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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/. */
5 :
6 : #ifndef MOZILLA_GFX_TOOLS_H_
7 : #define MOZILLA_GFX_TOOLS_H_
8 :
9 : #include "mozilla/CheckedInt.h"
10 : #include "mozilla/Move.h"
11 : #include "mozilla/TypeTraits.h"
12 : #include "Types.h"
13 : #include "Point.h"
14 : #include <math.h>
15 :
16 : namespace mozilla {
17 : namespace gfx {
18 :
19 : static inline bool
20 429 : IsOperatorBoundByMask(CompositionOp aOp) {
21 429 : 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 14 : return false;
28 : default:
29 415 : return true;
30 : }
31 : }
32 :
33 : template <class T>
34 : struct ClassStorage
35 : {
36 : char bytes[sizeof(T)];
37 :
38 : const T *addr() const { return (const T *)bytes; }
39 0 : T *addr() { return (T *)(void *)bytes; }
40 : };
41 :
42 : static inline bool
43 4040 : FuzzyEqual(Float aA, Float aB, Float aErr)
44 : {
45 4040 : if ((aA + aErr >= aB) && (aA - aErr <= aB)) {
46 4032 : return true;
47 : }
48 8 : return false;
49 : }
50 :
51 : static inline void
52 3718 : NudgeToInteger(float *aVal)
53 : {
54 3718 : 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 3718 : if (FuzzyEqual(r, *aVal, r == 0.0f ? 1e-6f : fabs(r*1e-6f))) {
61 3710 : *aVal = r;
62 : }
63 3718 : }
64 :
65 : static inline void
66 96 : NudgeToInteger(float *aVal, float aErr)
67 : {
68 96 : float r = floorf(*aVal + 0.5f);
69 96 : if (FuzzyEqual(r, *aVal, aErr)) {
70 96 : *aVal = r;
71 : }
72 96 : }
73 :
74 : static inline void
75 324 : NudgeToInteger(double *aVal)
76 : {
77 324 : float f = float(*aVal);
78 324 : NudgeToInteger(&f);
79 324 : *aVal = f;
80 324 : }
81 :
82 : static inline Float
83 0 : Distance(Point aA, Point aB)
84 : {
85 0 : return hypotf(aB.x - aA.x, aB.y - aA.y);
86 : }
87 :
88 : static inline int
89 296 : BytesPerPixel(SurfaceFormat aFormat)
90 : {
91 296 : switch (aFormat) {
92 : case SurfaceFormat::A8:
93 0 : return 1;
94 : case SurfaceFormat::R5G6B5_UINT16:
95 0 : return 2;
96 : case SurfaceFormat::R8G8B8:
97 : case SurfaceFormat::B8G8R8:
98 0 : return 3;
99 : case SurfaceFormat::HSV:
100 : case SurfaceFormat::Lab:
101 0 : return 3 * sizeof(float);
102 : case SurfaceFormat::Depth:
103 0 : return sizeof(uint16_t);
104 : default:
105 296 : return 4;
106 : }
107 : }
108 :
109 : static inline bool
110 0 : IsOpaqueFormat(SurfaceFormat aFormat) {
111 0 : switch (aFormat) {
112 : case SurfaceFormat::B8G8R8X8:
113 : case SurfaceFormat::R8G8B8X8:
114 : case SurfaceFormat::X8R8G8B8:
115 : case SurfaceFormat::YUV:
116 : case SurfaceFormat::NV12:
117 : case SurfaceFormat::YUV422:
118 : case SurfaceFormat::R5G6B5_UINT16:
119 0 : return true;
120 : default:
121 0 : return false;
122 : }
123 : }
124 :
125 : template<typename T, int alignment = 16>
126 : struct AlignedArray
127 : {
128 : typedef T value_type;
129 :
130 0 : AlignedArray()
131 : : mPtr(nullptr)
132 0 : , mStorage(nullptr)
133 : {
134 0 : }
135 :
136 1 : explicit MOZ_ALWAYS_INLINE AlignedArray(size_t aCount, bool aZero = false)
137 : : mStorage(nullptr)
138 1 : , mCount(0)
139 : {
140 1 : Realloc(aCount, aZero);
141 1 : }
142 :
143 1 : MOZ_ALWAYS_INLINE ~AlignedArray()
144 : {
145 1 : Dealloc();
146 1 : }
147 :
148 1 : void Dealloc()
149 : {
150 : // If we fail this assert we'll need to uncomment the loop below to make
151 : // sure dtors are properly invoked. If we do that, we should check that the
152 : // comment about compiler dead code elimination is in fact true for all the
153 : // compilers that we care about.
154 : static_assert(mozilla::IsPod<T>::value,
155 : "Destructors must be invoked for this type");
156 : #if 0
157 : for (size_t i = 0; i < mCount; ++i) {
158 : // Since we used the placement |operator new| function to construct the
159 : // elements of this array we need to invoke their destructors manually.
160 : // For types where the destructor does nothing the compiler's dead code
161 : // elimination step should optimize this loop away.
162 : mPtr[i].~T();
163 : }
164 : #endif
165 :
166 1 : free(mStorage);
167 1 : mStorage = nullptr;
168 1 : mPtr = nullptr;
169 1 : }
170 :
171 1 : MOZ_ALWAYS_INLINE void Realloc(size_t aCount, bool aZero = false)
172 : {
173 1 : free(mStorage);
174 : CheckedInt32 storageByteCount =
175 1 : CheckedInt32(sizeof(T)) * aCount + (alignment - 1);
176 1 : if (!storageByteCount.isValid()) {
177 0 : mStorage = nullptr;
178 0 : mPtr = nullptr;
179 0 : mCount = 0;
180 0 : return;
181 : }
182 : // We don't create an array of T here, since we don't want ctors to be
183 : // invoked at the wrong places if we realign below.
184 1 : if (aZero) {
185 : // calloc can be more efficient than new[] for large chunks,
186 : // so we use calloc/malloc/free for everything.
187 0 : mStorage = static_cast<uint8_t *>(calloc(1, storageByteCount.value()));
188 : } else {
189 1 : mStorage = static_cast<uint8_t *>(malloc(storageByteCount.value()));
190 : }
191 1 : if (!mStorage) {
192 0 : mStorage = nullptr;
193 0 : mPtr = nullptr;
194 0 : mCount = 0;
195 0 : return;
196 : }
197 1 : if (uintptr_t(mStorage) % alignment) {
198 : // Our storage does not start at a <alignment>-byte boundary. Make sure mPtr does!
199 0 : mPtr = (T*)(uintptr_t(mStorage) + alignment - (uintptr_t(mStorage) % alignment));
200 : } else {
201 1 : mPtr = (T*)(mStorage);
202 : }
203 : // Now that mPtr is pointing to the aligned position we can use placement
204 : // |operator new| to invoke any ctors at the correct positions. For types
205 : // that have a no-op default constructor the compiler's dead code
206 : // elimination step should optimize this away.
207 1 : mPtr = new (mPtr) T[aCount];
208 1 : mCount = aCount;
209 : }
210 :
211 : void Swap(AlignedArray<T, alignment>& aOther)
212 : {
213 : mozilla::Swap(mPtr, aOther.mPtr);
214 : mozilla::Swap(mStorage, aOther.mStorage);
215 : mozilla::Swap(mCount, aOther.mCount);
216 : }
217 :
218 4 : MOZ_ALWAYS_INLINE operator T*()
219 : {
220 4 : return mPtr;
221 : }
222 :
223 : T *mPtr;
224 :
225 : private:
226 : uint8_t *mStorage;
227 : size_t mCount;
228 : };
229 :
230 : /**
231 : * Returns aWidth * aBytesPerPixel increased, if necessary, so that it divides
232 : * exactly into |alignment|.
233 : *
234 : * Note that currently |alignment| must be a power-of-2. If for some reason we
235 : * want to support NPOT alignment we can revert back to this functions old
236 : * implementation.
237 : */
238 : template<int alignment>
239 133 : int32_t GetAlignedStride(int32_t aWidth, int32_t aBytesPerPixel)
240 : {
241 : static_assert(alignment > 0 && (alignment & (alignment-1)) == 0,
242 : "This implementation currently require power-of-two alignment");
243 133 : const int32_t mask = alignment - 1;
244 133 : CheckedInt32 stride = CheckedInt32(aWidth) * CheckedInt32(aBytesPerPixel) + CheckedInt32(mask);
245 133 : if (stride.isValid()) {
246 133 : return stride.value() & ~mask;
247 : }
248 0 : return 0;
249 : }
250 :
251 : } // namespace gfx
252 : } // namespace mozilla
253 :
254 : #endif /* MOZILLA_GFX_TOOLS_H_ */
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