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)
21 extern "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.
36 void* 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.
39 void* 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.
GetLE16(const uint8_t * const data)45 static WEBP_INLINE int GetLE16(const uint8_t* const data) {
46 return (int)(data[0] << 0) | (data[1] << 8);
47 }
48
GetLE24(const uint8_t * const data)49 static WEBP_INLINE int GetLE24(const uint8_t* const data) {
50 return GetLE16(data) | (data[2] << 16);
51 }
52
GetLE32(const uint8_t * const data)53 static 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.
PutLE16(uint8_t * const data,int val)58 static 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
PutLE24(uint8_t * const data,int val)64 static 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
PutLE32(uint8_t * const data,uint32_t val)70 static 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