alloc.c

从iccavr7中破解得到的lib库源代码

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <_alloc.h>

#ifdef DEBUG
#define calloc	xcalloc
#define malloc	xmalloc
#define realloc xrealloc
#define free	xfree

void *malloc(), *realloc(), *calloc();
void free();
#endif

void *calloc(size_t nelem, size_t size)
	{
	void *p;

	size *= nelem;
	p = malloc(size);
	if (p == 0)
		return 0;
	memset(p, 0, size);

	return p;
	}

void *malloc(size_t size)
	{
	CELL_HDR **qb;
	CELL_HDR *p, *q;
	char *cp, *rp;
	int i;

	size = roundup(size, _BND);

	for (qb = &__FreeList; p = *qb; qb = &(*qb)->next)
		if (size <= p->size)
			{
			if (DELTA < p->size - size)
				{
				/* some space left, link it to the free list
				 */
				q = (CELL_HDR *)INCR_SIZE(p, size);
				q->next = p->next;
				q->size = p->size - REAL_SIZE(size);
				q->size &= ~_BND;
				q->EndAddr = p->EndAddr;
#ifdef DEBUG
				q->InUse = 0;
#endif
				p->EndAddr = q;
				p->size = NEW_SIZE(p, p->EndAddr);
				*qb = q;
				}
			else
				*qb = p->next;
			p->next = 0;
#ifdef DEBUG
			p->InUse = 1;
#endif
			cp = INCR_SIZE(p, 0);
			return cp;
			}
	return 0;
	}

void *realloc(void *p, size_t size)
	{
	CELL_HDR *cell = GET_HDR(p);
	void *q;

	if ((char *)cell->EndAddr >= (char *)p + size)
		{
		cell->size = size;
		return p;
		}
	q = malloc(size);
	if (q == 0)
		return 0;
	/* copy only the beginning portion
	 */
	if (size > cell->size)
		size = cell->size;
	memcpy(q, p, size);
	free(p);
	return q;
	}

static void Merge(CELL_HDR *cell)
	{
	CELL_HDR **qb;
	CELL_HDR *p;

	for (qb = &__FreeList; p = *qb; qb = &(*qb)->next)
		/* merge with next chunk
		 */
		if (cell->EndAddr == p)
			{
			*qb = p->next;
			cell->size += REAL_SIZE(p->size);  /* Added by wph */
			cell->EndAddr = p->EndAddr;
			Merge(cell);
			break;
			}
		/* merge with previous chunk
		 */
		else if (p->EndAddr == cell)
			{
			*qb = p->next;
			p->size += REAL_SIZE(cell->size);  /* Added by wph */
			p->EndAddr = cell->EndAddr;
			Merge(p);
			break;
			}
	if (!p)
		{
		cell->next = __FreeList;
		__FreeList = cell;
		}
	}

void free(void *p)
	{
	CELL_HDR *cell;

	if (!p)
		return;
	cell = GET_HDR(p);

	if ((char *)cell->EndAddr < INCR_SIZE(cell, cell->size)
#ifdef DEBUG
		|| !cell->InUse
#endif
		)
		{
#ifdef DEBUG
		printf("bad memory %x\n", p);
#endif
		return;
		}

#ifdef DEBUG
	cell->InUse = 0;
#endif
	Merge(cell);
	}

#ifdef DEBUG
void _PrintMemList(void)
	{
	CELL_HDR *p;

	for (p = __FreeList; p; p = p->next)
		printf("start %x end %x %s\n", p, p->EndAddr,
				(p->InUse) ? "!in use!" : "");
	}
#endif