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 */
safeMul32(int32_t a,int32_t b)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
computeImageSize() const24 size_t SkMask::computeImageSize() const {
25 return safeMul32(fBounds.height(), fRowBytes);
26 }
27
computeTotalImageSize() const28 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 */
AllocImage(size_t size)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 */
FreeImage(void * image)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
maskFormatToShift(SkMask::Format format)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
getAddr(int x,int y) const67 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