summary refs log tree commit diff
path: root/stdlib/random_r.c
diff options
context:
space:
mode:
authorRoland McGrath <roland@gnu.org>1995-09-17 20:23:15 +0000
committerRoland McGrath <roland@gnu.org>1995-09-17 20:23:15 +0000
commit60478656fad8d8a487e9bc52d025f69767c3262b (patch)
tree0ae0836023f1c2f80064e7611f91d19c482208d9 /stdlib/random_r.c
parent9fd18b6c1b397e1af82a0b544f10f946c73864b6 (diff)
downloadglibc-60478656fad8d8a487e9bc52d025f69767c3262b.tar.gz
glibc-60478656fad8d8a487e9bc52d025f69767c3262b.tar.xz
glibc-60478656fad8d8a487e9bc52d025f69767c3262b.zip
Sat Sep 16 17:47:19 1995 Ulrich Drepper <drepper@ipd.info.uni-karlsruhe.de>
	* elf/elf.h (AT_GID): Fix typo: Read -> Real.

	* misc/efgvt_r.c: New file.  Reentrant version of [efg]cvt functions.
	* misc/efgcvt.c: Rewrite to use reentrant functions.
	* misc/hsearch_r.c: New file.  Reentrant version of functions from
	hsearch family.
	* misc/hsearch.c, misc/tsearch.c: New files.
	* misc/Makefile (routines): Add efgcvt_r, hsearch_r, hsearch, tsearch.

	* posix/unistd.h (ttyname_r): Add prototype for new function.

	* stdlib/drand48_r.c, stdlib/erand48_r.c, stdlib/jrand48_r.c,
	stdlib/lrand48_r.c, stdlib/mrand48_r.c, stdlib/nrand48_r.c,
	stdlib/seed48_r.c, stdlib/srand48_r.c, stdlib/lcong48_r.c,
	stdlib/drand48-iter.c: New files implementing reentrant versions
	of functions from drand48 family.
	* stdlib/seed48.c, stdlib/drand48.c, stdlib/erand48.c,
	stdlib/jrand48.c, stdlib/lrand48.c, stdlib/mrand48.c,
	stdlib/nrand48.c, stdlib/srand48.c, stdlib/lcong48.c:
	Rewrite to use reentrant versions.
	* stdlib/a64l.c, stdlib/l64a.c: New files.  Implement a64l()
	and l64a() functions from SysV library.
	* stdlib/Makefile (routines): Add drand48_r, erand48_r, lrand48_r,
	nrand48_r, mrand48_r, jrand48_r, srand48_r, seed48_r, lcong48_r,
	drand48-iter, a64l, l64a.
	* stdlib/stdlib.h: Declare them.

	* stdlib/random_r.c: New file.  Reentrant version of functions
	from random family.
	* stdlib/stdlib.h: Declare them.
	* stdlib/random.c: Rewrite to use reentrant functions.

	* string/strerror_r.c: New file.  Reentrant version.
	* string/strerror.c: Change for new _strerror_internal form.
	* string/Makefile (routines): Add strerror_r.

	* sysdeps/generic/dl-sysdep.c (_dl_sysdep_start): Set default
	value of user_entry to `_start'.
	Close AT_ENTRY case with `break'.

	* sysdeps/generic/strstr.c: New and much faster implementation
	by Stephen R. van den Berg.

	* sysdeps/generic/_strerror.c: _strerror_internal now takes
	three argument and has and explicit buffer length.
	* sysdeps/mach/_strerror.c: Change for new interface with three
	arguments.
	* stdio/perror.c, stdio/vfprintf.c: Callers changed.
	
	* sysdeps/mach/hurd/ttyname_r.c: New file.  Reentrant version.
	* sysdeps/posix/ttyname_r.c: New file.  Reentrant version.
	* sysdeps/stub/ttyname_r: New file.  Define as dummy function.

	* sysdeps/posix/utimes.c: Include <utime.h> for prototype.
	(utimes): First parameter to utime must be file, not path.

	* sysdeps/posix/sysconf.c (__sysconf): Test for CLK_TCK in case
	_SC_CLK_TCK and return it when available.
	Test for STREAM_MAX in case _SC_STREAM_MAX and return it when
	available.
	Add case for _SC_2_LOCALEDEF which is now available.

	* posix/sys/types.h [__USE_SVID] (key_t): New type.
	* sysvipc/Makefile, sysvipc/ftok.c, sysvipc/sys/ipc.h,
	sysvipc/sys/msg.h, sysvipc/sys/sem.h, sysvipc/sys/shm.h,
	sysdeps/stub/sys/msq_buf.h, sysdeps/stub/sys/sem_buf.h,
	sysdeps/stub/sys/shm_buf.h, sysdeps/stub/sys/ipc_buf.h,
	sysdeps/stub/semctl.c, sysdeps/stub/semget.c, sysdeps/stub/semop.c,
	sysdeps/stub/shmat.c, sysdeps/stub/shmctl.c, sysdeps/stub/shmdt.c,
	sysdeps/stub/shmget.c, sysdeps/stub/msgctl.c, sysdeps/stub/msgget.c,
	sysdeps/stub/msgrcv.c, sysdeps/stub/msgsnd.c: New files.
	Add implementation of System V IPC.
Diffstat (limited to 'stdlib/random_r.c')
-rw-r--r--stdlib/random_r.c337
1 files changed, 337 insertions, 0 deletions
diff --git a/stdlib/random_r.c b/stdlib/random_r.c
new file mode 100644
index 0000000000..aa7a33fa6b
--- /dev/null
+++ b/stdlib/random_r.c
@@ -0,0 +1,337 @@
+/*
+ * Copyright (c) 1983 Regents of the University of California.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that the above copyright notice and this paragraph are
+ * duplicated in all such forms and that any documentation,
+ * advertising materials, and other materials related to such
+ * distribution and use acknowledge that the software was developed
+ * by the University of California, Berkeley.  The name of the
+ * University may not be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ */
+
+/*
+ * This is derived from the Berkeley source:
+ *	@(#)random.c	5.5 (Berkeley) 7/6/88
+ * It was reworked for the GNU C Library by Roland McGrath.
+ * Rewritten to be reentrent by Ulrich Drepper, 1995
+ */
+
+#include <errno.h>
+#include <limits.h>
+#include <stddef.h>
+#include <stdlib.h>
+
+
+/* An improved random number generation package.  In addition to the standard
+   rand()/srand() like interface, this package also has a special state info
+   interface.  The initstate() routine is called with a seed, an array of
+   bytes, and a count of how many bytes are being passed in; this array is
+   then initialized to contain information for random number generation with
+   that much state information.  Good sizes for the amount of state
+   information are 32, 64, 128, and 256 bytes.  The state can be switched by
+   calling the setstate() function with the same array as was initiallized
+   with initstate().  By default, the package runs with 128 bytes of state
+   information and generates far better random numbers than a linear
+   congruential generator.  If the amount of state information is less than
+   32 bytes, a simple linear congruential R.N.G. is used.  Internally, the
+   state information is treated as an array of longs; the zeroeth element of
+   the array is the type of R.N.G. being used (small integer); the remainder
+   of the array is the state information for the R.N.G.  Thus, 32 bytes of
+   state information will give 7 longs worth of state information, which will
+   allow a degree seven polynomial.  (Note: The zeroeth word of state
+   information also has some other information stored in it; see setstate
+   for details).  The random number generation technique is a linear feedback
+   shift register approach, employing trinomials (since there are fewer terms
+   to sum up that way).  In this approach, the least significant bit of all
+   the numbers in the state table will act as a linear feedback shift register,
+   and will have period 2^deg - 1 (where deg is the degree of the polynomial
+   being used, assuming that the polynomial is irreducible and primitive).
+   The higher order bits will have longer periods, since their values are
+   also influenced by pseudo-random carries out of the lower bits.  The
+   total period of the generator is approximately deg*(2**deg - 1); thus
+   doubling the amount of state information has a vast influence on the
+   period of the generator.  Note: The deg*(2**deg - 1) is an approximation
+   only good for large deg, when the period of the shift register is the
+   dominant factor.  With deg equal to seven, the period is actually much
+   longer than the 7*(2**7 - 1) predicted by this formula.  */
+
+
+
+/* For each of the currently supported random number generators, we have a
+   break value on the amount of state information (you need at least thi
+   bytes of state info to support this random number generator), a degree for
+   the polynomial (actually a trinomial) that the R.N.G. is based on, and
+   separation between the two lower order coefficients of the trinomial.  */
+
+/* Linear congruential.  */
+#define	TYPE_0		0
+#define	BREAK_0		8
+#define	DEG_0		0
+#define	SEP_0		0
+
+/* x**7 + x**3 + 1.  */
+#define	TYPE_1		1
+#define	BREAK_1		32
+#define	DEG_1		7
+#define	SEP_1		3
+
+/* x**15 + x + 1.  */
+#define	TYPE_2		2
+#define	BREAK_2		64
+#define	DEG_2		15
+#define	SEP_2		1
+
+/* x**31 + x**3 + 1.  */
+#define	TYPE_3		3
+#define	BREAK_3		128
+#define	DEG_3		31
+#define	SEP_3		3
+
+/* x**63 + x + 1.  */
+#define	TYPE_4		4
+#define	BREAK_4		256
+#define	DEG_4		63
+#define	SEP_4		1
+
+
+/* Array versions of the above information to make code run faster.
+   Relies on fact that TYPE_i == i.  */
+
+#define	MAX_TYPES	5	/* Max number of types above.  */
+
+static const int degrees[MAX_TYPES] = { DEG_0, DEG_1, DEG_2, DEG_3, DEG_4 };
+static const int seps[MAX_TYPES] = { SEP_0, SEP_1, SEP_2, SEP_3, SEP_4 };
+
+
+
+
+/* Initialize the random number generator based on the given seed.  If the
+   type is the trivial no-state-information type, just remember the seed.
+   Otherwise, initializes state[] based on the given "seed" via a linear
+   congruential generator.  Then, the pointers are set to known locations
+   that are exactly rand_sep places apart.  Lastly, it cycles the state
+   information a given number of times to get rid of any initial dependencies
+   introduced by the L.C.R.N.G.  Note that the initialization of randtbl[]
+   for default usage relies on values produced by this routine.  */
+int
+__srandom_r (x, buf)
+     unsigned int x;
+     struct random_data *buf;
+{
+  if (buf == NULL || buf->rand_type < TYPE_0 || buf->rand_type > TYPE_4)
+    return -1;
+
+  buf->state[0] = x;
+  if (buf->rand_type != TYPE_0)
+    {
+      long int i;
+      for (i = 1; i < buf->rand_deg; ++i)
+	{
+	  /* This does:
+	       state[i] = (16807 * state[i - 1]) % 2147483647;
+	     but avoids overflowing 31 bits.  */
+	  long int hi = buf->state[i - 1] / 127773;
+	  long int lo = buf->state[i - 1] % 127773;
+	  long int test = 16807 * lo - 2836 * hi;
+	  buf->state[i] = test + (test < 0 ? 2147483647 : 0);
+	}
+      buf->fptr = &buf->state[buf->rand_sep];
+      buf->rptr = &buf->state[0];
+      for (i = 0; i < 10 * buf->rand_deg; ++i)
+	{
+	  long int discard;
+	  (void) __random_r (buf, &discard);
+	}
+    }
+
+  return 0;
+}
+
+weak_alias (__srandom_r, srandom_r)
+weak_alias (__srandom_r, srand_r)
+
+/* Initialize the state information in the given array of N bytes for
+   future random number generation.  Based on the number of bytes we
+   are given, and the break values for the different R.N.G.'s, we choose
+   the best (largest) one we can and set things up for it.  srandom is
+   then called to initialize the state information.  Note that on return
+   from srandom, we set state[-1] to be the type multiplexed with the current
+   value of the rear pointer; this is so successive calls to initstate won't
+   lose this information and will be able to restart with setstate.
+   Note: The first thing we do is save the current state, if any, just like
+   setstate so that it doesn't matter when initstate is called.
+   Returns a pointer to the old state.  */
+int
+__initstate_r (seed, arg_state, n, buf)
+     unsigned int seed;
+     void *arg_state;
+     size_t n;
+     struct random_data *buf;
+{
+  if (buf == NULL)
+    return -1;
+
+  if (buf->rand_type == TYPE_0)
+    buf->state[-1] = buf->rand_type;
+  else
+    buf->state[-1] = (MAX_TYPES * (buf->rptr - buf->state)) + buf->rand_type;
+  if (n < BREAK_1)
+    {
+      if (n < BREAK_0)
+	{
+	  errno = EINVAL;
+	  return -1;
+	}
+      buf->rand_type = TYPE_0;
+      buf->rand_deg = DEG_0;
+      buf->rand_sep = SEP_0;
+    }
+  else if (n < BREAK_2)
+    {
+      buf->rand_type = TYPE_1;
+      buf->rand_deg = DEG_1;
+      buf->rand_sep = SEP_1;
+    }
+  else if (n < BREAK_3)
+    {
+      buf->rand_type = TYPE_2;
+      buf->rand_deg = DEG_2;
+      buf->rand_sep = SEP_2;
+    }
+  else if (n < BREAK_4)
+    {
+      buf->rand_type = TYPE_3;
+      buf->rand_deg = DEG_3;
+      buf->rand_sep = SEP_3;
+    }
+  else
+    {
+      buf->rand_type = TYPE_4;
+      buf->rand_deg = DEG_4;
+      buf->rand_sep = SEP_4;
+    }
+
+  buf->state = &((long int *) arg_state)[1];	/* First location.  */
+  /* Must set END_PTR before srandom.  */
+  buf->end_ptr = &buf->state[buf->rand_deg];
+
+  __srandom_r (seed, buf);
+
+  if (buf->rand_type == TYPE_0)
+    buf->state[-1] = buf->rand_type;
+  else
+    buf->state[-1] = (MAX_TYPES * (buf->rptr - buf->state)) + buf->rand_type;
+
+  return 0;
+}
+
+weak_alias (__initstate_r, initstate_r)
+
+/* Restore the state from the given state array.
+   Note: It is important that we also remember the locations of the pointers
+   in the current state information, and restore the locations of the pointers
+   from the old state information.  This is done by multiplexing the pointer
+   location into the zeroeth word of the state information. Note that due
+   to the order in which things are done, it is OK to call setstate with the
+   same state as the current state
+   Returns a pointer to the old state information.  */
+int
+__setstate_r (arg_state, buf)
+     void *arg_state;
+     struct random_data *buf;
+{
+  long int *new_state = (long int *) arg_state;
+  int type = new_state[0] % MAX_TYPES;
+  int rear = new_state[0] / MAX_TYPES;
+
+  if (buf == NULL)
+    return -1;
+
+  if (buf->rand_type == TYPE_0)
+    buf->state[-1] = buf->rand_type;
+  else
+    buf->state[-1] = (MAX_TYPES * (buf->rptr - buf->state)) + buf->rand_type;
+
+  switch (type)
+    {
+    case TYPE_0:
+    case TYPE_1:
+    case TYPE_2:
+    case TYPE_3:
+    case TYPE_4:
+      buf->rand_type = type;
+      buf->rand_deg = degrees[type];
+      buf->rand_sep = seps[type];
+      break;
+    default:
+      /* State info munged.  */
+      errno = EINVAL;
+      return -1;
+    }
+
+  buf->state = &new_state[1];
+  if (buf->rand_type != TYPE_0)
+    {
+      buf->rptr = &buf->state[rear];
+      buf->fptr = &buf->state[(rear + buf->rand_sep) % buf->rand_deg];
+    }
+  /* Set end_ptr too.  */
+  buf->end_ptr = &buf->state[buf->rand_deg];
+
+  return 0;
+}
+
+weak_alias (__setstate_r, setstate_r)
+
+/* If we are using the trivial TYPE_0 R.N.G., just do the old linear
+   congruential bit.  Otherwise, we do our fancy trinomial stuff, which is the
+   same in all ther other cases due to all the global variables that have been
+   set up.  The basic operation is to add the number at the rear pointer into
+   the one at the front pointer.  Then both pointers are advanced to the next
+   location cyclically in the table.  The value returned is the sum generated,
+   reduced to 31 bits by throwing away the "least random" low bit.
+   Note: The code takes advantage of the fact that both the front and
+   rear pointers can't wrap on the same call by not testing the rear
+   pointer if the front one has wrapped.  Returns a 31-bit random number.  */
+
+int
+__random_r (buf, result)
+     struct random_data *buf;
+     long int *result;
+{
+  if (buf == NULL || result == NULL)
+    return -1;
+
+  if (buf->rand_type == TYPE_0)
+    {
+      buf->state[0] = ((buf->state[0] * 1103515245) + 12345) & LONG_MAX;
+      *result = buf->state[0];
+    }
+  else
+    {
+      *buf->fptr += *buf->rptr;
+      /* Chucking least random bit.  */
+      *result = (*buf->fptr >> 1) & LONG_MAX;
+      ++buf->fptr;
+      if (buf->fptr >= buf->end_ptr)
+	{
+	  buf->fptr = buf->state;
+	  ++buf->rptr;
+	}
+      else
+	{
+	  ++buf->rptr;
+	  if (buf->rptr >= buf->end_ptr)
+	    buf->rptr = buf->state;
+	}
+    }
+  return 0;
+}
+
+weak_alias (__random_r, random_r)