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/*
* malloc.c
*
* Very simple linked-list based malloc()/free().
*/
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <dprintf.h>
#include <minmax.h>
#include "malloc.h"
static void *__malloc_from_block(struct free_arena_header *fp,
size_t size, malloc_tag_t tag)
{
size_t fsize;
struct free_arena_header *nfp, *na;
unsigned int heap = ARENA_HEAP_GET(fp->a.attrs);
fsize = ARENA_SIZE_GET(fp->a.attrs);
/* We need the 2* to account for the larger requirements of a free block */
if ( fsize >= size+2*sizeof(struct arena_header) ) {
/* Bigger block than required -- split block */
nfp = (struct free_arena_header *)((char *)fp + size);
na = fp->a.next;
ARENA_TYPE_SET(nfp->a.attrs, ARENA_TYPE_FREE);
ARENA_HEAP_SET(nfp->a.attrs, heap);
ARENA_SIZE_SET(nfp->a.attrs, fsize-size);
nfp->a.tag = MALLOC_FREE;
ARENA_TYPE_SET(fp->a.attrs, ARENA_TYPE_USED);
ARENA_SIZE_SET(fp->a.attrs, size);
fp->a.tag = tag;
/* Insert into all-block chain */
nfp->a.prev = fp;
nfp->a.next = na;
na->a.prev = nfp;
fp->a.next = nfp;
/* Replace current block on free chain */
nfp->next_free = fp->next_free;
nfp->prev_free = fp->prev_free;
fp->next_free->prev_free = nfp;
fp->prev_free->next_free = nfp;
} else {
/* Allocate the whole block */
ARENA_TYPE_SET(fp->a.attrs, ARENA_TYPE_USED);
fp->a.tag = tag;
/* Remove from free chain */
fp->next_free->prev_free = fp->prev_free;
fp->prev_free->next_free = fp->next_free;
}
return (void *)(&fp->a + 1);
}
static void *_malloc(size_t size, enum heap heap, malloc_tag_t tag)
{
struct free_arena_header *fp;
struct free_arena_header *head = &__core_malloc_head[heap];
void *p = NULL;
dprintf("_malloc(%zu, %u, %u) @ %p = ",
size, heap, tag, __builtin_return_address(0));
if (size) {
/* Add the obligatory arena header, and round up */
size = (size + 2 * sizeof(struct arena_header) - 1) & ARENA_SIZE_MASK;
for ( fp = head->next_free ; fp != head ; fp = fp->next_free ) {
if ( ARENA_SIZE_GET(fp->a.attrs) >= size ) {
/* Found fit -- allocate out of this block */
p = __malloc_from_block(fp, size, tag);
break;
}
}
}
dprintf("%p\n", p);
return p;
}
void *malloc(size_t size)
{
return _malloc(size, HEAP_MAIN, MALLOC_CORE);
}
void *lmalloc(size_t size)
{
return _malloc(size, HEAP_LOWMEM, MALLOC_CORE);
}
void *pmapi_lmalloc(size_t size)
{
return _malloc(size, HEAP_LOWMEM, MALLOC_MODULE);
}
void *realloc(void *ptr, size_t size)
{
struct free_arena_header *ah, *nah;
struct free_arena_header *head;
void *newptr;
size_t newsize, oldsize, xsize;
if (!ptr)
return malloc(size);
if (size == 0) {
free(ptr);
return NULL;
}
ah = (struct free_arena_header *)
((struct arena_header *)ptr - 1);
head = &__core_malloc_head[ARENA_HEAP_GET(ah->a.attrs)];
/* Actual size of the old block */
//oldsize = ah->a.size;
oldsize = ARENA_SIZE_GET(ah->a.attrs);
/* Add the obligatory arena header, and round up */
newsize = (size + 2 * sizeof(struct arena_header) - 1) & ARENA_SIZE_MASK;
if (oldsize >= newsize && newsize >= (oldsize >> 2) &&
oldsize - newsize < 4096) {
/* This allocation is close enough already. */
return ptr;
} else {
xsize = oldsize;
nah = ah->a.next;
if ((char *)nah == (char *)ah + ARENA_SIZE_GET(ah->a.attrs) &&
ARENA_TYPE_GET(nah->a.attrs) == ARENA_TYPE_FREE &&
ARENA_SIZE_GET(nah->a.attrs) + oldsize >= newsize) {
//nah->a.type == ARENA_TYPE_FREE &&
//oldsize + nah->a.size >= newsize) {
/* Merge in subsequent free block */
ah->a.next = nah->a.next;
ah->a.next->a.prev = ah;
nah->next_free->prev_free = nah->prev_free;
nah->prev_free->next_free = nah->next_free;
ARENA_SIZE_SET(ah->a.attrs, ARENA_SIZE_GET(nah->a.attrs));
xsize = ARENA_SIZE_GET(ah->a.attrs);
//xsize = (ah->a.size += nah->a.size);
}
if (xsize >= newsize) {
/* We can reallocate in place */
if (xsize >= newsize + 2 * sizeof(struct arena_header)) {
/* Residual free block at end */
nah = (struct free_arena_header *)((char *)ah + newsize);
ARENA_TYPE_SET(nah->a.attrs, ARENA_TYPE_FREE);
ARENA_SIZE_SET(nah->a.attrs, xsize - newsize);
ARENA_SIZE_SET(ah->a.attrs, newsize);
//nah->a.type = ARENA_TYPE_FREE;
//nah->a.size = xsize - newsize;
//ah->a.size = newsize;
/* Insert into block list */
nah->a.next = ah->a.next;
ah->a.next = nah;
nah->a.next->a.prev = nah;
nah->a.prev = ah;
/* Insert into free list */
if (newsize > oldsize) {
/* Hack: this free block is in the path of a memory object
which has already been grown at least once. As such, put
it at the *end* of the freelist instead of the beginning;
trying to save it for future realloc()s of the same block. */
nah->prev_free = head->prev_free;
nah->next_free = head;
head->prev_free = nah;
nah->prev_free->next_free = nah;
} else {
nah->next_free = head->next_free;
nah->prev_free = head;
head->next_free = nah;
nah->next_free->prev_free = nah;
}
}
/* otherwise, use up the whole block */
return ptr;
} else {
/* Last resort: need to allocate a new block and copy */
oldsize -= sizeof(struct arena_header);
newptr = malloc(size);
if (newptr) {
memcpy(newptr, ptr, min(size, oldsize));
free(ptr);
}
return newptr;
}
}
}
void *zalloc(size_t size)
{
void *ptr;
ptr = malloc(size);
if (ptr)
memset(ptr, 0, size);
return ptr;
}
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