зеркало из https://github.com/mozilla/gecko-dev.git
1040 строки
36 KiB
C++
1040 строки
36 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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// This is a cross-platform BMP Decoder, which should work everywhere,
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// including big-endian machines like the PowerPC.
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//
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// BMP is a format that has been extended multiple times. To understand the
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// decoder you need to understand this history. The summary of the history
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// below was determined from the following documents.
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//
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// - http://www.fileformat.info/format/bmp/egff.htm
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// - http://www.fileformat.info/format/os2bmp/egff.htm
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// - http://fileformats.archiveteam.org/wiki/BMP
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// - http://fileformats.archiveteam.org/wiki/OS/2_BMP
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// - https://en.wikipedia.org/wiki/BMP_file_format
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// - https://upload.wikimedia.org/wikipedia/commons/c/c4/BMPfileFormat.png
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//
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// WINDOWS VERSIONS OF THE BMP FORMAT
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// ----------------------------------
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// WinBMPv1.
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// - This version is no longer used and can be ignored.
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//
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// WinBMPv2.
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// - First is a 14 byte file header that includes: the magic number ("BM"),
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// file size, and offset to the pixel data (|mDataOffset|).
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// - Next is a 12 byte info header which includes: the info header size
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// (mBIHSize), width, height, number of color planes, and bits-per-pixel
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// (|mBpp|) which must be 1, 4, 8 or 24.
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// - Next is the semi-optional color table, which has length 2^|mBpp| and has 3
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// bytes per value (BGR). The color table is required if |mBpp| is 1, 4, or 8.
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// - Next is an optional gap.
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// - Next is the pixel data, which is pointed to by |mDataOffset|.
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//
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// WinBMPv3. This is the most widely used version.
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// - It changed the info header to 40 bytes by taking the WinBMPv2 info
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// header, enlargening its width and height fields, and adding more fields
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// including: a compression type (|mCompression|) and number of colors
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// (|mNumColors|).
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// - The semi-optional color table is now 4 bytes per value (BGR0), and its
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// length is |mNumColors|, or 2^|mBpp| if |mNumColors| is zero.
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// - |mCompression| can be RGB (i.e. no compression), RLE4 (if |mBpp|==4) or
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// RLE8 (if |mBpp|==8) values.
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//
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// WinBMPv3-NT. A variant of WinBMPv3.
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// - It did not change the info header layout from WinBMPv3.
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// - |mBpp| can now be 16 or 32, in which case |mCompression| can be RGB or the
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// new BITFIELDS value; in the latter case an additional 12 bytes of color
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// bitfields follow the info header.
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//
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// WinBMPv4.
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// - It extended the info header to 108 bytes, including the 12 bytes of color
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// mask data from WinBMPv3-NT, plus alpha mask data, and also color-space and
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// gamma correction fields.
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//
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// WinBMPv5.
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// - It extended the info header to 124 bytes, adding color profile data.
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// - It also added an optional color profile table after the pixel data (and
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// another optional gap).
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//
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// WinBMPv3-ICO. This is a variant of WinBMPv3.
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// - It's the BMP format used for BMP images within ICO files.
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// - The only difference with WinBMPv3 is that if an image is 32bpp and has no
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// compression, then instead of treating the pixel data as 0RGB it is treated
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// as ARGB, but only if one or more of the A values are non-zero.
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//
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// Clipboard variants.
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// - It's the BMP format used for BMP images captured from the clipboard.
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// - It is missing the file header, containing the BM signature and the data
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// offset. Instead the data begins after the header.
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// - If it uses BITFIELDS compression, then there is always an additional 12
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// bytes of data after the header that must be read. In WinBMPv4+, the masks
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// are supposed to be included in the header size, which are the values we use
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// for decoding purposes, but there is additional three masks following the
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// header which must be skipped to get to the pixel data.
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//
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// OS/2 VERSIONS OF THE BMP FORMAT
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// -------------------------------
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// OS2-BMPv1.
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// - Almost identical to WinBMPv2; the differences are basically ignorable.
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//
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// OS2-BMPv2.
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// - Similar to WinBMPv3.
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// - The info header is 64 bytes but can be reduced to as little as 16; any
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// omitted fields are treated as zero. The first 40 bytes of these fields are
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// nearly identical to the WinBMPv3 info header; the remaining 24 bytes are
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// different.
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// - Also adds compression types "Huffman 1D" and "RLE24", which we don't
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// support.
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// - We treat OS2-BMPv2 files as if they are WinBMPv3 (i.e. ignore the extra 24
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// bytes in the info header), which in practice is good enough.
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#include "ImageLogging.h"
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#include "nsBMPDecoder.h"
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#include <stdlib.h>
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#include "mozilla/Attributes.h"
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#include "mozilla/EndianUtils.h"
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#include "mozilla/Likely.h"
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#include "nsIInputStream.h"
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#include "RasterImage.h"
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#include <algorithm>
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using namespace mozilla::gfx;
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namespace mozilla {
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namespace image {
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namespace bmp {
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struct Compression {
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enum { RGB = 0, RLE8 = 1, RLE4 = 2, BITFIELDS = 3 };
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};
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// RLE escape codes and constants.
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struct RLE {
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enum {
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ESCAPE = 0,
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ESCAPE_EOL = 0,
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ESCAPE_EOF = 1,
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ESCAPE_DELTA = 2,
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SEGMENT_LENGTH = 2,
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DELTA_LENGTH = 2
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};
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};
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} // namespace bmp
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using namespace bmp;
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/// Sets the pixel data in aDecoded to the given values.
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/// @param aDecoded pointer to pixel to be set, will be incremented to point to
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/// the next pixel.
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static void SetPixel(uint32_t*& aDecoded, uint8_t aRed, uint8_t aGreen,
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uint8_t aBlue, uint8_t aAlpha = 0xFF) {
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*aDecoded++ = gfxPackedPixel(aAlpha, aRed, aGreen, aBlue);
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}
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static void SetPixel(uint32_t*& aDecoded, uint8_t idx,
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const UniquePtr<ColorTableEntry[]>& aColors) {
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SetPixel(aDecoded, aColors[idx].mRed, aColors[idx].mGreen,
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aColors[idx].mBlue);
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}
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/// Sets two (or one if aCount = 1) pixels
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/// @param aDecoded where the data is stored. Will be moved 4 resp 8 bytes
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/// depending on whether one or two pixels are written.
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/// @param aData The values for the two pixels
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/// @param aCount Current count. Is decremented by one or two.
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static void Set4BitPixel(uint32_t*& aDecoded, uint8_t aData, uint32_t& aCount,
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const UniquePtr<ColorTableEntry[]>& aColors) {
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uint8_t idx = aData >> 4;
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SetPixel(aDecoded, idx, aColors);
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if (--aCount > 0) {
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idx = aData & 0xF;
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SetPixel(aDecoded, idx, aColors);
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--aCount;
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}
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}
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static mozilla::LazyLogModule sBMPLog("BMPDecoder");
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// The length of the mBIHSize field in the info header.
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static const uint32_t BIHSIZE_FIELD_LENGTH = 4;
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nsBMPDecoder::nsBMPDecoder(RasterImage* aImage, State aState, size_t aLength,
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bool aForClipboard)
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: Decoder(aImage),
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mLexer(Transition::To(aState, aLength), Transition::TerminateSuccess()),
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mIsWithinICO(false),
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mIsForClipboard(aForClipboard),
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mMayHaveTransparency(false),
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mDoesHaveTransparency(false),
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mNumColors(0),
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mColors(nullptr),
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mBytesPerColor(0),
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mPreGapLength(0),
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mPixelRowSize(0),
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mCurrentRow(0),
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mCurrentPos(0),
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mAbsoluteModeNumPixels(0) {}
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// Constructor for normal BMP files or from the clipboard.
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nsBMPDecoder::nsBMPDecoder(RasterImage* aImage, bool aForClipboard)
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: nsBMPDecoder(aImage,
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aForClipboard ? State::INFO_HEADER_SIZE : State::FILE_HEADER,
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aForClipboard ? BIHSIZE_FIELD_LENGTH : FILE_HEADER_LENGTH,
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aForClipboard) {}
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// Constructor used for WinBMPv3-ICO files, which lack a file header.
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nsBMPDecoder::nsBMPDecoder(RasterImage* aImage, uint32_t aDataOffset)
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: nsBMPDecoder(aImage, State::INFO_HEADER_SIZE, BIHSIZE_FIELD_LENGTH,
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/* aForClipboard */ false) {
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SetIsWithinICO();
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// Even though the file header isn't present in this case, the dataOffset
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// field is set as if it is, and so we must increment mPreGapLength
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// accordingly.
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mPreGapLength += FILE_HEADER_LENGTH;
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// This is the one piece of data we normally get from a BMP file header, so
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// it must be provided via an argument.
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mH.mDataOffset = aDataOffset;
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}
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nsBMPDecoder::~nsBMPDecoder() {}
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// Obtains the size of the compressed image resource.
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int32_t nsBMPDecoder::GetCompressedImageSize() const {
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// In the RGB case mImageSize might not be set, so compute it manually.
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MOZ_ASSERT(mPixelRowSize != 0);
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return mH.mCompression == Compression::RGB ? mPixelRowSize * AbsoluteHeight()
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: mH.mImageSize;
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}
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nsresult nsBMPDecoder::BeforeFinishInternal() {
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if (!IsMetadataDecode() && !mImageData) {
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return NS_ERROR_FAILURE; // No image; something went wrong.
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}
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return NS_OK;
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}
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nsresult nsBMPDecoder::FinishInternal() {
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// We shouldn't be called in error cases.
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MOZ_ASSERT(!HasError(), "Can't call FinishInternal on error!");
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// We should never make multiple frames.
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MOZ_ASSERT(GetFrameCount() <= 1, "Multiple BMP frames?");
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// Send notifications if appropriate.
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if (!IsMetadataDecode() && HasSize()) {
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// We should have image data.
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MOZ_ASSERT(mImageData);
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// If it was truncated, fill in the missing pixels as black.
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while (mCurrentRow > 0) {
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uint32_t* dst = RowBuffer();
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while (mCurrentPos < mH.mWidth) {
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SetPixel(dst, 0, 0, 0);
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mCurrentPos++;
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}
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mCurrentPos = 0;
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FinishRow();
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}
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// Invalidate.
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nsIntRect r(0, 0, mH.mWidth, AbsoluteHeight());
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PostInvalidation(r);
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MOZ_ASSERT_IF(mDoesHaveTransparency, mMayHaveTransparency);
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// We have transparency if we either detected some in the image itself
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// (i.e., |mDoesHaveTransparency| is true) or we're in an ICO, which could
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// mean we have an AND mask that provides transparency (i.e., |mIsWithinICO|
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// is true).
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// XXX(seth): We can tell when we create the decoder if the AND mask is
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// present, so we could be more precise about this.
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const Opacity opacity = mDoesHaveTransparency || mIsWithinICO
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? Opacity::SOME_TRANSPARENCY
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: Opacity::FULLY_OPAQUE;
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PostFrameStop(opacity);
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PostDecodeDone();
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}
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return NS_OK;
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}
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// ----------------------------------------
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// Actual Data Processing
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// ----------------------------------------
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void BitFields::Value::Set(uint32_t aMask) {
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mMask = aMask;
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// Handle this exceptional case first. The chosen values don't matter
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// (because a mask of zero will always give a value of zero) except that
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// mBitWidth:
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// - shouldn't be zero, because that would cause an infinite loop in Get();
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// - shouldn't be 5 or 8, because that could cause a false positive match in
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// IsR5G5B5() or IsR8G8B8().
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if (mMask == 0x0) {
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mRightShift = 0;
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mBitWidth = 1;
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return;
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}
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// Find the rightmost 1.
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uint8_t i;
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for (i = 0; i < 32; i++) {
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if (mMask & (1 << i)) {
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break;
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}
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}
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mRightShift = i;
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// Now find the leftmost 1 in the same run of 1s. (If there are multiple runs
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// of 1s -- which isn't valid -- we'll behave as if only the lowest run was
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// present, which seems reasonable.)
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for (i = i + 1; i < 32; i++) {
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if (!(mMask & (1 << i))) {
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break;
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}
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}
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mBitWidth = i - mRightShift;
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}
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MOZ_ALWAYS_INLINE uint8_t BitFields::Value::Get(uint32_t aValue) const {
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// Extract the unscaled value.
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uint32_t v = (aValue & mMask) >> mRightShift;
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// Idea: to upscale v precisely we need to duplicate its bits, possibly
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// repeatedly, possibly partially in the last case, from bit 7 down to bit 0
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// in v2. For example:
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//
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// - mBitWidth=1: v2 = v<<7 | v<<6 | ... | v<<1 | v>>0 k -> kkkkkkkk
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// - mBitWidth=2: v2 = v<<6 | v<<4 | v<<2 | v>>0 jk -> jkjkjkjk
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// - mBitWidth=3: v2 = v<<5 | v<<2 | v>>1 ijk -> ijkijkij
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// - mBitWidth=4: v2 = v<<4 | v>>0 hijk -> hijkhijk
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// - mBitWidth=5: v2 = v<<3 | v>>2 ghijk -> ghijkghi
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// - mBitWidth=6: v2 = v<<2 | v>>4 fghijk -> fghijkfg
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// - mBitWidth=7: v2 = v<<1 | v>>6 efghijk -> efghijke
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// - mBitWidth=8: v2 = v>>0 defghijk -> defghijk
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// - mBitWidth=9: v2 = v>>1 cdefghijk -> cdefghij
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// - mBitWidth=10: v2 = v>>2 bcdefghijk -> bcdefghi
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// - mBitWidth=11: v2 = v>>3 abcdefghijk -> abcdefgh
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// - etc.
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//
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uint8_t v2 = 0;
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int32_t i; // must be a signed integer
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for (i = 8 - mBitWidth; i > 0; i -= mBitWidth) {
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v2 |= v << uint32_t(i);
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}
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v2 |= v >> uint32_t(-i);
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return v2;
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}
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MOZ_ALWAYS_INLINE uint8_t BitFields::Value::GetAlpha(uint32_t aValue,
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bool& aHasAlphaOut) const {
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if (mMask == 0x0) {
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return 0xff;
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}
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aHasAlphaOut = true;
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return Get(aValue);
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}
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MOZ_ALWAYS_INLINE uint8_t BitFields::Value::Get5(uint32_t aValue) const {
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MOZ_ASSERT(mBitWidth == 5);
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uint32_t v = (aValue & mMask) >> mRightShift;
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return (v << 3u) | (v >> 2u);
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}
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MOZ_ALWAYS_INLINE uint8_t BitFields::Value::Get8(uint32_t aValue) const {
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MOZ_ASSERT(mBitWidth == 8);
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uint32_t v = (aValue & mMask) >> mRightShift;
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return v;
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}
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void BitFields::SetR5G5B5() {
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mRed.Set(0x7c00);
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mGreen.Set(0x03e0);
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mBlue.Set(0x001f);
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}
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void BitFields::SetR8G8B8() {
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mRed.Set(0xff0000);
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mGreen.Set(0xff00);
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mBlue.Set(0x00ff);
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}
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bool BitFields::IsR5G5B5() const {
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return mRed.mBitWidth == 5 && mGreen.mBitWidth == 5 && mBlue.mBitWidth == 5 &&
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mAlpha.mMask == 0x0;
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}
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bool BitFields::IsR8G8B8() const {
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return mRed.mBitWidth == 8 && mGreen.mBitWidth == 8 && mBlue.mBitWidth == 8 &&
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mAlpha.mMask == 0x0;
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}
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uint32_t* nsBMPDecoder::RowBuffer() {
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if (mDownscaler) {
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return reinterpret_cast<uint32_t*>(mDownscaler->RowBuffer()) + mCurrentPos;
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}
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// Convert from row (1..mHeight) to absolute line (0..mHeight-1).
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int32_t line = (mH.mHeight < 0) ? -mH.mHeight - mCurrentRow : mCurrentRow - 1;
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int32_t offset = line * mH.mWidth + mCurrentPos;
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return reinterpret_cast<uint32_t*>(mImageData) + offset;
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}
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void nsBMPDecoder::FinishRow() {
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if (mDownscaler) {
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mDownscaler->CommitRow();
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if (mDownscaler->HasInvalidation()) {
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DownscalerInvalidRect invalidRect = mDownscaler->TakeInvalidRect();
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PostInvalidation(invalidRect.mOriginalSizeRect,
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Some(invalidRect.mTargetSizeRect));
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}
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} else {
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PostInvalidation(IntRect(0, mCurrentRow, mH.mWidth, 1));
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}
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mCurrentRow--;
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}
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LexerResult nsBMPDecoder::DoDecode(SourceBufferIterator& aIterator,
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IResumable* aOnResume) {
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MOZ_ASSERT(!HasError(), "Shouldn't call DoDecode after error!");
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return mLexer.Lex(aIterator, aOnResume,
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[=](State aState, const char* aData, size_t aLength) {
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switch (aState) {
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case State::FILE_HEADER:
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return ReadFileHeader(aData, aLength);
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case State::INFO_HEADER_SIZE:
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return ReadInfoHeaderSize(aData, aLength);
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case State::INFO_HEADER_REST:
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return ReadInfoHeaderRest(aData, aLength);
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case State::BITFIELDS:
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return ReadBitfields(aData, aLength);
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case State::COLOR_TABLE:
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return ReadColorTable(aData, aLength);
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case State::GAP:
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return SkipGap();
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case State::AFTER_GAP:
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return AfterGap();
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case State::PIXEL_ROW:
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return ReadPixelRow(aData);
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case State::RLE_SEGMENT:
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return ReadRLESegment(aData);
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case State::RLE_DELTA:
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return ReadRLEDelta(aData);
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case State::RLE_ABSOLUTE:
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return ReadRLEAbsolute(aData, aLength);
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default:
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MOZ_CRASH("Unknown State");
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}
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});
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}
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LexerTransition<nsBMPDecoder::State> nsBMPDecoder::ReadFileHeader(
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const char* aData, size_t aLength) {
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mPreGapLength += aLength;
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bool signatureOk = aData[0] == 'B' && aData[1] == 'M';
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if (!signatureOk) {
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return Transition::TerminateFailure();
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}
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|
|
// We ignore the filesize (aData + 2) and reserved (aData + 6) fields.
|
|
|
|
mH.mDataOffset = LittleEndian::readUint32(aData + 10);
|
|
|
|
return Transition::To(State::INFO_HEADER_SIZE, BIHSIZE_FIELD_LENGTH);
|
|
}
|
|
|
|
// We read the info header in two steps: (a) read the mBIHSize field to
|
|
// determine how long the header is; (b) read the rest of the header.
|
|
LexerTransition<nsBMPDecoder::State> nsBMPDecoder::ReadInfoHeaderSize(
|
|
const char* aData, size_t aLength) {
|
|
mPreGapLength += aLength;
|
|
|
|
mH.mBIHSize = LittleEndian::readUint32(aData);
|
|
|
|
bool bihSizeOk = mH.mBIHSize == InfoHeaderLength::WIN_V2 ||
|
|
mH.mBIHSize == InfoHeaderLength::WIN_V3 ||
|
|
mH.mBIHSize == InfoHeaderLength::WIN_V4 ||
|
|
mH.mBIHSize == InfoHeaderLength::WIN_V5 ||
|
|
(mH.mBIHSize >= InfoHeaderLength::OS2_V2_MIN &&
|
|
mH.mBIHSize <= InfoHeaderLength::OS2_V2_MAX);
|
|
if (!bihSizeOk) {
|
|
return Transition::TerminateFailure();
|
|
}
|
|
// ICO BMPs must have a WinBMPv3 header. nsICODecoder should have already
|
|
// terminated decoding if this isn't the case.
|
|
MOZ_ASSERT_IF(mIsWithinICO, mH.mBIHSize == InfoHeaderLength::WIN_V3);
|
|
|
|
return Transition::To(State::INFO_HEADER_REST,
|
|
mH.mBIHSize - BIHSIZE_FIELD_LENGTH);
|
|
}
|
|
|
|
LexerTransition<nsBMPDecoder::State> nsBMPDecoder::ReadInfoHeaderRest(
|
|
const char* aData, size_t aLength) {
|
|
mPreGapLength += aLength;
|
|
|
|
// |mWidth| and |mHeight| may be signed (Windows) or unsigned (OS/2). We just
|
|
// read as unsigned because in practice that's good enough.
|
|
if (mH.mBIHSize == InfoHeaderLength::WIN_V2) {
|
|
mH.mWidth = LittleEndian::readUint16(aData + 0);
|
|
mH.mHeight = LittleEndian::readUint16(aData + 2);
|
|
// We ignore the planes (aData + 4) field; it should always be 1.
|
|
mH.mBpp = LittleEndian::readUint16(aData + 6);
|
|
} else {
|
|
mH.mWidth = LittleEndian::readUint32(aData + 0);
|
|
mH.mHeight = LittleEndian::readUint32(aData + 4);
|
|
// We ignore the planes (aData + 4) field; it should always be 1.
|
|
mH.mBpp = LittleEndian::readUint16(aData + 10);
|
|
|
|
// For OS2-BMPv2 the info header may be as little as 16 bytes, so be
|
|
// careful for these fields.
|
|
mH.mCompression = aLength >= 16 ? LittleEndian::readUint32(aData + 12) : 0;
|
|
mH.mImageSize = aLength >= 20 ? LittleEndian::readUint32(aData + 16) : 0;
|
|
// We ignore the xppm (aData + 20) and yppm (aData + 24) fields.
|
|
mH.mNumColors = aLength >= 32 ? LittleEndian::readUint32(aData + 28) : 0;
|
|
// We ignore the important_colors (aData + 36) field.
|
|
|
|
// For WinBMPv4, WinBMPv5 and (possibly) OS2-BMPv2 there are additional
|
|
// fields in the info header which we ignore, with the possible exception
|
|
// of the color bitfields (see below).
|
|
}
|
|
|
|
// The height for BMPs embedded inside an ICO includes spaces for the AND
|
|
// mask even if it is not present, thus we need to adjust for that here.
|
|
if (mIsWithinICO) {
|
|
// XXX(seth): Should we really be writing the absolute value from
|
|
// the BIH below? Seems like this could be problematic for inverted BMPs.
|
|
mH.mHeight = abs(mH.mHeight) / 2;
|
|
}
|
|
|
|
// Run with MOZ_LOG=BMPDecoder:5 set to see this output.
|
|
MOZ_LOG(sBMPLog, LogLevel::Debug,
|
|
("BMP: bihsize=%u, %d x %d, bpp=%u, compression=%u, colors=%u\n",
|
|
mH.mBIHSize, mH.mWidth, mH.mHeight, uint32_t(mH.mBpp),
|
|
mH.mCompression, mH.mNumColors));
|
|
|
|
// BMPs with negative width are invalid. Also, reject extremely wide images
|
|
// to keep the math sane. And reject INT_MIN as a height because you can't
|
|
// get its absolute value (because -INT_MIN is one more than INT_MAX).
|
|
const int32_t k64KWidth = 0x0000FFFF;
|
|
bool sizeOk =
|
|
0 <= mH.mWidth && mH.mWidth <= k64KWidth && mH.mHeight != INT_MIN;
|
|
if (!sizeOk) {
|
|
return Transition::TerminateFailure();
|
|
}
|
|
|
|
// Check mBpp and mCompression.
|
|
bool bppCompressionOk =
|
|
(mH.mCompression == Compression::RGB &&
|
|
(mH.mBpp == 1 || mH.mBpp == 4 || mH.mBpp == 8 || mH.mBpp == 16 ||
|
|
mH.mBpp == 24 || mH.mBpp == 32)) ||
|
|
(mH.mCompression == Compression::RLE8 && mH.mBpp == 8) ||
|
|
(mH.mCompression == Compression::RLE4 && mH.mBpp == 4) ||
|
|
(mH.mCompression == Compression::BITFIELDS &&
|
|
// For BITFIELDS compression we require an exact match for one of the
|
|
// WinBMP BIH sizes; this clearly isn't an OS2 BMP.
|
|
(mH.mBIHSize == InfoHeaderLength::WIN_V3 ||
|
|
mH.mBIHSize == InfoHeaderLength::WIN_V4 ||
|
|
mH.mBIHSize == InfoHeaderLength::WIN_V5) &&
|
|
(mH.mBpp == 16 || mH.mBpp == 32));
|
|
if (!bppCompressionOk) {
|
|
return Transition::TerminateFailure();
|
|
}
|
|
|
|
// Initialize our current row to the top of the image.
|
|
mCurrentRow = AbsoluteHeight();
|
|
|
|
// Round it up to the nearest byte count, then pad to 4-byte boundary.
|
|
// Compute this even for a metadate decode because GetCompressedImageSize()
|
|
// relies on it.
|
|
mPixelRowSize = (mH.mBpp * mH.mWidth + 7) / 8;
|
|
uint32_t surplus = mPixelRowSize % 4;
|
|
if (surplus != 0) {
|
|
mPixelRowSize += 4 - surplus;
|
|
}
|
|
|
|
size_t bitFieldsLengthStillToRead = 0;
|
|
if (mH.mCompression == Compression::BITFIELDS) {
|
|
// Need to read bitfields.
|
|
if (mH.mBIHSize >= InfoHeaderLength::WIN_V4) {
|
|
// Bitfields are present in the info header, so we can read them
|
|
// immediately.
|
|
mBitFields.ReadFromHeader(aData + 36, /* aReadAlpha = */ true);
|
|
|
|
// If this came from the clipboard, then we know that even if the header
|
|
// explicitly includes the bitfield masks, we need to add an additional
|
|
// offset for the start of the RGB data.
|
|
if (mIsForClipboard) {
|
|
mH.mDataOffset += BitFields::LENGTH;
|
|
}
|
|
} else {
|
|
// Bitfields are present after the info header, so we will read them in
|
|
// ReadBitfields().
|
|
bitFieldsLengthStillToRead = BitFields::LENGTH;
|
|
}
|
|
} else if (mH.mBpp == 16) {
|
|
// No bitfields specified; use the default 5-5-5 values.
|
|
mBitFields.SetR5G5B5();
|
|
} else if (mH.mBpp == 32) {
|
|
// No bitfields specified; use the default 8-8-8 values.
|
|
mBitFields.SetR8G8B8();
|
|
}
|
|
|
|
return Transition::To(State::BITFIELDS, bitFieldsLengthStillToRead);
|
|
}
|
|
|
|
void BitFields::ReadFromHeader(const char* aData, bool aReadAlpha) {
|
|
mRed.Set(LittleEndian::readUint32(aData + 0));
|
|
mGreen.Set(LittleEndian::readUint32(aData + 4));
|
|
mBlue.Set(LittleEndian::readUint32(aData + 8));
|
|
if (aReadAlpha) {
|
|
mAlpha.Set(LittleEndian::readUint32(aData + 12));
|
|
}
|
|
}
|
|
|
|
LexerTransition<nsBMPDecoder::State> nsBMPDecoder::ReadBitfields(
|
|
const char* aData, size_t aLength) {
|
|
mPreGapLength += aLength;
|
|
|
|
// If aLength is zero there are no bitfields to read, or we already read them
|
|
// in ReadInfoHeader().
|
|
if (aLength != 0) {
|
|
mBitFields.ReadFromHeader(aData, /* aReadAlpha = */ false);
|
|
}
|
|
|
|
// Note that RLE-encoded BMPs might be transparent because the 'delta' mode
|
|
// can skip pixels and cause implicit transparency.
|
|
mMayHaveTransparency = mIsWithinICO || mH.mCompression == Compression::RLE8 ||
|
|
mH.mCompression == Compression::RLE4 ||
|
|
(mH.mCompression == Compression::BITFIELDS &&
|
|
mBitFields.mAlpha.IsPresent());
|
|
if (mMayHaveTransparency) {
|
|
PostHasTransparency();
|
|
}
|
|
|
|
// Post our size to the superclass.
|
|
PostSize(mH.mWidth, AbsoluteHeight());
|
|
if (HasError()) {
|
|
return Transition::TerminateFailure();
|
|
}
|
|
|
|
// We've now read all the headers. If we're doing a metadata decode, we're
|
|
// done.
|
|
if (IsMetadataDecode()) {
|
|
return Transition::TerminateSuccess();
|
|
}
|
|
|
|
// Set up the color table, if present; it'll be filled in by ReadColorTable().
|
|
if (mH.mBpp <= 8) {
|
|
mNumColors = 1 << mH.mBpp;
|
|
if (0 < mH.mNumColors && mH.mNumColors < mNumColors) {
|
|
mNumColors = mH.mNumColors;
|
|
}
|
|
|
|
// Always allocate and zero 256 entries, even though mNumColors might be
|
|
// smaller, because the file might erroneously index past mNumColors.
|
|
mColors = MakeUnique<ColorTableEntry[]>(256);
|
|
memset(mColors.get(), 0, 256 * sizeof(ColorTableEntry));
|
|
|
|
// OS/2 Bitmaps have no padding byte.
|
|
mBytesPerColor = (mH.mBIHSize == InfoHeaderLength::WIN_V2) ? 3 : 4;
|
|
}
|
|
|
|
MOZ_ASSERT(!mImageData, "Already have a buffer allocated?");
|
|
nsresult rv = AllocateFrame(
|
|
OutputSize(), FullOutputFrame(),
|
|
mMayHaveTransparency ? SurfaceFormat::B8G8R8A8 : SurfaceFormat::B8G8R8X8);
|
|
if (NS_FAILED(rv)) {
|
|
return Transition::TerminateFailure();
|
|
}
|
|
MOZ_ASSERT(mImageData, "Should have a buffer now");
|
|
|
|
if (mDownscaler) {
|
|
// BMPs store their rows in reverse order, so the downscaler needs to
|
|
// reverse them again when writing its output. Unless the height is
|
|
// negative!
|
|
rv = mDownscaler->BeginFrame(Size(), Nothing(), mImageData,
|
|
mMayHaveTransparency,
|
|
/* aFlipVertically = */ mH.mHeight >= 0);
|
|
if (NS_FAILED(rv)) {
|
|
return Transition::TerminateFailure();
|
|
}
|
|
}
|
|
|
|
return Transition::To(State::COLOR_TABLE, mNumColors * mBytesPerColor);
|
|
}
|
|
|
|
LexerTransition<nsBMPDecoder::State> nsBMPDecoder::ReadColorTable(
|
|
const char* aData, size_t aLength) {
|
|
MOZ_ASSERT_IF(aLength != 0, mNumColors > 0 && mColors);
|
|
|
|
mPreGapLength += aLength;
|
|
|
|
for (uint32_t i = 0; i < mNumColors; i++) {
|
|
// The format is BGR or BGR0.
|
|
mColors[i].mBlue = uint8_t(aData[0]);
|
|
mColors[i].mGreen = uint8_t(aData[1]);
|
|
mColors[i].mRed = uint8_t(aData[2]);
|
|
aData += mBytesPerColor;
|
|
}
|
|
|
|
// If we are decoding a BMP from the clipboard, we did not know the data
|
|
// offset in advance. It is just defined as after the header and color table.
|
|
if (mIsForClipboard) {
|
|
mH.mDataOffset += mPreGapLength;
|
|
}
|
|
|
|
// We know how many bytes we've read so far (mPreGapLength) and we know the
|
|
// offset of the pixel data (mH.mDataOffset), so we can determine the length
|
|
// of the gap (possibly zero) between the color table and the pixel data.
|
|
//
|
|
// If the gap is negative the file must be malformed (e.g. mH.mDataOffset
|
|
// points into the middle of the color palette instead of past the end) and
|
|
// we give up.
|
|
if (mPreGapLength > mH.mDataOffset) {
|
|
return Transition::TerminateFailure();
|
|
}
|
|
|
|
uint32_t gapLength = mH.mDataOffset - mPreGapLength;
|
|
return Transition::ToUnbuffered(State::AFTER_GAP, State::GAP, gapLength);
|
|
}
|
|
|
|
LexerTransition<nsBMPDecoder::State> nsBMPDecoder::SkipGap() {
|
|
return Transition::ContinueUnbuffered(State::GAP);
|
|
}
|
|
|
|
LexerTransition<nsBMPDecoder::State> nsBMPDecoder::AfterGap() {
|
|
// If there are no pixels we can stop.
|
|
//
|
|
// XXX: normally, if there are no pixels we will have stopped decoding before
|
|
// now, outside of this decoder. However, if the BMP is within an ICO file,
|
|
// it's possible that the ICO claimed the image had a non-zero size while the
|
|
// BMP claims otherwise. This test is to catch that awkward case. If we ever
|
|
// come up with a more general solution to this ICO-and-BMP-disagree-on-size
|
|
// problem, this test can be removed.
|
|
if (mH.mWidth == 0 || mH.mHeight == 0) {
|
|
return Transition::TerminateSuccess();
|
|
}
|
|
|
|
bool hasRLE = mH.mCompression == Compression::RLE8 ||
|
|
mH.mCompression == Compression::RLE4;
|
|
return hasRLE ? Transition::To(State::RLE_SEGMENT, RLE::SEGMENT_LENGTH)
|
|
: Transition::To(State::PIXEL_ROW, mPixelRowSize);
|
|
}
|
|
|
|
LexerTransition<nsBMPDecoder::State> nsBMPDecoder::ReadPixelRow(
|
|
const char* aData) {
|
|
MOZ_ASSERT(mCurrentRow > 0);
|
|
MOZ_ASSERT(mCurrentPos == 0);
|
|
|
|
const uint8_t* src = reinterpret_cast<const uint8_t*>(aData);
|
|
uint32_t* dst = RowBuffer();
|
|
uint32_t lpos = mH.mWidth;
|
|
switch (mH.mBpp) {
|
|
case 1:
|
|
while (lpos > 0) {
|
|
int8_t bit;
|
|
uint8_t idx;
|
|
for (bit = 7; bit >= 0 && lpos > 0; bit--) {
|
|
idx = (*src >> bit) & 1;
|
|
SetPixel(dst, idx, mColors);
|
|
--lpos;
|
|
}
|
|
++src;
|
|
}
|
|
break;
|
|
|
|
case 4:
|
|
while (lpos > 0) {
|
|
Set4BitPixel(dst, *src, lpos, mColors);
|
|
++src;
|
|
}
|
|
break;
|
|
|
|
case 8:
|
|
while (lpos > 0) {
|
|
SetPixel(dst, *src, mColors);
|
|
--lpos;
|
|
++src;
|
|
}
|
|
break;
|
|
|
|
case 16:
|
|
if (mBitFields.IsR5G5B5()) {
|
|
// Specialize this common case.
|
|
while (lpos > 0) {
|
|
uint16_t val = LittleEndian::readUint16(src);
|
|
SetPixel(dst, mBitFields.mRed.Get5(val), mBitFields.mGreen.Get5(val),
|
|
mBitFields.mBlue.Get5(val));
|
|
--lpos;
|
|
src += 2;
|
|
}
|
|
} else {
|
|
bool anyHasAlpha = false;
|
|
while (lpos > 0) {
|
|
uint16_t val = LittleEndian::readUint16(src);
|
|
SetPixel(dst, mBitFields.mRed.Get(val), mBitFields.mGreen.Get(val),
|
|
mBitFields.mBlue.Get(val),
|
|
mBitFields.mAlpha.GetAlpha(val, anyHasAlpha));
|
|
--lpos;
|
|
src += 2;
|
|
}
|
|
if (anyHasAlpha) {
|
|
MOZ_ASSERT(mMayHaveTransparency);
|
|
mDoesHaveTransparency = true;
|
|
}
|
|
}
|
|
break;
|
|
|
|
case 24:
|
|
while (lpos > 0) {
|
|
SetPixel(dst, src[2], src[1], src[0]);
|
|
--lpos;
|
|
src += 3;
|
|
}
|
|
break;
|
|
|
|
case 32:
|
|
if (mH.mCompression == Compression::RGB && mIsWithinICO &&
|
|
mH.mBpp == 32) {
|
|
// This is a special case only used for 32bpp WinBMPv3-ICO files, which
|
|
// could be in either 0RGB or ARGB format. We start by assuming it's
|
|
// an 0RGB image. If we hit a non-zero alpha value, then we know it's
|
|
// actually an ARGB image, and change tack accordingly.
|
|
// (Note: a fully-transparent ARGB image is indistinguishable from a
|
|
// 0RGB image, and we will render such an image as a 0RGB image, i.e.
|
|
// opaquely. This is unlikely to be a problem in practice.)
|
|
while (lpos > 0) {
|
|
if (!mDoesHaveTransparency && src[3] != 0) {
|
|
// Up until now this looked like an 0RGB image, but we now know
|
|
// it's actually an ARGB image. Which means every pixel we've seen
|
|
// so far has been fully transparent. So we go back and redo them.
|
|
|
|
// Tell the Downscaler to go back to the start.
|
|
if (mDownscaler) {
|
|
mDownscaler->ResetForNextProgressivePass();
|
|
}
|
|
|
|
// Redo the complete rows we've already done.
|
|
MOZ_ASSERT(mCurrentPos == 0);
|
|
int32_t currentRow = mCurrentRow;
|
|
mCurrentRow = AbsoluteHeight();
|
|
while (mCurrentRow > currentRow) {
|
|
dst = RowBuffer();
|
|
for (int32_t i = 0; i < mH.mWidth; i++) {
|
|
SetPixel(dst, 0, 0, 0, 0);
|
|
}
|
|
FinishRow();
|
|
}
|
|
|
|
// Redo the part of this row we've already done.
|
|
dst = RowBuffer();
|
|
int32_t n = mH.mWidth - lpos;
|
|
for (int32_t i = 0; i < n; i++) {
|
|
SetPixel(dst, 0, 0, 0, 0);
|
|
}
|
|
|
|
MOZ_ASSERT(mMayHaveTransparency);
|
|
mDoesHaveTransparency = true;
|
|
}
|
|
|
|
// If mDoesHaveTransparency is false, treat this as an 0RGB image.
|
|
// Otherwise, treat this as an ARGB image.
|
|
SetPixel(dst, src[2], src[1], src[0],
|
|
mDoesHaveTransparency ? src[3] : 0xff);
|
|
src += 4;
|
|
--lpos;
|
|
}
|
|
} else if (mBitFields.IsR8G8B8()) {
|
|
// Specialize this common case.
|
|
while (lpos > 0) {
|
|
uint32_t val = LittleEndian::readUint32(src);
|
|
SetPixel(dst, mBitFields.mRed.Get8(val), mBitFields.mGreen.Get8(val),
|
|
mBitFields.mBlue.Get8(val));
|
|
--lpos;
|
|
src += 4;
|
|
}
|
|
} else {
|
|
bool anyHasAlpha = false;
|
|
while (lpos > 0) {
|
|
uint32_t val = LittleEndian::readUint32(src);
|
|
SetPixel(dst, mBitFields.mRed.Get(val), mBitFields.mGreen.Get(val),
|
|
mBitFields.mBlue.Get(val),
|
|
mBitFields.mAlpha.GetAlpha(val, anyHasAlpha));
|
|
--lpos;
|
|
src += 4;
|
|
}
|
|
if (anyHasAlpha) {
|
|
MOZ_ASSERT(mMayHaveTransparency);
|
|
mDoesHaveTransparency = true;
|
|
}
|
|
}
|
|
break;
|
|
|
|
default:
|
|
MOZ_CRASH("Unsupported color depth; earlier check didn't catch it?");
|
|
}
|
|
|
|
FinishRow();
|
|
return mCurrentRow == 0 ? Transition::TerminateSuccess()
|
|
: Transition::To(State::PIXEL_ROW, mPixelRowSize);
|
|
}
|
|
|
|
LexerTransition<nsBMPDecoder::State> nsBMPDecoder::ReadRLESegment(
|
|
const char* aData) {
|
|
if (mCurrentRow == 0) {
|
|
return Transition::TerminateSuccess();
|
|
}
|
|
|
|
uint8_t byte1 = uint8_t(aData[0]);
|
|
uint8_t byte2 = uint8_t(aData[1]);
|
|
|
|
if (byte1 != RLE::ESCAPE) {
|
|
// Encoded mode consists of two bytes: byte1 specifies the number of
|
|
// consecutive pixels to be drawn using the color index contained in
|
|
// byte2.
|
|
//
|
|
// Work around bitmaps that specify too many pixels.
|
|
uint32_t pixelsNeeded = std::min<uint32_t>(mH.mWidth - mCurrentPos, byte1);
|
|
if (pixelsNeeded) {
|
|
uint32_t* dst = RowBuffer();
|
|
mCurrentPos += pixelsNeeded;
|
|
if (mH.mCompression == Compression::RLE8) {
|
|
do {
|
|
SetPixel(dst, byte2, mColors);
|
|
pixelsNeeded--;
|
|
} while (pixelsNeeded);
|
|
} else {
|
|
do {
|
|
Set4BitPixel(dst, byte2, pixelsNeeded, mColors);
|
|
} while (pixelsNeeded);
|
|
}
|
|
}
|
|
return Transition::To(State::RLE_SEGMENT, RLE::SEGMENT_LENGTH);
|
|
}
|
|
|
|
if (byte2 == RLE::ESCAPE_EOL) {
|
|
mCurrentPos = 0;
|
|
FinishRow();
|
|
return mCurrentRow == 0
|
|
? Transition::TerminateSuccess()
|
|
: Transition::To(State::RLE_SEGMENT, RLE::SEGMENT_LENGTH);
|
|
}
|
|
|
|
if (byte2 == RLE::ESCAPE_EOF) {
|
|
return Transition::TerminateSuccess();
|
|
}
|
|
|
|
if (byte2 == RLE::ESCAPE_DELTA) {
|
|
return Transition::To(State::RLE_DELTA, RLE::DELTA_LENGTH);
|
|
}
|
|
|
|
// Absolute mode. |byte2| gives the number of pixels. The length depends on
|
|
// whether it's 4-bit or 8-bit RLE. Also, the length must be even (and zero
|
|
// padding is used to achieve this when necessary).
|
|
MOZ_ASSERT(mAbsoluteModeNumPixels == 0);
|
|
mAbsoluteModeNumPixels = byte2;
|
|
uint32_t length = byte2;
|
|
if (mH.mCompression == Compression::RLE4) {
|
|
length = (length + 1) / 2; // halve, rounding up
|
|
}
|
|
if (length & 1) {
|
|
length++;
|
|
}
|
|
return Transition::To(State::RLE_ABSOLUTE, length);
|
|
}
|
|
|
|
LexerTransition<nsBMPDecoder::State> nsBMPDecoder::ReadRLEDelta(
|
|
const char* aData) {
|
|
// Delta encoding makes it possible to skip pixels making part of the image
|
|
// transparent.
|
|
MOZ_ASSERT(mMayHaveTransparency);
|
|
mDoesHaveTransparency = true;
|
|
|
|
if (mDownscaler) {
|
|
// Clear the skipped pixels. (This clears to the end of the row,
|
|
// which is perfect if there's a Y delta and harmless if not).
|
|
mDownscaler->ClearRestOfRow(/* aStartingAtCol = */ mCurrentPos);
|
|
}
|
|
|
|
// Handle the XDelta.
|
|
mCurrentPos += uint8_t(aData[0]);
|
|
if (mCurrentPos > mH.mWidth) {
|
|
mCurrentPos = mH.mWidth;
|
|
}
|
|
|
|
// Handle the Y Delta.
|
|
int32_t yDelta = std::min<int32_t>(uint8_t(aData[1]), mCurrentRow);
|
|
mCurrentRow -= yDelta;
|
|
|
|
if (mDownscaler && yDelta > 0) {
|
|
// Commit the current row (the first of the skipped rows).
|
|
mDownscaler->CommitRow();
|
|
|
|
// Clear and commit the remaining skipped rows.
|
|
for (int32_t line = 1; line < yDelta; line++) {
|
|
mDownscaler->ClearRow();
|
|
mDownscaler->CommitRow();
|
|
}
|
|
}
|
|
|
|
return mCurrentRow == 0
|
|
? Transition::TerminateSuccess()
|
|
: Transition::To(State::RLE_SEGMENT, RLE::SEGMENT_LENGTH);
|
|
}
|
|
|
|
LexerTransition<nsBMPDecoder::State> nsBMPDecoder::ReadRLEAbsolute(
|
|
const char* aData, size_t aLength) {
|
|
uint32_t n = mAbsoluteModeNumPixels;
|
|
mAbsoluteModeNumPixels = 0;
|
|
|
|
if (mCurrentPos + n > uint32_t(mH.mWidth)) {
|
|
// Bad data. Stop decoding; at least part of the image may have been
|
|
// decoded.
|
|
return Transition::TerminateSuccess();
|
|
}
|
|
|
|
// In absolute mode, n represents the number of pixels that follow, each of
|
|
// which contains the color index of a single pixel.
|
|
uint32_t* dst = RowBuffer();
|
|
uint32_t iSrc = 0;
|
|
uint32_t* oldPos = dst;
|
|
if (mH.mCompression == Compression::RLE8) {
|
|
while (n > 0) {
|
|
SetPixel(dst, aData[iSrc], mColors);
|
|
n--;
|
|
iSrc++;
|
|
}
|
|
} else {
|
|
while (n > 0) {
|
|
Set4BitPixel(dst, aData[iSrc], n, mColors);
|
|
iSrc++;
|
|
}
|
|
}
|
|
mCurrentPos += dst - oldPos;
|
|
|
|
// We should read all the data (unless the last byte is zero padding).
|
|
MOZ_ASSERT(iSrc == aLength - 1 || iSrc == aLength);
|
|
|
|
return Transition::To(State::RLE_SEGMENT, RLE::SEGMENT_LENGTH);
|
|
}
|
|
|
|
} // namespace image
|
|
} // namespace mozilla
|