1 /* 2 * Copyright 2007 The Android Open Source Project 3 * 4 * Use of this source code is governed by a BSD-style license that can be 5 * found in the LICENSE file. 6 */ 7 8 #include "SkMask.h" 9 #include "SkMalloc.h" 10 #include "SkSafeMath.h" 11 12 /** returns the product if it is positive and fits in 31 bits. Otherwise this 13 returns 0. 14 */ 15 static int32_t safeMul32(int32_t a, int32_t b) { 16 int64_t size = sk_64_mul(a, b); 17 if (size > 0 && sk_64_isS32(size)) { 18 return sk_64_asS32(size); 19 } 20 return 0; 21 } 22 23 size_t SkMask::computeImageSize() const { 24 return safeMul32(fBounds.height(), fRowBytes); 25 } 26 27 size_t SkMask::computeTotalImageSize() const { 28 size_t size = this->computeImageSize(); 29 if (fFormat == SkMask::k3D_Format) { 30 size = safeMul32(SkToS32(size), 3); 31 } 32 return size; 33 } 34 35 /** We explicitly use this allocator for SkBimap pixels, so that we can 36 freely assign memory allocated by one class to the other. 37 */ 38 uint8_t* SkMask::AllocImage(size_t size, AllocType at) { 39 size_t aligned_size = SkSafeMath::Align4(size); 40 unsigned flags = SK_MALLOC_THROW; 41 if (at == kZeroInit_Alloc) { 42 flags |= SK_MALLOC_ZERO_INITIALIZE; 43 } 44 return static_cast<uint8_t*>(sk_malloc_flags(aligned_size, flags)); 45 } 46 47 /** We explicitly use this allocator for SkBimap pixels, so that we can 48 freely assign memory allocated by one class to the other. 49 */ 50 void SkMask::FreeImage(void* image) { 51 sk_free(image); 52 } 53 54 /////////////////////////////////////////////////////////////////////////////// 55 56 static const int gMaskFormatToShift[] = { 57 ~0, // BW -- not supported 58 0, // A8 59 0, // 3D 60 2, // ARGB32 61 1, // LCD16 62 }; 63 64 static int maskFormatToShift(SkMask::Format format) { 65 SkASSERT((unsigned)format < SK_ARRAY_COUNT(gMaskFormatToShift)); 66 SkASSERT(SkMask::kBW_Format != format); 67 return gMaskFormatToShift[format]; 68 } 69 70 void* SkMask::getAddr(int x, int y) const { 71 SkASSERT(kBW_Format != fFormat); 72 SkASSERT(fBounds.contains(x, y)); 73 SkASSERT(fImage); 74 75 char* addr = (char*)fImage; 76 addr += (y - fBounds.fTop) * fRowBytes; 77 addr += (x - fBounds.fLeft) << maskFormatToShift(fFormat); 78 return addr; 79 } 80
