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 9 #include "Sk64.h" 10 #include "SkMask.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 Sk64 size; 17 size.setMul(a, b); 18 if (size.is32() && size.isPos()) { 19 return size.get32(); 20 } 21 return 0; 22 } 23 24 size_t SkMask::computeImageSize() const { 25 return safeMul32(fBounds.height(), fRowBytes); 26 } 27 28 size_t SkMask::computeTotalImageSize() const { 29 size_t size = this->computeImageSize(); 30 if (fFormat == SkMask::k3D_Format) { 31 size = safeMul32(size, 3); 32 } 33 return size; 34 } 35 36 /** We explicitly use this allocator for SkBimap pixels, so that we can 37 freely assign memory allocated by one class to the other. 38 */ 39 uint8_t* SkMask::AllocImage(size_t size) { 40 return (uint8_t*)sk_malloc_throw(SkAlign4(size)); 41 } 42 43 /** We explicitly use this allocator for SkBimap pixels, so that we can 44 freely assign memory allocated by one class to the other. 45 */ 46 void SkMask::FreeImage(void* image) { 47 sk_free(image); 48 } 49 50 /////////////////////////////////////////////////////////////////////////////// 51 52 static const int gMaskFormatToShift[] = { 53 ~0, // BW -- not supported 54 0, // A8 55 0, // 3D 56 2, // ARGB32 57 1, // LCD16 58 2 // LCD32 59 }; 60 61 static int maskFormatToShift(SkMask::Format format) { 62 SkASSERT((unsigned)format < SK_ARRAY_COUNT(gMaskFormatToShift)); 63 SkASSERT(SkMask::kBW_Format != format); 64 return gMaskFormatToShift[format]; 65 } 66 67 void* SkMask::getAddr(int x, int y) const { 68 SkASSERT(kBW_Format != fFormat); 69 SkASSERT(fBounds.contains(x, y)); 70 SkASSERT(fImage); 71 72 char* addr = (char*)fImage; 73 addr += (y - fBounds.fTop) * fRowBytes; 74 addr += (x - fBounds.fLeft) << maskFormatToShift(fFormat); 75 return addr; 76 } 77 78
