third_party/libwebp/utils/utils.h

   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 #if defined(__cplusplus) || defined(c_plusplus)
  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 #if defined(__cplusplus) || defined(c_plusplus)
  80 }    // extern "C"
  81 #endif
  82
  83 #endif  /* WEBP_UTILS_UTILS_H_ */