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/*
* %CopyrightBegin%
*
* Copyright Ericsson AB 1996-2009. All Rights Reserved.
*
* The contents of this file are subject to the Erlang Public License,
* Version 1.1, (the "License"); you may not use this file except in
* compliance with the License. You should have received a copy of the
* Erlang Public License along with this software. If not, it can be
* retrieved online at http://www.erlang.org/.
*
* Software distributed under the License is distributed on an "AS IS"
* basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
* the License for the specific language governing rights and limitations
* under the License.
*
* %CopyrightEnd%
*/
/*
* Function: General purpose Memory allocator for fixed block
* size objects. This allocater is at least an order of
* magnitude faster than malloc().
*/
#include "eidef.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "ei_locking.h"
#include "erl_interface.h"
#include "erl_error.h"
#include "erl_malloc.h"
#include "erl_fix_alloc.h"
#include "erl_eterm.h"
#define WIPE_CHAR ((char)0xaa) /* 10101010 */
/* the freelist is a singly linked list of these */
/* i.e. the user structure and a link pointer */
struct fix_block {
ETERM term;
struct fix_block *next;
int free;
};
/* this is a struct just to keep namespace pollution low on VxWorks */
struct eterm_stateinfo {
struct fix_block *freelist;
unsigned long freed;
unsigned long allocated;
#ifdef _REENTRANT
ei_mutex_t *lock;
#endif /* _REENTRANT */
};
/* FIXME problem for threaded ? */
static struct eterm_stateinfo *erl_eterm_state=NULL;
int erl_init_eterm_alloc (void)
{
#if defined(PURIFY) && defined (DEBUG)
fprintf(stderr,"erl_fix_alloc() compiled for Purify - using \"real\" malloc()");
#endif
erl_eterm_state = malloc(sizeof(*erl_eterm_state));
if (erl_eterm_state == NULL) goto err1;
erl_eterm_state->freelist = NULL;
erl_eterm_state->freed = 0;
erl_eterm_state->allocated = 0;
#ifdef _REENTRANT
erl_eterm_state->lock = ei_mutex_create();
if (erl_eterm_state->lock == NULL) goto err2;
#endif /* _REENTRANT */
return 1;
/* Error cleanup */
#ifdef _REENTRANT
err2:
/* FIXME ENOMEM is not what went wrong... */
free(erl_eterm_state);
#endif /* _REENTRANT */
err1:
erl_errno = ENOMEM;
return 0;
}
/* get an eterm, from the freelist if possible or from malloc() */
void *erl_eterm_alloc (void)
{
#ifdef PURIFY
ETERM *p;
if ((p = malloc(sizeof(*p)))) {
memset(p, WIPE_CHAR, sizeof(*p));
}
return p;
#else
struct fix_block *b;
#ifdef _REENTRANT
ei_mutex_lock(erl_eterm_state->lock, 0);
#endif /* _REENTRANT */
/* try to pop block from head of freelist */
if ((b = erl_eterm_state->freelist) != NULL) {
erl_eterm_state->freelist = b->next;
erl_eterm_state->freed--;
} else if ((b = malloc(sizeof(*b))) == NULL) {
erl_errno = ENOMEM;
}
erl_eterm_state->allocated++;
b->free = 0;
b->next = NULL;
#ifdef _REENTRANT
ei_mutex_unlock(erl_eterm_state->lock);
#endif /* _REENTRANT */
return (void *) &b->term;
#endif /* !PURIFY */
}
/* free an eterm back to the freelist */
void erl_eterm_free(void *p)
{
#ifdef PURIFY
if (p) {
memset(p, WIPE_CHAR, sizeof(ETERM));
}
free(p);
#else
struct fix_block *b = p;
if (b) {
if (b->free) {
#ifdef DEBUG
fprintf(stderr,"erl_eterm_free: attempt to free already freed block %p\n",b);
#endif
return;
}
#ifdef _REENTRANT
ei_mutex_lock(erl_eterm_state->lock,0);
#endif /* _REENTRANT */
b->free = 1;
b->next = erl_eterm_state->freelist;
erl_eterm_state->freelist = b;
erl_eterm_state->freed++;
erl_eterm_state->allocated--;
#ifdef _REENTRANT
ei_mutex_unlock(erl_eterm_state->lock);
#endif /* _REENTRANT */
}
#endif /* !PURIFY */
}
/* really free the freelist */
void erl_eterm_release (void)
{
#if !defined(PURIFY)
struct fix_block *b;
#ifdef _REENTRANT
ei_mutex_lock(erl_eterm_state->lock,0);
#endif /* _REENTRANT */
{
while (erl_eterm_state->freelist != NULL) {
b = erl_eterm_state->freelist;
erl_eterm_state->freelist = b->next;
free(b);
erl_eterm_state->freed--;
}
}
#ifdef _REENTRANT
ei_mutex_unlock(erl_eterm_state->lock);
#endif /* _REENTRANT */
#endif /* !PURIFY */
}
void erl_eterm_statistics (unsigned long *allocd, unsigned long *freed)
{
if (allocd) *allocd = erl_eterm_state->allocated;
if (freed) *freed = erl_eterm_state->freed;
return;
}
/*
* Local Variables:
* compile-command: "cd ..; ERL_TOP=/clearcase/otp/erts make -k"
* End:
*/
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