mem.cpp

/*
 * default memory allocator for libavutil
 * Copyright (c) 2002 Fabrice Bellard
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file
 * default memory allocator for libavutil
 */

#define _XOPEN_SOURCE 600

#include <limits.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>

#include "compat.h"
#include "intreadwrite.h"
#include "mem.h"

 /**
  * Multiply two size_t values checking for overflow.
  * @return  0 if success, AVERROR(EINVAL) if overflow.
  */
static inline int av_size_mult(size_t a, size_t b, size_t *r)
{
    size_t t = a * b;
    /* Hack inspired from glibc: only try the division if nelem and elsize
     * are both greater than sqrt(SIZE_MAX). */
    if ((a | b) >= ((size_t)1 << (sizeof(size_t) * 4)) && a && t / a != b)
        return AVERROR(EINVAL);
    *r = t;
    return 0;
}

#define ALIGN (HAVE_AVX ? 32 : 16)

void *av_malloc(size_t size)
{
    void *ptr = NULL;
    ptr = malloc(size);
    if(!ptr && !size) {
        size = 1;
        ptr= av_malloc(1);
    }
    return ptr;
}

void *av_realloc(void *ptr, size_t size)
{
    return realloc(ptr, size + !size);
}

void *av_realloc_f(void *ptr, size_t nelem, size_t elsize)
{
    size_t size;
    void *r;

    if (av_size_mult(elsize, nelem, &size)) {
        av_free(ptr);
        return NULL;
    }
    r = av_realloc(ptr, size);
    if (!r && size)
        av_free(ptr);
    return r;
}

void av_free(void *ptr)
{
    free(ptr);
}

void av_freep(void *arg)
{
    void *val;

    memcpy(&val, arg, sizeof(val));
    memset(arg, 0, sizeof(val));
    av_free(val);
}

void *av_mallocz(size_t size)
{
    void *ptr = av_malloc(size);
    if (ptr)
        memset(ptr, 0, size);
    return ptr;
}