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 "src/webp/config.h" 20 #endif 21 22 #include <assert.h> 23 #include <limits.h> 24 25 #include "src/dsp/dsp.h" 26 #include "src/webp/types.h" 27 28 #ifdef __cplusplus 29 extern "C" { 30 #endif 31 32 //------------------------------------------------------------------------------ 33 // Memory allocation 34 35 // This is the maximum memory amount that libwebp will ever try to allocate. 36 #ifndef WEBP_MAX_ALLOCABLE_MEMORY 37 #if SIZE_MAX > (1ULL << 34) 38 #define WEBP_MAX_ALLOCABLE_MEMORY (1ULL << 34) 39 #else 40 // For 32-bit targets keep this below INT_MAX to avoid valgrind warnings. 41 #define WEBP_MAX_ALLOCABLE_MEMORY ((1ULL << 31) - (1 << 16)) 42 #endif 43 #endif // WEBP_MAX_ALLOCABLE_MEMORY 44 45 // size-checking safe malloc/calloc: verify that the requested size is not too 46 // large, or return NULL. You don't need to call these for constructs like 47 // malloc(sizeof(foo)), but only if there's picture-dependent size involved 48 // somewhere (like: malloc(num_pixels * sizeof(*something))). That's why this 49 // safe malloc() borrows the signature from calloc(), pointing at the dangerous 50 // underlying multiply involved. 51 WEBP_EXTERN void* WebPSafeMalloc(uint64_t nmemb, size_t size); 52 // Note that WebPSafeCalloc() expects the second argument type to be 'size_t' 53 // in order to favor the "calloc(num_foo, sizeof(foo))" pattern. 54 WEBP_EXTERN void* WebPSafeCalloc(uint64_t nmemb, size_t size); 55 56 // Companion deallocation function to the above allocations. 57 WEBP_EXTERN void WebPSafeFree(void* const ptr); 58 59 //------------------------------------------------------------------------------ 60 // Alignment 61 62 #define WEBP_ALIGN_CST 31 63 #define WEBP_ALIGN(PTR) (((uintptr_t)(PTR) + WEBP_ALIGN_CST) & ~WEBP_ALIGN_CST) 64 65 #include <string.h> 66 // memcpy() is the safe way of moving potentially unaligned 32b memory. 67 static WEBP_INLINE uint32_t WebPMemToUint32(const uint8_t* const ptr) { 68 uint32_t A; 69 memcpy(&A, ptr, sizeof(A)); 70 return A; 71 } 72 static WEBP_INLINE void WebPUint32ToMem(uint8_t* const ptr, uint32_t val) { 73 memcpy(ptr, &val, sizeof(val)); 74 } 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 // default: use the C-version. 128 // Returns 31 ^ clz(n) = log2(n). This is the default C-implementation, either 129 // based on table or not. Can be used as fallback if clz() is not available. 130 #define WEBP_NEED_LOG_TABLE_8BIT 131 extern const uint8_t WebPLogTable8bit[256]; 132 static WEBP_INLINE int WebPLog2FloorC(uint32_t n) { 133 int log_value = 0; 134 while (n >= 256) { 135 log_value += 8; 136 n >>= 8; 137 } 138 return log_value + WebPLogTable8bit[n]; 139 } 140 141 static WEBP_INLINE int BitsLog2Floor(uint32_t n) { return WebPLog2FloorC(n); } 142 #endif 143 144 //------------------------------------------------------------------------------ 145 // Pixel copying. 146 147 struct WebPPicture; 148 149 // Copy width x height pixels from 'src' to 'dst' honoring the strides. 150 WEBP_EXTERN void WebPCopyPlane(const uint8_t* src, int src_stride, 151 uint8_t* dst, int dst_stride, 152 int width, int height); 153 154 // Copy ARGB pixels from 'src' to 'dst' honoring strides. 'src' and 'dst' are 155 // assumed to be already allocated and using ARGB data. 156 WEBP_EXTERN void WebPCopyPixels(const struct WebPPicture* const src, 157 struct WebPPicture* const dst); 158 159 //------------------------------------------------------------------------------ 160 // Unique colors. 161 162 // Returns count of unique colors in 'pic', assuming pic->use_argb is true. 163 // If the unique color count is more than MAX_PALETTE_SIZE, returns 164 // MAX_PALETTE_SIZE+1. 165 // If 'palette' is not NULL and number of unique colors is less than or equal to 166 // MAX_PALETTE_SIZE, also outputs the actual unique colors into 'palette'. 167 // Note: 'palette' is assumed to be an array already allocated with at least 168 // MAX_PALETTE_SIZE elements. 169 WEBP_EXTERN int WebPGetColorPalette(const struct WebPPicture* const pic, 170 uint32_t* const palette); 171 172 //------------------------------------------------------------------------------ 173 174 #ifdef __cplusplus 175 } // extern "C" 176 #endif 177 178 #endif // WEBP_UTILS_UTILS_H_ 179