server/common/utils.C

/*
 * This file is part of Deliantra, the Roguelike Realtime MMORPG.
 * 
 * Copyright (©) 2005,2006,2007,2008,2009 Marc Alexander Lehmann / Robin Redeker / the Deliantra team
 * 
 * Deliantra is free software: you can redistribute it and/or modify it under
 * the terms of the Affero GNU General Public License as published by the
 * Free Software Foundation, either version 3 of the License, or (at your
 * option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the Affero GNU General Public License
 * and the GNU General Public License along with this program. If not, see
 * <http://www.gnu.org/licenses/>.
 * 
 * The authors can be reached via e-mail to <support@deliantra.net>
 */

/*
 * General convenience functions for deliantra.
 */

#include <cstdlib>
#include <sys/types.h>
#include <unistd.h>
#include <sys/time.h>
#include <time.h>
#include <signal.h>

#include <global.h>
#include <material.h>
#include <object.h>

#include <sys/time.h>
#include <sys/resource.h>

#include <glib.h>

refcnt_base::refcnt_t refcnt_dummy;
ssize_t slice_alloc;
rand_gen rndm, rmg_rndm;

#if !GCC_VERSION(3,4)
int least_significant_bit (uint32_t x)
{
  x &= -x; // this isolates the lowest bit

  int r = 0;

  if (x & 0xaaaaaaaa) r +=  1;
  if (x & 0xcccccccc) r +=  2;
  if (x & 0xf0f0f0f0) r +=  4;
  if (x & 0xff00ff00) r +=  8;
  if (x & 0xffff0000) r += 16;

  return r;
}
#endif

void
tausworthe_random_generator::seed (uint32_t seed)
{
  state [0] = seed      * 69069U; if (state [0] <   2U) state [0] +=   2U;
  state [1] = state [0] * 69069U; if (state [0] <   8U) state [0] +=   8U;
  state [2] = state [1] * 69069U; if (state [0] <  16U) state [0] +=  16U;
  state [3] = state [2] * 69069U; if (state [0] < 128U) state [0] += 128U;

  for (int i = 11; --i; )
    next ();
}

uint32_t
tausworthe_random_generator::next ()
{
  state [0] = ((state [0] & 0xFFFFFFFEU) << 18U) ^ (((state [0] <<  6U) ^ state [0]) >> 13U);
  state [1] = ((state [1] & 0xFFFFFFF8U) <<  2U) ^ (((state [1] <<  2U) ^ state [1]) >> 27U);
  state [2] = ((state [2] & 0xFFFFFFF0U) <<  7U) ^ (((state [2] << 13U) ^ state [2]) >> 21U);
  state [3] = ((state [3] & 0xFFFFFF80U) << 13U) ^ (((state [3] <<  3U) ^ state [3]) >> 12U);

  return state [0] ^ state [1] ^ state [2] ^ state [3];
}

template<class generator>
uint32_t
random_number_generator<generator>::get_range (uint32_t num)
{
  return (this->next () * (uint64_t)num) >> 32U;
}

// return a number within (min .. max)
template<class generator>
int 
random_number_generator<generator>::get_range (int r_min, int r_max)
{
  return r_min + get_range (max (r_max - r_min + 1, 0));
}

template struct random_number_generator<tausworthe_random_generator>;
template struct random_number_generator<xorshift_random_generator>;

/******************************************************************************/

/* Checks a player-provided string which will become the msg property of
 * an object for dangerous input.
 */
bool 
msg_is_safe (const char *msg)
{
  bool safe = true;

  /* Trying to cheat by getting data into the object */
  if (!strncmp (msg, "endmsg", sizeof ("endmsg") - 1)
      || strstr (msg, "\nendmsg"))
    safe = false;

  /* Trying to make the object talk, and potentially access arbitrary code */
  if (object::msg_has_dialogue (msg))
    safe = false;

  return safe;
}

/////////////////////////////////////////////////////////////////////////////

void
fork_abort (const char *msg)
{
  if (!fork ())
    {
      signal (SIGINT , SIG_IGN);
      signal (SIGTERM, SIG_IGN);
      signal (SIGABRT, SIG_IGN);

      signal (SIGSEGV, SIG_DFL);
      signal (SIGBUS , SIG_DFL);
      signal (SIGILL , SIG_DFL);
      signal (SIGTRAP, SIG_DFL);

      // try to put corefiles into a subdirectory, if existing, to allow
      // an administrator to reduce the I/O load.
      chdir ("cores");

      // try to detach us from as many external dependencies as possible
      // as coredumping can take time by closing all fd's.
      {
        struct rlimit lim;

        if (getrlimit (RLIMIT_NOFILE, &lim))
          lim.rlim_cur = 1024;

        for (int i = 0; i < lim.rlim_cur; ++i)
          close (i);
      }

      {
        sigset_t empty;
        sigemptyset (&empty);
        sigprocmask (SIG_SETMASK, &empty, 0);
      }

      // try to coredump with SIGTRAP
      kill (getpid (), SIGTRAP);
      abort ();
    }

  LOG (llevError, "fork abort: %s\n", msg);
}

void *salloc_ (int n) throw (std::bad_alloc)
{
  void *ptr = g_slice_alloc (n);

  if (!ptr)
    throw std::bad_alloc ();

  slice_alloc += n;
  return ptr;
}

void *salloc_ (int n, void *src) throw (std::bad_alloc)
{
  void *ptr = salloc_ (n);

  if (src)
    memcpy (ptr, src, n);
  else
    memset (ptr, 0, n);

  return ptr;
}

/******************************************************************************/

#if DEBUG_SALLOC

#define MAGIC 0xa1b2c35543deadLL

void *g_slice_alloc (unsigned long size)
{
  unsigned long *p = (unsigned long *) (g_slice_alloc)(size + sizeof (unsigned long));
  *p++ = size ^ MAGIC;
  //fprintf (stderr, "g_slice_alloc %ld %p\n", size, p);//D
  return (void *)p;
}

void *g_slice_alloc0 (unsigned long size)
{
  return memset (g_slice_alloc (size), 0, size);
}

void g_slice_free1 (unsigned long size, void *ptr)
{
  //fprintf (stderr, "g_slice_free %ld %p\n", size, ptr);//D
  if (expect_true (ptr))
    {
      unsigned long *p = (unsigned long *)ptr;
      unsigned long s = *--p ^ MAGIC;

      if (size != (unsigned long)(*p ^ MAGIC))
        {
          LOG (logBacktrace | llevError, "slice free size (%lx) doesn't match alloc size (%lx)\n", size, s);
          abort ();
        }

      *p = MAGIC;

      (g_slice_free1)(s + sizeof (unsigned long), p);
    }
}

#endif

/******************************************************************************/

int
assign (char *dst, const char *src, int maxsize)
{
  if (!src)
    src = "";

  int len = strlen (src);

  if (len >= maxsize)
    {
      if (maxsize <= 4)
        {
          memset (dst, '.', maxsize - 2);
          dst [maxsize - 1] = 0;
        }
      else
        {
          memcpy (dst, src, maxsize - 4);
          memcpy (dst + maxsize - 4, "...", 4);
        }

      len = maxsize;
    }
  else
    memcpy (dst, src, ++len);

  return len;
}

char *
vformat (const char *format, va_list ap)
{
  static dynbuf_text buf; buf.clear ();
  buf.vprintf (format, ap);
  return buf;
}

char *
format (const char *format, ...)
{
  va_list ap;
  va_start (ap, format);
  char *buf = vformat (format, ap);
  va_end (ap);

  return buf;
}

tstamp now ()
{
  struct timeval tv;

  gettimeofday (&tv, 0);
  return tstamp (tv.tv_sec) + tstamp (tv.tv_usec) * tstamp (1e-6);
}

int
similar_direction (int a, int b)
{
  if (!a || !b)
    return 0;

  int diff = (b - a) & 7;
  return diff <= 1 || diff >= 7;
}

/* crc32 0xdebb20e3 table and supplementary functions.  */
extern const uint32_t crc_32_tab[256] =
{
    0x00000000UL, 0x77073096UL, 0xee0e612cUL, 0x990951baUL, 0x076dc419UL,
    0x706af48fUL, 0xe963a535UL, 0x9e6495a3UL, 0x0edb8832UL, 0x79dcb8a4UL,
    0xe0d5e91eUL, 0x97d2d988UL, 0x09b64c2bUL, 0x7eb17cbdUL, 0xe7b82d07UL,
    0x90bf1d91UL, 0x1db71064UL, 0x6ab020f2UL, 0xf3b97148UL, 0x84be41deUL,
    0x1adad47dUL, 0x6ddde4ebUL, 0xf4d4b551UL, 0x83d385c7UL, 0x136c9856UL,
    0x646ba8c0UL, 0xfd62f97aUL, 0x8a65c9ecUL, 0x14015c4fUL, 0x63066cd9UL,
    0xfa0f3d63UL, 0x8d080df5UL, 0x3b6e20c8UL, 0x4c69105eUL, 0xd56041e4UL,
    0xa2677172UL, 0x3c03e4d1UL, 0x4b04d447UL, 0xd20d85fdUL, 0xa50ab56bUL,
    0x35b5a8faUL, 0x42b2986cUL, 0xdbbbc9d6UL, 0xacbcf940UL, 0x32d86ce3UL,
    0x45df5c75UL, 0xdcd60dcfUL, 0xabd13d59UL, 0x26d930acUL, 0x51de003aUL,
    0xc8d75180UL, 0xbfd06116UL, 0x21b4f4b5UL, 0x56b3c423UL, 0xcfba9599UL,
    0xb8bda50fUL, 0x2802b89eUL, 0x5f058808UL, 0xc60cd9b2UL, 0xb10be924UL,
    0x2f6f7c87UL, 0x58684c11UL, 0xc1611dabUL, 0xb6662d3dUL, 0x76dc4190UL,
    0x01db7106UL, 0x98d220bcUL, 0xefd5102aUL, 0x71b18589UL, 0x06b6b51fUL,
    0x9fbfe4a5UL, 0xe8b8d433UL, 0x7807c9a2UL, 0x0f00f934UL, 0x9609a88eUL,
    0xe10e9818UL, 0x7f6a0dbbUL, 0x086d3d2dUL, 0x91646c97UL, 0xe6635c01UL,
    0x6b6b51f4UL, 0x1c6c6162UL, 0x856530d8UL, 0xf262004eUL, 0x6c0695edUL,
    0x1b01a57bUL, 0x8208f4c1UL, 0xf50fc457UL, 0x65b0d9c6UL, 0x12b7e950UL,
    0x8bbeb8eaUL, 0xfcb9887cUL, 0x62dd1ddfUL, 0x15da2d49UL, 0x8cd37cf3UL,
    0xfbd44c65UL, 0x4db26158UL, 0x3ab551ceUL, 0xa3bc0074UL, 0xd4bb30e2UL,
    0x4adfa541UL, 0x3dd895d7UL, 0xa4d1c46dUL, 0xd3d6f4fbUL, 0x4369e96aUL,
    0x346ed9fcUL, 0xad678846UL, 0xda60b8d0UL, 0x44042d73UL, 0x33031de5UL,
    0xaa0a4c5fUL, 0xdd0d7cc9UL, 0x5005713cUL, 0x270241aaUL, 0xbe0b1010UL,
    0xc90c2086UL, 0x5768b525UL, 0x206f85b3UL, 0xb966d409UL, 0xce61e49fUL,
    0x5edef90eUL, 0x29d9c998UL, 0xb0d09822UL, 0xc7d7a8b4UL, 0x59b33d17UL,
    0x2eb40d81UL, 0xb7bd5c3bUL, 0xc0ba6cadUL, 0xedb88320UL, 0x9abfb3b6UL,
    0x03b6e20cUL, 0x74b1d29aUL, 0xead54739UL, 0x9dd277afUL, 0x04db2615UL,
    0x73dc1683UL, 0xe3630b12UL, 0x94643b84UL, 0x0d6d6a3eUL, 0x7a6a5aa8UL,
    0xe40ecf0bUL, 0x9309ff9dUL, 0x0a00ae27UL, 0x7d079eb1UL, 0xf00f9344UL,
    0x8708a3d2UL, 0x1e01f268UL, 0x6906c2feUL, 0xf762575dUL, 0x806567cbUL,
    0x196c3671UL, 0x6e6b06e7UL, 0xfed41b76UL, 0x89d32be0UL, 0x10da7a5aUL,
    0x67dd4accUL, 0xf9b9df6fUL, 0x8ebeeff9UL, 0x17b7be43UL, 0x60b08ed5UL,
    0xd6d6a3e8UL, 0xa1d1937eUL, 0x38d8c2c4UL, 0x4fdff252UL, 0xd1bb67f1UL,
    0xa6bc5767UL, 0x3fb506ddUL, 0x48b2364bUL, 0xd80d2bdaUL, 0xaf0a1b4cUL,
    0x36034af6UL, 0x41047a60UL, 0xdf60efc3UL, 0xa867df55UL, 0x316e8eefUL,
    0x4669be79UL, 0xcb61b38cUL, 0xbc66831aUL, 0x256fd2a0UL, 0x5268e236UL,
    0xcc0c7795UL, 0xbb0b4703UL, 0x220216b9UL, 0x5505262fUL, 0xc5ba3bbeUL,
    0xb2bd0b28UL, 0x2bb45a92UL, 0x5cb36a04UL, 0xc2d7ffa7UL, 0xb5d0cf31UL,
    0x2cd99e8bUL, 0x5bdeae1dUL, 0x9b64c2b0UL, 0xec63f226UL, 0x756aa39cUL,
    0x026d930aUL, 0x9c0906a9UL, 0xeb0e363fUL, 0x72076785UL, 0x05005713UL,
    0x95bf4a82UL, 0xe2b87a14UL, 0x7bb12baeUL, 0x0cb61b38UL, 0x92d28e9bUL,
    0xe5d5be0dUL, 0x7cdcefb7UL, 0x0bdbdf21UL, 0x86d3d2d4UL, 0xf1d4e242UL,
    0x68ddb3f8UL, 0x1fda836eUL, 0x81be16cdUL, 0xf6b9265bUL, 0x6fb077e1UL,
    0x18b74777UL, 0x88085ae6UL, 0xff0f6a70UL, 0x66063bcaUL, 0x11010b5cUL,
    0x8f659effUL, 0xf862ae69UL, 0x616bffd3UL, 0x166ccf45UL, 0xa00ae278UL,
    0xd70dd2eeUL, 0x4e048354UL, 0x3903b3c2UL, 0xa7672661UL, 0xd06016f7UL,
    0x4969474dUL, 0x3e6e77dbUL, 0xaed16a4aUL, 0xd9d65adcUL, 0x40df0b66UL,
    0x37d83bf0UL, 0xa9bcae53UL, 0xdebb9ec5UL, 0x47b2cf7fUL, 0x30b5ffe9UL,
    0xbdbdf21cUL, 0xcabac28aUL, 0x53b39330UL, 0x24b4a3a6UL, 0xbad03605UL,
    0xcdd70693UL, 0x54de5729UL, 0x23d967bfUL, 0xb3667a2eUL, 0xc4614ab8UL,
    0x5d681b02UL, 0x2a6f2b94UL, 0xb40bbe37UL, 0xc30c8ea1UL, 0x5a05df1bUL,
    0x2d02ef8dL
};

void thread::start (void *(*start_routine)(void *), void *arg)
{
  pthread_attr_t attr;

  pthread_attr_init (&attr);
  pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED);
  pthread_attr_setstacksize (&attr, PTHREAD_STACK_MIN < sizeof (long) * 4096
                                    ? sizeof (long) * 4096 : PTHREAD_STACK_MIN);
#ifdef PTHREAD_SCOPE_PROCESS
  pthread_attr_setscope (&attr, PTHREAD_SCOPE_PROCESS);
#endif

  sigset_t fullsigset, oldsigset;
  sigfillset (&fullsigset);

  pthread_sigmask (SIG_SETMASK, &fullsigset, &oldsigset);

  if (pthread_create (&id, &attr, start_routine, arg))
    cleanup ("unable to create a new thread");

  pthread_sigmask (SIG_SETMASK, &oldsigset, 0);
}

Revision:	1.94
Committed:	Wed Nov 11 03:52:44 2009 UTC (14 years, 6 months ago) by root
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rel-2_92, rel-2_93
Changes since 1.93:	+17 -0 lines
Log Message:	fix icecube thawing bug
#	Content
1	/*
2	* This file is part of Deliantra, the Roguelike Realtime MMORPG.
3	*
4	* Copyright (©) 2005,2006,2007,2008,2009 Marc Alexander Lehmann / Robin Redeker / the Deliantra team
5	*
6	* Deliantra is free software: you can redistribute it and/or modify it under
7	* the terms of the Affero GNU General Public License as published by the
8	* Free Software Foundation, either version 3 of the License, or (at your
9	* option) any later version.
10	*
11	* This program is distributed in the hope that it will be useful,
12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14	* GNU General Public License for more details.
15	*
16	* You should have received a copy of the Affero GNU General Public License
17	* and the GNU General Public License along with this program. If not, see
18	* <http://www.gnu.org/licenses/>.
19	*
20	* The authors can be reached via e-mail to <support@deliantra.net>
21	*/
22
23	/*
24	* General convenience functions for deliantra.
25	*/
26
27	#include <cstdlib>
28	#include <sys/types.h>
29	#include <unistd.h>
30	#include <sys/time.h>
31	#include <time.h>
32	#include <signal.h>
33
34	#include <global.h>
35	#include <material.h>
36	#include <object.h>
37
38	#include <sys/time.h>
39	#include <sys/resource.h>
40
41	#include <glib.h>
42
43	refcnt_base::refcnt_t refcnt_dummy;
44	ssize_t slice_alloc;
45	rand_gen rndm, rmg_rndm;
46
47	#if !GCC_VERSION(3,4)
48	int least_significant_bit (uint32_t x)
49	{
50	x &= -x; // this isolates the lowest bit
51
52	int r = 0;
53
54	if (x & 0xaaaaaaaa) r += 1;
55	if (x & 0xcccccccc) r += 2;
56	if (x & 0xf0f0f0f0) r += 4;
57	if (x & 0xff00ff00) r += 8;
58	if (x & 0xffff0000) r += 16;
59
60	return r;
61	}
62	#endif
63
64	void
65	tausworthe_random_generator::seed (uint32_t seed)
66	{
67	state [0] = seed * 69069U; if (state [0] < 2U) state [0] += 2U;
68	state [1] = state [0] * 69069U; if (state [0] < 8U) state [0] += 8U;
69	state [2] = state [1] * 69069U; if (state [0] < 16U) state [0] += 16U;
70	state [3] = state [2] * 69069U; if (state [0] < 128U) state [0] += 128U;
71
72	for (int i = 11; --i; )
73	next ();
74	}
75
76	uint32_t
77	tausworthe_random_generator::next ()
78	{
79	state [0] = ((state [0] & 0xFFFFFFFEU) << 18U) ^ (((state [0] << 6U) ^ state [0]) >> 13U);
80	state [1] = ((state [1] & 0xFFFFFFF8U) << 2U) ^ (((state [1] << 2U) ^ state [1]) >> 27U);
81	state [2] = ((state [2] & 0xFFFFFFF0U) << 7U) ^ (((state [2] << 13U) ^ state [2]) >> 21U);
82	state [3] = ((state [3] & 0xFFFFFF80U) << 13U) ^ (((state [3] << 3U) ^ state [3]) >> 12U);
83
84	return state [0] ^ state [1] ^ state [2] ^ state [3];
85	}
86
87	template<class generator>
88	uint32_t
89	random_number_generator<generator>::get_range (uint32_t num)
90	{
91	return (this->next () * (uint64_t)num) >> 32U;
92	}
93
94	// return a number within (min .. max)
95	template<class generator>
96	int
97	random_number_generator<generator>::get_range (int r_min, int r_max)
98	{
99	return r_min + get_range (max (r_max - r_min + 1, 0));
100	}
101
102	template struct random_number_generator<tausworthe_random_generator>;
103	template struct random_number_generator<xorshift_random_generator>;
104
105	/******************************************************************************/
106
107	/* Checks a player-provided string which will become the msg property of
108	* an object for dangerous input.
109	*/
110	bool
111	msg_is_safe (const char *msg)
112	{
113	bool safe = true;
114
115	/* Trying to cheat by getting data into the object */
116	if (!strncmp (msg, "endmsg", sizeof ("endmsg") - 1)
117	\|\| strstr (msg, "\nendmsg"))
118	safe = false;
119
120	/* Trying to make the object talk, and potentially access arbitrary code */
121	if (object::msg_has_dialogue (msg))
122	safe = false;
123
124	return safe;
125	}
126
127	/////////////////////////////////////////////////////////////////////////////
128
129	void
130	fork_abort (const char *msg)
131	{
132	if (!fork ())
133	{
134	signal (SIGINT , SIG_IGN);
135	signal (SIGTERM, SIG_IGN);
136	signal (SIGABRT, SIG_IGN);
137
138	signal (SIGSEGV, SIG_DFL);
139	signal (SIGBUS , SIG_DFL);
140	signal (SIGILL , SIG_DFL);
141	signal (SIGTRAP, SIG_DFL);
142
143	// try to put corefiles into a subdirectory, if existing, to allow
144	// an administrator to reduce the I/O load.
145	chdir ("cores");
146
147	// try to detach us from as many external dependencies as possible
148	// as coredumping can take time by closing all fd's.
149	{
150	struct rlimit lim;
151
152	if (getrlimit (RLIMIT_NOFILE, &lim))
153	lim.rlim_cur = 1024;
154
155	for (int i = 0; i < lim.rlim_cur; ++i)
156	close (i);
157	}
158
159	{
160	sigset_t empty;
161	sigemptyset (&empty);
162	sigprocmask (SIG_SETMASK, &empty, 0);
163	}
164
165	// try to coredump with SIGTRAP
166	kill (getpid (), SIGTRAP);
167	abort ();
168	}
169
170	LOG (llevError, "fork abort: %s\n", msg);
171	}
172
173	void *salloc_ (int n) throw (std::bad_alloc)
174	{
175	void *ptr = g_slice_alloc (n);
176
177	if (!ptr)
178	throw std::bad_alloc ();
179
180	slice_alloc += n;
181	return ptr;
182	}
183
184	void salloc_ (int n, void src) throw (std::bad_alloc)
185	{
186	void *ptr = salloc_ (n);
187
188	if (src)
189	memcpy (ptr, src, n);
190	else
191	memset (ptr, 0, n);
192
193	return ptr;
194	}
195
196	/******************************************************************************/
197
198	#if DEBUG_SALLOC
199
200	#define MAGIC 0xa1b2c35543deadLL
201
202	void *g_slice_alloc (unsigned long size)
203	{
204	unsigned long p = (unsigned long ) (g_slice_alloc)(size + sizeof (unsigned long));
205	*p++ = size ^ MAGIC;
206	//fprintf (stderr, "g_slice_alloc %ld %p\n", size, p);//D
207	return (void *)p;
208	}
209
210	void *g_slice_alloc0 (unsigned long size)
211	{
212	return memset (g_slice_alloc (size), 0, size);
213	}
214
215	void g_slice_free1 (unsigned long size, void *ptr)
216	{
217	//fprintf (stderr, "g_slice_free %ld %p\n", size, ptr);//D
218	if (expect_true (ptr))
219	{
220	unsigned long p = (unsigned long )ptr;
221	unsigned long s = *--p ^ MAGIC;
222
223	if (size != (unsigned long)(*p ^ MAGIC))
224	{
225	LOG (logBacktrace \| llevError, "slice free size (%lx) doesn't match alloc size (%lx)\n", size, s);
226	abort ();
227	}
228
229	*p = MAGIC;
230
231	(g_slice_free1)(s + sizeof (unsigned long), p);
232	}
233	}
234
235	#endif
236
237	/******************************************************************************/
238
239	int
240	assign (char dst, const char src, int maxsize)
241	{
242	if (!src)
243	src = "";
244
245	int len = strlen (src);
246
247	if (len >= maxsize)
248	{
249	if (maxsize <= 4)
250	{
251	memset (dst, '.', maxsize - 2);
252	dst [maxsize - 1] = 0;
253	}
254	else
255	{
256	memcpy (dst, src, maxsize - 4);
257	memcpy (dst + maxsize - 4, "...", 4);
258	}
259
260	len = maxsize;
261	}
262	else
263	memcpy (dst, src, ++len);
264
265	return len;
266	}
267
268	char *
269	vformat (const char *format, va_list ap)
270	{
271	static dynbuf_text buf; buf.clear ();
272	buf.vprintf (format, ap);
273	return buf;
274	}
275
276	char *
277	format (const char *format, ...)
278	{
279	va_list ap;
280	va_start (ap, format);
281	char *buf = vformat (format, ap);
282	va_end (ap);
283
284	return buf;
285	}
286
287	tstamp now ()
288	{
289	struct timeval tv;
290
291	gettimeofday (&tv, 0);
292	return tstamp (tv.tv_sec) + tstamp (tv.tv_usec) * tstamp (1e-6);
293	}
294
295	int
296	similar_direction (int a, int b)
297	{
298	if (!a \|\| !b)
299	return 0;
300
301	int diff = (b - a) & 7;
302	return diff <= 1 \|\| diff >= 7;
303	}
304
305	/* crc32 0xdebb20e3 table and supplementary functions. */
306	extern const uint32_t crc_32_tab[256] =
307	{
308	0x00000000UL, 0x77073096UL, 0xee0e612cUL, 0x990951baUL, 0x076dc419UL,
309	0x706af48fUL, 0xe963a535UL, 0x9e6495a3UL, 0x0edb8832UL, 0x79dcb8a4UL,
310	0xe0d5e91eUL, 0x97d2d988UL, 0x09b64c2bUL, 0x7eb17cbdUL, 0xe7b82d07UL,
311	0x90bf1d91UL, 0x1db71064UL, 0x6ab020f2UL, 0xf3b97148UL, 0x84be41deUL,
312	0x1adad47dUL, 0x6ddde4ebUL, 0xf4d4b551UL, 0x83d385c7UL, 0x136c9856UL,
313	0x646ba8c0UL, 0xfd62f97aUL, 0x8a65c9ecUL, 0x14015c4fUL, 0x63066cd9UL,
314	0xfa0f3d63UL, 0x8d080df5UL, 0x3b6e20c8UL, 0x4c69105eUL, 0xd56041e4UL,
315	0xa2677172UL, 0x3c03e4d1UL, 0x4b04d447UL, 0xd20d85fdUL, 0xa50ab56bUL,
316	0x35b5a8faUL, 0x42b2986cUL, 0xdbbbc9d6UL, 0xacbcf940UL, 0x32d86ce3UL,
317	0x45df5c75UL, 0xdcd60dcfUL, 0xabd13d59UL, 0x26d930acUL, 0x51de003aUL,
318	0xc8d75180UL, 0xbfd06116UL, 0x21b4f4b5UL, 0x56b3c423UL, 0xcfba9599UL,
319	0xb8bda50fUL, 0x2802b89eUL, 0x5f058808UL, 0xc60cd9b2UL, 0xb10be924UL,
320	0x2f6f7c87UL, 0x58684c11UL, 0xc1611dabUL, 0xb6662d3dUL, 0x76dc4190UL,
321	0x01db7106UL, 0x98d220bcUL, 0xefd5102aUL, 0x71b18589UL, 0x06b6b51fUL,
322	0x9fbfe4a5UL, 0xe8b8d433UL, 0x7807c9a2UL, 0x0f00f934UL, 0x9609a88eUL,
323	0xe10e9818UL, 0x7f6a0dbbUL, 0x086d3d2dUL, 0x91646c97UL, 0xe6635c01UL,
324	0x6b6b51f4UL, 0x1c6c6162UL, 0x856530d8UL, 0xf262004eUL, 0x6c0695edUL,
325	0x1b01a57bUL, 0x8208f4c1UL, 0xf50fc457UL, 0x65b0d9c6UL, 0x12b7e950UL,
326	0x8bbeb8eaUL, 0xfcb9887cUL, 0x62dd1ddfUL, 0x15da2d49UL, 0x8cd37cf3UL,
327	0xfbd44c65UL, 0x4db26158UL, 0x3ab551ceUL, 0xa3bc0074UL, 0xd4bb30e2UL,
328	0x4adfa541UL, 0x3dd895d7UL, 0xa4d1c46dUL, 0xd3d6f4fbUL, 0x4369e96aUL,
329	0x346ed9fcUL, 0xad678846UL, 0xda60b8d0UL, 0x44042d73UL, 0x33031de5UL,
330	0xaa0a4c5fUL, 0xdd0d7cc9UL, 0x5005713cUL, 0x270241aaUL, 0xbe0b1010UL,
331	0xc90c2086UL, 0x5768b525UL, 0x206f85b3UL, 0xb966d409UL, 0xce61e49fUL,
332	0x5edef90eUL, 0x29d9c998UL, 0xb0d09822UL, 0xc7d7a8b4UL, 0x59b33d17UL,
333	0x2eb40d81UL, 0xb7bd5c3bUL, 0xc0ba6cadUL, 0xedb88320UL, 0x9abfb3b6UL,
334	0x03b6e20cUL, 0x74b1d29aUL, 0xead54739UL, 0x9dd277afUL, 0x04db2615UL,
335	0x73dc1683UL, 0xe3630b12UL, 0x94643b84UL, 0x0d6d6a3eUL, 0x7a6a5aa8UL,
336	0xe40ecf0bUL, 0x9309ff9dUL, 0x0a00ae27UL, 0x7d079eb1UL, 0xf00f9344UL,
337	0x8708a3d2UL, 0x1e01f268UL, 0x6906c2feUL, 0xf762575dUL, 0x806567cbUL,
338	0x196c3671UL, 0x6e6b06e7UL, 0xfed41b76UL, 0x89d32be0UL, 0x10da7a5aUL,
339	0x67dd4accUL, 0xf9b9df6fUL, 0x8ebeeff9UL, 0x17b7be43UL, 0x60b08ed5UL,
340	0xd6d6a3e8UL, 0xa1d1937eUL, 0x38d8c2c4UL, 0x4fdff252UL, 0xd1bb67f1UL,
341	0xa6bc5767UL, 0x3fb506ddUL, 0x48b2364bUL, 0xd80d2bdaUL, 0xaf0a1b4cUL,
342	0x36034af6UL, 0x41047a60UL, 0xdf60efc3UL, 0xa867df55UL, 0x316e8eefUL,
343	0x4669be79UL, 0xcb61b38cUL, 0xbc66831aUL, 0x256fd2a0UL, 0x5268e236UL,
344	0xcc0c7795UL, 0xbb0b4703UL, 0x220216b9UL, 0x5505262fUL, 0xc5ba3bbeUL,
345	0xb2bd0b28UL, 0x2bb45a92UL, 0x5cb36a04UL, 0xc2d7ffa7UL, 0xb5d0cf31UL,
346	0x2cd99e8bUL, 0x5bdeae1dUL, 0x9b64c2b0UL, 0xec63f226UL, 0x756aa39cUL,
347	0x026d930aUL, 0x9c0906a9UL, 0xeb0e363fUL, 0x72076785UL, 0x05005713UL,
348	0x95bf4a82UL, 0xe2b87a14UL, 0x7bb12baeUL, 0x0cb61b38UL, 0x92d28e9bUL,
349	0xe5d5be0dUL, 0x7cdcefb7UL, 0x0bdbdf21UL, 0x86d3d2d4UL, 0xf1d4e242UL,
350	0x68ddb3f8UL, 0x1fda836eUL, 0x81be16cdUL, 0xf6b9265bUL, 0x6fb077e1UL,
351	0x18b74777UL, 0x88085ae6UL, 0xff0f6a70UL, 0x66063bcaUL, 0x11010b5cUL,
352	0x8f659effUL, 0xf862ae69UL, 0x616bffd3UL, 0x166ccf45UL, 0xa00ae278UL,
353	0xd70dd2eeUL, 0x4e048354UL, 0x3903b3c2UL, 0xa7672661UL, 0xd06016f7UL,
354	0x4969474dUL, 0x3e6e77dbUL, 0xaed16a4aUL, 0xd9d65adcUL, 0x40df0b66UL,
355	0x37d83bf0UL, 0xa9bcae53UL, 0xdebb9ec5UL, 0x47b2cf7fUL, 0x30b5ffe9UL,
356	0xbdbdf21cUL, 0xcabac28aUL, 0x53b39330UL, 0x24b4a3a6UL, 0xbad03605UL,
357	0xcdd70693UL, 0x54de5729UL, 0x23d967bfUL, 0xb3667a2eUL, 0xc4614ab8UL,
358	0x5d681b02UL, 0x2a6f2b94UL, 0xb40bbe37UL, 0xc30c8ea1UL, 0x5a05df1bUL,
359	0x2d02ef8dL
360	};
361
362	void thread::start (void (start_routine)(void ), void arg)
363	{
364	pthread_attr_t attr;
365
366	pthread_attr_init (&attr);
367	pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED);
368	pthread_attr_setstacksize (&attr, PTHREAD_STACK_MIN < sizeof (long) * 4096
369	? sizeof (long) * 4096 : PTHREAD_STACK_MIN);
370	#ifdef PTHREAD_SCOPE_PROCESS
371	pthread_attr_setscope (&attr, PTHREAD_SCOPE_PROCESS);
372	#endif
373
374	sigset_t fullsigset, oldsigset;
375	sigfillset (&fullsigset);
376
377	pthread_sigmask (SIG_SETMASK, &fullsigset, &oldsigset);
378
379	if (pthread_create (&id, &attr, start_routine, arg))
380	cleanup ("unable to create a new thread");
381
382	pthread_sigmask (SIG_SETMASK, &oldsigset, 0);
383	}
384