Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 716 insertions, 0 deletions

diff --git a/image/encoders/bmp/nsBMPEncoder.cpp b/image/encoders/bmp/nsBMPEncoder.cpp
new file mode 100644
index 0000000000..697950d7af
--- /dev/null
+++ b/image/encoders/bmp/nsBMPEncoder.cpp
@@ -0,0 +1,716 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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/. */
+
+#include "nsCRT.h"
+#include "mozilla/EndianUtils.h"
+#include "mozilla/UniquePtrExtensions.h"
+#include "nsBMPEncoder.h"
+#include "nsString.h"
+#include "nsStreamUtils.h"
+#include "nsTArray.h"
+#include "mozilla/CheckedInt.h"
+#include "BMPHeaders.h"
+
+using namespace mozilla;
+using namespace mozilla::image;
+using namespace mozilla::image::bmp;
+
+NS_IMPL_ISUPPORTS(nsBMPEncoder, imgIEncoder, nsIInputStream,
+                  nsIAsyncInputStream)
+
+nsBMPEncoder::nsBMPEncoder()
+    : mBMPInfoHeader{},
+      mImageBufferStart(nullptr),
+      mImageBufferCurr(0),
+      mImageBufferSize(0),
+      mImageBufferReadPoint(0),
+      mFinished(false),
+      mCallback(nullptr),
+      mCallbackTarget(nullptr),
+      mNotifyThreshold(0) {
+  this->mBMPFileHeader.filesize = 0;
+  this->mBMPFileHeader.reserved = 0;
+  this->mBMPFileHeader.dataoffset = 0;
+}
+
+nsBMPEncoder::~nsBMPEncoder() {
+  if (mImageBufferStart) {
+    free(mImageBufferStart);
+    mImageBufferStart = nullptr;
+    mImageBufferCurr = nullptr;
+  }
+}
+
+// nsBMPEncoder::InitFromData
+//
+// One output option is supported: bpp=<bpp_value>
+// bpp specifies the bits per pixel to use where bpp_value can be 24 or 32
+NS_IMETHODIMP
+nsBMPEncoder::InitFromData(const uint8_t* aData,
+                           uint32_t aLength,  // (unused, req'd by JS)
+                           uint32_t aWidth, uint32_t aHeight, uint32_t aStride,
+                           uint32_t aInputFormat,
+                           const nsAString& aOutputOptions) {
+  // validate input format
+  if (aInputFormat != INPUT_FORMAT_RGB && aInputFormat != INPUT_FORMAT_RGBA &&
+      aInputFormat != INPUT_FORMAT_HOSTARGB) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  CheckedInt32 check = CheckedInt32(aWidth) * 4;
+  if (MOZ_UNLIKELY(!check.isValid())) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  // Stride is the padded width of each row, so it better be longer
+  if ((aInputFormat == INPUT_FORMAT_RGB && aStride < aWidth * 3) ||
+      ((aInputFormat == INPUT_FORMAT_RGBA ||
+        aInputFormat == INPUT_FORMAT_HOSTARGB) &&
+       aStride < aWidth * 4)) {
+    NS_WARNING("Invalid stride for InitFromData");
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  nsresult rv;
+  rv = StartImageEncode(aWidth, aHeight, aInputFormat, aOutputOptions);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  rv = AddImageFrame(aData, aLength, aWidth, aHeight, aStride, aInputFormat,
+                     aOutputOptions);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  rv = EndImageEncode();
+  return rv;
+}
+
+// Just a helper method to make it explicit in calculations that we are dealing
+// with bytes and not bits
+static inline uint16_t BytesPerPixel(uint16_t aBPP) { return aBPP / 8; }
+
+// Calculates the number of padding bytes that are needed per row of image data
+static inline uint32_t PaddingBytes(uint16_t aBPP, uint32_t aWidth) {
+  uint32_t rowSize = aWidth * BytesPerPixel(aBPP);
+  uint8_t paddingSize = 0;
+  if (rowSize % 4) {
+    paddingSize = (4 - (rowSize % 4));
+  }
+  return paddingSize;
+}
+
+// See ::InitFromData for other info.
+NS_IMETHODIMP
+nsBMPEncoder::StartImageEncode(uint32_t aWidth, uint32_t aHeight,
+                               uint32_t aInputFormat,
+                               const nsAString& aOutputOptions) {
+  // can't initialize more than once
+  if (mImageBufferStart || mImageBufferCurr) {
+    return NS_ERROR_ALREADY_INITIALIZED;
+  }
+
+  // validate input format
+  if (aInputFormat != INPUT_FORMAT_RGB && aInputFormat != INPUT_FORMAT_RGBA &&
+      aInputFormat != INPUT_FORMAT_HOSTARGB) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  // parse and check any provided output options
+  Version version;
+  uint16_t bpp;
+  nsresult rv = ParseOptions(aOutputOptions, version, bpp);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+  MOZ_ASSERT(bpp <= 32);
+
+  rv = InitFileHeader(version, bpp, aWidth, aHeight);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+  rv = InitInfoHeader(version, bpp, aWidth, aHeight);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  mImageBufferSize = mBMPFileHeader.filesize;
+  mImageBufferStart = static_cast<uint8_t*>(malloc(mImageBufferSize));
+  if (!mImageBufferStart) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+  mImageBufferCurr = mImageBufferStart;
+
+  EncodeFileHeader();
+  EncodeInfoHeader();
+
+  return NS_OK;
+}
+
+// Returns the number of bytes in the image buffer used.
+// For a BMP file, this is all bytes in the buffer.
+NS_IMETHODIMP
+nsBMPEncoder::GetImageBufferUsed(uint32_t* aOutputSize) {
+  NS_ENSURE_ARG_POINTER(aOutputSize);
+  *aOutputSize = mImageBufferSize;
+  return NS_OK;
+}
+
+// Returns a pointer to the start of the image buffer
+NS_IMETHODIMP
+nsBMPEncoder::GetImageBuffer(char** aOutputBuffer) {
+  NS_ENSURE_ARG_POINTER(aOutputBuffer);
+  *aOutputBuffer = reinterpret_cast<char*>(mImageBufferStart);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBMPEncoder::AddImageFrame(const uint8_t* aData,
+                            uint32_t aLength,  // (unused, req'd by JS)
+                            uint32_t aWidth, uint32_t aHeight, uint32_t aStride,
+                            uint32_t aInputFormat,
+                            const nsAString& aFrameOptions) {
+  // must be initialized
+  if (!mImageBufferStart || !mImageBufferCurr) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+
+  // validate input format
+  if (aInputFormat != INPUT_FORMAT_RGB && aInputFormat != INPUT_FORMAT_RGBA &&
+      aInputFormat != INPUT_FORMAT_HOSTARGB) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  if (mBMPInfoHeader.width < 0) {
+    return NS_ERROR_ILLEGAL_VALUE;
+  }
+
+  CheckedUint32 size = CheckedUint32(mBMPInfoHeader.width) *
+                       CheckedUint32(BytesPerPixel(mBMPInfoHeader.bpp));
+  if (MOZ_UNLIKELY(!size.isValid())) {
+    return NS_ERROR_FAILURE;
+  }
+
+  auto row = MakeUniqueFallible<uint8_t[]>(size.value());
+  if (!row) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+
+  CheckedUint32 check = CheckedUint32(mBMPInfoHeader.height) * aStride;
+  if (MOZ_UNLIKELY(!check.isValid())) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // write each row: if we add more input formats, we may want to
+  // generalize the conversions
+  if (aInputFormat == INPUT_FORMAT_HOSTARGB) {
+    // BMP requires RGBA with post-multiplied alpha, so we need to convert
+    for (int32_t y = mBMPInfoHeader.height - 1; y >= 0; y--) {
+      ConvertHostARGBRow(&aData[y * aStride], row, mBMPInfoHeader.width);
+      if (mBMPInfoHeader.bpp == 24) {
+        EncodeImageDataRow24(row.get());
+      } else {
+        EncodeImageDataRow32(row.get());
+      }
+    }
+  } else if (aInputFormat == INPUT_FORMAT_RGBA) {
+    // simple RGBA, no conversion needed
+    for (int32_t y = 0; y < mBMPInfoHeader.height; y++) {
+      if (mBMPInfoHeader.bpp == 24) {
+        EncodeImageDataRow24(row.get());
+      } else {
+        EncodeImageDataRow32(row.get());
+      }
+    }
+  } else if (aInputFormat == INPUT_FORMAT_RGB) {
+    // simple RGB, no conversion needed
+    for (int32_t y = 0; y < mBMPInfoHeader.height; y++) {
+      if (mBMPInfoHeader.bpp == 24) {
+        EncodeImageDataRow24(&aData[y * aStride]);
+      } else {
+        EncodeImageDataRow32(&aData[y * aStride]);
+      }
+    }
+  } else {
+    MOZ_ASSERT_UNREACHABLE("Bad format type");
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBMPEncoder::EndImageEncode() {
+  // must be initialized
+  if (!mImageBufferStart || !mImageBufferCurr) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+
+  mFinished = true;
+  NotifyListener();
+
+  // if output callback can't get enough memory, it will free our buffer
+  if (!mImageBufferStart || !mImageBufferCurr) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+
+  return NS_OK;
+}
+
+// Parses the encoder options and sets the bits per pixel to use
+// See InitFromData for a description of the parse options
+nsresult nsBMPEncoder::ParseOptions(const nsAString& aOptions,
+                                    Version& aVersionOut, uint16_t& aBppOut) {
+  aVersionOut = VERSION_3;
+  aBppOut = 24;
+
+  // Parse the input string into a set of name/value pairs.
+  // From a format like: name=value;bpp=<bpp_value>;name=value
+  // to format: [0] = name=value, [1] = bpp=<bpp_value>, [2] = name=value
+  nsTArray<nsCString> nameValuePairs;
+  ParseString(NS_ConvertUTF16toUTF8(aOptions), ';', nameValuePairs);
+
+  // For each name/value pair in the set
+  for (uint32_t i = 0; i < nameValuePairs.Length(); ++i) {
+    // Split the name value pair [0] = name, [1] = value
+    nsTArray<nsCString> nameValuePair;
+    ParseString(nameValuePairs[i], '=', nameValuePair);
+    if (nameValuePair.Length() != 2) {
+      return NS_ERROR_INVALID_ARG;
+    }
+
+    // Parse the bpp portion of the string name=value;version=<version_value>;
+    // name=value
+    if (nameValuePair[0].Equals("version",
+                                nsCaseInsensitiveCStringComparator)) {
+      if (nameValuePair[1].EqualsLiteral("3")) {
+        aVersionOut = VERSION_3;
+      } else if (nameValuePair[1].EqualsLiteral("5")) {
+        aVersionOut = VERSION_5;
+      } else {
+        return NS_ERROR_INVALID_ARG;
+      }
+    }
+
+    // Parse the bpp portion of the string name=value;bpp=<bpp_value>;name=value
+    if (nameValuePair[0].Equals("bpp", nsCaseInsensitiveCStringComparator)) {
+      if (nameValuePair[1].EqualsLiteral("24")) {
+        aBppOut = 24;
+      } else if (nameValuePair[1].EqualsLiteral("32")) {
+        aBppOut = 32;
+      } else {
+        return NS_ERROR_INVALID_ARG;
+      }
+    }
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBMPEncoder::Close() {
+  if (mImageBufferStart) {
+    free(mImageBufferStart);
+    mImageBufferStart = nullptr;
+    mImageBufferSize = 0;
+    mImageBufferReadPoint = 0;
+    mImageBufferCurr = nullptr;
+  }
+
+  return NS_OK;
+}
+
+// Obtains the available bytes to read
+NS_IMETHODIMP
+nsBMPEncoder::Available(uint64_t* _retval) {
+  if (!mImageBufferStart || !mImageBufferCurr) {
+    return NS_BASE_STREAM_CLOSED;
+  }
+
+  *_retval = GetCurrentImageBufferOffset() - mImageBufferReadPoint;
+  return NS_OK;
+}
+
+// Obtains the stream's status
+NS_IMETHODIMP
+nsBMPEncoder::StreamStatus() {
+  return mImageBufferStart && mImageBufferCurr ? NS_OK : NS_BASE_STREAM_CLOSED;
+}
+
+// [noscript] Reads bytes which are available
+NS_IMETHODIMP
+nsBMPEncoder::Read(char* aBuf, uint32_t aCount, uint32_t* _retval) {
+  return ReadSegments(NS_CopySegmentToBuffer, aBuf, aCount, _retval);
+}
+
+// [noscript] Reads segments
+NS_IMETHODIMP
+nsBMPEncoder::ReadSegments(nsWriteSegmentFun aWriter, void* aClosure,
+                           uint32_t aCount, uint32_t* _retval) {
+  uint32_t maxCount = GetCurrentImageBufferOffset() - mImageBufferReadPoint;
+  if (maxCount == 0) {
+    *_retval = 0;
+    return mFinished ? NS_OK : NS_BASE_STREAM_WOULD_BLOCK;
+  }
+
+  if (aCount > maxCount) {
+    aCount = maxCount;
+  }
+  nsresult rv = aWriter(
+      this, aClosure,
+      reinterpret_cast<const char*>(mImageBufferStart + mImageBufferReadPoint),
+      0, aCount, _retval);
+  if (NS_SUCCEEDED(rv)) {
+    NS_ASSERTION(*_retval <= aCount, "bad write count");
+    mImageBufferReadPoint += *_retval;
+  }
+  // errors returned from the writer end here!
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBMPEncoder::IsNonBlocking(bool* _retval) {
+  *_retval = true;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBMPEncoder::AsyncWait(nsIInputStreamCallback* aCallback, uint32_t aFlags,
+                        uint32_t aRequestedCount, nsIEventTarget* aTarget) {
+  if (aFlags != 0) {
+    return NS_ERROR_NOT_IMPLEMENTED;
+  }
+
+  if (mCallback || mCallbackTarget) {
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  mCallbackTarget = aTarget;
+  // 0 means "any number of bytes except 0"
+  mNotifyThreshold = aRequestedCount;
+  if (!aRequestedCount) {
+    mNotifyThreshold = 1024;  // We don't want to notify incessantly
+  }
+
+  // We set the callback absolutely last, because NotifyListener uses it to
+  // determine if someone needs to be notified.  If we don't set it last,
+  // NotifyListener might try to fire off a notification to a null target
+  // which will generally cause non-threadsafe objects to be used off the
+  // main thread
+  mCallback = aCallback;
+
+  // What we are being asked for may be present already
+  NotifyListener();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBMPEncoder::CloseWithStatus(nsresult aStatus) { return Close(); }
+
+// nsBMPEncoder::ConvertHostARGBRow
+//
+//    Our colors are stored with premultiplied alphas, but we need
+//    an output with no alpha in machine-independent byte order.
+//
+void nsBMPEncoder::ConvertHostARGBRow(const uint8_t* aSrc,
+                                      const UniquePtr<uint8_t[]>& aDest,
+                                      uint32_t aPixelWidth) {
+  uint16_t bytes = BytesPerPixel(mBMPInfoHeader.bpp);
+
+  if (mBMPInfoHeader.bpp == 32) {
+    for (uint32_t x = 0; x < aPixelWidth; x++) {
+      const uint32_t& pixelIn = ((const uint32_t*)(aSrc))[x];
+      uint8_t* pixelOut = &aDest[x * bytes];
+
+      pixelOut[0] = (pixelIn & 0x00ff0000) >> 16;
+      pixelOut[1] = (pixelIn & 0x0000ff00) >> 8;
+      pixelOut[2] = (pixelIn & 0x000000ff) >> 0;
+      pixelOut[3] = (pixelIn & 0xff000000) >> 24;
+    }
+  } else {
+    for (uint32_t x = 0; x < aPixelWidth; x++) {
+      const uint32_t& pixelIn = ((const uint32_t*)(aSrc))[x];
+      uint8_t* pixelOut = &aDest[x * bytes];
+
+      pixelOut[0] = (pixelIn & 0xff0000) >> 16;
+      pixelOut[1] = (pixelIn & 0x00ff00) >> 8;
+      pixelOut[2] = (pixelIn & 0x0000ff) >> 0;
+    }
+  }
+}
+
+void nsBMPEncoder::NotifyListener() {
+  if (mCallback && (GetCurrentImageBufferOffset() - mImageBufferReadPoint >=
+                        mNotifyThreshold ||
+                    mFinished)) {
+    nsCOMPtr<nsIInputStreamCallback> callback;
+    if (mCallbackTarget) {
+      callback = NS_NewInputStreamReadyEvent("nsBMPEncoder::NotifyListener",
+                                             mCallback, mCallbackTarget);
+    } else {
+      callback = mCallback;
+    }
+
+    NS_ASSERTION(callback, "Shouldn't fail to make the callback");
+    // Null the callback first because OnInputStreamReady could
+    // reenter AsyncWait
+    mCallback = nullptr;
+    mCallbackTarget = nullptr;
+    mNotifyThreshold = 0;
+
+    callback->OnInputStreamReady(this);
+  }
+}
+
+// Initializes the BMP file header mBMPFileHeader to the passed in values
+nsresult nsBMPEncoder::InitFileHeader(Version aVersion, uint16_t aBPP,
+                                      uint32_t aWidth, uint32_t aHeight) {
+  memset(&mBMPFileHeader, 0, sizeof(mBMPFileHeader));
+  mBMPFileHeader.signature[0] = 'B';
+  mBMPFileHeader.signature[1] = 'M';
+
+  if (aVersion == VERSION_3) {
+    mBMPFileHeader.dataoffset = FILE_HEADER_LENGTH + InfoHeaderLength::WIN_V3;
+  } else {  // aVersion == 5
+    mBMPFileHeader.dataoffset = FILE_HEADER_LENGTH + InfoHeaderLength::WIN_V5;
+  }
+
+  // The color table is present only if BPP is <= 8
+  if (aBPP <= 8) {
+    uint32_t numColors = 1 << aBPP;
+    mBMPFileHeader.dataoffset += 4 * numColors;
+    CheckedUint32 filesize = CheckedUint32(mBMPFileHeader.dataoffset) +
+                             CheckedUint32(aWidth) * aHeight;
+    if (MOZ_UNLIKELY(!filesize.isValid())) {
+      return NS_ERROR_INVALID_ARG;
+    }
+    mBMPFileHeader.filesize = filesize.value();
+  } else {
+    CheckedUint32 filesize = CheckedUint32(mBMPFileHeader.dataoffset) +
+                             (CheckedUint32(aWidth) * BytesPerPixel(aBPP) +
+                              PaddingBytes(aBPP, aWidth)) *
+                                 aHeight;
+    if (MOZ_UNLIKELY(!filesize.isValid())) {
+      return NS_ERROR_INVALID_ARG;
+    }
+    mBMPFileHeader.filesize = filesize.value();
+  }
+
+  mBMPFileHeader.reserved = 0;
+
+  return NS_OK;
+}
+
+#define ENCODE(pImageBufferCurr, value)            \
+  memcpy(*pImageBufferCurr, &value, sizeof value); \
+  *pImageBufferCurr += sizeof value;
+
+// Initializes the bitmap info header mBMPInfoHeader to the passed in values
+nsresult nsBMPEncoder::InitInfoHeader(Version aVersion, uint16_t aBPP,
+                                      uint32_t aWidth, uint32_t aHeight) {
+  memset(&mBMPInfoHeader, 0, sizeof(mBMPInfoHeader));
+  if (aVersion == VERSION_3) {
+    mBMPInfoHeader.bihsize = InfoHeaderLength::WIN_V3;
+  } else {
+    MOZ_ASSERT(aVersion == VERSION_5);
+    mBMPInfoHeader.bihsize = InfoHeaderLength::WIN_V5;
+  }
+
+  CheckedInt32 width(aWidth);
+  CheckedInt32 height(aHeight);
+  if (MOZ_UNLIKELY(!width.isValid() || !height.isValid())) {
+    return NS_ERROR_INVALID_ARG;
+  }
+  mBMPInfoHeader.width = width.value();
+  mBMPInfoHeader.height = height.value();
+
+  mBMPInfoHeader.planes = 1;
+  mBMPInfoHeader.bpp = aBPP;
+  mBMPInfoHeader.compression = 0;
+  mBMPInfoHeader.colors = 0;
+  mBMPInfoHeader.important_colors = 0;
+
+  CheckedUint32 check = CheckedUint32(aWidth) * BytesPerPixel(aBPP);
+  if (MOZ_UNLIKELY(!check.isValid())) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  if (aBPP <= 8) {
+    CheckedUint32 imagesize = CheckedUint32(aWidth) * aHeight;
+    if (MOZ_UNLIKELY(!imagesize.isValid())) {
+      return NS_ERROR_INVALID_ARG;
+    }
+    mBMPInfoHeader.image_size = imagesize.value();
+  } else {
+    CheckedUint32 imagesize = (CheckedUint32(aWidth) * BytesPerPixel(aBPP) +
+                               PaddingBytes(aBPP, aWidth)) *
+                              CheckedUint32(aHeight);
+    if (MOZ_UNLIKELY(!imagesize.isValid())) {
+      return NS_ERROR_INVALID_ARG;
+    }
+    mBMPInfoHeader.image_size = imagesize.value();
+  }
+  mBMPInfoHeader.xppm = 0;
+  mBMPInfoHeader.yppm = 0;
+  if (aVersion >= VERSION_5) {
+    mBMPInfoHeader.red_mask = 0x000000FF;
+    mBMPInfoHeader.green_mask = 0x0000FF00;
+    mBMPInfoHeader.blue_mask = 0x00FF0000;
+    mBMPInfoHeader.alpha_mask = 0xFF000000;
+    mBMPInfoHeader.color_space = V5InfoHeader::COLOR_SPACE_LCS_SRGB;
+    mBMPInfoHeader.white_point.r.x = 0;
+    mBMPInfoHeader.white_point.r.y = 0;
+    mBMPInfoHeader.white_point.r.z = 0;
+    mBMPInfoHeader.white_point.g.x = 0;
+    mBMPInfoHeader.white_point.g.y = 0;
+    mBMPInfoHeader.white_point.g.z = 0;
+    mBMPInfoHeader.white_point.b.x = 0;
+    mBMPInfoHeader.white_point.b.y = 0;
+    mBMPInfoHeader.white_point.b.z = 0;
+    mBMPInfoHeader.gamma_red = 0;
+    mBMPInfoHeader.gamma_green = 0;
+    mBMPInfoHeader.gamma_blue = 0;
+    mBMPInfoHeader.intent = 0;
+    mBMPInfoHeader.profile_offset = 0;
+    mBMPInfoHeader.profile_size = 0;
+    mBMPInfoHeader.reserved = 0;
+  }
+
+  return NS_OK;
+}
+
+// Encodes the BMP file header mBMPFileHeader
+void nsBMPEncoder::EncodeFileHeader() {
+  FileHeader littleEndianBFH = mBMPFileHeader;
+  NativeEndian::swapToLittleEndianInPlace(&littleEndianBFH.filesize, 1);
+  NativeEndian::swapToLittleEndianInPlace(&littleEndianBFH.reserved, 1);
+  NativeEndian::swapToLittleEndianInPlace(&littleEndianBFH.dataoffset, 1);
+
+  ENCODE(&mImageBufferCurr, littleEndianBFH.signature);
+  ENCODE(&mImageBufferCurr, littleEndianBFH.filesize);
+  ENCODE(&mImageBufferCurr, littleEndianBFH.reserved);
+  ENCODE(&mImageBufferCurr, littleEndianBFH.dataoffset);
+}
+
+// Encodes the BMP info header mBMPInfoHeader
+void nsBMPEncoder::EncodeInfoHeader() {
+  V5InfoHeader littleEndianmBIH = mBMPInfoHeader;
+  NativeEndian::swapToLittleEndianInPlace(&littleEndianmBIH.bihsize, 1);
+  NativeEndian::swapToLittleEndianInPlace(&littleEndianmBIH.width, 1);
+  NativeEndian::swapToLittleEndianInPlace(&littleEndianmBIH.height, 1);
+  NativeEndian::swapToLittleEndianInPlace(&littleEndianmBIH.planes, 1);
+  NativeEndian::swapToLittleEndianInPlace(&littleEndianmBIH.bpp, 1);
+  NativeEndian::swapToLittleEndianInPlace(&littleEndianmBIH.compression, 1);
+  NativeEndian::swapToLittleEndianInPlace(&littleEndianmBIH.image_size, 1);
+  NativeEndian::swapToLittleEndianInPlace(&littleEndianmBIH.xppm, 1);
+  NativeEndian::swapToLittleEndianInPlace(&littleEndianmBIH.yppm, 1);
+  NativeEndian::swapToLittleEndianInPlace(&littleEndianmBIH.colors, 1);
+  NativeEndian::swapToLittleEndianInPlace(&littleEndianmBIH.important_colors,
+                                          1);
+  NativeEndian::swapToLittleEndianInPlace(&littleEndianmBIH.red_mask, 1);
+  NativeEndian::swapToLittleEndianInPlace(&littleEndianmBIH.green_mask, 1);
+  NativeEndian::swapToLittleEndianInPlace(&littleEndianmBIH.blue_mask, 1);
+  NativeEndian::swapToLittleEndianInPlace(&littleEndianmBIH.alpha_mask, 1);
+  NativeEndian::swapToLittleEndianInPlace(&littleEndianmBIH.color_space, 1);
+  NativeEndian::swapToLittleEndianInPlace(&littleEndianmBIH.white_point.r.x, 1);
+  NativeEndian::swapToLittleEndianInPlace(&littleEndianmBIH.white_point.r.y, 1);
+  NativeEndian::swapToLittleEndianInPlace(&littleEndianmBIH.white_point.r.z, 1);
+  NativeEndian::swapToLittleEndianInPlace(&littleEndianmBIH.white_point.g.x, 1);
+  NativeEndian::swapToLittleEndianInPlace(&littleEndianmBIH.white_point.g.y, 1);
+  NativeEndian::swapToLittleEndianInPlace(&littleEndianmBIH.white_point.g.z, 1);
+  NativeEndian::swapToLittleEndianInPlace(&littleEndianmBIH.white_point.b.x, 1);
+  NativeEndian::swapToLittleEndianInPlace(&littleEndianmBIH.white_point.b.y, 1);
+  NativeEndian::swapToLittleEndianInPlace(&littleEndianmBIH.white_point.b.z, 1);
+  NativeEndian::swapToLittleEndianInPlace(&littleEndianmBIH.gamma_red, 1);
+  NativeEndian::swapToLittleEndianInPlace(&littleEndianmBIH.gamma_green, 1);
+  NativeEndian::swapToLittleEndianInPlace(&littleEndianmBIH.gamma_blue, 1);
+  NativeEndian::swapToLittleEndianInPlace(&littleEndianmBIH.intent, 1);
+  NativeEndian::swapToLittleEndianInPlace(&littleEndianmBIH.profile_offset, 1);
+  NativeEndian::swapToLittleEndianInPlace(&littleEndianmBIH.profile_size, 1);
+
+  ENCODE(&mImageBufferCurr, littleEndianmBIH.bihsize);
+  ENCODE(&mImageBufferCurr, littleEndianmBIH.width);
+  ENCODE(&mImageBufferCurr, littleEndianmBIH.height);
+  ENCODE(&mImageBufferCurr, littleEndianmBIH.planes);
+  ENCODE(&mImageBufferCurr, littleEndianmBIH.bpp);
+  ENCODE(&mImageBufferCurr, littleEndianmBIH.compression);
+  ENCODE(&mImageBufferCurr, littleEndianmBIH.image_size);
+  ENCODE(&mImageBufferCurr, littleEndianmBIH.xppm);
+  ENCODE(&mImageBufferCurr, littleEndianmBIH.yppm);
+  ENCODE(&mImageBufferCurr, littleEndianmBIH.colors);
+  ENCODE(&mImageBufferCurr, littleEndianmBIH.important_colors);
+
+  if (mBMPInfoHeader.bihsize > InfoHeaderLength::WIN_V3) {
+    ENCODE(&mImageBufferCurr, littleEndianmBIH.red_mask);
+    ENCODE(&mImageBufferCurr, littleEndianmBIH.green_mask);
+    ENCODE(&mImageBufferCurr, littleEndianmBIH.blue_mask);
+    ENCODE(&mImageBufferCurr, littleEndianmBIH.alpha_mask);
+    ENCODE(&mImageBufferCurr, littleEndianmBIH.color_space);
+    ENCODE(&mImageBufferCurr, littleEndianmBIH.white_point.r.x);
+    ENCODE(&mImageBufferCurr, littleEndianmBIH.white_point.r.y);
+    ENCODE(&mImageBufferCurr, littleEndianmBIH.white_point.r.z);
+    ENCODE(&mImageBufferCurr, littleEndianmBIH.white_point.g.x);
+    ENCODE(&mImageBufferCurr, littleEndianmBIH.white_point.g.y);
+    ENCODE(&mImageBufferCurr, littleEndianmBIH.white_point.g.z);
+    ENCODE(&mImageBufferCurr, littleEndianmBIH.white_point.b.x);
+    ENCODE(&mImageBufferCurr, littleEndianmBIH.white_point.b.y);
+    ENCODE(&mImageBufferCurr, littleEndianmBIH.white_point.b.z);
+    ENCODE(&mImageBufferCurr, littleEndianmBIH.gamma_red);
+    ENCODE(&mImageBufferCurr, littleEndianmBIH.gamma_green);
+    ENCODE(&mImageBufferCurr, littleEndianmBIH.gamma_blue);
+    ENCODE(&mImageBufferCurr, littleEndianmBIH.intent);
+    ENCODE(&mImageBufferCurr, littleEndianmBIH.profile_offset);
+    ENCODE(&mImageBufferCurr, littleEndianmBIH.profile_size);
+    ENCODE(&mImageBufferCurr, littleEndianmBIH.reserved);
+  }
+}
+
+// Sets a pixel in the image buffer that doesn't have alpha data
+static inline void SetPixel24(uint8_t*& imageBufferCurr, uint8_t aRed,
+                              uint8_t aGreen, uint8_t aBlue) {
+  *imageBufferCurr = aBlue;
+  *(imageBufferCurr + 1) = aGreen;
+  *(imageBufferCurr + 2) = aRed;
+}
+
+// Sets a pixel in the image buffer with alpha data
+static inline void SetPixel32(uint8_t*& imageBufferCurr, uint8_t aRed,
+                              uint8_t aGreen, uint8_t aBlue,
+                              uint8_t aAlpha = 0xFF) {
+  *imageBufferCurr = aBlue;
+  *(imageBufferCurr + 1) = aGreen;
+  *(imageBufferCurr + 2) = aRed;
+  *(imageBufferCurr + 3) = aAlpha;
+}
+
+// Encodes a row of image data which does not have alpha data
+void nsBMPEncoder::EncodeImageDataRow24(const uint8_t* aData) {
+  for (int32_t x = 0; x < mBMPInfoHeader.width; x++) {
+    uint32_t pos = x * BytesPerPixel(mBMPInfoHeader.bpp);
+    SetPixel24(mImageBufferCurr, aData[pos], aData[pos + 1], aData[pos + 2]);
+    mImageBufferCurr += BytesPerPixel(mBMPInfoHeader.bpp);
+  }
+
+  for (uint32_t x = 0;
+       x < PaddingBytes(mBMPInfoHeader.bpp, mBMPInfoHeader.width); x++) {
+    *mImageBufferCurr++ = 0;
+  }
+}
+
+// Encodes a row of image data which does have alpha data
+void nsBMPEncoder::EncodeImageDataRow32(const uint8_t* aData) {
+  for (int32_t x = 0; x < mBMPInfoHeader.width; x++) {
+    uint32_t pos = x * BytesPerPixel(mBMPInfoHeader.bpp);
+    SetPixel32(mImageBufferCurr, aData[pos], aData[pos + 1], aData[pos + 2],
+               aData[pos + 3]);
+    mImageBufferCurr += 4;
+  }
+
+  for (uint32_t x = 0;
+       x < PaddingBytes(mBMPInfoHeader.bpp, mBMPInfoHeader.width); x++) {
+    *mImageBufferCurr++ = 0;
+  }
+}