gfx/2d/Tools.h@97036ab72558
gfx/2d/Tools.h
Tue, 06 Jan 2015 21:39:09 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Tue, 06 Jan 2015 21:39:09 +0100
- branch
- TOR_BUG_9701
- changeset 8
- 97036ab72558
- permissions
- -rw-r--r--
Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.
1 /* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
2 * This Source Code Form is subject to the terms of the Mozilla Public
3 * License, v. 2.0. If a copy of the MPL was not distributed with this
4 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
6 #ifndef MOZILLA_GFX_TOOLS_H_
7 #define MOZILLA_GFX_TOOLS_H_
9 #include "Types.h"
10 #include "Point.h"
11 #include <math.h>
12 #if defined(_MSC_VER) && (_MSC_VER < 1600)
13 #define hypotf _hypotf
14 #endif
16 namespace mozilla {
17 namespace gfx {
19 static inline bool
20 IsOperatorBoundByMask(CompositionOp aOp) {
21 switch (aOp) {
22 case CompositionOp::OP_IN:
23 case CompositionOp::OP_OUT:
24 case CompositionOp::OP_DEST_IN:
25 case CompositionOp::OP_DEST_ATOP:
26 case CompositionOp::OP_SOURCE:
27 return false;
28 default:
29 return true;
30 }
31 }
33 template <class T>
34 struct ClassStorage
35 {
36 char bytes[sizeof(T)];
38 const T *addr() const { return (const T *)bytes; }
39 T *addr() { return (T *)(void *)bytes; }
40 };
42 static inline bool
43 FuzzyEqual(Float aA, Float aB, Float aErr)
44 {
45 if ((aA + aErr >= aB) && (aA - aErr <= aB)) {
46 return true;
47 }
48 return false;
49 }
51 static inline void
52 NudgeToInteger(float *aVal)
53 {
54 float r = floorf(*aVal + 0.5f);
55 // The error threshold should be proportional to the rounded value. This
56 // bounds the relative error introduced by the nudge operation. However,
57 // when the rounded value is 0, the error threshold can't be proportional
58 // to the rounded value (we'd never round), so we just choose the same
59 // threshold as for a rounded value of 1.
60 if (FuzzyEqual(r, *aVal, r == 0.0f ? 1e-6f : fabs(r*1e-6f))) {
61 *aVal = r;
62 }
63 }
65 static inline Float
66 Distance(Point aA, Point aB)
67 {
68 return hypotf(aB.x - aA.x, aB.y - aA.y);
69 }
71 static inline int
72 BytesPerPixel(SurfaceFormat aFormat)
73 {
74 switch (aFormat) {
75 case SurfaceFormat::A8:
76 return 1;
77 case SurfaceFormat::R5G6B5:
78 return 2;
79 default:
80 return 4;
81 }
82 }
84 template<typename T, int alignment = 16>
85 struct AlignedArray
86 {
87 AlignedArray()
88 : mStorage(nullptr)
89 , mPtr(nullptr)
90 {
91 }
93 MOZ_ALWAYS_INLINE AlignedArray(size_t aSize)
94 : mStorage(nullptr)
95 {
96 Realloc(aSize);
97 }
99 MOZ_ALWAYS_INLINE ~AlignedArray()
100 {
101 delete [] mStorage;
102 }
104 void Dealloc()
105 {
106 delete [] mStorage;
107 mStorage = mPtr = nullptr;
108 }
110 MOZ_ALWAYS_INLINE void Realloc(size_t aSize)
111 {
112 delete [] mStorage;
113 mStorage = new (std::nothrow) T[aSize + (alignment - 1)];
114 if (uintptr_t(mStorage) % alignment) {
115 // Our storage does not start at a <alignment>-byte boundary. Make sure mData does!
116 mPtr = (T*)(uintptr_t(mStorage) +
117 (alignment - (uintptr_t(mStorage) % alignment)));
118 } else {
119 mPtr = mStorage;
120 }
121 }
123 MOZ_ALWAYS_INLINE operator T*()
124 {
125 return mPtr;
126 }
128 T *mStorage;
129 T *mPtr;
130 };
132 template<int alignment>
133 int32_t GetAlignedStride(int32_t aStride)
134 {
135 if (aStride % alignment) {
136 return aStride + (alignment - (aStride % alignment));
137 }
139 return aStride;
140 }
142 }
143 }
145 #endif /* MOZILLA_GFX_TOOLS_H_ */
