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 */
safeMul32(int32_t a,int32_t b)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
computeImageSize() const21 size_t SkMask::computeImageSize() const {
22 return safeMul32(fBounds.height(), fRowBytes);
23 }
24
computeTotalImageSize() const25 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 */
AllocImage(size_t size)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 */
FreeImage(void * image)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
maskFormatToShift(SkMask::Format format)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
getAddr(int x,int y) const64 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