The Tor Browser: image/encoders/bmp/nsBMPEncoder.cpp@ac0c01689b40 (annotated)

image/encoders/bmp/nsBMPEncoder.cpp@ac0c01689b40 (annotated)

image/encoders/bmp/nsBMPEncoder.cpp

Thu, 15 Jan 2015 15:59:08 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 15 Jan 2015 15:59:08 +0100
branch: TOR_BUG_9701
changeset 10: ac0c01689b40
permissions: -rw-r--r--

Implement a real Private Browsing Mode condition by changing the API/ABI;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

 /* 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/Endian.h"
 #include "nsBMPEncoder.h"
 #include "prprf.h"
 #include "nsString.h"
 #include "nsStreamUtils.h"
 #include "nsTArray.h"
 #include "nsAutoPtr.h"
 using namespace mozilla;
 NS_IMPL_ISUPPORTS(nsBMPEncoder, imgIEncoder, nsIInputStream, nsIAsyncInputStream)
 nsBMPEncoder::nsBMPEncoder() : mImageBufferStart(nullptr),
                                mImageBufferCurr(0),
                                mImageBufferSize(0),
                                mImageBufferReadPoint(0),
                                mFinished(false),
                                mCallback(nullptr),
                                mCallbackTarget(nullptr),
                                mNotifyThreshold(0)
 {
 }
 nsBMPEncoder::~nsBMPEncoder()
 {
   if (mImageBufferStart) {
     moz_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;
   }
   // 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 uint32_t
 BytesPerPixel(uint32_t aBPP)
 {
   return aBPP / 8;
 }
 // Calculates the number of padding bytes that are needed per row of image data
 static inline uint32_t
 PaddingBytes(uint32_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;
   uint32_t bpp;
   nsresult rv = ParseOptions(aOutputOptions, &version, &bpp);
   if (NS_FAILED(rv)) {
     return rv;
   }
   InitFileHeader(version, bpp, aWidth, aHeight);
   InitInfoHeader(version, bpp, aWidth, aHeight);
   mImageBufferSize = mBMPFileHeader.filesize;
   mImageBufferStart = static_cast<uint8_t*>(moz_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;
   }
   static fallible_t fallible = fallible_t();
   nsAutoArrayPtr<uint8_t> row(new (fallible)
                               uint8_t[mBMPInfoHeader.width *
                               BytesPerPixel(mBMPInfoHeader.bpp)]);
   if (!row) {
     return NS_ERROR_OUT_OF_MEMORY;
   }
   // 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);
       } else {
         EncodeImageDataRow32(row);
       }
     }
   } 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);
       } else {
         EncodeImageDataRow32(row);
       }
     }
   } 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 {
     NS_NOTREACHED("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* version,
                            uint32_t* bpp)
 {
   if (version) {
     *version = VERSION_3;
   }
   if (bpp) {
     *bpp = 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;
   if (!ParseString(NS_ConvertUTF16toUTF8(aOptions), ';', nameValuePairs)) {
     return NS_ERROR_INVALID_ARG;
   }
   // 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;
     if (!ParseString(nameValuePairs[i], '=', nameValuePair)) {
       return NS_ERROR_INVALID_ARG;
     }
     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].Equals("3")) {
         *version = VERSION_3;
       } else if (nameValuePair[1].Equals("5")) {
         *version = 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].Equals("24")) {
         *bpp = 24;
       } else if (nameValuePair[1].Equals("32")) {
         *bpp = 32;
       } else {
         return NS_ERROR_INVALID_ARG;
       }
     }
   }
   return NS_OK;
 }
 NS_IMETHODIMP nsBMPEncoder::Close()
 {
   if (mImageBufferStart) {
     moz_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;
 }
 // [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),
 , 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, uint8_t* aDest,
                                  uint32_t aPixelWidth)
 {
   int 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(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
 void
 nsBMPEncoder::InitFileHeader(Version aVersion, uint32_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 = WIN_V3_HEADER_LENGTH;
   } else { // aVersion == 5
     mBMPFileHeader.dataoffset = WIN_V5_HEADER_LENGTH;
   }
   // The color table is present only if BPP is <= 8
   if (aBPP <= 8) {
     uint32_t numColors = 1 << aBPP;
     mBMPFileHeader.dataoffset += 4 * numColors;
     mBMPFileHeader.filesize = mBMPFileHeader.dataoffset + aWidth * aHeight;
   } else {
     mBMPFileHeader.filesize = mBMPFileHeader.dataoffset + (aWidth *
                               BytesPerPixel(aBPP) + PaddingBytes(aBPP, aWidth)) *
                               aHeight;
   }
   mBMPFileHeader.reserved = 0;
   if (aVersion == VERSION_3) {
     mBMPFileHeader.bihsize = WIN_V3_BIH_LENGTH;
   } else { // aVersion == VERSION_5
     mBMPFileHeader.bihsize = WIN_V5_BIH_LENGTH;
   }
 }
 #define ENCODE(pImageBufferCurr, value) \
     memcpy(*pImageBufferCurr, &value, sizeof value); \
     *pImageBufferCurr += sizeof value;
 // Initializes the bitmap info header mBMPInfoHeader to the passed in values
 void
 nsBMPEncoder::InitInfoHeader(Version aVersion, uint32_t aBPP, uint32_t aWidth,
                              uint32_t aHeight)
 {
   memset(&mBMPInfoHeader, 0, sizeof(mBMPInfoHeader));
   mBMPInfoHeader.width = aWidth;
   mBMPInfoHeader.height = aHeight;
   mBMPInfoHeader.planes = 1;
   mBMPInfoHeader.bpp = aBPP;
   mBMPInfoHeader.compression = 0;
   mBMPInfoHeader.colors = 0;
   mBMPInfoHeader.important_colors = 0;
   if (aBPP <= 8) {
     mBMPInfoHeader.image_size = aWidth * aHeight;
   } else {
     mBMPInfoHeader.image_size = (aWidth * BytesPerPixel(aBPP) +
                                  PaddingBytes(aBPP, aWidth)) * aHeight;
   }
   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 = 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;
   }
 }
 // Encodes the BMP file header mBMPFileHeader
 void
 nsBMPEncoder::EncodeFileHeader()
 {
   mozilla::image::BMPFILEHEADER littleEndianBFH = mBMPFileHeader;
   NativeEndian::swapToLittleEndianInPlace(&littleEndianBFH.filesize, 1);
   NativeEndian::swapToLittleEndianInPlace(&littleEndianBFH.reserved, 1);
   NativeEndian::swapToLittleEndianInPlace(&littleEndianBFH.dataoffset, 1);
   NativeEndian::swapToLittleEndianInPlace(&littleEndianBFH.bihsize, 1);
   ENCODE(&mImageBufferCurr, littleEndianBFH.signature);
   ENCODE(&mImageBufferCurr, littleEndianBFH.filesize);
   ENCODE(&mImageBufferCurr, littleEndianBFH.reserved);
   ENCODE(&mImageBufferCurr, littleEndianBFH.dataoffset);
   ENCODE(&mImageBufferCurr, littleEndianBFH.bihsize);
 }
 // Encodes the BMP infor header mBMPInfoHeader
 void
 nsBMPEncoder::EncodeInfoHeader()
 {
   mozilla::image::BITMAPV5HEADER littleEndianmBIH = mBMPInfoHeader;
   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);
   if (mBMPFileHeader.bihsize == OS2_BIH_LENGTH) {
       uint16_t width = (uint16_t) littleEndianmBIH.width;
       ENCODE(&mImageBufferCurr, width);
       uint16_t height = (uint16_t) littleEndianmBIH.width;
       ENCODE(&mImageBufferCurr, height);
   } else {
       ENCODE(&mImageBufferCurr, littleEndianmBIH.width);
       ENCODE(&mImageBufferCurr, littleEndianmBIH.height);
   }
   ENCODE(&mImageBufferCurr, littleEndianmBIH.planes);
   ENCODE(&mImageBufferCurr, littleEndianmBIH.bpp);
   if (mBMPFileHeader.bihsize > OS2_BIH_LENGTH) {
     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 (mBMPFileHeader.bihsize > WIN_V3_BIH_LENGTH) {
     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;
   }
 }

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image/encoders/bmp/nsBMPEncoder.cpp@ac0c01689b40 (annotated)

image/encoders/bmp/nsBMPEncoder.cpp