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