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#ifdef HAVE_CONFIG_H 19#include "../webp/config.h" 20#endif 21 22#include <assert.h> 23#include <limits.h> 24 25#include "../dsp/dsp.h" 26#include "../webp/types.h" 27 28#ifdef __cplusplus 29extern "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. 51WEBP_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. 54WEBP_EXTERN(void*) WebPSafeCalloc(uint64_t nmemb, size_t size); 55 56// Companion deallocation function to the above allocations. 57WEBP_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. 67static WEBP_INLINE uint32_t WebPMemToUint32(const uint8_t* const ptr) { 68 uint32_t A; 69 memcpy(&A, (const int*)ptr, sizeof(A)); 70 return A; 71} 72static 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. 80static WEBP_INLINE int GetLE16(const uint8_t* const data) { 81 return (int)(data[0] << 0) | (data[1] << 8); 82} 83 84static WEBP_INLINE int GetLE24(const uint8_t* const data) { 85 return GetLE16(data) | (data[2] << 16); 86} 87 88static 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. 93static 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 99static 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 105static 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 31 ^ clz(n) = log2(n). This is the default C-implementation, either 111// based on table or not. Can be used as fallback if clz() is not available. 112#define WEBP_NEED_LOG_TABLE_8BIT 113extern const uint8_t WebPLogTable8bit[256]; 114static WEBP_INLINE int WebPLog2FloorC(uint32_t n) { 115 int log = 0; 116 while (n >= 256) { 117 log += 8; 118 n >>= 8; 119 } 120 return log + WebPLogTable8bit[n]; 121} 122 123// Returns (int)floor(log2(n)). n must be > 0. 124// use GNU builtins where available. 125#if defined(__GNUC__) && \ 126 ((__GNUC__ == 3 && __GNUC_MINOR__ >= 4) || __GNUC__ >= 4) 127static WEBP_INLINE int BitsLog2Floor(uint32_t n) { 128 return 31 ^ __builtin_clz(n); 129} 130#elif defined(_MSC_VER) && _MSC_VER > 1310 && \ 131 (defined(_M_X64) || defined(_M_IX86)) 132#include <intrin.h> 133#pragma intrinsic(_BitScanReverse) 134 135static WEBP_INLINE int BitsLog2Floor(uint32_t n) { 136 unsigned long first_set_bit; 137 _BitScanReverse(&first_set_bit, n); 138 return first_set_bit; 139} 140#else // default: use the C-version. 141static WEBP_INLINE int BitsLog2Floor(uint32_t n) { return WebPLog2FloorC(n); } 142#endif 143 144//------------------------------------------------------------------------------ 145// Pixel copying. 146 147struct WebPPicture; 148 149// Copy width x height pixels from 'src' to 'dst' honoring the strides. 150WEBP_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. 156WEBP_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. 169WEBP_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