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 (at) gmail.com) 13 // Urvang (urvang (at) google.com) 14 15 #ifndef WEBP_UTILS_UTILS_H_ 16 #define WEBP_UTILS_UTILS_H_ 17 18 #ifdef HAVE_CONFIG_H 19 #include "../webp/config.h" 20 #endif 21 22 #include <assert.h> 23 24 #include "../webp/types.h" 25 26 #ifdef __cplusplus 27 extern "C" { 28 #endif 29 30 //------------------------------------------------------------------------------ 31 // Memory allocation 32 33 // This is the maximum memory amount that libwebp will ever try to allocate. 34 #define WEBP_MAX_ALLOCABLE_MEMORY (1ULL << 40) 35 36 // size-checking safe malloc/calloc: verify that the requested size is not too 37 // large, or return NULL. You don't need to call these for constructs like 38 // malloc(sizeof(foo)), but only if there's picture-dependent size involved 39 // somewhere (like: malloc(num_pixels * sizeof(*something))). That's why this 40 // safe malloc() borrows the signature from calloc(), pointing at the dangerous 41 // underlying multiply involved. 42 WEBP_EXTERN(void*) WebPSafeMalloc(uint64_t nmemb, size_t size); 43 // Note that WebPSafeCalloc() expects the second argument type to be 'size_t' 44 // in order to favor the "calloc(num_foo, sizeof(foo))" pattern. 45 WEBP_EXTERN(void*) WebPSafeCalloc(uint64_t nmemb, size_t size); 46 47 // Companion deallocation function to the above allocations. 48 WEBP_EXTERN(void) WebPSafeFree(void* const ptr); 49 50 //------------------------------------------------------------------------------ 51 // Alignment 52 53 #define WEBP_ALIGN_CST 31 54 #define WEBP_ALIGN(PTR) ((uintptr_t)((PTR) + WEBP_ALIGN_CST) & ~WEBP_ALIGN_CST) 55 56 #if defined(WEBP_FORCE_ALIGNED) 57 #include <string.h> 58 // memcpy() is the safe way of moving potentially unaligned 32b memory. 59 static WEBP_INLINE uint32_t WebPMemToUint32(const uint8_t* const ptr) { 60 uint32_t A; 61 memcpy(&A, (const int*)ptr, sizeof(A)); 62 return A; 63 } 64 static WEBP_INLINE void WebPUint32ToMem(uint8_t* const ptr, uint32_t val) { 65 memcpy(ptr, &val, sizeof(val)); 66 } 67 #else 68 static WEBP_INLINE uint32_t WebPMemToUint32(const uint8_t* const ptr) { 69 return *(const uint32_t*)ptr; 70 } 71 static WEBP_INLINE void WebPUint32ToMem(uint8_t* const ptr, uint32_t val) { 72 *(uint32_t*)ptr = val; 73 } 74 #endif 75 76 //------------------------------------------------------------------------------ 77 // Reading/writing data. 78 79 // Read 16, 24 or 32 bits stored in little-endian order. 80 static WEBP_INLINE int GetLE16(const uint8_t* const data) { 81 return (int)(data[0] << 0) | (data[1] << 8); 82 } 83 84 static WEBP_INLINE int GetLE24(const uint8_t* const data) { 85 return GetLE16(data) | (data[2] << 16); 86 } 87 88 static WEBP_INLINE uint32_t GetLE32(const uint8_t* const data) { 89 return GetLE16(data) | ((uint32_t)GetLE16(data + 2) << 16); 90 } 91 92 // Store 16, 24 or 32 bits in little-endian order. 93 static WEBP_INLINE void PutLE16(uint8_t* const data, int val) { 94 assert(val < (1 << 16)); 95 data[0] = (val >> 0); 96 data[1] = (val >> 8); 97 } 98 99 static WEBP_INLINE void PutLE24(uint8_t* const data, int val) { 100 assert(val < (1 << 24)); 101 PutLE16(data, val & 0xffff); 102 data[2] = (val >> 16); 103 } 104 105 static WEBP_INLINE void PutLE32(uint8_t* const data, uint32_t val) { 106 PutLE16(data, (int)(val & 0xffff)); 107 PutLE16(data + 2, (int)(val >> 16)); 108 } 109 110 // Returns (int)floor(log2(n)). n must be > 0. 111 // use GNU builtins where available. 112 #if defined(__GNUC__) && \ 113 ((__GNUC__ == 3 && __GNUC_MINOR__ >= 4) || __GNUC__ >= 4) 114 static WEBP_INLINE int BitsLog2Floor(uint32_t n) { 115 return 31 ^ __builtin_clz(n); 116 } 117 #elif defined(_MSC_VER) && _MSC_VER > 1310 && \ 118 (defined(_M_X64) || defined(_M_IX86)) 119 #include <intrin.h> 120 #pragma intrinsic(_BitScanReverse) 121 122 static WEBP_INLINE int BitsLog2Floor(uint32_t n) { 123 unsigned long first_set_bit; 124 _BitScanReverse(&first_set_bit, n); 125 return first_set_bit; 126 } 127 #else 128 static WEBP_INLINE int BitsLog2Floor(uint32_t n) { 129 int log = 0; 130 uint32_t value = n; 131 int i; 132 133 for (i = 4; i >= 0; --i) { 134 const int shift = (1 << i); 135 const uint32_t x = value >> shift; 136 if (x != 0) { 137 value = x; 138 log += shift; 139 } 140 } 141 return log; 142 } 143 #endif 144 145 //------------------------------------------------------------------------------ 146 // Pixel copying. 147 148 struct WebPPicture; 149 150 // Copy width x height pixels from 'src' to 'dst' honoring the strides. 151 WEBP_EXTERN(void) WebPCopyPlane(const uint8_t* src, int src_stride, 152 uint8_t* dst, int dst_stride, 153 int width, int height); 154 155 // Copy ARGB pixels from 'src' to 'dst' honoring strides. 'src' and 'dst' are 156 // assumed to be already allocated and using ARGB data. 157 WEBP_EXTERN(void) WebPCopyPixels(const struct WebPPicture* const src, 158 struct WebPPicture* const dst); 159 160 //------------------------------------------------------------------------------ 161 162 #ifdef __cplusplus 163 } // extern "C" 164 #endif 165 166 #endif /* WEBP_UTILS_UTILS_H_ */ 167
