Algorithm-FEC/FEC.xs

#include "EXTERN.h"
#include "perl.h"
#include "XSUB.h"

#include <string.h>
#include <unistd.h>
#include <sys/mman.h>

#include "fec.h"

struct fec_imp {
  void (*fec_free)(void *p) ;
  void *(*fec_new)(int k, int n) ;
  void (*fec_encode)(void *code, void *src[], void *dst, int index, int sz) ;
  int (*fec_decode)(void *code, void *pkt[], int index[], int sz) ;
};

static struct fec_imp fec8_imp  = { fec8_free , fec8_new , fec8_encode , fec8_decode  };
static struct fec_imp fec16_imp = { fec16_free, fec16_new, fec16_encode, fec16_decode };

typedef struct state {
  struct fec_imp *imp;
  void *code;
  int sz;
  int dp, ep;

  void **b_addr;
  void **b_mmap;
  int *b_sz;
  SV **b_sv;
  int **idx; /* the decoding indices */
} *Algorithm__FEC;

static void
chk_array (SV *sv, int size, const char *func, const char *var)
{
  if (!SvROK (sv)
      || SvTYPE (SvRV (sv)) != SVt_PVAV
      || av_len ((AV *)SvRV (sv)) != size - 1)
    croak ("%s: %s must be a reference to an array of size %d", size);
}

static void
free_files (struct state *self)
{
  int i;

  if (self->b_addr && self->b_sv)
    for (i = 0; i < self->dp; i++)
      if (self->b_sv[i])
        SvREFCNT_dec (self->b_sv[i]);
      else if (self->b_mmap[i])
        munmap (self->b_mmap[i], self->b_sz[i]);

  Safefree (self->b_addr); self->b_addr = 0;
  Safefree (self->b_mmap); self->b_mmap = 0;
  Safefree (self->b_sz  ); self->b_sz   = 0;
  Safefree (self->b_sv  ); self->b_sv   = 0;
  Safefree (self->idx   ); self->idx    = 0;
}

static void
realloc_files (struct state *self)
{
  free_files (self);

  Newz (0, self->b_addr, self->dp, void *);
  Newz (0, self->b_mmap, self->dp, void *);
  Newz (0, self->b_sz  , self->dp, int);
  Newz (0, self->b_sv  , self->dp, SV *);
}

static void
force_addrs (struct state *self, int dp)
{
  int i;

  for (i = 0; i < dp; i++)
    if (self->b_sv[i])
      {
        STRLEN size;
        self->b_addr[i] = SvPV (self->b_sv[i], size);

        if (size != self->sz)
          croak ("block #%d (a string) has size %d, not %d", i, (int)size, self->sz);
      } else if (!self->b_mmap[i]) {
        croak ("block #%d neither string nor file, did set_blocks fail and you ignored it?", i);
      }
}

static void
open_file (struct state *self, int idx, SV *sv, int rw)
{
  IO *io = 0;
  off_t offset;
  
  if (SvROK (sv) && SvTYPE (SvRV (sv)) == SVt_PVAV)
    {
      io = sv_2io (*av_fetch ((AV *)SvRV (sv), 0, 1));
      offset = SvIV (*av_fetch ((AV *)SvRV (sv), 1, 1));
      sv = 0;
    }
  else if (!SvPOK (sv))
    {
      io = sv_2io (sv);
      offset = 0;
      sv = 0;
    }

  if (io)
    {
      int fd = PerlIO_fileno (IoIFP (io));
      off_t ofs2 = offset & ~((off_t)getpagesize () - 1);
      void *mm;

      if (fd <= 0)
        croak ("invalid file descriptor for block #%d", idx);

      mm = mmap (0, self->sz + (offset - ofs2),
                       rw ? PROT_READ | PROT_WRITE : PROT_READ,
                       MAP_SHARED, fd, ofs2);

      if (mm == MAP_FAILED)
        croak ("unable to mmap block #%d (wrong offset or size?): %s", idx, strerror (errno));

      self->b_mmap[idx] = mm;
      self->b_addr[idx] = (void *)((char *)mm + (offset - ofs2));
      self->b_sz  [idx] = self->sz + (offset - ofs2);
    }
  else if (sv)
    self->b_sv[idx] = SvREFCNT_inc (sv);
  else
    croak ("unable to open block #%d, must be either string, filehandle, or [filehandle, offset]", idx);
}

static void
open_files (struct state *self, AV *av, int rw)
{
  int i;

  realloc_files (self);

  for (i = 0; i < self->dp; i++)
    open_file (self, i, *av_fetch (av, i, 1), rw);
}

MODULE = Algorithm::FEC         PACKAGE = Algorithm::FEC

PROTOTYPES: ENABLE

Algorithm::FEC
new(class, data_packets, encoded_packets, blocksize)
        SV *    class
        int     data_packets
        int     encoded_packets
        int     blocksize
        CODE:
        void *code;
        struct fec_imp *imp;

        if (data_packets < 2)
          croak ("the number of data packets must be >= 2"); /* for copy_blocks :) */

        if (encoded_packets < data_packets)
          croak ("the number of encoded packets must be >= the number of data packets");

        if (GF_SIZE16 < encoded_packets)
          croak ("the number of encoded packets must be <= %d", GF_SIZE16);

        imp = GF_SIZE8 < encoded_packets ? &fec16_imp : &fec8_imp;

        code = imp->fec_new (data_packets, encoded_packets);
        if (!code)
          croak ("FATAL: unable to create fec state");

        Newz(0, RETVAL, 1, struct state);
        RETVAL->imp = imp;
        RETVAL->code = code;
        RETVAL->sz = blocksize;
        RETVAL->dp = data_packets;
        RETVAL->ep = encoded_packets;
        OUTPUT:
        RETVAL

void
set_encode_blocks (self, blocks)
        Algorithm::FEC self
        SV *    blocks
        CODE:

        free_files (self);

        if (SvOK (blocks))
          {
            chk_array (blocks, self->dp, "set_encode_blocks", "blocks");
            open_files (self, (AV *)SvRV (blocks), 0);
          }

SV *
encode (self, block_index)
        Algorithm::FEC self
        int     block_index
        CODE:

        if (block_index < 0 || self->ep <= block_index)
          croak ("encode: block_index %d out of range, must be 0 <= block_index < %d",
                 block_index, self->ep);

        if (!self->b_addr)
          croak ("no blocks specified by a preceding call to set_encode_blocks");

        force_addrs (self, self->dp);

        RETVAL = newSV (self->sz);
        if (!RETVAL)
          croak ("unable to allocate result block (out of memory)");

        SvPOK_only (RETVAL);
        SvCUR_set (RETVAL, self->sz);

        self->imp->fec_encode (self->code, self->b_addr,
                               SvPVX (RETVAL), block_index, self->sz);

        OUTPUT:
        RETVAL

void
set_decode_blocks (self, blocks, indices)
        Algorithm::FEC self
        SV *    blocks
        SV *    indices
        CODE:
{
        int i;

        chk_array (blocks,  self->dp, "set_decode_blocks", "blocks");
        chk_array (indices, self->dp, "set_decode_blocks", "indices");

        Newz (0, self->idx, self->dp, int);

        /* copy and check */
        for (i = 0; i < self->dp; i++)
          {
            self->idx[i] = SvIV (*av_fetch ((AV *)SvRV (indices), i, 1));

            if (self->idx[i] < 0 || self->idx[i] >= self->ep)
              {
                free_files ();
                croak ("index %d in array out of bounds (0 <= %d < %d != true)",
                       i, self->idx[i], self->ep);
              }
          }

        /*
         * do the same shuffling as fec_decode does here,
         * so we know the order.
         */
        for (i = 0; i < self->dp; i++)
          while (self->idx[i] < self->dp && self->idx[i] != i)
            {
              SV **a, **b, **e, **f;
              int d;
              void *p;
              SV *s;
              int j = self->idx[i];

              if (self->idx[j] == j)
                {
                  free_files ();
                  croak ("error while shuffling, duplicate indices?");
                }

              a = av_fetch ((AV *)SvRV (indices), i, 1);
              b = av_fetch ((AV *)SvRV (indices), j, 1);
              e = av_fetch ((AV *)SvRV (blocks ), i, 1);
              f = av_fetch ((AV *)SvRV (blocks ), j, 1);

              d = self->idx[i]; self->idx[i] = self->idx[j]; self->idx[j] = d;
              s = *a;           *a           = *b;           *b = s;
              s = *e;           *e           = *f;           *f = s;
            }

        open_files (self, (AV *)SvRV (blocks), 1);
}

void
decode (self)
        Algorithm::FEC self
        CODE:

        if (!self->idx)
          croak ("index array must be set by a prior call to set_decode_blocks";

        force_addrs (self, self->dp);
        self->imp->fec_decode (self->code, self->b_addr, self->idx, self->sz);
        free_files (self);

void
copy (self, srcblock, dstblock)
        Algorithm::FEC self
        SV *    srcblock
        SV *    dstblock
        CODE:
        realloc_files (self);
        open_file (self, 0, srcblock, 0);
        open_file (self, 1, dstblock, 1);
        force_addrs (self, 2);
        Copy (self->b_addr[0], self->b_addr[1], self->sz, char);
        free_files (self);

void
DESTROY(self)
        Algorithm::FEC self
        CODE:
        self->imp->fec_free (self->code);
        free_files (self);
        Safefree(self);

Revision:	1.5
Committed:	Sat Sep 13 21:02:28 2003 UTC (23 years ago) by root
Branch:	MAIN
Changes since 1.4:	+38 -31 lines
Log Message:	* empty log message *
#	User	Rev	Content
1	root	1.1	#include "EXTERN.h"
2			#include "perl.h"
3			#include "XSUB.h"
4
5			#include <string.h>
6			#include <unistd.h>
7			#include <sys/mman.h>
8
9			#include "fec.h"
10
11			struct fec_imp {
12			void (fec_free)(void p) ;
13			void (fec_new)(int k, int n) ;
14			void (fec_encode)(void code, void src[], void dst, int index, int sz) ;
15			int (fec_decode)(void code, void *pkt[], int index[], int sz) ;
16			};
17
18			static struct fec_imp fec8_imp = { fec8_free , fec8_new , fec8_encode , fec8_decode };
19			static struct fec_imp fec16_imp = { fec16_free, fec16_new, fec16_encode, fec16_decode };
20
21			typedef struct state {
22			struct fec_imp *imp;
23			void *code;
24			int sz;
25			int dp, ep;
26
27			void **b_addr;
28			void **b_mmap;
29			int *b_sz;
30			SV **b_sv;
31	root	1.5	int *idx; / the decoding indices */
32	root	1.3	} *Algorithm__FEC;
33	root	1.1
34			static void
35			chk_array (SV sv, int size, const char func, const char *var)
36			{
37			if (!SvROK (sv)
38			\|\| SvTYPE (SvRV (sv)) != SVt_PVAV
39			\|\| av_len ((AV *)SvRV (sv)) != size - 1)
40			croak ("%s: %s must be a reference to an array of size %d", size);
41			}
42
43			static void
44			free_files (struct state *self)
45			{
46			int i;
47
48			if (self->b_addr && self->b_sv)
49			for (i = 0; i < self->dp; i++)
50			if (self->b_sv[i])
51			SvREFCNT_dec (self->b_sv[i]);
52			else if (self->b_mmap[i])
53			munmap (self->b_mmap[i], self->b_sz[i]);
54
55			Safefree (self->b_addr); self->b_addr = 0;
56			Safefree (self->b_mmap); self->b_mmap = 0;
57			Safefree (self->b_sz ); self->b_sz = 0;
58			Safefree (self->b_sv ); self->b_sv = 0;
59	root	1.5	Safefree (self->idx ); self->idx = 0;
60	root	1.1	}
61
62			static void
63			realloc_files (struct state *self)
64			{
65			free_files (self);
66
67			Newz (0, self->b_addr, self->dp, void *);
68			Newz (0, self->b_mmap, self->dp, void *);
69			Newz (0, self->b_sz , self->dp, int);
70			Newz (0, self->b_sv , self->dp, SV *);
71			}
72
73			static void
74	root	1.2	force_addrs (struct state *self, int dp)
75	root	1.1	{
76			int i;
77
78	root	1.2	for (i = 0; i < dp; i++)
79	root	1.1	if (self->b_sv[i])
80			{
81			STRLEN size;
82			self->b_addr[i] = SvPV (self->b_sv[i], size);
83
84			if (size != self->sz)
85			croak ("block #%d (a string) has size %d, not %d", i, (int)size, self->sz);
86			} else if (!self->b_mmap[i]) {
87	root	1.2	croak ("block #%d neither string nor file, did set_blocks fail and you ignored it?", i);
88	root	1.1	}
89			}
90
91			static void
92			open_file (struct state self, int idx, SV sv, int rw)
93			{
94			IO *io = 0;
95			off_t offset;
96
97			if (SvROK (sv) && SvTYPE (SvRV (sv)) == SVt_PVAV)
98			{
99			io = sv_2io (av_fetch ((AV )SvRV (sv), 0, 1));
100			offset = SvIV (av_fetch ((AV )SvRV (sv), 1, 1));
101			sv = 0;
102			}
103			else if (!SvPOK (sv))
104			{
105			io = sv_2io (sv);
106			offset = 0;
107			sv = 0;
108			}
109
110			if (io)
111			{
112			int fd = PerlIO_fileno (IoIFP (io));
113			off_t ofs2 = offset & ~((off_t)getpagesize () - 1);
114			void *mm;
115
116			if (fd <= 0)
117			croak ("invalid file descriptor for block #%d", idx);
118
119			mm = mmap (0, self->sz + (offset - ofs2),
120			rw ? PROT_READ \| PROT_WRITE : PROT_READ,
121			MAP_SHARED, fd, ofs2);
122
123			if (mm == MAP_FAILED)
124			croak ("unable to mmap block #%d (wrong offset or size?): %s", idx, strerror (errno));
125
126			self->b_mmap[idx] = mm;
127			self->b_addr[idx] = (void )((char )mm + (offset - ofs2));
128			self->b_sz [idx] = self->sz + (offset - ofs2);
129			}
130			else if (sv)
131			self->b_sv[idx] = SvREFCNT_inc (sv);
132			else
133			croak ("unable to open block #%d, must be either string, filehandle, or [filehandle, offset]", idx);
134			}
135
136			static void
137			open_files (struct state self, AV av, int rw)
138			{
139			int i;
140
141			realloc_files (self);
142
143			for (i = 0; i < self->dp; i++)
144			open_file (self, i, *av_fetch (av, i, 1), rw);
145			}
146
147	root	1.3	MODULE = Algorithm::FEC PACKAGE = Algorithm::FEC
148	root	1.1
149			PROTOTYPES: ENABLE
150
151	root	1.3	Algorithm::FEC
152	root	1.1	new(class, data_packets, encoded_packets, blocksize)
153			SV * class
154			int data_packets
155			int encoded_packets
156			int blocksize
157			CODE:
158			void *code;
159			struct fec_imp *imp;
160
161			if (data_packets < 2)
162			croak ("the number of data packets must be >= 2"); /* for copy_blocks :) */
163
164			if (encoded_packets < data_packets)
165			croak ("the number of encoded packets must be >= the number of data packets");
166
167			if (GF_SIZE16 < encoded_packets)
168			croak ("the number of encoded packets must be <= %d", GF_SIZE16);
169
170			imp = GF_SIZE8 < encoded_packets ? &fec16_imp : &fec8_imp;
171
172			code = imp->fec_new (data_packets, encoded_packets);
173			if (!code)
174			croak ("FATAL: unable to create fec state");
175
176			Newz(0, RETVAL, 1, struct state);
177			RETVAL->imp = imp;
178			RETVAL->code = code;
179			RETVAL->sz = blocksize;
180			RETVAL->dp = data_packets;
181			RETVAL->ep = encoded_packets;
182			OUTPUT:
183			RETVAL
184
185			void
186	root	1.5	set_encode_blocks (self, blocks)
187	root	1.3	Algorithm::FEC self
188	root	1.1	SV * blocks
189			CODE:
190
191			free_files (self);
192
193			if (SvOK (blocks))
194			{
195	root	1.5	chk_array (blocks, self->dp, "set_encode_blocks", "blocks");
196	root	1.1	open_files (self, (AV *)SvRV (blocks), 0);
197			}
198
199			SV *
200			encode (self, block_index)
201	root	1.3	Algorithm::FEC self
202	root	1.1	int block_index
203			CODE:
204
205			if (block_index < 0 \|\| self->ep <= block_index)
206			croak ("encode: block_index %d out of range, must be 0 <= block_index < %d",
207			block_index, self->ep);
208
209			if (!self->b_addr)
210	root	1.5	croak ("no blocks specified by a preceding call to set_encode_blocks");
211	root	1.1
212	root	1.2	force_addrs (self, self->dp);
213	root	1.1
214			RETVAL = newSV (self->sz);
215			if (!RETVAL)
216			croak ("unable to allocate result block (out of memory)");
217	root	1.5
218	root	1.1	SvPOK_only (RETVAL);
219			SvCUR_set (RETVAL, self->sz);
220
221			self->imp->fec_encode (self->code, self->b_addr,
222			SvPVX (RETVAL), block_index, self->sz);
223
224			OUTPUT:
225			RETVAL
226
227			void
228	root	1.5	set_decode_blocks (self, blocks, indices)
229	root	1.3	Algorithm::FEC self
230	root	1.1	SV * blocks
231			SV * indices
232			CODE:
233			{
234			int i;
235
236	root	1.5	chk_array (blocks, self->dp, "set_decode_blocks", "blocks");
237			chk_array (indices, self->dp, "set_decode_blocks", "indices");
238	root	1.1
239	root	1.5	Newz (0, self->idx, self->dp, int);
240	root	1.1
241			/* copy and check */
242			for (i = 0; i < self->dp; i++)
243			{
244	root	1.5	self->idx[i] = SvIV (av_fetch ((AV )SvRV (indices), i, 1));
245	root	1.1
246	root	1.5	if (self->idx[i] < 0 \|\| self->idx[i] >= self->ep)
247	root	1.1	{
248	root	1.5	free_files ();
249	root	1.1	croak ("index %d in array out of bounds (0 <= %d < %d != true)",
250	root	1.5	i, self->idx[i], self->ep);
251	root	1.1	}
252			}
253
254			/*
255			* do the same shuffling as fec_decode does here,
256			* so we know the order.
257			*/
258			for (i = 0; i < self->dp; i++)
259	root	1.5	while (self->idx[i] < self->dp && self->idx[i] != i)
260	root	1.1	{
261	root	1.5	SV a, b, e, f;
262	root	1.1	int d;
263			void *p;
264			SV *s;
265	root	1.5	int j = self->idx[i];
266	root	1.1
267	root	1.5	if (self->idx[j] == j)
268	root	1.1	{
269	root	1.5	free_files ();
270			croak ("error while shuffling, duplicate indices?");
271	root	1.1	}
272
273			a = av_fetch ((AV *)SvRV (indices), i, 1);
274	root	1.5	b = av_fetch ((AV *)SvRV (indices), j, 1);
275			e = av_fetch ((AV *)SvRV (blocks ), i, 1);
276			f = av_fetch ((AV *)SvRV (blocks ), j, 1);
277
278			d = self->idx[i]; self->idx[i] = self->idx[j]; self->idx[j] = d;
279			s = a; a = b; b = s;
280			s = e; e = f; f = s;
281			}
282	root	1.1
283	root	1.5	open_files (self, (AV *)SvRV (blocks), 1);
284			}
285	root	1.1
286	root	1.5	void
287			decode (self)
288			Algorithm::FEC self
289			CODE:
290	root	1.1
291	root	1.5	if (!self->idx)
292			croak ("index array must be set by a prior call to set_decode_blocks";
293	root	1.1
294	root	1.5	force_addrs (self, self->dp);
295			self->imp->fec_decode (self->code, self->b_addr, self->idx, self->sz);
296	root	1.1	free_files (self);
297
298			void
299	root	1.2	copy (self, srcblock, dstblock)
300	root	1.3	Algorithm::FEC self
301	root	1.1	SV * srcblock
302			SV * dstblock
303			CODE:
304	root	1.2	realloc_files (self);
305			open_file (self, 0, srcblock, 0);
306			open_file (self, 1, dstblock, 1);
307			force_addrs (self, 2);
308			Copy (self->b_addr[0], self->b_addr[1], self->sz, char);
309			free_files (self);
310	root	1.1
311			void
312			DESTROY(self)
313	root	1.3	Algorithm::FEC self
314	root	1.1	CODE:
315			self->imp->fec_free (self->code);
316			free_files (self);
317			Safefree(self);
318