mvmemoryalloc.c

优化过的xvid1.1.2源代码

#include "MVGlobal.h"
#include "MVMemoryalloc.h"

void *  xvid_malloc(size_t size,
		        	uint8_t alignment)
{
	uint8_t *mem_ptr;

	if (!alignment)
	{

		if ((mem_ptr = (uint8_t *) malloc(size + 1)) != NULL) 
		{

			*mem_ptr = (uint8_t)1;

			return ((void *)(mem_ptr+1));
		}
	} 
	else
	{
		uint8_t *tmp;

		if ((tmp = (uint8_t *) malloc(size + alignment)) != NULL) 
		{

			mem_ptr = 	(uint8_t *) ((ptr_t) (tmp + alignment - 1) &
					            	 (~(ptr_t) (alignment - 1)));

			if (mem_ptr == tmp)
				mem_ptr += alignment;

			*(mem_ptr - 1) = (uint8_t) (mem_ptr - tmp);

			return ((void *)mem_ptr);
		}
	}

	return(NULL);
}


void xvid_free(void *mem_ptr)

{
	uint8_t *ptr;

	if (mem_ptr == NULL)
		return;

	ptr = mem_ptr;

	ptr -= *(ptr - 1);

	free(ptr);
}