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 10 /** returns the product if it is positive and fits in 31 bits. Otherwise this 11 returns 0. 12 */ 13 static int32_t safeMul32(int32_t a, int32_t b) { 14 int64_t size = sk_64_mul(a, b); 15 if (size > 0 && sk_64_isS32(size)) { 16 return sk_64_asS32(size); 17 } 18 return 0; 19 } 20 21 size_t SkMask::computeImageSize() const { 22 return safeMul32(fBounds.height(), fRowBytes); 23 } 24 25 size_t SkMask::computeTotalImageSize() const { 26 size_t size = this->computeImageSize(); 27 if (fFormat == SkMask::k3D_Format) { 28 size = safeMul32(SkToS32(size), 3); 29 } 30 return size; 31 } 32 33 /** We explicitly use this allocator for SkBimap pixels, so that we can 34 freely assign memory allocated by one class to the other. 35 */ 36 uint8_t* SkMask::AllocImage(size_t size) { 37 return (uint8_t*)sk_malloc_throw(SkAlign4(size)); 38 } 39 40 /** We explicitly use this allocator for SkBimap pixels, so that we can 41 freely assign memory allocated by one class to the other. 42 */ 43 void SkMask::FreeImage(void* image) { 44 sk_free(image); 45 } 46 47 /////////////////////////////////////////////////////////////////////////////// 48 49 static const int gMaskFormatToShift[] = { 50 ~0, // BW -- not supported 51 0, // A8 52 0, // 3D 53 2, // ARGB32 54 1, // LCD16 55 2 // LCD32 56 }; 57 58 static int maskFormatToShift(SkMask::Format format) { 59 SkASSERT((unsigned)format < SK_ARRAY_COUNT(gMaskFormatToShift)); 60 SkASSERT(SkMask::kBW_Format != format); 61 return gMaskFormatToShift[format]; 62 } 63 64 void* SkMask::getAddr(int x, int y) const { 65 SkASSERT(kBW_Format != fFormat); 66 SkASSERT(fBounds.contains(x, y)); 67 SkASSERT(fImage); 68 69 char* addr = (char*)fImage; 70 addr += (y - fBounds.fTop) * fRowBytes; 71 addr += (x - fBounds.fLeft) << maskFormatToShift(fFormat); 72 return addr; 73 } 74
