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 24#include "../webp/types.h" 25 26#ifdef __cplusplus 27extern "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. 42WEBP_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. 45WEBP_EXTERN(void*) WebPSafeCalloc(uint64_t nmemb, size_t size); 46 47// Companion deallocation function to the above allocations. 48WEBP_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. 59static 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} 64static WEBP_INLINE void WebPUint32ToMem(uint8_t* const ptr, uint32_t val) { 65 memcpy(ptr, &val, sizeof(val)); 66} 67#else 68static WEBP_INLINE uint32_t WebPMemToUint32(const uint8_t* const ptr) { 69 return *(const uint32_t*)ptr; 70} 71static 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. 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 (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) 114static 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 122static 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 128static 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 148struct WebPPicture; 149 150// Copy width x height pixels from 'src' to 'dst' honoring the strides. 151WEBP_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. 157WEBP_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