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 //#define TRACK_SKMASK_LIFETIME
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 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
computeImageSize() const23 size_t SkMask::computeImageSize() const {
24 return safeMul32(fBounds.height(), fRowBytes);
25 }
26
computeTotalImageSize() const27 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 #ifdef TRACK_SKMASK_LIFETIME
36 static int gCounter;
37 #endif
38
39 /** We explicitly use this allocator for SkBimap pixels, so that we can
40 freely assign memory allocated by one class to the other.
41 */
AllocImage(size_t size)42 uint8_t* SkMask::AllocImage(size_t size) {
43 #ifdef TRACK_SKMASK_LIFETIME
44 SkDebugf("SkMask::AllocImage %d\n", gCounter++);
45 #endif
46 return (uint8_t*)sk_malloc_throw(SkAlign4(size));
47 }
48
49 /** We explicitly use this allocator for SkBimap pixels, so that we can
50 freely assign memory allocated by one class to the other.
51 */
FreeImage(void * image)52 void SkMask::FreeImage(void* image) {
53 #ifdef TRACK_SKMASK_LIFETIME
54 if (image) {
55 SkDebugf("SkMask::FreeImage %d\n", --gCounter);
56 }
57 #endif
58 sk_free(image);
59 }
60
61 ///////////////////////////////////////////////////////////////////////////////
62
63 static const int gMaskFormatToShift[] = {
64 ~0, // BW -- not supported
65 0, // A8
66 0, // 3D
67 2, // ARGB32
68 1, // LCD16
69 };
70
maskFormatToShift(SkMask::Format format)71 static int maskFormatToShift(SkMask::Format format) {
72 SkASSERT((unsigned)format < SK_ARRAY_COUNT(gMaskFormatToShift));
73 SkASSERT(SkMask::kBW_Format != format);
74 return gMaskFormatToShift[format];
75 }
76
getAddr(int x,int y) const77 void* SkMask::getAddr(int x, int y) const {
78 SkASSERT(kBW_Format != fFormat);
79 SkASSERT(fBounds.contains(x, y));
80 SkASSERT(fImage);
81
82 char* addr = (char*)fImage;
83 addr += (y - fBounds.fTop) * fRowBytes;
84 addr += (x - fBounds.fLeft) << maskFormatToShift(fFormat);
85 return addr;
86 }
87