/*

 *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.

 *

 *  Use of this source code is governed by a BSD-style license

 *  that can be found in the LICENSE file in the root of the source

 *  tree. An additional intellectual property rights grant can be found

 *  in the file PATENTS.  All contributing project authors may

 *  be found in the AUTHORS file in the root of the source tree.

 */

#include "vpx_mem.h"

#include <limits.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include "include/vpx_mem_intrnl.h"

#include "vpx/vpx_integer.h"

#if !defined(VPX_MAX_ALLOCABLE_MEMORY)

#if SIZE_MAX > (1ULL << 40)

#define VPX_MAX_ALLOCABLE_MEMORY (1ULL << 40)

#else

// For 32-bit targets keep this below INT_MAX to avoid valgrind warnings.

#define VPX_MAX_ALLOCABLE_MEMORY ((1ULL << 31) - (1 << 16))

#endif

#endif

// Returns 0 in case of overflow of nmemb * size.

static int check_size_argument_overflow(uint64_t nmemb, uint64_t size) {

  const uint64_t total_size = nmemb * size;

  if (nmemb == 0) return 1;

  if (size > VPX_MAX_ALLOCABLE_MEMORY / nmemb) return 0;

  if (total_size != (size_t)total_size) return 0;

  return 1;

}

static size_t *get_malloc_address_location(void *const mem) {

  return ((size_t *)mem) - 1;

}

static uint64_t get_aligned_malloc_size(size_t size, size_t align) {

  return (uint64_t)size + align - 1 + ADDRESS_STORAGE_SIZE;

}

static void set_actual_malloc_address(void *const mem,

                                      const void *const malloc_addr) {

  size_t *const malloc_addr_location = get_malloc_address_location(mem);

  *malloc_addr_location = (size_t)malloc_addr;

}

static void *get_actual_malloc_address(void *const mem) {

  size_t *const malloc_addr_location = get_malloc_address_location(mem);

  return (void *)(*malloc_addr_location);

}

void *vpx_memalign(size_t align, size_t size) {

  void *x = NULL, *addr;

  const uint64_t aligned_size = get_aligned_malloc_size(size, align);

  if (!check_size_argument_overflow(1, aligned_size)) return NULL;

  addr = malloc((size_t)aligned_size);

  if (addr) {

    x = align_addr((unsigned char *)addr + ADDRESS_STORAGE_SIZE, align);

    set_actual_malloc_address(x, addr);

  }

  return x;

}

void *vpx_malloc(size_t size) { return vpx_memalign(DEFAULT_ALIGNMENT, size); }

void *vpx_calloc(size_t num, size_t size) {

  void *x;

  if (!check_size_argument_overflow(num, size)) return NULL;

  x = vpx_malloc(num * size);

  if (x) memset(x, 0, num * size);

  return x;

}

void vpx_free(void *memblk) {

  if (memblk) {

    void *addr = get_actual_malloc_address(memblk);

    free(addr);

  }

}