesting) {
                        switch (*e++) {
                        case ')':
                            if (--nesting == 0)
                                alen = (e - 1) - as;
                            break;
                        case '(':
                            ++nesting;
                            break;
                        case '\\':
                            /*
                             * It's a nul terminated string, not allowed
                             * to \ the terminating null. Anything other
                             * character is passed over.
                             */
                            if (*e++) {
                                break;
                            }
                            /*
                             * Drop through
                             */
                        case '\0':
                            e--;
                            if (ckWARN(WARN_LAYER))
                                Perl_warner(aTHX_ packWARN(WARN_LAYER),
                                      "Argument list not closed for PerlIO layer \"%.*s\"",
                                      (int) (e - s), s);
                            return -1;
                        default:
                            /*
                             * boring.
                             */
                            break;
                        }
                    }
                }
                if (e > s) {
                    bool warn_layer = ckWARN(WARN_LAYER);
                    PerlIO_funcs *layer =
                        PerlIO_find_layer(aTHX_ s, llen, 1);
                    if (layer) {
                        PerlIO_list_push(aTHX_ av, layer,
                                         (as) ? newSVpvn(as,
                                                         alen) :
                                         &PL_sv_undef);
                    }
                    else {
                        if (warn_layer)
                            Perl_warner(aTHX_ packWARN(WARN_LAYER), "Unknown PerlIO layer \"%.*s\"",
                                  (int) llen, s);
                        return -1;
                    }
                }
                s = e;
            }
        }
    }
    return 0;
}

void
PerlIO_default_buffer(pTHX_ PerlIO_list_t *av)
{
    PerlIO_funcs *tab = &PerlIO_perlio;
#ifdef PERLIO_USING_CRLF
    tab = &PerlIO_crlf;
#else
    if (PerlIO_stdio.Set_ptrcnt)
        tab = &PerlIO_stdio;
#endif
    PerlIO_debug("Pushing %s\n", tab->name);
    PerlIO_list_push(aTHX_ av, PerlIO_find_layer(aTHX_ tab->name, 0, 0),
                     &PL_sv_undef);
}

SV *
PerlIO_arg_fetch(PerlIO_list_t *av, IV n)
{
    return av->array[n].arg;
}

PerlIO_funcs *
PerlIO_layer_fetch(pTHX_ PerlIO_list_t *av, IV n, PerlIO_funcs *def)
{
    if (n >= 0 && n < av->cur) {
        PerlIO_debug("Layer %" IVdf " is %s\n", n,
                     av->array[n].funcs->name);
        return av->array[n].funcs;
    }
    if (!def)
        Perl_croak(aTHX_ "panic: PerlIO layer array corrupt");
    return def;
}

IV
PerlIOPop_pushed(pTHX_ PerlIO *f, const char *mode, SV *arg, PerlIO_funcs *tab)
{
    if (PerlIOValid(f)) {
        PerlIO_flush(f);
        PerlIO_pop(aTHX_ f);
        return 0;
    }
    return -1;
}

PerlIO_funcs PerlIO_remove = {
    sizeof(PerlIO_funcs),
    "pop",
    0,
    PERLIO_K_DUMMY | PERLIO_K_UTF8,
    PerlIOPop_pushed,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,                       /* flush */
    NULL,                       /* fill */
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,                       /* get_base */
    NULL,                       /* get_bufsiz */
    NULL,                       /* get_ptr */
    NULL,                       /* get_cnt */
    NULL,                       /* set_ptrcnt */
};

PerlIO_list_t *
PerlIO_default_layers(pTHX)
{
    if (!PL_def_layerlist) {
        const char *s = (PL_tainting) ? Nullch : PerlEnv_getenv("PERLIO");
        PerlIO_funcs *osLayer = &PerlIO_unix;
        PL_def_layerlist = PerlIO_list_alloc(aTHX);
        PerlIO_define_layer(aTHX_ & PerlIO_unix);
#if defined(WIN32)
        PerlIO_define_layer(aTHX_ & PerlIO_win32);
#if 0
        osLayer = &PerlIO_win32;
#endif
#endif
        PerlIO_define_layer(aTHX_ & PerlIO_raw);
        PerlIO_define_layer(aTHX_ & PerlIO_perlio);
        PerlIO_define_layer(aTHX_ & PerlIO_stdio);
        PerlIO_define_layer(aTHX_ & PerlIO_crlf);
#ifdef HAS_MMAP
        PerlIO_define_layer(aTHX_ & PerlIO_mmap);
#endif
        PerlIO_define_layer(aTHX_ & PerlIO_utf8);
        PerlIO_define_layer(aTHX_ & PerlIO_remove);
        PerlIO_define_layer(aTHX_ & PerlIO_byte);
        PerlIO_list_push(aTHX_ PL_def_layerlist,
                         PerlIO_find_layer(aTHX_ osLayer->name, 0, 0),
                         &PL_sv_undef);
        if (s) {
            PerlIO_parse_layers(aTHX_ PL_def_layerlist, s);
        }
        else {
            PerlIO_default_buffer(aTHX_ PL_def_layerlist);
        }
    }
    if (PL_def_layerlist->cur < 2) {
        PerlIO_default_buffer(aTHX_ PL_def_layerlist);
    }
    return PL_def_layerlist;
}

void
Perl_boot_core_PerlIO(pTHX)
{
#ifdef USE_ATTRIBUTES_FOR_PERLIO
    newXS("io::MODIFY_SCALAR_ATTRIBUTES", XS_io_MODIFY_SCALAR_ATTRIBUTES,
          __FILE__);
#endif
    newXS("PerlIO::Layer::find", XS_PerlIO__Layer__find, __FILE__);
    newXS("PerlIO::Layer::NoWarnings", XS_PerlIO__Layer__NoWarnings, __FILE__);
}

PerlIO_funcs *
PerlIO_default_layer(pTHX_ I32 n)
{
    PerlIO_list_t *av = PerlIO_default_layers(aTHX);
    if (n < 0)
        n += av->cur;
    return PerlIO_layer_fetch(aTHX_ av, n, &PerlIO_stdio);
}

#define PerlIO_default_top() PerlIO_default_layer(aTHX_ -1)
#define PerlIO_default_btm() PerlIO_default_layer(aTHX_ 0)

void
PerlIO_stdstreams(pTHX)
{
    if (!PL_perlio) {
        PerlIO_allocate(aTHX);
        PerlIO_fdopen(0, "Ir" PERLIO_STDTEXT);
        PerlIO_fdopen(1, "Iw" PERLIO_STDTEXT);
        PerlIO_fdopen(2, "Iw" PERLIO_STDTEXT);
    }
}

PerlIO *
PerlIO_push(pTHX_ PerlIO *f, PerlIO_funcs *tab, const char *mode, SV *arg)
{
    if (tab->fsize != sizeof(PerlIO_funcs)) {
      mismatch:
        Perl_croak(aTHX_ "Layer does not match this perl");
    }
    if (tab->size) {
        PerlIOl *l = NULL;
        if (tab->size < sizeof(PerlIOl)) {
            goto mismatch;
        }
        /* Real layer with a data area */
        Newc('L',l,tab->size,char,PerlIOl);
        if (l && f) {
            Zero(l, tab->size, char);
            l->next = *f;
            l->tab = tab;
            *f = l;
            PerlIO_debug("PerlIO_push f=%p %s %s %p\n", (void*)f, tab->name,
                        (mode) ? mode : "(Null)", (void*)arg);
            if (*l->tab->Pushed &&
                (*l->tab->Pushed) (aTHX_ f, mode, arg, tab) != 0) {
                PerlIO_pop(aTHX_ f);
                return NULL;
            }
        }
    }
    else if (f) {
        /* Pseudo-layer where push does its own stack adjust */
        PerlIO_debug("PerlIO_push f=%p %s %s %p\n", (void*)f, tab->name,
                     (mode) ? mode : "(Null)", (void*)arg);
        if (tab->Pushed &&
            (*tab->Pushed) (aTHX_ f, mode, arg, tab) != 0) {
             return NULL;
        }
    }
    return f;
}

IV
PerlIOBase_binmode(pTHX_ PerlIO *f)
{
   if (PerlIOValid(f)) {
        /* Is layer suitable for raw stream ? */
        if (PerlIOBase(f)->tab->kind & PERLIO_K_RAW) {
            /* Yes - turn off UTF-8-ness, to undo UTF-8 locale effects */
            PerlIOBase(f)->flags &= ~PERLIO_F_UTF8;
        }
        else {
            /* Not suitable - pop it */
            PerlIO_pop(aTHX_ f);
        }
        return 0;
   }
   return -1;
}

IV
PerlIORaw_pushed(pTHX_ PerlIO *f, const char *mode, SV *arg, PerlIO_funcs *tab)
{

    if (PerlIOValid(f)) {
        PerlIO *t;
        PerlIOl *l;
        PerlIO_flush(f);
        /*
         * Strip all layers that are not suitable for a raw stream
         */
        t = f;
        while (t && (l = *t)) {
            if (l->tab->Binmode) {
                /* Has a handler - normal case */
                if ((*l->tab->Binmode)(aTHX_ f) == 0) {
                    if (*t == l) {
                        /* Layer still there - move down a layer */
                        t = PerlIONext(t);
                    }
                }
                else {
                    return -1;
                }
            }
            else {
                /* No handler - pop it */
                PerlIO_pop(aTHX_ t);
            }
        }
        if (PerlIOValid(f)) {
            PerlIO_debug(":raw f=%p :%s\n", (void*)f, PerlIOBase(f)->tab->name);
            return 0;
        }
    }
    return -1;
}

int
PerlIO_apply_layera(pTHX_ PerlIO *f, const char *mode,
                    PerlIO_list_t *layers, IV n, IV max)
{
    int code = 0;
    while (n < max) {
        PerlIO_funcs *tab = PerlIO_layer_fetch(aTHX_ layers, n, NULL);
        if (tab) {
            if (!PerlIO_push(aTHX_ f, tab, mode, PerlIOArg)) {
                code = -1;
                break;
            }
        }
        n++;
    }
    return code;
}

int
PerlIO_apply_layers(pTHX_ PerlIO *f, const char *mode, const char *names)
{
    int code = 0;
    if (f && names) {
        PerlIO_list_t *layers = PerlIO_list_alloc(aTHX);
        code = PerlIO_parse_layers(aTHX_ layers, names);
        if (code == 0) {
            code = PerlIO_apply_layera(aTHX_ f, mode, layers, 0, layers->cur);
        }
        PerlIO_list_free(aTHX_ layers);
    }
    return code;
}


/*--------------------------------------------------------------------------------------*/
/*
 * Given the abstraction above the public API functions
 */

int
PerlIO_binmode(pTHX_ PerlIO *f, int iotype, int mode, const char *names)
{
    PerlIO_debug("PerlIO_binmode f=%p %s %c %x %s\n",
                 (void*)f, PerlIOBase(f)->tab->name, iotype, mode,
                 (names) ? names : "(Null)");
    if (names) {
        /* Do not flush etc. if (e.g.) switching encodings.
           if a pushed layer knows it needs to flush lower layers
           (for example :unix which is never going to call them)
           it can do the flush when it is pushed.
         */
        return PerlIO_apply_layers(aTHX_ f, NULL, names) == 0 ? TRUE : FALSE;
    }
    else {
        /* Fake 5.6 legacy of using this call to turn ON O_TEXT */
#ifdef PERLIO_USING_CRLF
        /* Legacy binmode only has meaning if O_TEXT has a value distinct from
           O_BINARY so we can look for it in mode.
         */
        if (!(mode & O_BINARY)) {
            /* Text mode */
            /* FIXME?: Looking down the layer stack seems wrong,
               but is a way of reaching past (say) an encoding layer
               to flip CRLF-ness of the layer(s) below
             */
            while (*f) {
                /* Perhaps we should turn on bottom-most aware layer
                   e.g. Ilya's idea that UNIX TTY could serve
                 */
                if (PerlIOBase(f)->tab->kind & PERLIO_K_CANCRLF) {
                    if (!(PerlIOBase(f)->flags & PERLIO_F_CRLF)) {
                        /* Not in text mode - flush any pending stuff and flip it */
                        PerlIO_flush(f);
                        PerlIOBase(f)->flags |= PERLIO_F_CRLF;
                    }
                    /* Only need to turn it on in one layer so we are done */
                    return TRUE;
                }
                f = PerlIONext(f);
            }
            /* Not finding a CRLF aware layer presumably means we are binary
               which is not what was requested - so we failed
               We _could_ push :crlf layer but so could caller
             */
            return FALSE;
        }
#endif
        /* Legacy binmode is now _defined_ as being equivalent to pushing :raw
           So code that used to be here is now in PerlIORaw_pushed().
         */
        return PerlIO_push(aTHX_ f, &PerlIO_raw, Nullch, Nullsv) ? TRUE : FALSE;
    }
}

int
PerlIO__close(pTHX_ PerlIO *f)
{
    if (PerlIOValid(f)) {
        PerlIO_funcs *tab = PerlIOBase(f)->tab;
        if (tab && tab->Close)
            return (*tab->Close)(aTHX_ f);
        else
            return PerlIOBase_close(aTHX_ f);
    }
    else {
        SETERRNO(EBADF, SS_IVCHAN);
        return -1;
    }
}

int
Perl_PerlIO_close(pTHX_ PerlIO *f)
{
    int code = PerlIO__close(aTHX_ f);
    while (PerlIOValid(f)) {
        PerlIO_pop(aTHX_ f);
    }
    return code;
}

int
Perl_PerlIO_fileno(pTHX_ PerlIO *f)
{
     Perl_PerlIO_or_Base(f, Fileno, fileno, -1, (aTHX_ f));
}

static const char *
PerlIO_context_layers(pTHX_ const char *mode)
{
    const char *type = NULL;
    /*
     * Need to supply default layer info from open.pm
     */
    if (PL_curcop) {
        SV *layers = PL_curcop->cop_io;
        if (layers) {
            STRLEN len;
            type = SvPV(layers, len);
            if (type && mode[0] != 'r') {
                /*
                 * Skip to write part
                 */
                const char *s = strchr(type, 0);
                if (s && (STRLEN)(s - type) < len) {
                    type = s + 1;
                }
            }
        }
    }
    return type;
}

static PerlIO_funcs *
PerlIO_layer_from_ref(pTHX_ SV *sv)
{
    /*
     * For any scalar type load the handler which is bundled with perl
     */
    if (SvTYPE(sv) < SVt_PVAV)
        return PerlIO_find_layer(aTHX_ "scalar", 6, 1);

    /*
     * For other types allow if layer is known but don't try and load it
     */
    switch (SvTYPE(sv)) {
    case SVt_PVAV:
        return PerlIO_find_layer(aTHX_ "Array", 5, 0);
    case SVt_PVHV:
        return PerlIO_find_layer(aTHX_ "Hash", 4, 0);
    case SVt_PVCV:
        return PerlIO_find_layer(aTHX_ "Code", 4, 0);
    case SVt_PVGV:
        return PerlIO_find_layer(aTHX_ "Glob", 4, 0);
    }
    return NULL;
}

PerlIO_list_t *
PerlIO_resolve_layers(pTHX_ const char *layers,
                      const char *mode, int narg, SV **args)
{
    PerlIO_list_t *def = PerlIO_default_layers(aTHX);
    int incdef = 1;
    if (!PL_perlio)
        PerlIO_stdstreams(aTHX);
    if (narg) {
        SV *arg = *args;
        /*
         * If it is a reference but not an object see if we have a handler
         * for it
         */
        if (SvROK(arg) && !sv_isobject(arg)) {
            PerlIO_funcs *handler = PerlIO_layer_from_ref(aTHX_ SvRV(arg));
            if (handler) {
                def = PerlIO_list_alloc(aTHX);
                PerlIO_list_push(aTHX_ def, handler, &PL_sv_undef);
                incdef = 0;
            }
            /*
             * Don't fail if handler cannot be found :via(...) etc. may do
             * something sensible else we will just stringfy and open
             * resulting string.
             */
        }
    }
    if (!layers)
        layers = PerlIO_context_layers(aTHX_ mode);
    if (layers && *layers) {
        PerlIO_list_t *av;
        if (incdef) {
            IV i = def->cur;
            av = PerlIO_list_alloc(aTHX);
            for (i = 0; i < def->cur; i++) {
                PerlIO_list_push(aTHX_ av, def->array[i].funcs,
                                 def->array[i].arg);
            }
        }
        else {
            av = def;
        }
        if (PerlIO_parse_layers(aTHX_ av, layers) == 0) {
             return av;
        }
        else {
            PerlIO_list_free(aTHX_ av);
            return (PerlIO_list_t *) NULL;
        }
    }
    else {
        if (incdef)
            def->refcnt++;
        return def;
    }
}

PerlIO *
PerlIO_openn(pTHX_ const char *layers, const char *mode, int fd,
             int imode, int perm, PerlIO *f, int narg, SV **args)
{
    if (!f && narg == 1 && *args == &PL_sv_undef) {
        if ((f = PerlIO_tmpfile())) {
            if (!layers)
                layers = PerlIO_context_layers(aTHX_ mode);
            if (layers && *layers)
                PerlIO_apply_layers(aTHX_ f, mode, layers);
        }
    }
    else {
        PerlIO_list_t *layera = NULL;
        IV n;
        PerlIO_funcs *tab = NULL;
        if (PerlIOValid(f)) {
            /*
             * This is "reopen" - it is not tested as perl does not use it
             * yet
             */
            PerlIOl *l = *f;
            layera = PerlIO_list_alloc(aTHX);
            while (l) {
                SV *arg = (l->tab->Getarg)
                        ? (*l->tab->Getarg) (aTHX_ &l, NULL, 0)
                        : &PL_sv_undef;
                PerlIO_list_push(aTHX_ layera, l->tab, arg);
                l = *PerlIONext(&l);
            }
        }
        else {
            layera = PerlIO_resolve_layers(aTHX_ layers, mode, narg, args);
            if (!layera) {
                return NULL;
            }
        }
        /*
         * Start at "top" of layer stack
         */
        n = layera->cur - 1;
        while (n >= 0) {
            PerlIO_funcs *t = PerlIO_layer_fetch(aTHX_ layera, n, NULL);
            if (t && t->Open) {
                tab = t;
                break;
            }
            n--;
        }
        if (tab) {
            /*
             * Found that layer 'n' can do opens - call it
             */
            if (narg > 1 && !(tab->kind & PERLIO_K_MULTIARG)) {
                Perl_croak(aTHX_ "More than one argument to open(,':%s')",tab->name);
            }
            PerlIO_debug("openn(%s,'%s','%s',%d,%x,%o,%p,%d,%p)\n",
                         tab->name, layers, mode, fd, imode, perm,
                         (void*)f, narg, (void*)args);
            if (tab->Open)
                 f = (*tab->Open) (aTHX_ tab, layera, n, mode, fd, imode, perm,
                                   f, narg, args);
            else {
                 SETERRNO(EINVAL, LIB_INVARG);
                 f = NULL;
            }
            if (f) {
                if (n + 1 < layera->cur) {
                    /*
                     * More layers above the one that we used to open -
                     * apply them now
                     */
                    if (PerlIO_apply_layera(aTHX_ f, mode, layera, n + 1, layera->cur) != 0) {
                        /* If pushing layers fails close the file */
                        PerlIO_close(f);
                        f = NULL;
                    }
                }
            }
        }
        PerlIO_list_free(aTHX_ layera);
    }
    return f;
}


SSize_t
Perl_PerlIO_read(pTHX_ PerlIO *f, void *vbuf, Size_t count)
{
     Perl_PerlIO_or_Base(f, Read, read, -1, (aTHX_ f, vbuf, count));
}

SSize_t
Perl_PerlIO_unread(pTHX_ PerlIO *f, const void *vbuf, Size_t count)
{
     Perl_PerlIO_or_Base(f, Unread, unread, -1, (aTHX_ f, vbuf, count));
}

SSize_t
Perl_PerlIO_write(pTHX_ PerlIO *f, const void *vbuf, Size_t count)
{
     Perl_PerlIO_or_fail(f, Write, -1, (aTHX_ f, vbuf, count));
}

int
Perl_PerlIO_seek(pTHX_ PerlIO *f, Off_t offset, int whence)
{
     Perl_PerlIO_or_fail(f, Seek, -1, (aTHX_ f, offset, whence));
}

Off_t
Perl_PerlIO_tell(pTHX_ PerlIO *f)
{
     Perl_PerlIO_or_fail(f, Tell, -1, (aTHX_ f));
}

int
Perl_PerlIO_flush(pTHX_ PerlIO *f)
{
    if (f) {
        if (*f) {
            PerlIO_funcs *tab = PerlIOBase(f)->tab;

            if (tab && tab->Flush)
                return (*tab->Flush) (aTHX_ f);
            else
                 return 0; /* If no Flush defined, silently succeed. */
        }
        else {
            PerlIO_debug("Cannot flush f=%p\n", (void*)f);
            SETERRNO(EBADF, SS_IVCHAN);
            return -1;
        }
    }
    else {
        /*
         * Is it good API design to do flush-all on NULL, a potentially
         * errorneous input? Maybe some magical value (PerlIO*
         * PERLIO_FLUSH_ALL = (PerlIO*)-1;)? Yes, stdio does similar
         * things on fflush(NULL), but should we be bound by their design
         * decisions? --jhi
         */
        PerlIO **table = &PL_perlio;
        int code = 0;
        while ((f = *table)) {
            int i;
            table = (PerlIO **) (f++);
            for (i = 1; i < PERLIO_TABLE_SIZE; i++) {
                if (*f && PerlIO_flush(f) != 0)
                    code = -1;
                f++;
            }
        }
        return code;
    }
}

void
PerlIOBase_flush_linebuf(pTHX)
{
    PerlIO **table = &PL_perlio;
    PerlIO *f;
    while ((f = *table)) {
        int i;
        table = (PerlIO **) (f++);
        for (i = 1; i < PERLIO_TABLE_SIZE; i++) {
            if (*f
                && (PerlIOBase(f)->
                    flags & (PERLIO_F_LINEBUF | PERLIO_F_CANWRITE))
                == (PERLIO_F_LINEBUF | PERLIO_F_CANWRITE))
                PerlIO_flush(f);
            f++;
        }
    }
}

int
Perl_PerlIO_fill(pTHX_ PerlIO *f)
{
     Perl_PerlIO_or_fail(f, Fill, -1, (aTHX_ f));
}

int
PerlIO_isutf8(PerlIO *f)
{
     if (PerlIOValid(f))
          return (PerlIOBase(f)->flags & PERLIO_F_UTF8) != 0;
     else
          SETERRNO(EBADF, SS_IVCHAN);

     return -1;
}

int
Perl_PerlIO_eof(pTHX_ PerlIO *f)
{
     Perl_PerlIO_or_Base(f, Eof, eof, -1, (aTHX_ f));
}

int
Perl_PerlIO_error(pTHX_ PerlIO *f)
{
     Perl_PerlIO_or_Base(f, Error, error, -1, (aTHX_ f));
}

void
Perl_PerlIO_clearerr(pTHX_ PerlIO *f)
{
     Perl_PerlIO_or_Base_void(f, Clearerr, clearerr, (aTHX_ f));
}

void
Perl_PerlIO_setlinebuf(pTHX_ PerlIO *f)
{
     Perl_PerlIO_or_Base_void(f, Setlinebuf, setlinebuf, (aTHX_ f));
}

int
PerlIO_has_base(PerlIO *f)
{
     if (PerlIOValid(f)) {
          PerlIO_funcs *tab = PerlIOBase(f)->tab;

          if (tab)
               return (tab->Get_base != NULL);
          SETERRNO(EINVAL, LIB_INVARG);
     }
     else
          SETERRNO(EBADF, SS_IVCHAN);

     return 0;
}

int
PerlIO_fast_gets(PerlIO *f)
{
    if (PerlIOValid(f) && (PerlIOBase(f)->flags & PERLIO_F_FASTGETS)) {
         PerlIO_funcs *tab = PerlIOBase(f)->tab;

         if (tab)
              return (tab->Set_ptrcnt != NULL);
         SETERRNO(EINVAL, LIB_INVARG);
    }
    else
         SETERRNO(EBADF, SS_IVCHAN);

    return 0;
}

int
PerlIO_has_cntptr(PerlIO *f)
{
    if (PerlIOValid(f)) {
        PerlIO_funcs *tab = PerlIOBase(f)->tab;

        if (tab)
             return (tab->Get_ptr != NULL && tab->Get_cnt != NULL);
          SETERRNO(EINVAL, LIB_INVARG);
    }
    else
         SETERRNO(EBADF, SS_IVCHAN);

    return 0;
}

int
PerlIO_canset_cnt(PerlIO *f)
{
    if (PerlIOValid(f)) {
          PerlIO_funcs *tab = PerlIOBase(f)->tab;

          if (tab)
               return (tab->Set_ptrcnt != NULL);
          SETERRNO(EINVAL, LIB_INVARG);
    }
    else
         SETERRNO(EBADF, SS_IVCHAN);

    return 0;
}

STDCHAR *
Perl_PerlIO_get_base(pTHX_ PerlIO *f)
{
     Perl_PerlIO_or_fail(f, Get_base, NULL, (aTHX_ f));
}

int
Perl_PerlIO_get_bufsiz(pTHX_ PerlIO *f)
{
     Perl_PerlIO_or_fail(f, Get_bufsiz, -1, (aTHX_ f));
}

STDCHAR *
Perl_PerlIO_get_ptr(pTHX_ PerlIO *f)
{
     Perl_PerlIO_or_fail(f, Get_ptr, NULL, (aTHX_ f));
}

int
Perl_PerlIO_get_cnt(pTHX_ PerlIO *f)
{
     Perl_PerlIO_or_fail(f, Get_cnt, -1, (aTHX_ f));
}

void
Perl_PerlIO_set_cnt(pTHX_ PerlIO *f, int cnt)
{
     Perl_PerlIO_or_fail_void(f, Set_ptrcnt, (aTHX_ f, NULL, cnt));
}

void
Perl_PerlIO_set_ptrcnt(pTHX_ PerlIO *f, STDCHAR * ptr, int cnt)
{
     Perl_PerlIO_or_fail_void(f, Set_ptrcnt, (aTHX_ f, ptr, cnt));
}


/*--------------------------------------------------------------------------------------*/
/*
 * utf8 and raw dummy layers
 */

IV
PerlIOUtf8_pushed(pTHX_ PerlIO *f, const char *mode, SV *arg, PerlIO_funcs *tab)
{
    if (PerlIOValid(f)) {
        if (tab->kind & PERLIO_K_UTF8)
            PerlIOBase(f)->flags |= PERLIO_F_UTF8;
        else
            PerlIOBase(f)->flags &= ~PERLIO_F_UTF8;
        return 0;
    }
    return -1;
}

PerlIO_funcs PerlIO_utf8 = {
    sizeof(PerlIO_funcs),
    "utf8",
    0,
    PERLIO_K_DUMMY | PERLIO_K_UTF8,
    PerlIOUtf8_pushed,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,                       /* flush */
    NULL,                       /* fill */
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,                       /* get_base */
    NULL,                       /* get_bufsiz */
    NULL,                       /* get_ptr */
    NULL,                       /* get_cnt */
    NULL,                       /* set_ptrcnt */
};

PerlIO_funcs PerlIO_byte = {
    sizeof(PerlIO_funcs),
    "bytes",
    0,
    PERLIO_K_DUMMY,
    PerlIOUtf8_pushed,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,                       /* flush */
    NULL,                       /* fill */
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,                       /* get_base */
    NULL,                       /* get_bufsiz */
    NULL,                       /* get_ptr */
    NULL,                       /* get_cnt */
    NULL,                       /* set_ptrcnt */
};

PerlIO *
PerlIORaw_open(pTHX_ PerlIO_funcs *self, PerlIO_list_t *layers,
               IV n, const char *mode, int fd, int imode, int perm,
               PerlIO *old, int narg, SV **args)
{
    PerlIO_funcs *tab = PerlIO_default_btm();
    if (tab && tab->Open)
         return (*tab->Open) (aTHX_ tab, layers, n - 1, mode, fd, imode, perm,
                              old, narg, args);
    SETERRNO(EINVAL, LIB_INVARG);
    return NULL;
}

PerlIO_funcs PerlIO_raw = {
    sizeof(PerlIO_funcs),
    "raw",
    0,
    PERLIO_K_DUMMY,
    PerlIORaw_pushed,
    PerlIOBase_popped,
    PerlIORaw_open,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,                       /* flush */
    NULL,                       /* fill */
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,                       /* get_base */
    NULL,                       /* get_bufsiz */
    NULL,                       /* get_ptr */
    NULL,                       /* get_cnt */
    NULL,                       /* set_ptrcnt */
};
/*--------------------------------------------------------------------------------------*/
/*--------------------------------------------------------------------------------------*/
/*
 * "Methods" of the "base class"
 */

IV
PerlIOBase_fileno(pTHX_ PerlIO *f)
{
    return PerlIOValid(f) ? PerlIO_fileno(PerlIONext(f)) : -1;
}

char *
PerlIO_modestr(PerlIO * f, char *buf)
{
    char *s = buf;
    if (PerlIOValid(f)) {
        IV flags = PerlIOBase(f)->flags;
        if (flags & PERLIO_F_APPEND) {
            *s++ = 'a';
            if (flags & PERLIO_F_CANREAD) {
                *s++ = '+';
            }
        }
        else if (flags & PERLIO_F_CANREAD) {
            *s++ = 'r';
            if (flags & PERLIO_F_CANWRITE)
                *s++ = '+';
        }
        else if (flags & PERLIO_F_CANWRITE) {
            *s++ = 'w';
            if (flags & PERLIO_F_CANREAD) {
                *s++ = '+';
            }
        }
#ifdef PERLIO_USING_CRLF
        if (!(flags & PERLIO_F_CRLF))
            *s++ = 'b';
#endif
    }
    *s = '\0';
    return buf;
}


IV
PerlIOBase_pushed(pTHX_ PerlIO *f, const char *mode, SV *arg, PerlIO_funcs *tab)
{
    PerlIOl *l = PerlIOBase(f);
#if 0
    const char *omode = mode;
    char temp[8];
#endif
    l->flags &= ~(PERLIO_F_CANREAD | PERLIO_F_CANWRITE |
                  PERLIO_F_TRUNCATE | PERLIO_F_APPEND);
    if (tab->Set_ptrcnt != NULL)
        l->flags |= PERLIO_F_FASTGETS;
    if (mode) {
        if (*mode == IoTYPE_NUMERIC || *mode == IoTYPE_IMPLICIT)
            mode++;
        switch (*mode++) {
        case 'r':
            l->flags |= PERLIO_F_CANREAD;
            break;
        case 'a':
            l->flags |= PERLIO_F_APPEND | PERLIO_F_CANWRITE;
            break;
        case 'w':
            l->flags |= PERLIO_F_TRUNCATE | PERLIO_F_CANWRITE;
            break;
        default:
            SETERRNO(EINVAL, LIB_INVARG);
            return -1;
        }
        while (*mode) {
            switch (*mode++) {
            case '+':
                l->flags |= PERLIO_F_CANREAD | PERLIO_F_CANWRITE;
                break;
            case 'b':
                l->flags &= ~PERLIO_F_CRLF;
                break;
            case 't':
                l->flags |= PERLIO_F_CRLF;
                break;
            default:
                SETERRNO(EINVAL, LIB_INVARG);
                return -1;
            }
        }
    }
    else {
        if (l->next) {
            l->flags |= l->next->flags &
                (PERLIO_F_CANREAD | PERLIO_F_CANWRITE | PERLIO_F_TRUNCATE |
                 PERLIO_F_APPEND);
        }
    }
#if 0
    PerlIO_debug("PerlIOBase_pushed f=%p %s %s fl=%08" UVxf " (%s)\n",
                 f, PerlIOBase(f)->tab->name, (omode) ? omode : "(Null)",
                 l->flags, PerlIO_modestr(f, temp));
#endif
    return 0;
}

IV
PerlIOBase_popped(pTHX_ PerlIO *f)
{
    return 0;
}

SSize_t
PerlIOBase_unread(pTHX_ PerlIO *f, const void *vbuf, Size_t count)
{
    /*
     * Save the position as current head considers it
     */
    Off_t old = PerlIO_tell(f);
    SSize_t done;
    PerlIO_push(aTHX_ f, &PerlIO_pending, "r", Nullsv);
    PerlIOSelf(f, PerlIOBuf)->posn = old;
    done = PerlIOBuf_unread(aTHX_ f, vbuf, count);
    return done;
}

SSize_t
PerlIOBase_read(pTHX_ PerlIO *f, void *vbuf, Size_t count)
{
    STDCHAR *buf = (STDCHAR *) vbuf;
    if (f) {
        if (!(PerlIOBase(f)->flags & PERLIO_F_CANREAD)) {
            PerlIOBase(f)->flags |= PERLIO_F_ERROR;
            SETERRNO(EBADF, SS_IVCHAN);
            return 0;
        }
        while (count > 0) {
            SSize_t avail = PerlIO_get_cnt(f);
            SSize_t take = 0;
            if (avail > 0)
                take = ((SSize_t)count < avail) ? count : avail;
            if (take > 0) {
                STDCHAR *ptr = PerlIO_get_ptr(f);
                Copy(ptr, buf, take, STDCHAR);
                PerlIO_set_ptrcnt(f, ptr + take, (avail -= take));
                count -= take;
                buf += take;
            }
            if (count > 0 && avail <= 0) {
                if (PerlIO_fill(f) != 0)
                    break;
            }
        }
        return (buf - (STDCHAR *) vbuf);
    }
    return 0;
}

IV
PerlIOBase_noop_ok(pTHX_ PerlIO *f)
{
    return 0;
}

IV
PerlIOBase_noop_fail(pTHX_ PerlIO *f)
{
    return -1;
}

IV
PerlIOBase_close(pTHX_ PerlIO *f)
{
    IV code = -1;
    if (PerlIOValid(f)) {
        PerlIO *n = PerlIONext(f);
        code = PerlIO_flush(f);
        PerlIOBase(f)->flags &=
           ~(PERLIO_F_CANREAD | PERLIO_F_CANWRITE | PERLIO_F_OPEN);
        while (PerlIOValid(n)) {
            PerlIO_funcs *tab = PerlIOBase(n)->tab;
            if (tab && tab->Close) {
                if ((*tab->Close)(aTHX_ n) != 0)
                    code = -1;
                break;
            }
            else {
                PerlIOBase(n)->flags &=
                    ~(PERLIO_F_CANREAD | PERLIO_F_CANWRITE | PERLIO_F_OPEN);
            }
            n = PerlIONext(n);
        }
    }
    else {
        SETERRNO(EBADF, SS_IVCHAN);
    }
    return code;
}

IV
PerlIOBase_eof(pTHX_ PerlIO *f)
{
    if (PerlIOValid(f)) {
        return (PerlIOBase(f)->flags & PERLIO_F_EOF) != 0;
    }
    return 1;
}

IV
PerlIOBase_error(pTHX_ PerlIO *f)
{
    if (PerlIOValid(f)) {
        return (PerlIOBase(f)->flags & PERLIO_F_ERROR) != 0;
    }
    return 1;
}

void
PerlIOBase_clearerr(pTHX_ PerlIO *f)
{
    if (PerlIOValid(f)) {
        PerlIO *n = PerlIONext(f);
        PerlIOBase(f)->flags &= ~(PERLIO_F_ERROR | PERLIO_F_EOF);
        if (PerlIOValid(n))
            PerlIO_clearerr(n);
    }
}

void
PerlIOBase_setlinebuf(pTHX_ PerlIO *f)
{
    if (PerlIOValid(f)) {
        PerlIOBase(f)->flags |= PERLIO_F_LINEBUF;
    }
}

SV *
PerlIO_sv_dup(pTHX_ SV *arg, CLONE_PARAMS *param)
{
    if (!arg)
        return Nullsv;
#ifdef sv_dup
    if (param) {
        return sv_dup(arg, param);
    }
    else {
        return newSVsv(arg);
    }
#else
    return newSVsv(arg);
#endif
}

PerlIO *
PerlIOBase_dup(pTHX_ PerlIO *f, PerlIO *o, CLONE_PARAMS *param, int flags)
{
    PerlIO *nexto = PerlIONext(o);
    if (PerlIOValid(nexto)) {
        PerlIO_funcs *tab = PerlIOBase(nexto)->tab;
        if (tab && tab->Dup)
            f = (*tab->Dup)(aTHX_ f, nexto, param, flags);
        else
            f = PerlIOBase_dup(aTHX_ f, nexto, param, flags);
    }
    if (f) {
        PerlIO_funcs *self = PerlIOBase(o)->tab;
        SV *arg;
        char buf[8];
        PerlIO_debug("PerlIOBase_dup %s f=%p o=%p param=%p\n",
                     self->name, (void*)f, (void*)o, (void*)param);
        if (self->Getarg)
            arg = (*self->Getarg)(aTHX_ o, param, flags);
        else {
            arg = Nullsv;
        }
        f = PerlIO_push(aTHX_ f, self, PerlIO_modestr(o,buf), arg);
        if (arg) {
            SvREFCNT_dec(arg);
        }
    }
    return f;
}

#define PERLIO_MAX_REFCOUNTABLE_FD 2048
#ifdef USE_THREADS
perl_mutex PerlIO_mutex;
#endif
int PerlIO_fd_refcnt[PERLIO_MAX_REFCOUNTABLE_FD];

void
PerlIO_init(pTHX)
{
 /* Place holder for stdstreams call ??? */
#ifdef USE_THREADS
 MUTEX_INIT(&PerlIO_mutex);
#endif
}

void
PerlIOUnix_refcnt_inc(int fd)
{
    if (fd >= 0 && fd < PERLIO_MAX_REFCOUNTABLE_FD) {
#ifdef USE_THREADS
        MUTEX_LOCK(&PerlIO_mutex);
#endif
        PerlIO_fd_refcnt[fd]++;
        PerlIO_debug("fd %d refcnt=%d\n",fd,PerlIO_fd_refcnt[fd]);
#ifdef USE_THREADS
        MUTEX_UNLOCK(&PerlIO_mutex);
#endif
    }
}

int
PerlIOUnix_refcnt_dec(int fd)
{
    int cnt = 0;
    if (fd >= 0 && fd < PERLIO_MAX_REFCOUNTABLE_FD) {
#ifdef USE_THREADS
        MUTEX_LOCK(&PerlIO_mutex);
#endif
        cnt = --PerlIO_fd_refcnt[fd];
        PerlIO_debug("fd %d refcnt=%d\n",fd,cnt);
#ifdef USE_THREADS
        MUTEX_UNLOCK(&PerlIO_mutex);
#endif
    }
    return cnt;
}

void
PerlIO_cleanup(pTHX)
{
    int i;
#ifdef USE_ITHREADS
    PerlIO_debug("Cleanup layers for %p\n",aTHX);
#else
    PerlIO_debug("Cleanup layers\n");
#endif
    /* Raise STDIN..STDERR refcount so we don't close them */
    for (i=0; i < 3; i++)
        PerlIOUnix_refcnt_inc(i);
    PerlIO_cleantable(aTHX_ &PL_perlio);
    /* Restore STDIN..STDERR refcount */
    for (i=0; i < 3; i++)
        PerlIOUnix_refcnt_dec(i);

    if (PL_known_layers) {
        PerlIO_list_free(aTHX_ PL_known_layers);
        PL_known_layers = NULL;
    }
    if(PL_def_layerlist) {
        PerlIO_list_free(aTHX_ PL_def_layerlist);
        PL_def_layerlist = NULL;
    }
}


/*--------------------------------------------------------------------------------------*/
/*
 * Bottom-most level for UNIX-like case
 */

typedef struct {
    struct _PerlIO base;        /* The generic part */
    int fd;                     /* UNIX like file descriptor */
    int oflags;                 /* open/fcntl flags */
} PerlIOUnix;

int
PerlIOUnix_oflags(const char *mode)
{
    int oflags = -1;
    if (*mode == IoTYPE_IMPLICIT || *mode == IoTYPE_NUMERIC)
        mode++;
    switch (*mode) {
    case 'r':
        oflags = O_RDONLY;
        if (*++mode == '+') {
            oflags = O_RDWR;
            mode++;
        }
        break;

    case 'w':
        oflags = O_CREAT | O_TRUNC;
        if (*++mode == '+') {
            oflags |= O_RDWR;
            mode++;
        }
        else
            oflags |= O_WRONLY;
        break;

    case 'a':
        oflags = O_CREAT | O_APPEND;
        if (*++mode == '+') {
            oflags |= O_RDWR;
            mode++;
        }
        else
            oflags |= O_WRONLY;
        break;
    }
    if (*mode == 'b') {
        oflags |= O_BINARY;
        oflags &= ~O_TEXT;
        mode++;
    }
    else if (*mode == 't') {
        oflags |= O_TEXT;
        oflags &= ~O_BINARY;
        mode++;
    }
    /*
     * Always open in binary mode
     */
    oflags |= O_BINARY;
    if (*mode || oflags == -1) {
        SETERRNO(EINVAL, LIB_INVARG);
        oflags = -1;
    }
    return oflags;
}

IV
PerlIOUnix_fileno(pTHX_ PerlIO *f)
{
    return PerlIOSelf(f, PerlIOUnix)->fd;
}

static void
PerlIOUnix_setfd(pTHX_ PerlIO *f, int fd, int imode)
{
    PerlIOUnix *s = PerlIOSelf(f, PerlIOUnix);
#if defined(WIN32)
    Stat_t st;
    if (PerlLIO_fstat(fd, &st) == 0) {
        if (!S_ISREG(st.st_mode)) {
            PerlIO_debug("%d is not regular file\n",fd);
            PerlIOBase(f)->flags |= PERLIO_F_NOTREG;
        }
        else {
            PerlIO_debug("%d _is_ a regular file\n",fd);
        }
    }
#endif
    s->fd = fd;
    s->oflags = imode;
    PerlIOUnix_refcnt_inc(fd);
}

IV
PerlIOUnix_pushed(pTHX_ PerlIO *f, const char *mode, SV *arg, PerlIO_funcs *tab)
{
    IV code = PerlIOBase_pushed(aTHX_ f, mode, arg, tab);
    if (*PerlIONext(f)) {
        /* We never call down so do any pending stuff now */
        PerlIO_flush(PerlIONext(f));
        /*
         * XXX could (or should) we retrieve the oflags from the open file
         * handle rather than believing the "mode" we are passed in? XXX
         * Should the value on NULL mode be 0 or -1?
         */
        PerlIOUnix_setfd(aTHX_ f, PerlIO_fileno(PerlIONext(f)),
                         mode ? PerlIOUnix_oflags(mode) : -1);
    }
    PerlIOBase(f)->flags |= PERLIO_F_OPEN;

    return code;
}

IV
PerlIOUnix_seek(pTHX_ PerlIO *f, Off_t offset, int whence)
{
    int fd = PerlIOSelf(f, PerlIOUnix)->fd;
    Off_t new_loc;
    if (PerlIOBase(f)->flags & PERLIO_F_NOTREG) {
#ifdef  ESPIPE
        SETERRNO(ESPIPE, LIB_INVARG);
#else
        SETERRNO(EINVAL, LIB_INVARG);
#endif
        return -1;
    }
    new_loc = PerlLIO_lseek(fd, offset, whence);
    if (new_loc == (Off_t) - 1)
     {
      return -1;
     }
    PerlIOBase(f)->flags &= ~PERLIO_F_EOF;
    return  0;
}

PerlIO *
PerlIOUnix_open(pTHX_ PerlIO_funcs *self, PerlIO_list_t *layers,
                IV n, const char *mode, int fd, int imode,
                int perm, PerlIO *f, int narg, SV **args)
{
    if (PerlIOValid(f)) {
        if (PerlIOBase(f)->flags & PERLIO_F_OPEN)
            (*PerlIOBase(f)->tab->Close)(aTHX_ f);
    }
    if (narg > 0) {
        char *path = SvPV_nolen(*args);
        if (*mode == IoTYPE_NUMERIC)
            mode++;
        else {
            imode = PerlIOUnix_oflags(mode);
            perm = 0666;
        }
        if (imode != -1) {
            fd = PerlLIO_open3(path, imode, perm);
        }
    }
    if (fd >= 0) {
        if (*mode == IoTYPE_IMPLICIT)
            mode++;
        if (!f) {
            f = PerlIO_allocate(aTHX);
        }
        if (!PerlIOValid(f)) {
            if (!(f = PerlIO_push(aTHX_ f, self, mode, PerlIOArg))) {
                return NULL;
            }
        }
        PerlIOUnix_setfd(aTHX_ f, fd, imode);
        PerlIOBase(f)->flags |= PERLIO_F_OPEN;
        if (*mode == IoTYPE_APPEND)
            PerlIOUnix_seek(aTHX_ f, 0, SEEK_END);
        return f;
    }
    else {
        if (f) {
            /*
             * FIXME: pop layers ???
             */
        }
        return NULL;
    }
}

PerlIO *
PerlIOUnix_dup(pTHX_ PerlIO *f, PerlIO *o, CLONE_PARAMS *param, int flags)
{
    PerlIOUnix *os = PerlIOSelf(o, PerlIOUnix);
    int fd = os->fd;
    if (flags & PERLIO_DUP_FD) {
        fd = PerlLIO_dup(fd);
    }
    if (fd >= 0 && fd < PERLIO_MAX_REFCOUNTABLE_FD) {
        f = PerlIOBase_dup(aTHX_ f, o, param, flags);
        if (f) {
            /* If all went well overwrite fd in dup'ed lay with the dup()'ed fd */
            PerlIOUnix_setfd(aTHX_ f, fd, os->oflags);
            return f;
        }
    }
    return NULL;
}


SSize_t
PerlIOUnix_read(pTHX_ PerlIO *f, void *vbuf, Size_t count)
{
    int fd = PerlIOSelf(f, PerlIOUnix)->fd;
    if (!(PerlIOBase(f)->flags & PERLIO_F_CANREAD) ||
         PerlIOBase(f)->flags & (PERLIO_F_EOF|PERLIO_F_ERROR)) {
        return 0;
    }
    while (1) {
        SSize_t len = PerlLIO_read(fd, vbuf, count);
        if (len >= 0 || errno != EINTR) {
            if (len < 0) {
                if (errno != EAGAIN) {
                    PerlIOBase(f)->flags |= PERLIO_F_ERROR;
                }
            }
            else if (len == 0 && count != 0) {
                PerlIOBase(f)->flags |= PERLIO_F_EOF;
                SETERRNO(0,0);
            }
            return len;
        }
        PERL_ASYNC_CHECK();
    }
}

SSize_t
PerlIOUnix_write(pTHX_ PerlIO *f, const void *vbuf, Size_t count)
{
    int fd = PerlIOSelf(f, PerlIOUnix)->fd;
    while (1) {
        SSize_t len = PerlLIO_write(fd, vbuf, count);
        if (len >= 0 || errno != EINTR) {
            if (len < 0) {
                if (errno != EAGAIN) {
                    PerlIOBase(f)->flags |= PERLIO_F_ERROR;
                }
            }
            return len;
        }
        PERL_ASYNC_CHECK();
    }
}

Off_t
PerlIOUnix_tell(pTHX_ PerlIO *f)
{
    return PerlLIO_lseek(PerlIOSelf(f, PerlIOUnix)->fd, 0, SEEK_CUR);
}


IV
PerlIOUnix_close(pTHX_ PerlIO *f)
{
    int fd = PerlIOSelf(f, PerlIOUnix)->fd;
    int code = 0;
    if (PerlIOBase(f)->flags & PERLIO_F_OPEN) {
        if (PerlIOUnix_refcnt_dec(fd) > 0) {
            PerlIOBase(f)->flags &= ~PERLIO_F_OPEN;
            return 0;
        }
    }
    else {
        SETERRNO(EBADF,SS_IVCHAN);
        return -1;
    }
    while (PerlLIO_close(fd) != 0) {
        if (errno != EINTR) {
            code = -1;
            break;
        }
        PERL_ASYNC_CHECK();
    }
    if (code == 0) {
        PerlIOBase(f)->flags &= ~PERLIO_F_OPEN;
    }
    return code;
}

PerlIO_funcs PerlIO_unix = {
    sizeof(PerlIO_funcs),
    "unix",
    sizeof(PerlIOUnix),
    PERLIO_K_RAW,
    PerlIOUnix_pushed,
    PerlIOBase_popped,
    PerlIOUnix_open,
    PerlIOBase_binmode,         /* binmode */
    NULL,
    PerlIOUnix_fileno,
    PerlIOUnix_dup,
    PerlIOUnix_read,
    PerlIOBase_unread,
    PerlIOUnix_write,
    PerlIOUnix_seek,
    PerlIOUnix_tell,
    PerlIOUnix_close,
    PerlIOBase_noop_ok,         /* flush */
    PerlIOBase_noop_fail,       /* fill */
    PerlIOBase_eof,
    PerlIOBase_error,
    PerlIOBase_clearerr,
    PerlIOBase_setlinebuf,
    NULL,                       /* get_base */
    NULL,                       /* get_bufsiz */
    NULL,                       /* get_ptr */
    NULL,                       /* get_cnt */
    NULL,                       /* set_ptrcnt */
};

/*--------------------------------------------------------------------------------------*/
/*
 * stdio as a layer
 */

#if defined(VMS) && !defined(STDIO_BUFFER_WRITABLE)
/* perl5.8 - This ensures the last minute VMS ungetc fix is not
   broken by the last second glibc 2.3 fix
 */
#define STDIO_BUFFER_WRITABLE
#endif


typedef struct {
    struct _PerlIO base;
    FILE *stdio;                /* The stream */
} PerlIOStdio;

IV
PerlIOStdio_fileno(pTHX_ PerlIO *f)
{
    FILE *s;
    if (PerlIOValid(f) && (s = PerlIOSelf(f, PerlIOStdio)->stdio)) {
        return PerlSIO_fileno(s);
    }
    errno = EBADF;
    return -1;
}

char *
PerlIOStdio_mode(const char *mode, char *tmode)
{
    char *ret = tmode;
    if (mode) {
        while (*mode) {
            *tmode++ = *mode++;
        }
    }
#if defined(PERLIO_USING_CRLF) || defined(__CYGWIN__)
    *tmode++ = 'b';
#endif
    *tmode = '\0';
    return ret;
}

IV
PerlIOStdio_pushed(pTHX_ PerlIO *f, const char *mode, SV *arg, PerlIO_funcs *tab)
{
    PerlIO *n;
    if (PerlIOValid(f) && PerlIOValid(n = PerlIONext(f))) {
        PerlIO_funcs *toptab = PerlIOBase(n)->tab;
        if (toptab == tab) {
            /* Top is already stdio - pop self (duplicate) and use original */
            PerlIO_pop(aTHX_ f);
            return 0;
        } else {
            int fd = PerlIO_fileno(n);
            char tmode[8];
            FILE *stdio;
            if (fd >= 0 && (stdio  = PerlSIO_fdopen(fd,
                            mode = PerlIOStdio_mode(mode, tmode)))) {
                PerlIOSelf(f, PerlIOStdio)->stdio = stdio;
                /* We never call down so do any pending stuff now */
                PerlIO_flush(PerlIONext(f));
            }
            else {
                return -1;
            }
        }
    }
    return PerlIOBase_pushed(aTHX_ f, mode, arg, tab);
}


PerlIO *
PerlIO_importFILE(FILE *stdio, const char *mode)
{
    dTHX;
    PerlIO *f = NULL;
    if (stdio) {
        PerlIOStdio *s;
        if (!mode || !*mode) {
            /* We need to probe to see how we can open the stream
               so start with read/write and then try write and read
               we dup() so that we can fclose without loosing the fd.

               Note that the errno value set by a failing fdopen
               varies between stdio implementations.
             */
            int fd = PerlLIO_dup(fileno(stdio));
            FILE *f2 = PerlSIO_fdopen(fd, (mode = "r+"));
            if (!f2) {
                f2 = PerlSIO_fdopen(fd, (mode = "w"));
            }
            if (!f2) {
                f2 = PerlSIO_fdopen(fd, (mode = "r"));
            }
            if (!f2) {
                /* Don't seem to be able to open */
                PerlLIO_close(fd);
                return f;
            }
            fclose(f2);
        }
        if ((f = PerlIO_push(aTHX_(f = PerlIO_allocate(aTHX)), &PerlIO_stdio, mode, Nullsv))) {
            s = PerlIOSelf(f, PerlIOStdio);
            s->stdio = stdio;
        }
    }
    return f;
}

PerlIO *
PerlIOStdio_open(pTHX_ PerlIO_funcs *self, PerlIO_list_t *layers,
                 IV n, const char *mode, int fd, int imode,
                 int perm, PerlIO *f, int narg, SV **args)
{
    char tmode[8];
    if (PerlIOValid(f)) {
        char *path = SvPV_nolen(*args);
        PerlIOStdio *s = PerlIOSelf(f, PerlIOStdio);
        FILE *stdio;
        PerlIOUnix_refcnt_dec(fileno(s->stdio));
        stdio = PerlSIO_freopen(path, (mode = PerlIOStdio_mode(mode, tmode)),
                            s->stdio);
        if (!s->stdio)
            return NULL;
        s->stdio = stdio;
        PerlIOUnix_refcnt_inc(fileno(s->stdio));
        return f;
    }
    else {
        if (narg > 0) {
            char *path = SvPV_nolen(*args);
            if (*mode == IoTYPE_NUMERIC) {
                mode++;
                fd = PerlLIO_open3(path, imode, perm);
            }
            else {
                FILE *stdio;
                bool appended = FALSE;
#ifdef __CYGWIN__
                /* Cygwin wants its 'b' early. */
                appended = TRUE;
                mode = PerlIOStdio_mode(mode, tmode);
#endif
                stdio = PerlSIO_fopen(path, mode);
                if (stdio) {
                    PerlIOStdio *s;
                    if (!f) {
                        f = PerlIO_allocate(aTHX);
                    }
                    if (!appended)
                        mode = PerlIOStdio_mode(mode, tmode);
                    f = PerlIO_push(aTHX_ f, self, mode, PerlIOArg);
                    if (f) {
                        s = PerlIOSelf(f, PerlIOStdio);
                        s->stdio = stdio;
                        PerlIOUnix_refcnt_inc(fileno(s->stdio));
                    }
                    return f;
                }
                else {
                    return NULL;
                }
            }
        }
        if (fd >= 0) {
            FILE *stdio = NULL;
            int init = 0;
            if (*mode == IoTYPE_IMPLICIT) {
                init = 1;
                mode++;
            }
            if (init) {
                switch (fd) {
                case 0:
                    stdio = PerlSIO_stdin;
                    break;
                case 1:
                    stdio = PerlSIO_stdout;
                    break;
                case 2:
                    stdio = PerlSIO_stderr;
                    break;
                }
            }
            else {
                stdio = PerlSIO_fdopen(fd, mode =
                                       PerlIOStdio_mode(mode, tmode));
            }
            if (stdio) {
                PerlIOStdio *s;
                if (!f) {
                    f = PerlIO_allocate(aTHX);
                }
                if ((f = PerlIO_push(aTHX_ f, self, mode, PerlIOArg))) {
                    s = PerlIOSelf(f, PerlIOStdio);
                    s->stdio = stdio;
                    PerlIOUnix_refcnt_inc(fileno(s->stdio));
                }
                return f;
            }
        }
    }
    return NULL;
}

PerlIO *
PerlIOStdio_dup(pTHX_ PerlIO *f, PerlIO *o, CLONE_PARAMS *param, int flags)
{
    /* This assumes no layers underneath - which is what
       happens, but is not how I remember it. NI-S 2001/10/16
     */
    if ((f = PerlIOBase_dup(aTHX_ f, o, param, flags))) {
        FILE *stdio = PerlIOSelf(o, PerlIOStdio)->stdio;
        int fd = fileno(stdio);
        char mode[8];
        if (flags & PERLIO_DUP_FD) {
            int dfd = PerlLIO_dup(fileno(stdio));
            if (dfd >= 0) {
                stdio = PerlSIO_fdopen(dfd, PerlIO_modestr(o,mode));
                goto set_this;
            }
            else {
                /* FIXME: To avoid messy error recovery if dup fails
                   re-use the existing stdio as though flag was not set
                 */
            }
        }
        stdio = PerlSIO_fdopen(fd, PerlIO_modestr(o,mode));
    set_this:
        PerlIOSelf(f, PerlIOStdio)->stdio = stdio;
        PerlIOUnix_refcnt_inc(fileno(stdio));
    }
    return f;
}

static int
PerlIOStdio_invalidate_fileno(pTHX_ FILE *f)
{
    /* XXX this could use PerlIO_canset_fileno() and
     * PerlIO_set_fileno() support from Configure
     */
#  if defined(__UCLIBC__)
    /* uClibc must come before glibc because it defines __GLIBC__ as well. */
    f->__filedes = -1;
    return 1;
#  elif defined(__GLIBC__)
    /* There may be a better way for GLIBC:
        - libio.h defines a flag to not close() on cleanup
     */ 
    f->_fileno = -1;
    return 1;
#  elif defined(__sun__)
#    if defined(_LP64)
    /* On solaris, if _LP64 is defined, the FILE structure is this:
     *
     *  struct FILE {
     *      long __pad[16];
     *  };
     *
     * It turns out that the fd is stored in the top 32 bits of
     * file->__pad[4]. The lower 32 bits contain flags. file->pad[5] appears
     * to contain a pointer or offset into another structure. All the
     * remaining fields are zero.
     *
     * We set the top bits to -1 (0xFFFFFFFF).
     */
    f->__pad[4] |= 0xffffffff00000000L;
    assert(fileno(f) == 0xffffffff);
#    else /* !defined(_LP64) */
    /* _file is just a unsigned char :-(
       Not clear why we dup() rather than using -1
       even if that would be treated as 0xFF - so will
       a dup fail ...
     */
    f->_file = PerlLIO_dup(fileno(f));
#    endif /* defined(_LP64) */
    return 1;
#  elif defined(__hpux)
    f->__fileH = 0xff;
    f->__fileL = 0xff;
    return 1;
   /* Next one ->_file seems to be a reasonable fallback, i.e. if
      your platform does not have special entry try this one.
      [For OSF only have confirmation for Tru64 (alpha)
      but assume other OSFs will be similar.]
    */
#  elif defined(_AIX) || defined(__osf__) || defined(__irix__)
    f->_file = -1;
    return 1;
#  elif defined(__FreeBSD__)
    /* There may be a better way on FreeBSD:
        - we could insert a dummy func in the _close function entry
        f->_close = (int (*)(void *)) dummy_close;
     */
    f->_file = -1;
    return 1;
#  elif defined(__OpenBSD__)
    /* There may be a better way on OpenBSD:
        - we could insert a dummy func in the _close function entry
        f->_close = (int (*)(void *)) dummy_close;
     */
    f->_file = -1;
    return 1;
#  elif defined(__EMX__)
    /* f->_flags &= ~_IOOPEN; */        /* Will leak stream->_buffer */
    f->_handle = -1;
    return 1;
#  elif defined(__CYGWIN__)
    /* There may be a better way on CYGWIN:
        - we could insert a dummy func in the _close function entry
        f->_close = (int (*)(void *)) dummy_close;
     */
    f->_file = -1;
    return 1;
#  elif defined(WIN32)
#    if defined(__BORLANDC__)
    f->fd = PerlLIO_dup(fileno(f));
#    elif defined(UNDER_CE)
    /* WIN_CE does not have access to FILE internals, it hardly has FILE
       structure at all
     */
#    else
    f->_file = -1;
#    endif
    return 1;
#  else
#if 0
    /* Sarathy's code did this - we fall back to a dup/dup2 hack
       (which isn't thread safe) instead
     */
#    error "Don't know how to set FILE.fileno on your platform"
#endif
    return 0;
#  endif
}

IV
PerlIOStdio_close(pTHX_ PerlIO *f)
{
    FILE *stdio = PerlIOSelf(f, PerlIOStdio)->stdio;
    if (!stdio) {
        errno = EBADF;
        return -1;
    }
    else {
        int fd = fileno(stdio);
        int socksfd = 0;
        int invalidate = 0;
        IV result = 0;
        int saveerr = 0;
        int dupfd = 0;
#ifdef SOCKS5_VERSION_NAME
        /* Socks lib overrides close() but stdio isn't linked to
           that library (though we are) - so we must call close()
           on sockets on stdio's behalf.
         */
        int optval;
        Sock_size_t optlen = sizeof(int);
        if (getsockopt(fd, SOL_SOCKET, SO_TYPE, (void *) &optval, &optlen) == 0) {
            socksfd = 1;
            invalidate = 1;
        }
#endif
        if (PerlIOUnix_refcnt_dec(fd) > 0) {
            /* File descriptor still in use */
            invalidate = 1;
            socksfd = 0;
        }
        if (invalidate) {
            /* For STD* handles don't close the stdio at all
               this is because we have shared the FILE * too
             */
            if (stdio == stdin) {
                /* Some stdios are buggy fflush-ing inputs */
                return 0;
            }
            else if (stdio == stdout || stdio == stderr) {
                return PerlIO_flush(f);
            }
            /* Tricky - must fclose(stdio) to free memory but not close(fd)
               Use Sarathy's trick from maint-5.6 to invalidate the
               fileno slot of the FILE *
            */
            result = PerlIO_flush(f);
            saveerr = errno;
            if (!(invalidate = PerlIOStdio_invalidate_fileno(aTHX_ stdio))) {
                dupfd = PerlLIO_dup(fd);
            }
        }
        result = PerlSIO_fclose(stdio);
        /* We treat error from stdio as success if we invalidated
           errno may NOT be expected EBADF
         */
        if (invalidate && result != 0) {
            errno = saveerr;
            result = 0;
        }
        if (socksfd) {
            /* in SOCKS case let close() determine return value */
            result = close(fd);
        }
        if (dupfd) {
            PerlLIO_dup2(dupfd,fd);
            PerlLIO_close(dupfd);
        }
        return result;
    }
}

SSize_t
PerlIOStdio_read(pTHX_ PerlIO *f, void *vbuf, Size_t count)
{
    FILE *s = PerlIOSelf(f, PerlIOStdio)->stdio;
    SSize_t got = 0;
    for (;;) {
        if (count == 1) {
            STDCHAR *buf = (STDCHAR *) vbuf;
            /*
             * Perl is expecting PerlIO_getc() to fill the buffer Linux's
             * stdio does not do that for fread()
             */
            int ch = PerlSIO_fgetc(s);
            if (ch != EOF) {
                *buf = ch;
                got = 1;
            }
        }
        else
            got = PerlSIO_fread(vbuf, 1, count, s);
        if (got == 0 && PerlSIO_ferror(s))
            got = -1;
        if (got >= 0 || errno != EINTR)
            break;
        PERL_ASYNC_CHECK();
        SETERRNO(0,0);  /* just in case */
    }
    return got;
}

SSize_t
PerlIOStdio_unread(pTHX_ PerlIO *f, const void *vbuf, Size_t count)
{
    SSize_t unread = 0;
    FILE *s = PerlIOSelf(f, PerlIOStdio)->stdio;

#ifdef STDIO_BUFFER_WRITABLE
    if (PerlIO_fast_gets(f) && PerlIO_has_base(f)) {
        STDCHAR *buf = ((STDCHAR *) vbuf) + count;
        STDCHAR *base = PerlIO_get_base(f);
        SSize_t cnt   = PerlIO_get_cnt(f);
        STDCHAR *ptr  = PerlIO_get_ptr(f);
        SSize_t avail = ptr - base;
        if (avail > 0) {
            if (avail > count) {
                avail = count;
            }
            ptr -= avail;
            Move(buf-avail,ptr,avail,STDCHAR);
            count -= avail;
            unread += avail;
            PerlIO_set_ptrcnt(f,ptr,cnt+avail);
            if (PerlSIO_feof(s) && unread >= 0)
                PerlSIO_clearerr(s);
        }
    }
    else
#endif
    if (PerlIO_has_cntptr(f)) {
        /* We can get pointer to buffer but not its base
           Do ungetc() but check chars are ending up in the
           buffer
         */
        STDCHAR *eptr = (STDCHAR*)PerlSIO_get_ptr(s);
        STDCHAR *buf = ((STDCHAR *) vbuf) + count;
        while (count > 0) {
            int ch = *--buf & 0xFF;
            if (ungetc(ch,s) != ch) {
                /* ungetc did not work */
                break;
            }
            if ((STDCHAR*)PerlSIO_get_ptr(s) != --eptr || ((*eptr & 0xFF) != ch)) {
                /* Did not change pointer as expected */
                fgetc(s);  /* get char back again */
                break;
            }
            /* It worked ! */
            count--;
            unread++;
        }
    }

    if (count > 0) {
        unread += PerlIOBase_unread(aTHX_ f, vbuf, count);
    }
    return unread;
}

SSize_t
PerlIOStdio_write(pTHX_ PerlIO *f, const void *vbuf, Size_t count)
{
    SSize_t got;
    for (;;) {
        got = PerlSIO_fwrite(vbuf, 1, count,
                              PerlIOSelf(f, PerlIOStdio)->stdio);
        if (got >= 0 || errno != EINTR)
            break;
        PERL_ASYNC_CHECK();
        SETERRNO(0,0);  /* just in case */
    }
    return got;
}

IV
PerlIOStdio_seek(pTHX_ PerlIO *f, Off_t offset, int whence)
{
    FILE *stdio = PerlIOSelf(f, PerlIOStdio)->stdio;
    return PerlSIO_fseek(stdio, offset, whence);
}

Off_t
PerlIOStdio_tell(pTHX_ PerlIO *f)
{
    FILE *stdio = PerlIOSelf(f, PerlIOStdio)->stdio;
    return PerlSIO_ftell(stdio);
}

IV
PerlIOStdio_flush(pTHX_ PerlIO *f)
{
    FILE *stdio = PerlIOSelf(f, PerlIOStdio)->stdio;
    if (PerlIOBase(f)->flags & PERLIO_F_CANWRITE) {
        return PerlSIO_fflush(stdio);
    }
    else {
#if 0
        /*
         * FIXME: This discards ungetc() and pre-read stuff which is not
         * right if this is just a "sync" from a layer above Suspect right
         * design is to do _this_ but not have layer above flush this
         * layer read-to-read
         */
        /*
         * Not writeable - sync by attempting a seek
         */
        int err = errno;
        if (PerlSIO_fseek(stdio, (Off_t) 0, SEEK_CUR) != 0)
            errno = err;
#endif
    }
    return 0;
}

IV
PerlIOStdio_eof(pTHX_ PerlIO *f)
{
    return PerlSIO_feof(PerlIOSelf(f, PerlIOStdio)->stdio);
}

IV
PerlIOStdio_error(pTHX_ PerlIO *f)
{
    return PerlSIO_ferror(PerlIOSelf(f, PerlIOStdio)->stdio);
}

void
PerlIOStdio_clearerr(pTHX_ PerlIO *f)
{
    PerlSIO_clearerr(PerlIOSelf(f, PerlIOStdio)->stdio);
}

void
PerlIOStdio_setlinebuf(pTHX_ PerlIO *f)
{
#ifdef HAS_SETLINEBUF
    PerlSIO_setlinebuf(PerlIOSelf(f, PerlIOStdio)->stdio);
#else
    PerlSIO_setvbuf(PerlIOSelf(f, PerlIOStdio)->stdio, Nullch, _IOLBF, 0);
#endif
}

#ifdef FILE_base
STDCHAR *
PerlIOStdio_get_base(pTHX_ PerlIO *f)
{
    FILE *stdio = PerlIOSelf(f, PerlIOStdio)->stdio;
    return (STDCHAR*)PerlSIO_get_base(stdio);
}

Size_t
PerlIOStdio_get_bufsiz(pTHX_ PerlIO *f)
{
    FILE *stdio = PerlIOSelf(f, PerlIOStdio)->stdio;
    return PerlSIO_get_bufsiz(stdio);
}
#endif

#ifdef USE_STDIO_PTR
STDCHAR *
PerlIOStdio_get_ptr(pTHX_ PerlIO *f)
{
    FILE *stdio = PerlIOSelf(f, PerlIOStdio)->stdio;
    return (STDCHAR*)PerlSIO_get_ptr(stdio);
}

SSize_t
PerlIOStdio_get_cnt(pTHX_ PerlIO *f)
{
    FILE *stdio = PerlIOSelf(f, PerlIOStdio)->stdio;
    return PerlSIO_get_cnt(stdio);
}

void
PerlIOStdio_set_ptrcnt(pTHX_ PerlIO *f, STDCHAR * ptr, SSize_t cnt)
{
    FILE *stdio = PerlIOSelf(f, PerlIOStdio)->stdio;
    if (ptr != NULL) {
#ifdef STDIO_PTR_LVALUE
        PerlSIO_set_ptr(stdio, (void*)ptr); /* LHS STDCHAR* cast non-portable */
#ifdef STDIO_PTR_LVAL_SETS_CNT
        if (PerlSIO_get_cnt(stdio) != (cnt)) {
            assert(PerlSIO_get_cnt(stdio) == (cnt));
        }
#endif
#if (!defined(STDIO_PTR_LVAL_NOCHANGE_CNT))
        /*
         * Setting ptr _does_ change cnt - we are done
         */
        return;
#endif
#else                           /* STDIO_PTR_LVALUE */
        PerlProc_abort();
#endif                          /* STDIO_PTR_LVALUE */
    }
    /*
     * Now (or only) set cnt
     */
#ifdef STDIO_CNT_LVALUE
    PerlSIO_set_cnt(stdio, cnt);
#else                           /* STDIO_CNT_LVALUE */
#if (defined(STDIO_PTR_LVALUE) && defined(STDIO_PTR_LVAL_SETS_CNT))
    PerlSIO_set_ptr(stdio,
                    PerlSIO_get_ptr(stdio) + (PerlSIO_get_cnt(stdio) -
                                              cnt));
#else                           /* STDIO_PTR_LVAL_SETS_CNT */
    PerlProc_abort();
#endif                          /* STDIO_PTR_LVAL_SETS_CNT */
#endif                          /* STDIO_CNT_LVALUE */
}


#endif

IV
PerlIOStdio_fill(pTHX_ PerlIO *f)
{
    FILE *stdio = PerlIOSelf(f, PerlIOStdio)->stdio;
    int c;
    /*
     * fflush()ing read-only streams can cause trouble on some stdio-s
     */
    if ((PerlIOBase(f)->flags & PERLIO_F_CANWRITE)) {
        if (PerlSIO_fflush(stdio) != 0)
            return EOF;
    }
    c = PerlSIO_fgetc(stdio);
    if (c == EOF)
        return EOF;

#if (defined(STDIO_PTR_LVALUE) && (defined(STDIO_CNT_LVALUE) || defined(STDIO_PTR_LVAL_SETS_CNT)))

#ifdef STDIO_BUFFER_WRITABLE
    if (PerlIO_fast_gets(f) && PerlIO_has_base(f)) {
        /* Fake ungetc() to the real buffer in case system's ungetc
           goes elsewhere
         */
        STDCHAR *base = (STDCHAR*)PerlSIO_get_base(stdio);
        SSize_t cnt   = PerlSIO_get_cnt(stdio);
        STDCHAR *ptr  = (STDCHAR*)PerlSIO_get_ptr(stdio);
        if (ptr == base+1) {
            *--ptr = (STDCHAR) c;
            PerlIOStdio_set_ptrcnt(aTHX_ f,ptr,cnt+1);
            if (PerlSIO_feof(stdio))
                PerlSIO_clearerr(stdio);
            return 0;
        }
    }
    else
#endif
    if (PerlIO_has_cntptr(f)) {
        STDCHAR ch = c;
        if (PerlIOStdio_unread(aTHX_ f,&ch,1) == 1) {
            return 0;
        }
    }
#endif

#if defined(VMS)
    /* An ungetc()d char is handled separately from the regular
     * buffer, so we stuff it in the buffer ourselves.
     * Should never get called as should hit code above
     */
    *(--((*stdio)->_ptr)) = (unsigned char) c;
    (*stdio)->_cnt++;
#else
    /* If buffer snoop scheme above fails fall back to
       using ungetc().
     */
    if (PerlSIO_ungetc(c, stdio) != c)
        return EOF;
#endif
    return 0;
}


PerlIO_funcs PerlIO_stdio = {
    sizeof(PerlIO_funcs),
    "stdio",
    sizeof(PerlIOStdio),
    PERLIO_K_BUFFERED|PERLIO_K_RAW,
    PerlIOStdio_pushed,
    PerlIOBase_popped,
    PerlIOStdio_open,
    PerlIOBase_binmode,         /* binmode */
    NULL,
    PerlIOStdio_fileno,
    PerlIOStdio_dup,
    PerlIOStdio_read,
    PerlIOStdio_unread,
    PerlIOStdio_write,
    PerlIOStdio_seek,
    PerlIOStdio_tell,
    PerlIOStdio_close,
    PerlIOStdio_flush,
    PerlIOStdio_fill,
    PerlIOStdio_eof,
    PerlIOStdio_error,
    PerlIOStdio_clearerr,
    PerlIOStdio_setlinebuf,
#ifdef FILE_base
    PerlIOStdio_get_base,
    PerlIOStdio_get_bufsiz,
#else
    NULL,
    NULL,
#endif
#ifdef USE_STDIO_PTR
    PerlIOStdio_get_ptr,
    PerlIOStdio_get_cnt,
#   if defined(HAS_FAST_STDIO) && defined(USE_FAST_STDIO)
    PerlIOStdio_set_ptrcnt,
#   else
    NULL,
#   endif /* HAS_FAST_STDIO && USE_FAST_STDIO */
#else
    NULL,
    NULL,
    NULL,
#endif /* USE_STDIO_PTR */
};

/* Note that calls to PerlIO_exportFILE() are reversed using
 * PerlIO_releaseFILE(), not importFILE. */
FILE *
PerlIO_exportFILE(PerlIO * f, const char *mode)
{
    dTHX;
    FILE *stdio = NULL;
    if (PerlIOValid(f)) {
        char buf[8];
        PerlIO_flush(f);
        if (!mode || !*mode) {
            mode = PerlIO_modestr(f, buf);
        }
        stdio = PerlSIO_fdopen(PerlIO_fileno(f), mode);
        if (stdio) {
            PerlIOl *l = *f;
            PerlIO *f2;
            /* De-link any lower layers so new :stdio sticks */
            *f = NULL;
            if ((f2 = PerlIO_push(aTHX_ f, &PerlIO_stdio, buf, Nullsv))) {
                PerlIOStdio *s = PerlIOSelf((f = f2), PerlIOStdio);
                s->stdio = stdio;
                /* Link previous lower layers under new one */
                *PerlIONext(f) = l;
            }
            else {
                /* restore layers list */
                *f = l;
            }
        }
    }
    return stdio;
}


FILE *
PerlIO_findFILE(PerlIO *f)
{
    PerlIOl *l = *f;
    while (l) {
        if (l->tab == &PerlIO_stdio) {
            PerlIOStdio *s = PerlIOSelf(&l, PerlIOStdio);
            return s->stdio;
        }
        l = *PerlIONext(&l);
    }
    /* Uses fallback "mode" via PerlIO_modestr() in PerlIO_exportFILE */
    return PerlIO_exportFILE(f, Nullch);
}

/* Use this to reverse PerlIO_exportFILE calls. */
void
PerlIO_releaseFILE(PerlIO *p, FILE *f)
{
    PerlIOl *l;
    while ((l = *p)) {
        if (l->tab == &PerlIO_stdio) {
            PerlIOStdio *s = PerlIOSelf(&l, PerlIOStdio);
            if (s->stdio == f) {
                dTHX;
                PerlIO_pop(aTHX_ p);
                return;
            }
        }
        p = PerlIONext(p);
    }
    return;
}

/*--------------------------------------------------------------------------------------*/
/*
 * perlio buffer layer
 */

IV
PerlIOBuf_pushed(pTHX_ PerlIO *f, const char *mode, SV *arg, PerlIO_funcs *tab)
{
    PerlIOBuf *b = PerlIOSelf(f, PerlIOBuf);
    int fd = PerlIO_fileno(f);
    if (fd >= 0 && PerlLIO_isatty(fd)) {
        PerlIOBase(f)->flags |= PERLIO_F_LINEBUF | PERLIO_F_TTY;
    }
    if (*PerlIONext(f)) {
        Off_t posn = PerlIO_tell(PerlIONext(f));
        if (posn != (Off_t) - 1) {
            b->posn = posn;
        }
    }
    return PerlIOBase_pushed(aTHX_ f, mode, arg, tab);
}

PerlIO *
PerlIOBuf_open(pTHX_ PerlIO_funcs *self, PerlIO_list_t *layers,
               IV n, const char *mode, int fd, int imode, int perm,
               PerlIO *f, int narg, SV **args)
{
    if (PerlIOValid(f)) {
        PerlIO *next = PerlIONext(f);
        PerlIO_funcs *tab =
             PerlIO_layer_fetch(aTHX_ layers, n - 1, PerlIOBase(next)->tab);
        if (tab && tab->Open)
             next =
                  (*tab->Open)(aTHX_ tab, layers, n - 1, mode, fd, imode, perm,
                               next, narg, args);
        if (!next || (*PerlIOBase(f)->tab->Pushed) (aTHX_ f, mode, PerlIOArg, self) != 0) {
            return NULL;
        }
    }
    else {
        PerlIO_funcs *tab = PerlIO_layer_fetch(aTHX_ layers, n - 1, PerlIO_default_btm());
        int init = 0;
        if (*mode == IoTYPE_IMPLICIT) {
            init = 1;
            /*
             * mode++;
             */
        }
        if (tab && tab->Open)
             f = (*tab->Open)(aTHX_ tab, layers, n - 1, mode, fd, imode, perm,
                              f, narg, args);
        else
             SETERRNO(EINVAL, LIB_INVARG);
        if (f) {
            if (PerlIO_push(aTHX_ f, self, mode, PerlIOArg) == 0) {
                /*
                 * if push fails during open, open fails. close will pop us.
                 */
                PerlIO_close (f);
                return NULL;
            } else {
                fd = PerlIO_fileno(f);
                if (init && fd == 2) {
                    /*
                     * Initial stderr is unbuffered
                     */
                    PerlIOBase(f)->flags |= PERLIO_F_UNBUF;
                }
#ifdef PERLIO_USING_CRLF
#  ifdef PERLIO_IS_BINMODE_FD
                if (PERLIO_IS_BINMODE_FD(fd))
                    PerlIO_binmode(aTHX_ f,  '<'/*not used*/, O_BINARY, Nullch);
                else
#  endif
                /*
                 * do something about failing setmode()? --jhi
                 */
                PerlLIO_setmode(fd, O_BINARY);
#endif
            }
        }
    }
    return f;
}

/*
 * This "flush" is akin to sfio's sync in that it handles files in either
 * read or write state
 */
IV
PerlIOBuf_flush(pTHX_ PerlIO *f)
{
    PerlIOBuf *b = PerlIOSelf(f, PerlIOBuf);
    int code = 0;
    PerlIO *n = PerlIONext(f);
    if (PerlIOBase(f)->flags & PERLIO_F_WRBUF) {
        /*
         * write() the buffer
         */
        STDCHAR *buf = b->buf;
        STDCHAR *p = buf;
        while (p < b->ptr) {
            SSize_t count = PerlIO_write(n, p, b->ptr - p);
            if (count > 0) {
                p += count;
            }
            else if (count < 0 || PerlIO_error(n)) {
                PerlIOBase(f)->flags |= PERLIO_F_ERROR;
                code = -1;
                break;
            }
        }
        b->posn += (p - buf);
    }
    else if (PerlIOBase(f)->flags & PERLIO_F_RDBUF) {
        STDCHAR *buf = PerlIO_get_base(f);
        /*
         * Note position change
         */
        b->posn += (b->ptr - buf);
        if (b->ptr < b->end) {
            /* We did not consume all of it - try and seek downstream to
               our logical position
             */
            if (PerlIOValid(n) && PerlIO_seek(n, b->posn, SEEK_SET) == 0) {
                /* Reload n as some layers may pop themselves on seek */
                b->posn = PerlIO_tell(n = PerlIONext(f));
            }
            else {
                /* Seek failed (e.g. pipe or tty). Do NOT clear buffer or pre-read
                   data is lost for good - so return saying "ok" having undone
                   the position adjust
                 */
                b->posn -= (b->ptr - buf);
                return code;
            }
        }
    }
    b->ptr = b->end = b->buf;
    PerlIOBase(f)->flags &= ~(PERLIO_F_RDBUF | PERLIO_F_WRBUF);
    /* We check for Valid because of dubious decision to make PerlIO_flush(NULL) flush all */
    if (PerlIOValid(n) && PerlIO_flush(n) != 0)
        code = -1;
    return code;
}

IV
PerlIOBuf_fill(pTHX_ PerlIO *f)
{
    PerlIOBuf *b = PerlIOSelf(f, PerlIOBuf);
    PerlIO *n = PerlIONext(f);
    SSize_t avail;
    /*
     * Down-stream flush is defined not to loose read data so is harmless.
     * we would not normally be fill'ing if there was data left in anycase.
     */
    if (PerlIO_flush(f) != 0)
        return -1;
    if (PerlIOBase(f)->flags & PERLIO_F_TTY)
        PerlIOBase_flush_linebuf(aTHX);

    if (!b->buf)
        PerlIO_get_base(f);     /* allocate via vtable */

    b->ptr = b->end = b->buf;

    if (!PerlIOValid(n)) {
        PerlIOBase(f)->flags |= PERLIO_F_EOF;
        return -1;
    }

    if (PerlIO_fast_gets(n)) {
        /*
         * Layer below is also buffered. We do _NOT_ want to call its
         * ->Read() because that will loop till it gets what we asked for
         * which may hang on a pipe etc. Instead take anything it has to
         * hand, or ask it to fill _once_.
         */
        avail = PerlIO_get_cnt(n);
        if (avail <= 0) {
            avail = PerlIO_fill(n);
            if (avail == 0)
                avail = PerlIO_get_cnt(n);
            else {
                if (!PerlIO_error(n) && PerlIO_eof(n))
                    avail = 0;
            }
        }
        if (avail > 0) {
            STDCHAR *ptr = PerlIO_get_ptr(n);
            SSize_t cnt = avail;
            if (avail > (SSize_t)b->bufsiz)
                avail = b->bufsiz;
            Copy(ptr, b->buf, avail, STDCHAR);
            PerlIO_set_ptrcnt(n, ptr + avail, cnt - avail);
        }
    }
    else {
        avail = PerlIO_read(n, b->ptr, b->bufsiz);
    }
    if (avail <= 0) {
        if (avail == 0)
            PerlIOBase(f)->flags |= PERLIO_F_EOF;
        else
            PerlIOBase(f)->flags |= PERLIO_F_ERROR;
        return -1;
    }
    b->end = b->buf + avail;
    PerlIOBase(f)->flags |= PERLIO_F_RDBUF;
    return 0;
}

SSize_t
PerlIOBuf_read(pTHX_ PerlIO *f, void *vbuf, Size_t count)
{
    PerlIOBuf *b = PerlIOSelf(f, PerlIOBuf);
    if (PerlIOValid(f)) {
        if (!b->ptr)
            PerlIO_get_base(f);
        return PerlIOBase_read(aTHX_ f, vbuf, count);
    }
    return 0;
}

SSize_t
PerlIOBuf_unread(pTHX_ PerlIO *f, const void *vbuf, Size_t count)
{
    const STDCHAR *buf = (const STDCHAR *) vbuf + count;
    PerlIOBuf *b = PerlIOSelf(f, PerlIOBuf);
    SSize_t unread = 0;
    SSize_t avail;
    if (PerlIOBase(f)->flags & PERLIO_F_WRBUF)
        PerlIO_flush(f);
    if (!b->buf)
        PerlIO_get_base(f);
    if (b->buf) {
        if (PerlIOBase(f)->flags & PERLIO_F_RDBUF) {
            /*
             * Buffer is already a read buffer, we can overwrite any chars
             * which have been read back to buffer start
             */
            avail = (b->ptr - b->buf);
        }
        else {
            /*
             * Buffer is idle, set it up so whole buffer is available for
             * unread
             */
            avail = b->bufsiz;
            b->end = b->buf + avail;
            b->ptr = b->end;
            PerlIOBase(f)->flags |= PERLIO_F_RDBUF;
            /*
             * Buffer extends _back_ from where we are now
             */
            b->posn -= b->bufsiz;
        }
        if (avail > (SSize_t) count) {
            /*
             * If we have space for more than count, just move count
             */
            avail = count;
        }
        if (avail > 0) {
            b->ptr -= avail;
            buf -= avail;
            /*
             * In simple stdio-like ungetc() case chars will be already
             * there
             */
            if (buf != b->ptr) {
                Copy(buf, b->ptr, avail, STDCHAR);
            }
            count -= avail;
            unread += avail;
            PerlIOBase(f)->flags &= ~PERLIO_F_EOF;
        }
    }
    if (count > 0) {
        unread += PerlIOBase_unread(aTHX_ f, vbuf, count);
    }
    return unread;
}

SSize_t
PerlIOBuf_write(pTHX_ PerlIO *f, const void *vbuf, Size_t count)
{
    PerlIOBuf *b = PerlIOSelf(f, PerlIOBuf);
    const STDCHAR *buf = (const STDCHAR *) vbuf;
    const STDCHAR *flushptr = buf;
    Size_t written = 0;
    if (!b->buf)
        PerlIO_get_base(f);
    if (!(PerlIOBase(f)->flags & PERLIO_F_CANWRITE))
        return 0;
    if (PerlIOBase(f)->flags & PERLIO_F_RDBUF) {
        if (PerlIO_flush(f) != 0) {
            return 0;
        }
    }   
    if (PerlIOBase(f)->flags & PERLIO_F_LINEBUF) {
        flushptr = buf + count;
        while (flushptr > buf && *(flushptr - 1) != '\n')
            --flushptr;
    }
    while (count > 0) {
        SSize_t avail = b->bufsiz - (b->ptr - b->buf);
        if ((SSize_t) count < avail)
            avail = count;
        if (flushptr > buf && flushptr <= buf + avail)
            avail = flushptr - buf;
        PerlIOBase(f)->flags |= PERLIO_F_WRBUF;
        if (avail) {
            Copy(buf, b->ptr, avail, STDCHAR);
            count -= avail;
            buf += avail;
            written += avail;
            b->ptr += avail;
            if (buf == flushptr)
                PerlIO_flush(f);
        }
        if (b->ptr >= (b->buf + b->bufsiz))
            PerlIO_flush(f);
    }
    if (PerlIOBase(f)->flags & PERLIO_F_UNBUF)
        PerlIO_flush(f);
    return written;
}

IV
PerlIOBuf_seek(pTHX_ PerlIO *f, Off_t offset, int whence)
{
    IV code;
    if ((code = PerlIO_flush(f)) == 0) {
        PerlIOBuf *b = PerlIOSelf(f, PerlIOBuf);
        PerlIOBase(f)->flags &= ~PERLIO_F_EOF;
        code = PerlIO_seek(PerlIONext(f), offset, whence);
        if (code == 0) {
            b->posn = PerlIO_tell(PerlIONext(f));
        }
    }
    return code;
}

Off_t
PerlIOBuf_tell(pTHX_ PerlIO *f)
{
    PerlIOBuf *b = PerlIOSelf(f, PerlIOBuf);
    /*
     * b->posn is file position where b->buf was read, or will be written
     */
    Off_t posn = b->posn;
    if ((PerlIOBase(f)->flags & PERLIO_F_APPEND) &&
        (PerlIOBase(f)->flags & PERLIO_F_WRBUF)) {
#if 1
        /* As O_APPEND files are normally shared in some sense it is better
           to flush :
         */     
        PerlIO_flush(f);
#else   
        /* when file is NOT shared then this is sufficient */
        PerlIO_seek(PerlIONext(f),0, SEEK_END);
#endif
        posn = b->posn = PerlIO_tell(PerlIONext(f));
    }
    if (b->buf) {
        /*
         * If buffer is valid adjust position by amount in buffer
         */
        posn += (b->ptr - b->buf);
    }
    return posn;
}

IV
PerlIOBuf_popped(pTHX_ PerlIO *f)
{
    IV code = PerlIOBase_popped(aTHX_ f);
    PerlIOBuf *b = PerlIOSelf(f, PerlIOBuf);
    if (b->buf && b->buf != (STDCHAR *) & b->oneword) {
        Safefree(b->buf);
    }
    b->buf = NULL;
    b->ptr = b->end = b->buf;
    PerlIOBase(f)->flags &= ~(PERLIO_F_RDBUF | PERLIO_F_WRBUF);
    return code;
}

IV
PerlIOBuf_close(pTHX_ PerlIO *f)
{
    IV code = PerlIOBase_close(aTHX_ f);
    PerlIOBuf *b = PerlIOSelf(f, PerlIOBuf);
    if (b->buf && b->buf != (STDCHAR *) & b->oneword) {
        Safefree(b->buf);
    }
    b->buf = NULL;
    b->ptr = b->end = b->buf;
    PerlIOBase(f)->flags &= ~(PERLIO_F_RDBUF | PERLIO_F_WRBUF);
    return code;
}

STDCHAR *
PerlIOBuf_get_ptr(pTHX_ PerlIO *f)
{
    PerlIOBuf *b = PerlIOSelf(f, PerlIOBuf);
    if (!b->buf)
        PerlIO_get_base(f);
    return b->ptr;
}

SSize_t
PerlIOBuf_get_cnt(pTHX_ PerlIO *f)
{
    PerlIOBuf *b = PerlIOSelf(f, PerlIOBuf);
    if (!b->buf)
        PerlIO_get_base(f);
    if (PerlIOBase(f)->flags & PERLIO_F_RDBUF)
        return (b->end - b->ptr);
    return 0;
}

STDCHAR *
PerlIOBuf_get_base(pTHX_ PerlIO *f)
{
    PerlIOBuf *b = PerlIOSelf(f, PerlIOBuf);
    if (!b->buf) {
        if (!b->bufsiz)
            b->bufsiz = 4096;
        b->buf =
        Newz('B',b->buf,b->bufsiz, STDCHAR);
        if (!b->buf) {
            b->buf = (STDCHAR *) & b->oneword;
            b->bufsiz = sizeof(b->oneword);
        }
        b->ptr = b->buf;
        b->end = b->ptr;
    }
    return b->buf;
}

Size_t
PerlIOBuf_bufsiz(pTHX_ PerlIO *f)
{
    PerlIOBuf *b = PerlIOSelf(f, PerlIOBuf);
    if (!b->buf)
        PerlIO_get_base(f);
    return (b->end - b->buf);
}

void
PerlIOBuf_set_ptrcnt(pTHX_ PerlIO *f, STDCHAR * ptr, SSize_t cnt)
{
    PerlIOBuf *b = PerlIOSelf(f, PerlIOBuf);
    if (!b->buf)
        PerlIO_get_base(f);
    b->ptr = ptr;
    if (PerlIO_get_cnt(f) != cnt || b->ptr < b->buf) {
        assert(PerlIO_get_cnt(f) == cnt);
        assert(b->ptr >= b->buf);
    }
    PerlIOBase(f)->flags |= PERLIO_F_RDBUF;
}

PerlIO *
PerlIOBuf_dup(pTHX_ PerlIO *f, PerlIO *o, CLONE_PARAMS *param, int flags)
{
 return PerlIOBase_dup(aTHX_ f, o, param, flags);
}


PerlIO_funcs PerlIO_perlio = {
    sizeof(PerlIO_funcs),
    "perlio",
    sizeof(PerlIOBuf),
    PERLIO_K_BUFFERED|PERLIO_K_RAW,
    PerlIOBuf_pushed,
    PerlIOBuf_popped,
    PerlIOBuf_open,
    PerlIOBase_binmode,         /* binmode */
    NULL,
    PerlIOBase_fileno,
    PerlIOBuf_dup,
    PerlIOBuf_read,
    PerlIOBuf_unread,
    PerlIOBuf_write,
    PerlIOBuf_seek,
    PerlIOBuf_tell,
    PerlIOBuf_close,
    PerlIOBuf_flush,
    PerlIOBuf_fill,
    PerlIOBase_eof,
    PerlIOBase_error,
    PerlIOBase_clearerr,
    PerlIOBase_setlinebuf,
    PerlIOBuf_get_base,
    PerlIOBuf_bufsiz,
    PerlIOBuf_get_ptr,
    PerlIOBuf_get_cnt,
    PerlIOBuf_set_ptrcnt,
};

/*--------------------------------------------------------------------------------------*/
/*
 * Temp layer to hold unread chars when cannot do it any other way
 */

IV
PerlIOPending_fill(pTHX_ PerlIO *f)
{
    /*
     * Should never happen
     */
    PerlIO_flush(f);
    return 0;
}

IV
PerlIOPending_close(pTHX_ PerlIO *f)
{
    /*
     * A tad tricky - flush pops us, then we close new top
     */
    PerlIO_flush(f);
    return PerlIO_close(f);
}

IV
PerlIOPending_seek(pTHX_ PerlIO *f, Off_t offset, int whence)
{
    /*
     * A tad tricky - flush pops us, then we seek new top
     */
    PerlIO_flush(f);
    return PerlIO_seek(f, offset, whence);
}


IV
PerlIOPending_flush(pTHX_ PerlIO *f)
{
    PerlIOBuf *b = PerlIOSelf(f, PerlIOBuf);
    if (b->buf && b->buf != (STDCHAR *) & b->oneword) {
        Safefree(b->buf);
        b->buf = NULL;
    }
    PerlIO_pop(aTHX_ f);
    return 0;
}

void
PerlIOPending_set_ptrcnt(pTHX_ PerlIO *f, STDCHAR * ptr, SSize_t cnt)
{
    if (cnt <= 0) {
        PerlIO_flush(f);
    }
    else {
        PerlIOBuf_set_ptrcnt(aTHX_ f, ptr, cnt);
    }
}

IV
PerlIOPending_pushed(pTHX_ PerlIO *f, const char *mode, SV *arg, PerlIO_funcs *tab)
{
    IV code = PerlIOBase_pushed(aTHX_ f, mode, arg, tab);
    PerlIOl *l = PerlIOBase(f);
    /*
     * Our PerlIO_fast_gets must match what we are pushed on, or sv_gets()
     * etc. get muddled when it changes mid-string when we auto-pop.
     */
    l->flags = (l->flags & ~(PERLIO_F_FASTGETS | PERLIO_F_UTF8)) |
        (PerlIOBase(PerlIONext(f))->
         flags & (PERLIO_F_FASTGETS | PERLIO_F_UTF8));
    return code;
}

SSize_t
PerlIOPending_read(pTHX_ PerlIO *f, void *vbuf, Size_t count)
{
    SSize_t avail = PerlIO_get_cnt(f);
    SSize_t got = 0;
    if ((SSize_t)count < avail)
        avail = count;
    if (avail > 0)
        got = PerlIOBuf_read(aTHX_ f, vbuf, avail);
    if (got >= 0 && got < (SSize_t)count) {
        SSize_t more =
            PerlIO_read(f, ((STDCHAR *) vbuf) + got, count - got);
        if (more >= 0 || got == 0)
            got += more;
    }
    return got;
}

PerlIO_funcs PerlIO_pending = {
    sizeof(PerlIO_funcs),
    "pending",
    sizeof(PerlIOBuf),
    PERLIO_K_BUFFERED|PERLIO_K_RAW,  /* not sure about RAW here */
    PerlIOPending_pushed,
    PerlIOBuf_popped,
    NULL,
    PerlIOBase_binmode,         /* binmode */
    NULL,
    PerlIOBase_fileno,
    PerlIOBuf_dup,
    PerlIOPending_read,
    PerlIOBuf_unread,
    PerlIOBuf_write,
    PerlIOPending_seek,
    PerlIOBuf_tell,
    PerlIOPending_close,
    PerlIOPending_flush,
    PerlIOPending_fill,
    PerlIOBase_eof,
    PerlIOBase_error,
    PerlIOBase_clearerr,
    PerlIOBase_setlinebuf,
    PerlIOBuf_get_base,
    PerlIOBuf_bufsiz,
    PerlIOBuf_get_ptr,
    PerlIOBuf_get_cnt,
    PerlIOPending_set_ptrcnt,
};


/*--------------------------------------------------------------------------------------*/
/*
 * crlf - translation On read translate CR,LF to "\n" we do this by
 * overriding ptr/cnt entries to hand back a line at a time and keeping a
 * record of which nl we "lied" about. On write translate "\n" to CR,LF
 */

typedef struct {
    PerlIOBuf base;             /* PerlIOBuf stuff */
    STDCHAR *nl;                /* Position of crlf we "lied" about in the
                                 * buffer */
} PerlIOCrlf;

IV
PerlIOCrlf_pushed(pTHX_ PerlIO *f, const char *mode, SV *arg, PerlIO_funcs *tab)
{
    IV code;
    PerlIOBase(f)->flags |= PERLIO_F_CRLF;
    code = PerlIOBuf_pushed(aTHX_ f, mode, arg, tab);
#if 0
    PerlIO_debug("PerlIOCrlf_pushed f=%p %s %s fl=%08" UVxf "\n",
                 f, PerlIOBase(f)->tab->name, (mode) ? mode : "(Null)",
                 PerlIOBase(f)->flags);
#endif
    {
      /* Enable the first CRLF capable layer you can find, but if none
       * found, the one we just pushed is fine.  This results in at
       * any given moment at most one CRLF-capable layer being enabled
       * in the whole layer stack. */
         PerlIO *g = PerlIONext(f);
         while (g && *g) {
              PerlIOl *b = PerlIOBase(g);
              if (b && b->tab == &PerlIO_crlf) {
                   if (!(b->flags & PERLIO_F_CRLF))
                        b->flags |= PERLIO_F_CRLF;
                   PerlIO_pop(aTHX_ f);
                   return code;
              }           
              g = PerlIONext(g);
         }
    }
    return code;
}


SSize_t
PerlIOCrlf_unread(pTHX_ PerlIO *f, const void *vbuf, Size_t count)
{
    PerlIOCrlf *c = PerlIOSelf(f, PerlIOCrlf);
    if (c->nl) {
        *(c->nl) = 0xd;
        c->nl = NULL;
    }
    if (!(PerlIOBase(f)->flags & PERLIO_F_CRLF))
        return PerlIOBuf_unread(aTHX_ f, vbuf, count);
    else {
        const STDCHAR *buf = (const STDCHAR *) vbuf + count;
        PerlIOBuf *b = PerlIOSelf(f, PerlIOBuf);
        SSize_t unread = 0;
        if (PerlIOBase(f)->flags & PERLIO_F_WRBUF)
            PerlIO_flush(f);
        if (!b->buf)
            PerlIO_get_base(f);
        if (b->buf) {
            if (!(PerlIOBase(f)->flags & PERLIO_F_RDBUF)) {
                b->end = b->ptr = b->buf + b->bufsiz;
                PerlIOBase(f)->flags |= PERLIO_F_RDBUF;
                b->posn -= b->bufsiz;
            }
            while (count > 0 && b->ptr > b->buf) {
                int ch = *--buf;
                if (ch == '\n') {
                    if (b->ptr - 2 >= b->buf) {
                        *--(b->ptr) = 0xa;
                        *--(b->ptr) = 0xd;
                        unread++;
                        count--;
                    }
                    else {
                        buf++;
                        break;
                    }
                }
                else {
                    *--(b->ptr) = ch;
                    unread++;
                    count--;
                }
            }
        }
        return unread;
    }
}

SSize_t
PerlIOCrlf_get_cnt(pTHX_ PerlIO *f)
{
    PerlIOBuf *b = PerlIOSelf(f, PerlIOBuf);
    if (!b->buf)
        PerlIO_get_base(f);
    if (PerlIOBase(f)->flags & PERLIO_F_RDBUF) {
        PerlIOCrlf *c = PerlIOSelf(f, PerlIOCrlf);
        if ((PerlIOBase(f)->flags & PERLIO_F_CRLF) && (!c->nl || *c->nl == 0xd)) {
            STDCHAR *nl = (c->nl) ? c->nl : b->ptr;
          scan:
            while (nl < b->end && *nl != 0xd)
                nl++;
            if (nl < b->end && *nl == 0xd) {
              test:
                if (nl + 1 < b->end) {
                    if (nl[1] == 0xa) {
                        *nl = '\n';
                        c->nl = nl;
                    }
                    else {
                        /*
                         * Not CR,LF but just CR
                         */
                        nl++;
                        goto scan;
                    }
                }
                else {
                    /*
                     * Blast - found CR as last char in buffer
                     */

                    if (b->ptr < nl) {
                        /*
                         * They may not care, defer work as long as
                         * possible
                         */
                        c->nl = nl;
                        return (nl - b->ptr);
                    }
                    else {
                        int code;
                        b->ptr++;       /* say we have read it as far as
                                         * flush() is concerned */
                        b->buf++;       /* Leave space in front of buffer */
                        /* Note as we have moved buf up flush's
                           posn += ptr-buf
                           will naturally make posn point at CR
                         */
                        b->bufsiz--;    /* Buffer is thus smaller */
                        code = PerlIO_fill(f);  /* Fetch some more */
                        b->bufsiz++;    /* Restore size for next time */
                        b->buf--;       /* Point at space */
                        b->ptr = nl = b->buf;   /* Which is what we hand
                                                 * off */
                        *nl = 0xd;      /* Fill in the CR */
                        if (code == 0)
                            goto test;  /* fill() call worked */
                        /*
                         * CR at EOF - just fall through
                         */
                        /* Should we clear EOF though ??? */
                    }
                }
            }
        }
        return (((c->nl) ? (c->nl + 1) : b->end) - b->ptr);
    }
    return 0;
}

void
PerlIOCrlf_set_ptrcnt(pTHX_ PerlIO *f, STDCHAR * ptr, SSize_t cnt)
{
    PerlIOBuf *b = PerlIOSelf(f, PerlIOBuf);
    PerlIOCrlf *c = PerlIOSelf(f, PerlIOCrlf);
    if (!b->buf)
        PerlIO_get_base(f);
    if (!ptr) {
        if (c->nl) {
            ptr = c->nl + 1;
            if (ptr == b->end && *c->nl == 0xd) {
                /* Defered CR at end of buffer case - we lied about count */
                ptr--;
            }
        }
        else {
            ptr = b->end;
        }
        ptr -= cnt;
    }
    else {
#if 0
        /*
         * Test code - delete when it works ...
         */
        IV flags = PerlIOBase(f)->flags;
        STDCHAR *chk = (c->nl) ? (c->nl+1) : b->end;
        if (ptr+cnt == c->nl && c->nl+1 == b->end && *c->nl == 0xd) {
          /* Defered CR at end of buffer case - we lied about count */
          chk--;
        }
        chk -= cnt;

        if (ptr != chk ) {
            Perl_croak(aTHX_ "ptr wrong %p != %p fl=%08" UVxf
                       " nl=%p e=%p for %d", ptr, chk, flags, c->nl,
                       b->end, cnt);
        }
#endif
    }
    if (c->nl) {
        if (ptr > c->nl) {
            /*
             * They have taken what we lied about
             */
            *(c->nl) = 0xd;
            c->nl = NULL;
            ptr++;
        }
    }
    b->ptr = ptr;
    PerlIOBase(f)->flags |= PERLIO_F_RDBUF;
}

SSize_t
PerlIOCrlf_write(pTHX_ PerlIO *f, const void *vbuf, Size_t count)
{
    if (!(PerlIOBase(f)->flags & PERLIO_F_CRLF))
        return PerlIOBuf_write(aTHX_ f, vbuf, count);
    else {
        PerlIOBuf *b = PerlIOSelf(f, PerlIOBuf);
        const STDCHAR *buf = (const STDCHAR *) vbuf;
        const STDCHAR *ebuf = buf + count;
        if (!b->buf)
            PerlIO_get_base(f);
        if (!(PerlIOBase(f)->flags & PERLIO_F_CANWRITE))
            return 0;
        while (buf < ebuf) {
            STDCHAR *eptr = b->buf + b->bufsiz;
            PerlIOBase(f)->flags |= PERLIO_F_WRBUF;
            while (buf < ebuf && b->ptr < eptr) {
                if (*buf == '\n') {
                    if ((b->ptr + 2) > eptr) {
                        /*
                         * Not room for both
                         */
                        PerlIO_flush(f);
                        break;
                    }
                    else {
                        *(b->ptr)++ = 0xd;      /* CR */
                        *(b->ptr)++ = 0xa;      /* LF */
                        buf++;
                        if (PerlIOBase(f)->flags & PERLIO_F_LINEBUF) {
                            PerlIO_flush(f);
                            break;
                        }
                    }
                }
                else {
                    int ch = *buf++;
                    *(b->ptr)++ = ch;
                }
                if (b->ptr >= eptr) {
                    PerlIO_flush(f);
                    break;
                }
            }
        }
        if (PerlIOBase(f)->flags & PERLIO_F_UNBUF)
            PerlIO_flush(f);
        return (buf - (STDCHAR *) vbuf);
    }
}

IV
PerlIOCrlf_flush(pTHX_ PerlIO *f)
{
    PerlIOCrlf *c = PerlIOSelf(f, PerlIOCrlf);
    if (c->nl) {
        *(c->nl) = 0xd;
        c->nl = NULL;
    }
    return PerlIOBuf_flush(aTHX_ f);
}

IV
PerlIOCrlf_binmode(pTHX_ PerlIO *f)
{
    if ((PerlIOBase(f)->flags & PERLIO_F_CRLF)) {
        /* In text mode - flush any pending stuff and flip it */
        PerlIOBase(f)->flags &= ~PERLIO_F_CRLF;
#ifndef PERLIO_USING_CRLF
        /* CRLF is unusual case - if this is just the :crlf layer pop it */
        if (PerlIOBase(f)->tab == &PerlIO_crlf) {
                PerlIO_pop(aTHX_ f);
        }
#endif
    }
    return 0;
}

PerlIO_funcs PerlIO_crlf = {
    sizeof(PerlIO_funcs),
    "crlf",
    sizeof(PerlIOCrlf),
    PERLIO_K_BUFFERED | PERLIO_K_CANCRLF | PERLIO_K_RAW,
    PerlIOCrlf_pushed,
    PerlIOBuf_popped,         /* popped */
    PerlIOBuf_open,
    PerlIOCrlf_binmode,       /* binmode */
    NULL,
    PerlIOBase_fileno,
    PerlIOBuf_dup,
    PerlIOBuf_read,             /* generic read works with ptr/cnt lies
                                 * ... */
    PerlIOCrlf_unread,          /* Put CR,LF in buffer for each '\n' */
    PerlIOCrlf_write,           /* Put CR,LF in buffer for each '\n' */
    PerlIOBuf_seek,
    PerlIOBuf_tell,
    PerlIOBuf_close,
    PerlIOCrlf_flush,
    PerlIOBuf_fill,
    PerlIOBase_eof,
    PerlIOBase_error,
    PerlIOBase_clearerr,
    PerlIOBase_setlinebuf,
    PerlIOBuf_get_base,
    PerlIOBuf_bufsiz,
    PerlIOBuf_get_ptr,
    PerlIOCrlf_get_cnt,
    PerlIOCrlf_set_ptrcnt,
};

#ifdef HAS_MMAP
/*--------------------------------------------------------------------------------------*/
/*
 * mmap as "buffer" layer
 */

typedef struct {
    PerlIOBuf base;             /* PerlIOBuf stuff */
    Mmap_t mptr;                /* Mapped address */
    Size_t len;                 /* mapped length */
    STDCHAR *bbuf;              /* malloced buffer if map fails */
} PerlIOMmap;

static size_t page_size = 0;

IV
PerlIOMmap_map(pTHX_ PerlIO *f)
{
    PerlIOMmap *m = PerlIOSelf(f, PerlIOMmap);
    IV flags = PerlIOBase(f)->flags;
    IV code = 0;
    if (m->len)
        abort();
    if (flags & PERLIO_F_CANREAD) {
        PerlIOBuf *b = PerlIOSelf(f, PerlIOBuf);
        int fd = PerlIO_fileno(f);
        Stat_t st;
        code = Fstat(fd, &st);
        if (code == 0 && S_ISREG(st.st_mode)) {
            SSize_t len = st.st_size - b->posn;
            if (len > 0) {
                Off_t posn;
                if (!page_size) {
#if defined(HAS_SYSCONF) && (defined(_SC_PAGESIZE) || defined(_SC_PAGE_SIZE))
                    {
                        SETERRNO(0, SS_NORMAL);
#   ifdef _SC_PAGESIZE
                        page_size = sysconf(_SC_PAGESIZE);
#   else
                        page_size = sysconf(_SC_PAGE_SIZE);
#   endif
                        if ((long) page_size < 0) {
                            if (errno) {
                                SV *error = ERRSV;
                                char *msg;
                                STRLEN n_a;
                                (void) SvUPGRADE(error, SVt_PV);
                                msg = SvPVx(error, n_a);
                                Perl_croak(aTHX_ "panic: sysconf: %s",
                                           msg);
                            }
                            else
                                Perl_croak(aTHX_
                                           "panic: sysconf: pagesize unknown");
                        }
                    }
#else
#   ifdef HAS_GETPAGESIZE
                    page_size = getpagesize();
#   else
#       if defined(I_SYS_PARAM) && defined(PAGESIZE)
                    page_size = PAGESIZE;       /* compiletime, bad */
#       endif
#   endif
#endif
                    if ((IV) page_size <= 0)
                        Perl_croak(aTHX_ "panic: bad pagesize %" IVdf,
                                   (IV) page_size);
                }
                if (b->posn < 0) {
                    /*
                     * This is a hack - should never happen - open should
                     * have set it !
                     */
                    b->posn = PerlIO_tell(PerlIONext(f));
                }
                posn = (b->posn / page_size) * page_size;
                len = st.st_size - posn;
                m->mptr = mmap(NULL, len, PROT_READ, MAP_SHARED, fd, posn);
                if (m->mptr && m->mptr != (Mmap_t) - 1) {
#if 0 && defined(HAS_MADVISE) && defined(MADV_SEQUENTIAL)
                    madvise(m->mptr, len, MADV_SEQUENTIAL);
#endif
#if 0 && defined(HAS_MADVISE) && defined(MADV_WILLNEED)
                    madvise(m->mptr, len, MADV_WILLNEED);
#endif
                    PerlIOBase(f)->flags =
                        (flags & ~PERLIO_F_EOF) | PERLIO_F_RDBUF;
                    b->end = ((STDCHAR *) m->mptr) + len;
                    b->buf = ((STDCHAR *) m->mptr) + (b->posn - posn);
                    b->ptr = b->buf;
                    m->len = len;
                }
                else {
                    b->buf = NULL;
                }
            }
            else {
                PerlIOBase(f)->flags =
                    flags | PERLIO_F_EOF | PERLIO_F_RDBUF;
                b->buf = NULL;
                b->ptr = b->end = b->ptr;
                code = -1;
            }
        }
    }
    return code;
}

IV
PerlIOMmap_unmap(pTHX_ PerlIO *f)
{
    PerlIOMmap *m = PerlIOSelf(f, PerlIOMmap);
    PerlIOBuf *b = &m->base;
    IV code = 0;
    if (m->len) {
        if (b->buf) {
            code = munmap(m->mptr, m->len);
            b->buf = NULL;
            m->len = 0;
            m->mptr = NULL;
            if (PerlIO_seek(PerlIONext(f), b->posn, SEEK_SET) != 0)
                code = -1;
        }
        b->ptr = b->end = b->buf;
        PerlIOBase(f)->flags &= ~(PERLIO_F_RDBUF | PERLIO_F_WRBUF);
    }
    return code;
}

STDCHAR *
PerlIOMmap_get_base(pTHX_ PerlIO *f)
{
    PerlIOMmap *m = PerlIOSelf(f, PerlIOMmap);
    PerlIOBuf *b = &m->base;
    if (b->buf && (PerlIOBase(f)->flags & PERLIO_F_RDBUF)) {
        /*
         * Already have a readbuffer in progress
         */
        return b->buf;
    }
    if (b->buf) {
        /*
         * We have a write buffer or flushed PerlIOBuf read buffer
         */
        m->bbuf = b->buf;       /* save it in case we need it again */
        b->buf = NULL;          /* Clear to trigger below */
    }
    if (!b->buf) {
        PerlIOMmap_map(aTHX_ f);        /* Try and map it */
        if (!b->buf) {
            /*
             * Map did not work - recover PerlIOBuf buffer if we have one
             */
            b->buf = m->bbuf;
        }
    }
    b->ptr = b->end = b->buf;
    if (b->buf)
        return b->buf;
    return PerlIOBuf_get_base(aTHX_ f);
}

SSize_t
PerlIOMmap_unread(pTHX_ PerlIO *f, const void *vbuf, Size_t count)
{
    PerlIOMmap *m = PerlIOSelf(f, PerlIOMmap);
    PerlIOBuf *b = &m->base;
    if (PerlIOBase(f)->flags & PERLIO_F_WRBUF)
        PerlIO_flush(f);
    if (b->ptr && (b->ptr - count) >= b->buf
        && memEQ(b->ptr - count, vbuf, count)) {
        b->ptr -= count;
        PerlIOBase(f)->flags &= ~PERLIO_F_EOF;
        return count;
    }
    if (m->len) {
        /*
         * Loose the unwritable mapped buffer
         */
        PerlIO_flush(f);
        /*
         * If flush took the "buffer" see if we have one from before
         */
        if (!b->buf && m->bbuf)
            b->buf = m->bbuf;
        if (!b->buf) {
            PerlIOBuf_get_base(aTHX_ f);
            m->bbuf = b->buf;
        }
    }
    return PerlIOBuf_unread(aTHX_ f, vbuf, count);
}

SSize_t
PerlIOMmap_write(pTHX_ PerlIO *f, const void *vbuf, Size_t count)
{
    PerlIOMmap *m = PerlIOSelf(f, PerlIOMmap);
    PerlIOBuf *b = &m->base;
    if (!b->buf || !(PerlIOBase(f)->flags & PERLIO_F_WRBUF)) {
        /*
         * No, or wrong sort of, buffer
         */
        if (m->len) {
            if (PerlIOMmap_unmap(aTHX_ f) != 0)
                return 0;
        }
        /*
         * If unmap took the "buffer" see if we have one from before
         */
        if (!b->buf && m->bbuf)
            b->buf = m->bbuf;
        if (!b->buf) {
            PerlIOBuf_get_base(aTHX_ f);
            m->bbuf = b->buf;
        }
    }
    return PerlIOBuf_write(aTHX_ f, vbuf, count);
}

IV
PerlIOMmap_flush(pTHX_ PerlIO *f)
{
    PerlIOMmap *m = PerlIOSelf(f, PerlIOMmap);
    PerlIOBuf *b = &m->base;
    IV code = PerlIOBuf_flush(aTHX_ f);
    /*
     * Now we are "synced" at PerlIOBuf level
     */
    if (b->buf) {
        if (m->len) {
            /*
             * Unmap the buffer
             */
            if (PerlIOMmap_unmap(aTHX_ f) != 0)
                code = -1;
        }
        else {
            /*
             * We seem to have a PerlIOBuf buffer which was not mapped
             * remember it in case we need one later
             */
            m->bbuf = b->buf;
        }
    }
    return code;
}

IV
PerlIOMmap_fill(pTHX_ PerlIO *f)
{
    PerlIOBuf *b = PerlIOSelf(f, PerlIOBuf);
    IV code = PerlIO_flush(f);
    if (code == 0 && !b->buf) {
        code = PerlIOMmap_map(aTHX_ f);
    }
    if (code == 0 && !(PerlIOBase(f)->flags & PERLIO_F_RDBUF)) {
        code = PerlIOBuf_fill(aTHX_ f);
    }
    return code;
}

IV
PerlIOMmap_close(pTHX_ PerlIO *f)
{
    PerlIOMmap *m = PerlIOSelf(f, PerlIOMmap);
    PerlIOBuf *b = &m->base;
    IV code = PerlIO_flush(f);
    if (m->bbuf) {
        b->buf = m->bbuf;
        m->bbuf = NULL;
        b->ptr = b->end = b->buf;
    }
    if (PerlIOBuf_close(aTHX_ f) != 0)
        code = -1;
    return code;
}

PerlIO *
PerlIOMmap_dup(pTHX_ PerlIO *f, PerlIO *o, CLONE_PARAMS *param, int flags)
{
 return PerlIOBase_dup(aTHX_ f, o, param, flags);
}


PerlIO_funcs PerlIO_mmap = {
    sizeof(PerlIO_funcs),
    "mmap",
    sizeof(PerlIOMmap),
    PERLIO_K_BUFFERED|PERLIO_K_RAW,
    PerlIOBuf_pushed,
    PerlIOBuf_popped,
    PerlIOBuf_open,
    PerlIOBase_binmode,         /* binmode */
    NULL,
    PerlIOBase_fileno,
    PerlIOMmap_dup,
    PerlIOBuf_read,
    PerlIOMmap_unread,
    PerlIOMmap_write,
    PerlIOBuf_seek,
    PerlIOBuf_tell,
    PerlIOBuf_close,
    PerlIOMmap_flush,
    PerlIOMmap_fill,
    PerlIOBase_eof,
    PerlIOBase_error,
    PerlIOBase_clearerr,
    PerlIOBase_setlinebuf,
    PerlIOMmap_get_base,
    PerlIOBuf_bufsiz,
    PerlIOBuf_get_ptr,
    PerlIOBuf_get_cnt,
    PerlIOBuf_set_ptrcnt,
};

#endif                          /* HAS_MMAP */

PerlIO *
Perl_PerlIO_stdin(pTHX)
{
    if (!PL_perlio) {
        PerlIO_stdstreams(aTHX);
    }
    return &PL_perlio[1];
}

PerlIO *
Perl_PerlIO_stdout(pTHX)
{
    if (!PL_perlio) {
        PerlIO_stdstreams(aTHX);
    }
    return &PL_perlio[2];
}

PerlIO *
Perl_PerlIO_stderr(pTHX)
{
    if (!PL_perlio) {
        PerlIO_stdstreams(aTHX);
    }
    return &PL_perlio[3];
}

/*--------------------------------------------------------------------------------------*/

char *
PerlIO_getname(PerlIO *f, char *buf)
{
    dTHX;
    char *name = NULL;
#ifdef VMS
    bool exported = FALSE;
    FILE *stdio = PerlIOSelf(f, PerlIOStdio)->stdio;
    if (!stdio) {
        stdio = PerlIO_exportFILE(f,0);
        exported = TRUE;
    }
    if (stdio) {
        name = fgetname(stdio, buf);
        if (exported) PerlIO_releaseFILE(f,stdio);
    }
#else
    Perl_croak(aTHX_ "Don't know how to get file name");
#endif
    return name;
}


/*--------------------------------------------------------------------------------------*/
/*
 * Functions which can be called on any kind of PerlIO implemented in
 * terms of above
 */

#undef PerlIO_fdopen
PerlIO *
PerlIO_fdopen(int fd, const char *mode)
{
    dTHX;
    return PerlIO_openn(aTHX_ Nullch, mode, fd, 0, 0, NULL, 0, NULL);
}

#undef PerlIO_open
PerlIO *
PerlIO_open(const char *path, const char *mode)
{
    dTHX;
    SV *name = sv_2mortal(newSVpvn(path, strlen(path)));
    return PerlIO_openn(aTHX_ Nullch, mode, -1, 0, 0, NULL, 1, &name);
}

#undef Perlio_reopen
PerlIO *
PerlIO_reopen(const char *path, const char *mode, PerlIO *f)
{
    dTHX;
    SV *name = sv_2mortal(newSVpvn(path, strlen(path)));
    return PerlIO_openn(aTHX_ Nullch, mode, -1, 0, 0, f, 1, &name);
}

#undef PerlIO_getc
int
PerlIO_getc(PerlIO *f)
{
    dTHX;
    STDCHAR buf[1];
    SSize_t count = PerlIO_read(f, buf, 1);
    if (count == 1) {
        return (unsigned char) buf[0];
    }
    return EOF;
}

#undef PerlIO_ungetc
int
PerlIO_ungetc(PerlIO *f, int ch)
{
    dTHX;
    if (ch != EOF) {
        STDCHAR buf = ch;
        if (PerlIO_unread(f, &buf, 1) == 1)
            return ch;
    }
    return EOF;
}

#undef PerlIO_putc
int
PerlIO_putc(PerlIO *f, int ch)
{
    dTHX;
    STDCHAR buf = ch;
    return PerlIO_write(f, &buf, 1);
}

#undef PerlIO_puts
int
PerlIO_puts(PerlIO *f, const char *s)
{
    dTHX;
    STRLEN len = strlen(s);
    return PerlIO_write(f, s, len);
}

#undef PerlIO_rewind
void
PerlIO_rewind(PerlIO *f)
{
    dTHX;
    PerlIO_seek(f, (Off_t) 0, SEEK_SET);
    PerlIO_clearerr(f);
}

#undef PerlIO_vprintf
int
PerlIO_vprintf(PerlIO *f, const char *fmt, va_list ap)
{
    dTHX;
    SV *sv = newSVpvn("", 0);
    char *s;
    STRLEN len;
    SSize_t wrote;
#ifdef NEED_VA_COPY
    va_list apc;
    Perl_va_copy(ap, apc);
    sv_vcatpvf(sv, fmt, &apc);
#else
    sv_vcatpvf(sv, fmt, &ap);
#endif
    s = SvPV(sv, len);
    wrote = PerlIO_write(f, s, len);
    SvREFCNT_dec(sv);
    return wrote;
}

#undef PerlIO_printf
int
PerlIO_printf(PerlIO *f, const char *fmt, ...)
{
    va_list ap;
    int result;
    va_start(ap, fmt);
    result = PerlIO_vprintf(f, fmt, ap);
    va_end(ap);
    return result;
}

#undef PerlIO_stdoutf
int
PerlIO_stdoutf(const char *fmt, ...)
{
    dTHX;
    va_list ap;
    int result;
    va_start(ap, fmt);
    result = PerlIO_vprintf(PerlIO_stdout(), fmt, ap);
    va_end(ap);
    return result;
}

#undef PerlIO_tmpfile
PerlIO *
PerlIO_tmpfile(void)
{
     dTHX;
     PerlIO *f = NULL;
     int fd = -1;
#ifdef WIN32
     fd = win32_tmpfd();
     if (fd >= 0)
          f = PerlIO_fdopen(fd, "w+b");
#else /* WIN32 */
#    if defined(HAS_MKSTEMP) && ! defined(VMS) && ! defined(OS2)
     SV *sv = newSVpv("/tmp/PerlIO_XXXXXX", 0);

     /*
      * I have no idea how portable mkstemp() is ... NI-S
      */
     fd = mkstemp(SvPVX(sv));
     if (fd >= 0) {
          f = PerlIO_fdopen(fd, "w+");
          if (f)
               PerlIOBase(f)->flags |= PERLIO_F_TEMP;
          PerlLIO_unlink(SvPVX(sv));
          SvREFCNT_dec(sv);
     }
#    else       /* !HAS_MKSTEMP, fallback to stdio tmpfile(). */
     FILE *stdio = PerlSIO_tmpfile();

     if (stdio) {
          if ((f = PerlIO_push(aTHX_(PerlIO_allocate(aTHX)),
                               &PerlIO_stdio, "w+", Nullsv))) {
               PerlIOStdio *s = PerlIOSelf(f, PerlIOStdio);

               if (s)
                    s->stdio = stdio;
          }
     }
#    endif /* else HAS_MKSTEMP */
#endif /* else WIN32 */
     return f;
}

#undef HAS_FSETPOS
#undef HAS_FGETPOS

#endif                          /* USE_SFIO */
#endif                          /* PERLIO_IS_STDIO */

/*======================================================================================*/
/*
 * Now some functions in terms of above which may be needed even if we are
 * not in true PerlIO mode
 */

#ifndef HAS_FSETPOS
#undef PerlIO_setpos
int
PerlIO_setpos(PerlIO *f, SV *pos)
{
    dTHX;
    if (SvOK(pos)) {
        STRLEN len;
        Off_t *posn = (Off_t *) SvPV(pos, len);
        if (f && len == sizeof(Off_t))
            return PerlIO_seek(f, *posn, SEEK_SET);
    }
    SETERRNO(EINVAL, SS_IVCHAN);
    return -1;
}
#else
#undef PerlIO_setpos
int
PerlIO_setpos(PerlIO *f, SV *pos)
{
    dTHX;
    if (SvOK(pos)) {
        STRLEN len;
        Fpos_t *fpos = (Fpos_t *) SvPV(pos, len);
        if (f && len == sizeof(Fpos_t)) {
#if defined(USE_64_BIT_STDIO) && defined(USE_FSETPOS64)
            return fsetpos64(f, fpos);
#else
            return fsetpos(f, fpos);
#endif
        }
    }
    SETERRNO(EINVAL, SS_IVCHAN);
    return -1;
}
#endif

#ifndef HAS_FGETPOS
#undef PerlIO_getpos
int
PerlIO_getpos(PerlIO *f, SV *pos)
{
    dTHX;
    Off_t posn = PerlIO_tell(f);
    sv_setpvn(pos, (char *) &posn, sizeof(posn));
    return (posn == (Off_t) - 1) ? -1 : 0;
}
#else
#undef PerlIO_getpos
int
PerlIO_getpos(PerlIO *f, SV *pos)
{
    dTHX;
    Fpos_t fpos;
    int code;
#if defined(USE_64_BIT_STDIO) && defined(USE_FSETPOS64)
    code = fgetpos64(f, &fpos);
#else
    code = fgetpos(f, &fpos);
#endif
    sv_setpvn(pos, (char *) &fpos, sizeof(fpos));
    return code;
}
#endif

#if (defined(PERLIO_IS_STDIO) || !defined(USE_SFIO)) && !defined(HAS_VPRINTF)

int
vprintf(char *pat, char *args)
{
    _doprnt(pat, args, stdout);
    return 0;                   /* wrong, but perl doesn't use the return
                                 * value */
}

int
vfprintf(FILE *fd, char *pat, char *args)
{
    _doprnt(pat, args, fd);
    return 0;                   /* wrong, but perl doesn't use the return
                                 * value */
}

#endif

#ifndef PerlIO_vsprintf
int
PerlIO_vsprintf(char *s, int n, const char *fmt, va_list ap)
{
    int val = vsprintf(s, fmt, ap);
    if (n >= 0) {
        if (strlen(s) >= (STRLEN) n) {
            dTHX;
            (void) PerlIO_puts(Perl_error_log,
                               "panic: sprintf overflow - memory corrupted!\n");
            my_exit(1);
        }
    }
    return val;
}
#endif

#ifndef PerlIO_sprintf
int
PerlIO_sprintf(char *s, int n, const char *fmt, ...)
{
    va_list ap;
    int result;
    va_start(ap, fmt);
    result = PerlIO_vsprintf(s, n, fmt, ap);
    va_end(ap);
    return result;
}
#endif


Revision:	1.1
Committed:	Thu Jun 30 14:26:42 2005 UTC (21 years, 3 months ago) by root
Content type:	text/plain
Branch:	MAIN
CVS Tags:	PERL-5-8-7, HEAD
Branch point for:	PERL
Log Message:	* empty log message *