DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Mercurial (409f3966645a)

VCS Links

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef MOZILLA_GFX_TOOLS_H_
#define MOZILLA_GFX_TOOLS_H_

#include "mozilla/CheckedInt.h"
#include "mozilla/MemoryReporting.h" // for MallocSizeOf
#include "mozilla/Move.h"
#include "mozilla/TypeTraits.h"
#include "Types.h"
#include "Point.h"
#include <math.h>

namespace mozilla {
namespace gfx {

static inline bool
IsOperatorBoundByMask(CompositionOp aOp) {
  switch (aOp) {
  case CompositionOp::OP_IN:
  case CompositionOp::OP_OUT:
  case CompositionOp::OP_DEST_IN:
  case CompositionOp::OP_DEST_ATOP:
  case CompositionOp::OP_SOURCE:
    return false;
  default:
    return true;
  }
}

template <class T>
struct ClassStorage
{
  char bytes[sizeof(T)];

  const T *addr() const { return (const T *)bytes; }
  T *addr() { return (T *)(void *)bytes; }
};

static inline bool
FuzzyEqual(Float aA, Float aB, Float aErr)
{
  if ((aA + aErr >= aB) && (aA - aErr <= aB)) {
    return true;
  }
  return false;
}

static inline void
NudgeToInteger(float *aVal)
{
  float r = floorf(*aVal + 0.5f);
  // The error threshold should be proportional to the rounded value. This
  // bounds the relative error introduced by the nudge operation. However,
  // when the rounded value is 0, the error threshold can't be proportional
  // to the rounded value (we'd never round), so we just choose the same
  // threshold as for a rounded value of 1.
  if (FuzzyEqual(r, *aVal, r == 0.0f ? 1e-6f : fabs(r*1e-6f))) {
    *aVal = r;
  }
}

static inline void
NudgeToInteger(float *aVal, float aErr)
{
  float r = floorf(*aVal + 0.5f);
  if (FuzzyEqual(r, *aVal, aErr)) {
    *aVal = r;
  }
}

static inline void
NudgeToInteger(double *aVal)
{
  float f = float(*aVal);
  NudgeToInteger(&f);
  *aVal = f;
}

static inline Float
Distance(Point aA, Point aB)
{
  return hypotf(aB.x - aA.x, aB.y - aA.y);
}

static inline int
BytesPerPixel(SurfaceFormat aFormat)
{
  switch (aFormat) {
  case SurfaceFormat::A8:
    return 1;
  case SurfaceFormat::R5G6B5_UINT16:
  case SurfaceFormat::A16:
    return 2;
  case SurfaceFormat::R8G8B8:
  case SurfaceFormat::B8G8R8:
    return 3;
  case SurfaceFormat::HSV:
  case SurfaceFormat::Lab:
    return 3 * sizeof(float);
  case SurfaceFormat::Depth:
    return sizeof(uint16_t);
  default:
    return 4;
  }
}

static inline SurfaceFormat
SurfaceFormatForAlphaBitDepth(uint32_t aBitDepth)
{
  if (aBitDepth == 8) {
    return SurfaceFormat::A8;
  } else if (aBitDepth == 10 ||
             aBitDepth == 12) {
    return SurfaceFormat::A16;
  }
  MOZ_ASSERT_UNREACHABLE("Unsupported alpha bit depth");
  return SurfaceFormat::UNKNOWN;
}

static inline bool
IsOpaqueFormat(SurfaceFormat aFormat) {
  switch (aFormat) {
    case SurfaceFormat::B8G8R8X8:
    case SurfaceFormat::R8G8B8X8:
    case SurfaceFormat::X8R8G8B8:
    case SurfaceFormat::YUV:
    case SurfaceFormat::NV12:
    case SurfaceFormat::YUV422:
    case SurfaceFormat::R5G6B5_UINT16:
      return true;
    default:
      return false;
  }
}

template<typename T, int alignment = 16>
struct AlignedArray
{
  typedef T value_type;

  AlignedArray()
    : mPtr(nullptr)
    , mStorage(nullptr)
    , mCount(0)
  {
  }

  explicit MOZ_ALWAYS_INLINE AlignedArray(size_t aCount, bool aZero = false)
    : mPtr(nullptr)
    , mStorage(nullptr)
    , mCount(0)
  {
    Realloc(aCount, aZero);
  }

  MOZ_ALWAYS_INLINE ~AlignedArray()
  {
    Dealloc();
  }

  void Dealloc()
  {
    // If we fail this assert we'll need to uncomment the loop below to make
    // sure dtors are properly invoked. If we do that, we should check that the
    // comment about compiler dead code elimination is in fact true for all the
    // compilers that we care about.
    static_assert(mozilla::IsPod<T>::value,
                  "Destructors must be invoked for this type");
#if 0
    for (size_t i = 0; i < mCount; ++i) {
      // Since we used the placement |operator new| function to construct the
      // elements of this array we need to invoke their destructors manually.
      // For types where the destructor does nothing the compiler's dead code
      // elimination step should optimize this loop away.
      mPtr[i].~T();
    }
#endif

    free(mStorage);
    mStorage = nullptr;
    mPtr = nullptr;
  }

  MOZ_ALWAYS_INLINE void Realloc(size_t aCount, bool aZero = false)
  {
    free(mStorage);
    CheckedInt32 storageByteCount =
      CheckedInt32(sizeof(T)) * aCount + (alignment - 1);
    if (!storageByteCount.isValid()) {
      mStorage = nullptr;
      mPtr = nullptr;
      mCount = 0;
      return;
    }
    // We don't create an array of T here, since we don't want ctors to be
    // invoked at the wrong places if we realign below.
    if (aZero) {
      // calloc can be more efficient than new[] for large chunks,
      // so we use calloc/malloc/free for everything.
      mStorage = static_cast<uint8_t *>(calloc(1, storageByteCount.value()));
    } else {
      mStorage = static_cast<uint8_t *>(malloc(storageByteCount.value()));
    }
    if (!mStorage) {
      mStorage = nullptr;
      mPtr = nullptr;
      mCount = 0;
      return;
    }
    if (uintptr_t(mStorage) % alignment) {
      // Our storage does not start at a <alignment>-byte boundary. Make sure mPtr does!
      mPtr = (T*)(uintptr_t(mStorage) + alignment - (uintptr_t(mStorage) % alignment));
    } else {
      mPtr = (T*)(mStorage);
    }
    // Now that mPtr is pointing to the aligned position we can use placement
    // |operator new| to invoke any ctors at the correct positions. For types
    // that have a no-op default constructor the compiler's dead code
    // elimination step should optimize this away.
    mPtr = new (mPtr) T[aCount];
    mCount = aCount;
  }

  void Swap(AlignedArray<T, alignment>& aOther)
  {
    mozilla::Swap(mPtr, aOther.mPtr);
    mozilla::Swap(mStorage, aOther.mStorage);
    mozilla::Swap(mCount, aOther.mCount);
  }

  size_t
  HeapSizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const
  {
    return aMallocSizeOf(mStorage);
  }

  MOZ_ALWAYS_INLINE operator T*()
  {
    return mPtr;
  }

  T *mPtr;

private:
  uint8_t *mStorage;
  size_t mCount;
};

/**
 * Returns aWidth * aBytesPerPixel increased, if necessary, so that it divides
 * exactly into |alignment|.
 *
 * Note that currently |alignment| must be a power-of-2. If for some reason we
 * want to support NPOT alignment we can revert back to this functions old
 * implementation.
 */
template<int alignment>
int32_t GetAlignedStride(int32_t aWidth, int32_t aBytesPerPixel)
{
  static_assert(alignment > 0 && (alignment & (alignment-1)) == 0,
                "This implementation currently require power-of-two alignment");
  const int32_t mask = alignment - 1;
  CheckedInt32 stride = CheckedInt32(aWidth) * CheckedInt32(aBytesPerPixel) + CheckedInt32(mask);
  if (stride.isValid()) {
    return stride.value() & ~mask;
  }
  return 0;
}

} // namespace gfx
} // namespace mozilla

#endif /* MOZILLA_GFX_TOOLS_H_ */