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 #include "SkMalloc.h"
11
12 //#define TRACK_SKMASK_LIFETIME
13
14 /** returns the product if it is positive and fits in 31 bits. Otherwise this
15 returns 0.
16 */
safeMul32(int32_t a,int32_t b)17 static int32_t safeMul32(int32_t a, int32_t b) {
18 int64_t size = sk_64_mul(a, b);
19 if (size > 0 && sk_64_isS32(size)) {
20 return sk_64_asS32(size);
21 }
22 return 0;
23 }
24
computeImageSize() const25 size_t SkMask::computeImageSize() const {
26 return safeMul32(fBounds.height(), fRowBytes);
27 }
28
computeTotalImageSize() const29 size_t SkMask::computeTotalImageSize() const {
30 size_t size = this->computeImageSize();
31 if (fFormat == SkMask::k3D_Format) {
32 size = safeMul32(SkToS32(size), 3);
33 }
34 return size;
35 }
36
37 #ifdef TRACK_SKMASK_LIFETIME
38 static int gCounter;
39 #endif
40
41 /** We explicitly use this allocator for SkBimap pixels, so that we can
42 freely assign memory allocated by one class to the other.
43 */
AllocImage(size_t size)44 uint8_t* SkMask::AllocImage(size_t size) {
45 #ifdef TRACK_SKMASK_LIFETIME
46 SkDebugf("SkMask::AllocImage %d\n", gCounter++);
47 #endif
48 return (uint8_t*)sk_malloc_throw(SkAlign4(size));
49 }
50
51 /** We explicitly use this allocator for SkBimap pixels, so that we can
52 freely assign memory allocated by one class to the other.
53 */
FreeImage(void * image)54 void SkMask::FreeImage(void* image) {
55 #ifdef TRACK_SKMASK_LIFETIME
56 if (image) {
57 SkDebugf("SkMask::FreeImage %d\n", --gCounter);
58 }
59 #endif
60 sk_free(image);
61 }
62
63 ///////////////////////////////////////////////////////////////////////////////
64
65 static const int gMaskFormatToShift[] = {
66 ~0, // BW -- not supported
67 0, // A8
68 0, // 3D
69 2, // ARGB32
70 1, // LCD16
71 };
72
maskFormatToShift(SkMask::Format format)73 static int maskFormatToShift(SkMask::Format format) {
74 SkASSERT((unsigned)format < SK_ARRAY_COUNT(gMaskFormatToShift));
75 SkASSERT(SkMask::kBW_Format != format);
76 return gMaskFormatToShift[format];
77 }
78
getAddr(int x,int y) const79 void* SkMask::getAddr(int x, int y) const {
80 SkASSERT(kBW_Format != fFormat);
81 SkASSERT(fBounds.contains(x, y));
82 SkASSERT(fImage);
83
84 char* addr = (char*)fImage;
85 addr += (y - fBounds.fTop) * fRowBytes;
86 addr += (x - fBounds.fLeft) << maskFormatToShift(fFormat);
87 return addr;
88 }
89