Moving GraphicsContext and dependencies from core to platform.

Source/core/platform/image-decoders/bmp/BMPImageReader.h

-/*
- * Copyright (c) 2008, 2009, Google Inc. All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
- *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
-
-#ifndef BMPImageReader_h
-#define BMPImageReader_h
-
-#include <stdint.h>
-#include "core/platform/image-decoders/ImageDecoder.h"
-#include "wtf/CPU.h"
-
-namespace WebCore {
-
-    // This class decodes a BMP image.  It is used in the BMP and ICO decoders,
-    // which wrap it in the appropriate code to read file headers, etc.
-    class BMPImageReader {
-        WTF_MAKE_FAST_ALLOCATED;
-    public:
-        // Read a value from |data[offset]|, converting from little to native
-        // endianness.
-        static inline uint16_t readUint16(SharedBuffer* data, int offset)
-        {
-            uint16_t result;
-            memcpy(&result, &data->data()[offset], 2);
-        #if CPU(BIG_ENDIAN)
-            result = ((result & 0xff) << 8) | ((result & 0xff00) >> 8);
-        #endif
-            return result;
-        }
-
-        static inline uint32_t readUint32(SharedBuffer* data, int offset)
-        {
-            uint32_t result;
-            memcpy(&result, &data->data()[offset], 4);
-        #if CPU(BIG_ENDIAN)
-            result = ((result & 0xff) << 24) | ((result & 0xff00) << 8) | ((result & 0xff0000) >> 8) | ((result & 0xff000000) >> 24);
-        #endif
-            return result;
-        }
-
-        // |parent| is the decoder that owns us.
-        // |startOffset| points to the start of the BMP within the file.
-        // |buffer| points at an empty ImageFrame that we'll initialize and
-        // fill with decoded data.
-        BMPImageReader(ImageDecoder* parent, size_t decodedAndHeaderOffset, size_t imgDataOffset, bool usesAndMask);
-
-        void setBuffer(ImageFrame* buffer) { m_buffer = buffer; }
-        void setData(SharedBuffer* data) { m_data = data; }
-
-        // Does the actual decoding.  If |onlySize| is true, decoding only
-        // progresses as far as necessary to get the image size.  Returns
-        // whether decoding succeeded.
-        bool decodeBMP(bool onlySize);
-
-    private:
-        // The various BMP compression types.  We don't currently decode all
-        // these.
-        enum CompressionType {
-            // Universal types
-            RGB = 0,
-            RLE8 = 1,
-            RLE4 = 2,
-            // Windows V3+ only
-            BITFIELDS = 3,
-            JPEG = 4,
-            PNG = 5,
-            // OS/2 2.x-only
-            HUFFMAN1D,  // Stored in file as 3
-            RLE24,      // Stored in file as 4
-        };
-        enum AndMaskState {
-            None,
-            NotYetDecoded,
-            Decoding,
-        };
-        enum ProcessingResult {
-            Success,
-            Failure,
-            InsufficientData,
-        };
-
-        // These are based on the Windows BITMAPINFOHEADER and RGBTRIPLE
-        // structs, but with unnecessary entries removed.
-        struct BitmapInfoHeader {
-            uint32_t biSize;
-            int32_t biWidth;
-            int32_t biHeight;
-            uint16_t biBitCount;
-            CompressionType biCompression;
-            uint32_t biClrUsed;
-        };
-        struct RGBTriple {
-            uint8_t rgbBlue;
-            uint8_t rgbGreen;
-            uint8_t rgbRed;
-        };
-
-        inline uint16_t readUint16(int offset) const
-        {
-            return readUint16(m_data.get(), m_decodedOffset + offset);
-        }
-
-        inline uint32_t readUint32(int offset) const
-        {
-            return readUint32(m_data.get(), m_decodedOffset + offset);
-        }
-
-        // Determines the size of the BMP info header.  Returns true if the size
-        // is valid.
-        bool readInfoHeaderSize();
-
-        // Processes the BMP info header.  Returns true if the info header could
-        // be decoded.
-        bool processInfoHeader();
-
-        // Helper function for processInfoHeader() which does the actual reading
-        // of header values from the byte stream.  Returns false on error.
-        bool readInfoHeader();
-
-        // Returns true if this is a Windows V4+ BMP.
-        inline bool isWindowsV4Plus() const
-        {
-            // Windows V4 info header is 108 bytes.  V5 is 124 bytes.
-            return (m_infoHeader.biSize == 108) || (m_infoHeader.biSize == 124);
-        }
-
-        // Returns false if consistency errors are found in the info header.
-        bool isInfoHeaderValid() const;
-
-        // For BI_BITFIELDS images, initializes the m_bitMasks[] and
-        // m_bitOffsets[] arrays.  processInfoHeader() will initialize these for
-        // other compression types where needed.
-        bool processBitmasks();
-
-        // For paletted images, allocates and initializes the m_colorTable[]
-        // array.
-        bool processColorTable();
-
-        // Processes an RLE-encoded image.  Returns true if the entire image was
-        // decoded.
-        bool processRLEData();
-
-        // Processes a set of non-RLE-compressed pixels.  Two cases:
-        //   * inRLE = true: the data is inside an RLE-encoded bitmap.  Tries to
-        //     process |numPixels| pixels on the current row.
-        //   * inRLE = false: the data is inside a non-RLE-encoded bitmap.
-        //     |numPixels| is ignored.  Expects |m_coord| to point at the
-        //     beginning of the next row to be decoded.  Tries to process as
-        //     many complete rows as possible.  Returns InsufficientData if
-        //     there wasn't enough data to decode the whole image.
-        //
-        // This function returns a ProcessingResult instead of a bool so that it
-        // can avoid calling m_parent->setFailed(), which could lead to memory
-        // corruption since that will delete |this| but some callers still want
-        // to access member variables after this returns.
-        ProcessingResult processNonRLEData(bool inRLE, int numPixels);
-
-        // Returns true if the current y-coordinate plus |numRows| would be past
-        // the end of the image.  Here "plus" means "toward the end of the
-        // image", so downwards for m_isTopDown images and upwards otherwise.
-        inline bool pastEndOfImage(int numRows)
-        {
-            return m_isTopDown ? ((m_coord.y() + numRows) >= m_parent->size().height()) : ((m_coord.y() - numRows) < 0);
-        }
-
-        // Returns the pixel data for the current X coordinate in a uint32_t.
-        // Assumes m_decodedOffset has been set to the beginning of the current
-        // row.
-        // NOTE: Only as many bytes of the return value as are needed to hold
-        // the pixel data will actually be set.
-        inline uint32_t readCurrentPixel(int bytesPerPixel) const
-        {
-            const int offset = m_coord.x() * bytesPerPixel;
-            switch (bytesPerPixel) {
-            case 2:
-                return readUint16(offset);
-
-            case 3: {
-                // It doesn't matter that we never set the most significant byte
-                // of the return value here in little-endian mode, the caller
-                // won't read it.
-                uint32_t pixel;
-                memcpy(&pixel, &m_data->data()[m_decodedOffset + offset], 3);
-        #if CPU(BIG_ENDIAN)
-                pixel = ((pixel & 0xff00) << 8) | ((pixel & 0xff0000) >> 8) | ((pixel & 0xff000000) >> 24);
-        #endif
-                return pixel;
-            }
-
-            case 4:
-                return readUint32(offset);
-
-            default:
-                ASSERT_NOT_REACHED();
-                return 0;
-            }
-        }
-
-        // Returns the value of the desired component (0, 1, 2, 3 == R, G, B, A)
-        // in the given pixel data.
-        inline unsigned getComponent(uint32_t pixel, int component) const
-        {
-            return ((pixel & m_bitMasks[component]) >> m_bitShiftsRight[component]) << m_bitShiftsLeft[component];
-        }
-
-        inline unsigned getAlpha(uint32_t pixel) const
-        {
-            // For images without alpha, return alpha of 0xff.
-            return m_bitMasks[3] ? getComponent(pixel, 3) : 0xff;
-        }
-
-        // Sets the current pixel to the color given by |colorIndex|.  This also
-        // increments the relevant local variables to move the current pixel
-        // right by one.
-        inline void setI(size_t colorIndex)
-        {
-            setRGBA(m_colorTable[colorIndex].rgbRed, m_colorTable[colorIndex].rgbGreen, m_colorTable[colorIndex].rgbBlue, 0xff);
-        }
-
-        // Like setI(), but with the individual component values specified.
-        inline void setRGBA(unsigned red,
-                            unsigned green,
-                            unsigned blue,
-                            unsigned alpha)
-        {
-            m_buffer->setRGBA(m_coord.x(), m_coord.y(), red, green, blue, alpha);
-            m_coord.move(1, 0);
-        }
-
-        // Fills pixels from the current X-coordinate up to, but not including,
-        // |endCoord| with the color given by the individual components.  This
-        // also increments the relevant local variables to move the current
-        // pixel right to |endCoord|.
-        inline void fillRGBA(int endCoord,
-                             unsigned red,
-                             unsigned green,
-                             unsigned blue,
-                             unsigned alpha)
-        {
-            while (m_coord.x() < endCoord)
-                setRGBA(red, green, blue, alpha);
-        }
-
-        // Resets the relevant local variables to start drawing at the left edge
-        // of the "next" row, where "next" is above or below the current row
-        // depending on the value of |m_isTopDown|.
-        void moveBufferToNextRow();
-
-        // The decoder that owns us.
-        ImageDecoder* m_parent;
-
-        // The destination for the pixel data.
-        ImageFrame* m_buffer;
-
-        // The file to decode.
-        RefPtr<SharedBuffer> m_data;
-
-        // An index into |m_data| representing how much we've already decoded.
-        size_t m_decodedOffset;
-
-        // The file offset at which the BMP info header starts.
-        size_t m_headerOffset;
-
-        // The file offset at which the actual image bits start.  When decoding
-        // ICO files, this is set to 0, since it's not stored anywhere in a
-        // header; the reader functions expect the image data to start
-        // immediately after the header and (if necessary) color table.
-        size_t m_imgDataOffset;
-
-        // The BMP info header.
-        BitmapInfoHeader m_infoHeader;
-
-        // True if this is an OS/2 1.x (aka Windows 2.x) BMP.  The struct
-        // layouts for this type of BMP are slightly different from the later,
-        // more common formats.
-        bool m_isOS21x;
-
-        // True if this is an OS/2 2.x BMP.  The meanings of compression types 3
-        // and 4 for this type of BMP differ from Windows V3+ BMPs.
-        //
-        // This will be falsely negative in some cases, but only ones where the
-        // way we misinterpret the data is irrelevant.
-        bool m_isOS22x;
-
-        // True if the BMP is not vertically flipped, that is, the first line of
-        // raster data in the file is the top line of the image.
-        bool m_isTopDown;
-
-        // These flags get set to false as we finish each processing stage.
-        bool m_needToProcessBitmasks;
-        bool m_needToProcessColorTable;
-
-        // Masks/offsets for the color values for non-palette formats.  These
-        // are bitwise, with array entries 0, 1, 2, 3 corresponding to R, G, B,
-        // A.
-        //
-        // The right/left shift values are meant to be applied after the masks.
-        // We need to right shift to compensate for the bitfields' offsets into
-        // the 32 bits of pixel data, and left shift to scale the color values
-        // up for fields with less than 8 bits of precision.  Sadly, we can't
-        // just combine these into one shift value because the net shift amount
-        // could go either direction.  (If only "<< -x" were equivalent to
-        // ">> x"...)
-        uint32_t m_bitMasks[4];
-        int m_bitShiftsRight[4];
-        int m_bitShiftsLeft[4];
-
-        // The color palette, for paletted formats.
-        size_t m_tableSizeInBytes;
-        Vector<RGBTriple> m_colorTable;
-
-        // The coordinate to which we've decoded the image.
-        IntPoint m_coord;
-
-        // Variables that track whether we've seen pixels with alpha values != 0
-        // and == 0, respectively.  See comments in processNonRLEData() on how
-        // these are used.
-        bool m_seenNonZeroAlphaPixel;
-        bool m_seenZeroAlphaPixel;
-
-        // ICOs store a 1bpp "mask" immediately after the main bitmap image data
-        // (and, confusingly, add its height to the biHeight value in the info
-        // header, thus doubling it).  This variable tracks whether we have such
-        // a mask and if we've started decoding it yet.
-        AndMaskState m_andMaskState;
-    };
-
-} // namespace WebCore
-
-#endif