glibc/misc/hsearch_r.c
Roland McGrath 60478656fa 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.
1995-09-17 20:23:15 +00:00

230 lines
6.3 KiB
C

/* Copyright (C) 1993, 1995 Free Software Foundation, Inc.
Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu>
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C Library 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If
not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include <errno.h>
#include <malloc.h>
#include <string.h>
#include <search.h>
/* [Aho,Sethi,Ullman] Compilers: Principles, Techniques and Tools, 1986
[Knuth] The Art of Computer Programming, part 3 (6.4) */
/* The reentrent version has no static variables to maintain the state.
Instead the interface of all functions is extended to take an argument
which describes the current status. */
typedef struct _ENTRY
{
int used;
ENTRY entry;
}
_ENTRY;
/* For the used double hash method the table size has to be a prime. To
correct the user given table size we need a prime test. This trivial
algorithm is adequate because
a) the code is (most probably) called a few times per program run and
b) the number is small because the table must fit in the core */
static int
isprime (number)
unsigned int number;
{
/* no even number will be passed */
unsigned int div = 3;
while (div * div < number && number % div != 0)
div += 2;
return number % div != 0;
}
/* Before using the hash table we must allocate memory for it.
Test for an existing table are done. We allocate one element
more as the found prime number says. This is done for more effective
indexing as explained in the comment for the hsearch function.
The contents of the table is zeroed, especially the field used
becomes zero. */
int
hcreate_r (nel, htab)
unsigned int nel;
struct hsearch_data *htab;
{
/* Test for correct arguments. */
if (htab == NULL)
{
errno = EINVAL;
return 0;
}
/* There is still another table active. Return with error. */
if (htab->table != NULL)
return 0;
/* Change nel to the first prime number not smaller as nel. */
nel |= 1; /* make odd */
while (!isprime (nel))
nel += 2;
htab->size = nel;
htab->filled = 0;
/* allocate memory and zero out */
htab->table = (_ENTRY *) calloc (htab->size + 1, sizeof (_ENTRY));
if (htab->table == NULL)
return 0;
/* everything went alright */
return 1;
}
/* After using the hash table it has to be destroyed. The used memory can
be freed and the local static variable can be marked as not used. */
void
hdestroy_r (htab)
struct hsearch_data *htab;
{
/* Test for correct arguments. */
if (htab == NULL)
{
errno = EINVAL;
return;
}
if (htab->table != NULL)
/* free used memory */
free (htab->table);
/* the sign for an existing table is an value != NULL in htable */
htab->table = NULL;
}
/* This is the search function. It uses double hashing with open adressing.
The argument item.key has to be a pointer to an zero terminated, most
probably strings of chars. The function for generating a number of the
strings is simple but fast. It can be replaced by a more complex function
like ajw (see [Aho,Sethi,Ullman]) if the needs are shown.
We use an trick to speed up the lookup. The table is created by hcreate
with one more element available. This enables us to use the index zero
special. This index will never be used because we store the first hash
index in the field used where zero means not used. Every other value
means used. The used field can be used as a first fast comparison for
equality of the stored and the parameter value. This helps to prevent
unnecessary expensive calls of strcmp. */
int
hsearch_r (item, action, retval, htab)
ENTRY item;
ACTION action;
ENTRY **retval;
struct hsearch_data *htab;
{
unsigned int hval;
unsigned int count;
unsigned int len = strlen (item.key);
unsigned int idx;
/* If table is full and another entry should be entered return with
error. */
if (action == ENTER && htab->filled == htab->size)
{
errno = ENOMEM;
*retval = NULL;
return 0;
}
/* Compute an value for the given string. Perhaps use a better method. */
hval = len;
count = len;
while (count-- > 0)
{
hval <<= 4;
hval += item.key[count];
}
/* First hash function: simply take the modul but prevent zero. */
hval %= htab->size;
if (hval == 0)
++hval;
/* The first index tried. */
idx = hval;
if (htab->table[idx].used)
{
/* Further action might be required according to the action value. */
unsigned hval2;
if (htab->table[idx].used == hval
&& strcmp (item.key, htab->table[idx].entry.key) == 0)
{
if (action == ENTER)
htab->table[idx].entry.data = item.data;
*retval = &htab->table[idx].entry;
return 1;
}
/* Second hash function, as suggested in [Knuth] */
hval2 = 1 + hval % (htab->size - 2);
do
{
/* Because SIZE is prime this guarantees to step through all
available indeces. */
if (idx <= hval2)
idx = htab->size + idx - hval2;
else
idx -= hval2;
/* If entry is found use it. */
if (htab->table[idx].used == hval
&& strcmp (item.key, htab->table[idx].entry.key) == 0)
{
if (action == ENTER)
htab->table[idx].entry.data = item.data;
*retval = &htab->table[idx].entry;
return 1;
}
}
while (htab->table[idx].used);
}
/* An empty bucket has been found. */
if (action == ENTER)
{
htab->table[idx].used = hval;
htab->table[idx].entry = item;
++htab->filled;
*retval = &htab->table[idx].entry;
return 1;
}
errno = ESRCH;
*retval = NULL;
return 0;
}