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#include<stdio.h>
#include<stdlib.h>
#include<stddef.h>
#define align(d) (((d)+(sizeof(void*)-1))&(~(sizeof(void*)-1)))
#define HEAPIMPLEMENTATION
typedef struct{
struct heap_block *first;
struct heap_block *last;
long blocksize;
char *top_of_heap;
}heap;
struct heap_block{
struct heap_block *next;
long free;
};
#include"heap.h"
heap *heap_create( long block_size ) /* allocates memory for heap */
{
heap *HEAP;
HEAP = ( heap * )malloc( align( block_size) + sizeof(heap)+sizeof(struct heap_block));
if(NULL == HEAP)return(NULL);
HEAP->first = (struct heap_block*)(HEAP+1);
HEAP->last = HEAP->first;
HEAP->blocksize = align( block_size );
HEAP->top_of_heap = (char *)(HEAP->last+1); /* next free entry */
HEAP->first->next = NULL;
HEAP->first->free = block_size;
return(HEAP);
} /* heap_create() */
void *heap_allocate( heap *HEAP, long size ) /* allocates on heap */
{
void *help;
if ( HEAP->last->free < size )
{
if( NULL ==(HEAP->last->next = ( struct heap_block * )malloc( HEAP->blocksize+sizeof(struct heap_block))))return(NULL);
HEAP->last = HEAP->last->next;
HEAP->last->next = NULL;
HEAP->last->free = HEAP->blocksize;
HEAP->top_of_heap = (void *)(HEAP->last+1); /* next free entry */
}
help = HEAP->top_of_heap;
HEAP->top_of_heap += (align(size) + sizeof(char) -1) / sizeof(char);
HEAP->last->free -= align(size);
return(help);
} /* heap_allocate() */
void heap_resize( heap *HEAP, void *entry, long size )
{
HEAP->last->free += HEAP->top_of_heap - ( (char *)entry + align( size ) );
HEAP->top_of_heap = (char *)entry + align( size );
} /* heap_resize() */
void heap_delete( heap *HEAP )
{
struct heap_block *this, *next;
this = HEAP->first;
free(HEAP);
while(this)
{
next = this->next;
free(this);
this = next;
} /* of while(this) */
} /* of heap_delete() */
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