github.com/cellofellow/gopkg@v0.0.0-20140722061823-eec0544a62ad/image/webp/libwebp/src/utils/utils.h (about)

     1  // Copyright 2012 Google Inc. All Rights Reserved.
     2  //
     3  // Use of this source code is governed by a BSD-style license
     4  // that can be found in the COPYING file in the root of the source
     5  // tree. An additional intellectual property rights grant can be found
     6  // in the file PATENTS. All contributing project authors may
     7  // be found in the AUTHORS file in the root of the source tree.
     8  // -----------------------------------------------------------------------------
     9  //
    10  // Misc. common utility functions
    11  //
    12  // Authors: Skal (pascal.massimino@gmail.com)
    13  //          Urvang (urvang@google.com)
    14  
    15  #ifndef WEBP_UTILS_UTILS_H_
    16  #define WEBP_UTILS_UTILS_H_
    17  
    18  #include <assert.h>
    19  
    20  #include "../webp/types.h"
    21  
    22  #ifdef __cplusplus
    23  extern "C" {
    24  #endif
    25  
    26  //------------------------------------------------------------------------------
    27  // Memory allocation
    28  
    29  // This is the maximum memory amount that libwebp will ever try to allocate.
    30  #define WEBP_MAX_ALLOCABLE_MEMORY (1ULL << 40)
    31  
    32  // size-checking safe malloc/calloc: verify that the requested size is not too
    33  // large, or return NULL. You don't need to call these for constructs like
    34  // malloc(sizeof(foo)), but only if there's picture-dependent size involved
    35  // somewhere (like: malloc(num_pixels * sizeof(*something))). That's why this
    36  // safe malloc() borrows the signature from calloc(), pointing at the dangerous
    37  // underlying multiply involved.
    38  void* WebPSafeMalloc(uint64_t nmemb, size_t size);
    39  // Note that WebPSafeCalloc() expects the second argument type to be 'size_t'
    40  // in order to favor the "calloc(num_foo, sizeof(foo))" pattern.
    41  void* WebPSafeCalloc(uint64_t nmemb, size_t size);
    42  
    43  //------------------------------------------------------------------------------
    44  // Reading/writing data.
    45  
    46  // Read 16, 24 or 32 bits stored in little-endian order.
    47  static WEBP_INLINE int GetLE16(const uint8_t* const data) {
    48    return (int)(data[0] << 0) | (data[1] << 8);
    49  }
    50  
    51  static WEBP_INLINE int GetLE24(const uint8_t* const data) {
    52    return GetLE16(data) | (data[2] << 16);
    53  }
    54  
    55  static WEBP_INLINE uint32_t GetLE32(const uint8_t* const data) {
    56    return (uint32_t)GetLE16(data) | (GetLE16(data + 2) << 16);
    57  }
    58  
    59  // Store 16, 24 or 32 bits in little-endian order.
    60  static WEBP_INLINE void PutLE16(uint8_t* const data, int val) {
    61    assert(val < (1 << 16));
    62    data[0] = (val >> 0);
    63    data[1] = (val >> 8);
    64  }
    65  
    66  static WEBP_INLINE void PutLE24(uint8_t* const data, int val) {
    67    assert(val < (1 << 24));
    68    PutLE16(data, val & 0xffff);
    69    data[2] = (val >> 16);
    70  }
    71  
    72  static WEBP_INLINE void PutLE32(uint8_t* const data, uint32_t val) {
    73    PutLE16(data, (int)(val & 0xffff));
    74    PutLE16(data + 2, (int)(val >> 16));
    75  }
    76  
    77  //------------------------------------------------------------------------------
    78  
    79  #ifdef __cplusplus
    80  }    // extern "C"
    81  #endif
    82  
    83  #endif  /* WEBP_UTILS_UTILS_H_ */