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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/mman.h>
struct chunkControl {
size_t nodeCount;
size_t chunkSize;
};
struct nodeControl {
struct chunkControl *chunk;
size_t nodeSize;
};
#define ROUND_UP_LENGTH(len) ((len+7) & ~0x07)
extern struct nodeControl *mallocNextNode;
#ifdef L_malloc
/* This variable is a pointer to the next place to allocate from.
* Note: This variable makes the code NOT thread save. */
struct nodeControl *mallocNextNode = 0;
static size_t PageSize = 0;
#endif
#ifdef L_calloc_dbg
void *
calloc_dbg(size_t num, size_t size, char * function, char * file, int line)
{
void * ptr;
fprintf(stderr, "calloc of %d bytes at %s @%s:%d = ", num*size, function, file, line);
ptr = calloc(num,size);
fprintf(stderr, "%p\n", ptr);
return ptr;
}
#endif
#ifdef L_malloc_dbg
void *
malloc_dbg(size_t len, char * function, char * file, int line)
{
void * result;
fprintf(stderr, "malloc of %d bytes at %s @%s:%d = ", len, function, file, line);
result = malloc(len);
fprintf(stderr, "%p\n", result);
return result;
}
#endif
#ifdef L_free_dbg
void
free_dbg(void * ptr, char * function, char * file, int line)
{
fprintf(stderr, "free of %p at %s @%s:%d\n", ptr, function, file, line);
free(ptr);
}
#endif
#ifdef L_calloc
void *
calloc(size_t num, size_t size)
{
void * ptr = malloc(num*size);
if (ptr)
memset(ptr, 0, num*size);
return ptr;
}
#endif
#ifdef L_malloc
void *
malloc(size_t len)
{
void *result;
struct chunkControl *chunk;
struct nodeControl *next;
size_t size;
/* round len up to keep things on even boundaries */
len = ROUND_UP_LENGTH(len);
if (len == 0)
return 0;
TryAgain:
if (mallocNextNode != 0) {
/* first see if this request will fit on this chunk */
next = mallocNextNode;
chunk = next->chunk;
if (((char *)next + sizeof(struct nodeControl)*2 + len) <
((char *)chunk + chunk->chunkSize))
{
/* this request will fit, so simply move the next
* pointer ahead and update chunk node count */
next->nodeSize = len;
result = (char *)next + sizeof(struct nodeControl);
chunk->nodeCount++;
next = (struct nodeControl *)
((char *)next + (sizeof(struct nodeControl) + len));
next->chunk = chunk;
next->nodeSize = 0;
mallocNextNode = next;
return result; /* normal return path */
}
}
/* the request will not fit on this chunk, so get another chunk */
if (PageSize == 0) {
PageSize = getpagesize();
}
size = len + (sizeof(struct chunkControl) + (sizeof(struct nodeControl) * 2));
if (size < PageSize * 2) {
size = PageSize * 2;
}
size = (size + (PageSize-1)) & ~(PageSize-1);
chunk = mmap((void *)0, size, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
if (chunk == (void*)-1)
return 0;
chunk->chunkSize = size;
chunk->nodeCount = 0;
next = (struct nodeControl *)
((char *)chunk + sizeof(struct chunkControl));
next->chunk = chunk;
mallocNextNode = next;
goto TryAgain;
}
#endif
#ifdef L_free
void
free(void * ptr)
{
struct chunkControl *chunk;
struct nodeControl *node;
if (ptr == 0) {
return;
}
/* get a pointer to the control information for this memory node
* and the chunk it belongs to */
node = (struct nodeControl *)ptr - 1;
chunk = node->chunk;
/* decrement the node count and if it is zero free the chunk */
chunk->nodeCount--;
if (chunk->nodeCount == 0) {
if ((void *)mallocNextNode >= (void *)chunk &&
((void *)mallocNextNode < (void *)((char *)chunk + chunk->chunkSize)))
{
mallocNextNode = 0;
}
munmap(chunk, chunk->chunkSize);
}
}
#endif
#ifdef L_realloc
void *
realloc(void *ptr, size_t len)
{
struct nodeControl *node;
size_t oldSize;
void *new;
if (ptr == 0) {
return malloc(len);
}
if (len == 0) {
free(ptr);
return 0;
}
node = (struct nodeControl *)ptr - 1;
oldSize = node->nodeSize;
if (oldSize >= len) {
return ptr;
}
new = malloc(len);
memcpy(new, ptr, len);
free(ptr);
return new;
}
#endif
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