ossp-pkg/mm/mm_alloc.c
1.15
/* ====================================================================
* Copyright (c) 1999-2001 Ralf S. Engelschall. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. All advertising materials mentioning features or use of this
* software must display the following acknowledgment:
* "This product includes software developed by
* Ralf S. Engelschall <rse@engelschall.com>."
*
* 4. Redistributions of any form whatsoever must retain the following
* acknowledgment:
* "This product includes software developed by
* Ralf S. Engelschall <rse@engelschall.com>."
*
* THIS SOFTWARE IS PROVIDED BY RALF S. ENGELSCHALL ``AS IS'' AND ANY
* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RALF S. ENGELSCHALL OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
* ====================================================================
*/
/*
**
** mm_alloc.c -- Standard Malloc-Style API
**
*/
#define MM_PRIVATE
#include "mm.h"
/*
* Create a memory pool
*/
MM *mm_create(size_t usize, const char *file)
{
MM *mm = NULL;
void *core;
size_t size;
size_t maxsize;
/* defaults */
maxsize = mm_maxsize();
if (usize == 0)
usize = maxsize;
if (usize > maxsize)
usize = maxsize;
if (usize < MM_ALLOC_MINSIZE)
usize = MM_ALLOC_MINSIZE;
/* determine size */
size = usize+SIZEOF_mem_pool;
/* get a shared memory area */
if ((core = mm_core_create(size, file)) == NULL)
return NULL;
/* fill in the memory pool structure */
mm = (MM *)core;
mm->mp_size = size;
mm->mp_offset = SIZEOF_mem_pool;
/* first element of list of free chunks counts existing chunks */
mm->mp_freechunks.mc_size = 0; /* has to be 0 forever */
mm->mp_freechunks.mc_usize = 0; /* counts chunks */
mm->mp_freechunks.mc_u.mc_next = NULL;
return mm;
}
/*
* Set permissions on memory pools underlaying disk files
*/
int mm_permission(MM *mm, mode_t mode, uid_t owner, gid_t group)
{
if (mm == NULL)
return -1;
return mm_core_permission((void *)mm, mode, owner, group);
}
/*
* Destroy a memory pool
*/
void mm_destroy(MM *mm)
{
if (mm == NULL)
return;
/* wipe out the whole area to be safe */
memset(mm, 0, mm->mp_size);
/* and delete the core area */
(void)mm_core_delete((void *)mm);
return;
}
/*
* Lock a memory pool
*/
int mm_lock(MM *mm, mm_lock_mode mode)
{
if (mm == NULL)
return FALSE;
return mm_core_lock((void *)mm, mode);
}
/*
* Unlock a memory pool
*/
int mm_unlock(MM *mm)
{
if (mm == NULL)
return FALSE;
return mm_core_unlock((void *)mm);
}
/*
* Display debugging information
*/
void mm_display_info(MM *mm)
{
mem_chunk *mc;
int nFree;
int nAlloc;
int i;
if (!mm_core_lock((void *)mm, MM_LOCK_RD))
return;
mc = &(mm->mp_freechunks);
nFree = 0;
while (mc->mc_u.mc_next != NULL) {
mc = mc->mc_u.mc_next;
nFree += mc->mc_size;
}
nAlloc = mm->mp_offset-SIZEOF_mem_pool-nFree;
fprintf(stderr, "Information for MM\n");
fprintf(stderr, " memory area = 0x%lx - 0x%lx\n", (unsigned long)mm, (unsigned long)(mm+mm->mp_size));
fprintf(stderr, " memory size = %d\n", mm->mp_size);
fprintf(stderr, " memory offset = %d\n", mm->mp_offset);
fprintf(stderr, " bytes spare = %d\n", mm->mp_size-mm->mp_offset);
fprintf(stderr, " bytes free = %d (%d chunk%s)\n",
nFree, mm->mp_freechunks.mc_usize,
mm->mp_freechunks.mc_usize == 1 ? "" : "s");
fprintf(stderr, " bytes allocated = %d\n", nAlloc);
fprintf(stderr, " List of free chunks:\n");
if (mm->mp_freechunks.mc_usize > 0) {
mc = &(mm->mp_freechunks);
i = 1;
while (mc->mc_u.mc_next != NULL) {
mc = mc->mc_u.mc_next;
fprintf(stderr, " chunk #%03d: 0x%lx-0x%lx (%d bytes)\n",
i++, (unsigned long)mc, (unsigned long)(mc+mc->mc_size), mc->mc_size);
}
}
else {
fprintf(stderr, " <empty-list>\n");
}
mm_core_unlock((void *)mm);
return;
}
/*
* Insert a chunk to the list of free chunks. Algorithm used is:
* Insert in sorted manner to the list and merge with previous
* and/or next chunk when possible to form larger chunks out of
* smaller ones.
*/
static void mm_insert_chunk(MM *mm, mem_chunk *mcInsert)
{
mem_chunk *mc;
mem_chunk *mcPrev;
mem_chunk *mcNext;
if (!mm_core_lock((void *)mm, MM_LOCK_RW))
return;
mc = &(mm->mp_freechunks);
while (mc->mc_u.mc_next != NULL && (char *)(mc->mc_u.mc_next) < (char *)mcInsert)
mc = mc->mc_u.mc_next;
mcPrev = mc;
mcNext = mc->mc_u.mc_next;
if (mcPrev == mcInsert || mcNext == mcInsert) {
mm_core_unlock((void *)mm);
ERR(MM_ERR_ALLOC, "chunk of memory already in free list");
return;
}
if ((char *)mcPrev+(mcPrev->mc_size) == (char *)mcInsert &&
(mcNext != NULL && (char *)mcInsert+(mcInsert->mc_size) == (char *)mcNext)) {
/* merge with previous and next chunk */
mcPrev->mc_size += mcInsert->mc_size + mcNext->mc_size;
mcPrev->mc_u.mc_next = mcNext->mc_u.mc_next;
mm->mp_freechunks.mc_usize -= 1;
}
else if ((char *)mcPrev+(mcPrev->mc_size) == (char *)mcInsert) {
/* merge with previous chunk */
mcPrev->mc_size += mcInsert->mc_size;
}
else if (mcNext != NULL && (char *)mcInsert+(mcInsert->mc_size) == (char *)mcNext) {
/* merge with next chunk */
mcInsert->mc_size += mcNext->mc_size;
mcInsert->mc_u.mc_next = mcNext->mc_u.mc_next;
mcPrev->mc_u.mc_next = mcInsert;
}
else {
/* no merging possible, so insert as new chunk */
mcInsert->mc_u.mc_next = mcNext;
mcPrev->mc_u.mc_next = mcInsert;
mm->mp_freechunks.mc_usize += 1;
}
mm_core_unlock((void *)mm);
return;
}
/*
* Retrieve a chunk from the list of free chunks. Algorithm used
* is: Search for minimal-sized chunk which is larger or equal
* than the request size. But when the retrieved chunk is still a
* lot larger than the requested size, split out the requested
* size to not waste memory.
*/
static mem_chunk *mm_retrieve_chunk(MM *mm, size_t size)
{
mem_chunk *mc;
mem_chunk **pmcMin;
mem_chunk *mcRes;
size_t sMin;
size_t s;
if (size == 0)
return NULL;
if (mm->mp_freechunks.mc_usize == 0)
return NULL;
if (!mm_core_lock((void *)mm, MM_LOCK_RW))
return NULL;
/* find best-fitting chunk */
pmcMin = NULL;
sMin = mm->mp_size; /* initialize with maximum possible */
mc = &(mm->mp_freechunks);
while (mc->mc_u.mc_next != NULL) {
s = mc->mc_u.mc_next->mc_size;
if (s >= size && s < sMin) {
pmcMin = &(mc->mc_u.mc_next);
sMin = s;
if (s == size)
break;
}
mc = mc->mc_u.mc_next;
}
/* create result chunk */
if (pmcMin == NULL)
mcRes = NULL;
else {
mcRes = *pmcMin;
if (mcRes->mc_size >= (size + min_of(2*size,128))) {
/* split out in part */
s = mcRes->mc_size - size;
mcRes->mc_size = size;
/* add back remaining chunk part as new chunk */
mc = (mem_chunk *)((char *)mcRes + size);
mc->mc_size = s;
mc->mc_u.mc_next = mcRes->mc_u.mc_next;
*pmcMin = mc;
}
else {
/* split out as a whole */
*pmcMin = mcRes->mc_u.mc_next;
mm->mp_freechunks.mc_usize--;
}
}
mm_core_unlock((void *)mm);
return mcRes;
}
/*
* Allocate a chunk of memory
*/
void *mm_malloc(MM *mm, size_t usize)
{
mem_chunk *mc;
size_t size;
void *vp;
if (mm == NULL || usize == 0)
return NULL;
size = mm_core_align2word(SIZEOF_mem_chunk+usize);
if ((mc = mm_retrieve_chunk(mm, size)) != NULL) {
mc->mc_usize = usize;
return &(mc->mc_u.mc_base.mw_cp);
}
if (!mm_core_lock((void *)mm, MM_LOCK_RW))
return NULL;
if ((mm->mp_size - mm->mp_offset) < size) {
mm_core_unlock((void *)mm);
ERR(MM_ERR_ALLOC, "out of memory");
errno = ENOMEM;
return NULL;
}
mc = (mem_chunk *)((char *)mm + mm->mp_offset);
mc->mc_size = size;
mc->mc_usize = usize;
vp = (void *)&(mc->mc_u.mc_base.mw_cp);
mm->mp_offset += size;
mm_core_unlock((void *)mm);
return vp;
}
/*
* Reallocate a chunk of memory
*/
void *mm_realloc(MM *mm, void *ptr, size_t usize)
{
size_t size;
mem_chunk *mc;
void *vp;
if (mm == NULL || usize == 0)
return NULL;
if (ptr == NULL)
return mm_malloc(mm, usize); /* POSIX.1 semantics */
mc = (mem_chunk *)((char *)ptr - SIZEOF_mem_chunk);
if (usize <= mc->mc_usize) {
mc->mc_usize = usize;
return ptr;
}
size = mm_core_align2word(SIZEOF_mem_chunk+usize);
if (size <= mc->mc_size) {
mc->mc_usize = usize;
return ptr;
}
if ((vp = mm_malloc(mm, usize)) == NULL)
return NULL;
memcpy(vp, ptr, usize);
mm_free(mm, ptr);
return vp;
}
/*
* Free a chunk of memory
*/
void mm_free(MM *mm, void *ptr)
{
mem_chunk *mc;
if (mm == NULL || ptr == NULL)
return;
mc = (mem_chunk *)((char *)ptr - SIZEOF_mem_chunk);
mm_insert_chunk(mm, mc);
return;
}
/*
* Allocate and initialize a chunk of memory
*/
void *mm_calloc(MM *mm, size_t number, size_t usize)
{
void *vp;
if (mm == NULL || number*usize == 0)
return NULL;
if ((vp = mm_malloc(mm, number*usize)) == NULL)
return NULL;
memset(vp, 0, number*usize);
return vp;
}
/*
* Duplicate a string
*/
char *mm_strdup(MM *mm, const char *str)
{
int n;
void *vp;
if (mm == NULL || str == NULL)
return NULL;
n = strlen(str);
if ((vp = mm_malloc(mm, n+1)) == NULL)
return NULL;
memcpy(vp, str, n+1);
return vp;
}
/*
* Determine user size of a memory chunk
*/
size_t mm_sizeof(MM *mm, const void *ptr)
{
mem_chunk *mc;
if (mm == NULL || ptr == NULL)
return -1;
mc = (mem_chunk *)((char *)ptr - SIZEOF_mem_chunk);
return mc->mc_usize;
}
/*
* Determine maximum size of an allocateable memory pool
*/
size_t mm_maxsize(void)
{
return (mm_core_maxsegsize()-SIZEOF_mem_pool);
}
/*
* Determine available memory
*/
size_t mm_available(MM *mm)
{
mem_chunk *mc;
int nFree;
if (!mm_core_lock((void *)mm, MM_LOCK_RD))
return 0;
nFree = mm->mp_size-mm->mp_offset;
mc = &(mm->mp_freechunks);
while (mc->mc_u.mc_next != NULL) {
mc = mc->mc_u.mc_next;
nFree += mc->mc_size;
}
mm_core_unlock((void *)mm);
return nFree;
}
/*
* Return last error string
*/
char *mm_error(void)
{
return mm_lib_error_get();
}
/*EOF*/
