/*

 * Copyright (c) 2021, Alliance for Open Media. All rights reserved

 *

 * This source code is subject to the terms of the BSD 3-Clause Clear License

 * and the Alliance for Open Media Patent License 1.0. If the BSD 3-Clause Clear

 * License was not distributed with this source code in the LICENSE file, you

 * can obtain it at aomedia.org/license/software-license/bsd-3-c-c/.  If the

 * Alliance for Open Media Patent License 1.0 was not distributed with this

 * source code in the PATENTS file, you can obtain it at

 * aomedia.org/license/patent-license/.

 */

#include "avm_mem.h"

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include "include/avm_mem_intrnl.h"

#include "avm/avm_integer.h"

#if defined(AVM_MAX_ALLOCABLE_MEMORY)

// 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 > AVM_MAX_ALLOCABLE_MEMORY / nmemb) return 0;

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

  return 1;

}

#endif

static size_t GetAlignedMallocSize(size_t size, size_t align) {

  return size + align - 1 + ADDRESS_STORAGE_SIZE;

}

static size_t *GetMallocAddressLocation(void *const mem) {

  return ((size_t *)mem) - 1;

}

static void SetActualMallocAddress(void *const mem,

                                   const void *const malloc_addr) {

  size_t *const malloc_addr_location = GetMallocAddressLocation(mem);

  *malloc_addr_location = (size_t)malloc_addr;

}

static void *GetActualMallocAddress(void *const mem) {

  const size_t *const malloc_addr_location = GetMallocAddressLocation(mem);

  return (void *)(*malloc_addr_location);

}

void *avm_memalign(size_t align, size_t size) {

  void *x = NULL;

  const size_t aligned_size = GetAlignedMallocSize(size, align);

#if defined(AVM_MAX_ALLOCABLE_MEMORY)

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

#endif

  void *const addr = malloc(aligned_size);

  if (addr) {

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

    SetActualMallocAddress(x, addr);

  }

  return x;

}

void *avm_malloc(size_t size) { return avm_memalign(DEFAULT_ALIGNMENT, size); }

void *avm_calloc(size_t num, size_t size) {

  const size_t total_size = num * size;

  void *const x = avm_malloc(total_size);

  if (x) memset(x, 0, total_size);

  return x;

}

void avm_free(void *memblk) {

  if (memblk) {

    void *addr = GetActualMallocAddress(memblk);

    free(addr);

  }

}

void *avm_memset16(void *dest, int val, size_t length) {

  size_t i;

  uint16_t *dest16 = (uint16_t *)dest;

  for (i = 0; i < length; i++) *dest16++ = val;

  return dest;

}

void *avm_memset_int16(void *dest, int16_t val, size_t length) {

  size_t i;

  int16_t *dest16 = (int16_t *)dest;

  for (i = 0; i < length; i++) *dest16++ = val;

  return dest;

}