Rename GIFImageReader to SkGifImageReader

third_party/gif/GIFImageReader.h

-/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
-/* ***** BEGIN LICENSE BLOCK *****
- * Version: MPL 1.1/GPL 2.0/LGPL 2.1
- *
- * The contents of this file are subject to the Mozilla Public License Version
- * 1.1 (the "License"); you may not use this file except in compliance with
- * the License. You may obtain a copy of the License at
- * http://www.mozilla.org/MPL/
- *
- * Software distributed under the License is distributed on an "AS IS" basis,
- * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
- * for the specific language governing rights and limitations under the
- * License.
- *
- * The Original Code is Mozilla Communicator client code.
- *
- * The Initial Developer of the Original Code is
- * Netscape Communications Corporation.
- * Portions created by the Initial Developer are Copyright (C) 1998
- * the Initial Developer. All Rights Reserved.
- *
- * Contributor(s):
- *
- * Alternatively, the contents of this file may be used under the terms of
- * either the GNU General Public License Version 2 or later (the "GPL"), or
- * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
- * in which case the provisions of the GPL or the LGPL are applicable instead
- * of those above. If you wish to allow use of your version of this file only
- * under the terms of either the GPL or the LGPL, and not to allow others to
- * use your version of this file under the terms of the MPL, indicate your
- * decision by deleting the provisions above and replace them with the notice
- * and other provisions required by the GPL or the LGPL. If you do not delete
- * the provisions above, a recipient may use your version of this file under
- * the terms of any one of the MPL, the GPL or the LGPL.
- *
- * ***** END LICENSE BLOCK ***** */
-
-#ifndef GIFImageReader_h
-#define GIFImageReader_h
-
-// Define ourselves as the clientPtr.  Mozilla just hacked their C++ callback class into this old C decoder,
-// so we will too.
-class SkGifCodec;
-
-#include "SkCodec.h"
-#include "SkCodecPriv.h"
-#include "SkCodecAnimation.h"
-#include "SkColorTable.h"
-#include "SkData.h"
-#include "SkImageInfo.h"
-#include "SkStreamBuffer.h"
-#include "../private/SkTArray.h"
-#include <memory>
-#include <vector>
-
-typedef SkTArray<unsigned char, true> GIFRow;
-
-
-#define MAX_DICTIONARY_ENTRY_BITS 12
-#define MAX_DICTIONARY_ENTRIES    4096 // 2^MAX_DICTIONARY_ENTRY_BITS
-#define MAX_COLORS                256
-#define BYTES_PER_COLORMAP_ENTRY  3
-
-constexpr int cLoopCountNotSeen = -2;
-constexpr size_t kNotFound = static_cast<size_t>(-1);
-
-// List of possible parsing states.
-enum GIFState {
-    GIFType,
-    GIFGlobalHeader,
-    GIFGlobalColormap,
-    GIFImageStart,
-    GIFImageHeader,
-    GIFImageColormap,
-    GIFImageBody,
-    GIFLZWStart,
-    GIFLZW,
-    GIFSubBlock,
-    GIFExtension,
-    GIFControlExtension,
-    GIFConsumeBlock,
-    GIFSkipBlock,
-    GIFDone,
-    GIFCommentExtension,
-    GIFApplicationExtension,
-    GIFNetscapeExtensionBlock,
-    GIFConsumeNetscapeExtension,
-    GIFConsumeComment
-};
-
-struct GIFFrameContext;
-
-// LZW decoder state machine.
-class GIFLZWContext final : public SkNoncopyable {
-public:
-    GIFLZWContext(SkGifCodec* client, const GIFFrameContext* frameContext)
-        : codesize(0)
-        , codemask(0)
-        , clearCode(0)
-        , avail(0)
-        , oldcode(0)
-        , firstchar(0)
-        , bits(0)
-        , datum(0)
-        , ipass(0)
-        , irow(0)
-        , rowsRemaining(0)
-        , rowIter(0)
-        , m_client(client)
-        , m_frameContext(frameContext)
-    { }
-
-    bool prepareToDecode();
-    bool outputRow(const unsigned char* rowBegin);
-    bool doLZW(const unsigned char* block, size_t bytesInBlock);
-    bool hasRemainingRows() { return rowsRemaining; }
-
-private:
-    // LZW decoding states and output states.
-    int codesize;
-    int codemask;
-    int clearCode; // Codeword used to trigger dictionary reset.
-    int avail; // Index of next available slot in dictionary.
-    int oldcode;
-    unsigned char firstchar;
-    int bits; // Number of unread bits in "datum".
-    int datum; // 32-bit input buffer.
-    int ipass; // Interlace pass; Ranges 1-4 if interlaced.
-    size_t irow; // Current output row, starting at zero.
-    size_t rowsRemaining; // Rows remaining to be output.
-
-    unsigned short prefix[MAX_DICTIONARY_ENTRIES];
-    unsigned char suffix[MAX_DICTIONARY_ENTRIES];
-    unsigned short suffixLength[MAX_DICTIONARY_ENTRIES];
-    GIFRow rowBuffer; // Single scanline temporary buffer.
-    unsigned char* rowIter;
-
-    SkGifCodec* const m_client;
-    const GIFFrameContext* m_frameContext;
-};
-
-class GIFColorMap final {
-public:
-    GIFColorMap()
-        : m_isDefined(false)
-        , m_colors(0)
-        , m_packColorProc(nullptr)
-    {
-    }
-
-    void setNumColors(size_t colors) {
-        m_colors = colors;
-    }
-
-    size_t numColors() const { return m_colors; }
-
-    void setRawData(const char* data, size_t size)
-    {
-        // FIXME: Can we avoid this copy?
-        m_rawData = SkData::MakeWithCopy(data, size);
-        SkASSERT(m_colors * BYTES_PER_COLORMAP_ENTRY == size);
-        m_isDefined = true;
-    }
-    bool isDefined() const { return m_isDefined; }
-
-    // Build RGBA table using the data stream.
-    sk_sp<SkColorTable> buildTable(SkColorType dstColorType, size_t transparentPixel) const;
-
-private:
-    bool m_isDefined;
-    size_t m_colors;
-    sk_sp<SkData> m_rawData;
-    mutable PackColorProc m_packColorProc;
-    mutable sk_sp<SkColorTable> m_table;
-};
-
-// LocalFrame output state machine.
-struct GIFFrameContext : SkNoncopyable {
-public:
-    GIFFrameContext(int id)
-        : m_frameId(id)
-        , m_xOffset(0)
-        , m_yOffset(0)
-        , m_width(0)
-        , m_height(0)
-        , m_transparentPixel(kNotFound)
-        , m_disposalMethod(SkCodecAnimation::Keep_DisposalMethod)
-        , m_requiredFrame(SkCodec::kNone)
-        , m_dataSize(0)
-        , m_progressiveDisplay(false)
-        , m_interlaced(false)
-        , m_delayTime(0)
-        , m_currentLzwBlock(0)
-        , m_isComplete(false)
-        , m_isHeaderDefined(false)
-        , m_isDataSizeDefined(false)
-    {
-    }
-
-    ~GIFFrameContext()
-    {
-    }
-
-    void addLzwBlock(const void* data, size_t size)
-    {
-        m_lzwBlocks.push_back(SkData::MakeWithCopy(data, size));
-    }
-
-    bool decode(SkGifCodec* client, bool* frameDecoded);
-
-    int frameId() const { return m_frameId; }
-    void setRect(unsigned x, unsigned y, unsigned width, unsigned height)
-    {
-        m_xOffset = x;
-        m_yOffset = y;
-        m_width = width;
-        m_height = height;
-    }
-    SkIRect frameRect() const { return SkIRect::MakeXYWH(m_xOffset, m_yOffset, m_width, m_height); }
-    unsigned xOffset() const { return m_xOffset; }
-    unsigned yOffset() const { return m_yOffset; }
-    unsigned width() const { return m_width; }
-    unsigned height() const { return m_height; }
-    size_t transparentPixel() const { return m_transparentPixel; }
-    void setTransparentPixel(size_t pixel) { m_transparentPixel = pixel; }
-    SkCodecAnimation::DisposalMethod getDisposalMethod() const { return m_disposalMethod; }
-    void setDisposalMethod(SkCodecAnimation::DisposalMethod disposalMethod) { m_disposalMethod = disposalMethod; }
-    size_t getRequiredFrame() const { return m_requiredFrame; }
-    void setRequiredFrame(size_t req) { m_requiredFrame = req; }
-    unsigned delayTime() const { return m_delayTime; }
-    void setDelayTime(unsigned delay) { m_delayTime = delay; }
-    bool isComplete() const { return m_isComplete; }
-    void setComplete() { m_isComplete = true; }
-    bool isHeaderDefined() const { return m_isHeaderDefined; }
-    void setHeaderDefined() { m_isHeaderDefined = true; }
-    bool isDataSizeDefined() const { return m_isDataSizeDefined; }
-    int dataSize() const { return m_dataSize; }
-    void setDataSize(int size)
-    {
-        m_dataSize = size;
-        m_isDataSizeDefined = true;
-    }
-    bool progressiveDisplay() const { return m_progressiveDisplay; }
-    void setProgressiveDisplay(bool progressiveDisplay) { m_progressiveDisplay = progressiveDisplay; }
-    bool interlaced() const { return m_interlaced; }
-    void setInterlaced(bool interlaced) { m_interlaced = interlaced; }
-
-    void clearDecodeState() { m_lzwContext.reset(); }
-    const GIFColorMap& localColorMap() const { return m_localColorMap; }
-    GIFColorMap& localColorMap() { return m_localColorMap; }
-
-private:
-    int m_frameId;
-    unsigned m_xOffset;
-    unsigned m_yOffset; // With respect to "screen" origin.
-    unsigned m_width;
-    unsigned m_height;
-    size_t m_transparentPixel; // Index of transparent pixel. Value is kNotFound if there is no transparent pixel.
-    SkCodecAnimation::DisposalMethod m_disposalMethod; // Restore to background, leave in place, etc.
-    size_t m_requiredFrame;
-    int m_dataSize;
-
-    bool m_progressiveDisplay; // If true, do Haeberli interlace hack.
-    bool m_interlaced; // True, if scanlines arrive interlaced order.
-
-    unsigned m_delayTime; // Display time, in milliseconds, for this image in a multi-image GIF.
-
-    std::unique_ptr<GIFLZWContext> m_lzwContext;
-    std::vector<sk_sp<SkData>> m_lzwBlocks; // LZW blocks for this frame.
-    GIFColorMap m_localColorMap;
-
-    size_t m_currentLzwBlock;
-    bool m_isComplete;
-    bool m_isHeaderDefined;
-    bool m_isDataSizeDefined;
-};
-
-class GIFImageReader final : public SkNoncopyable {
-public:
-    // This takes ownership of stream.
-    GIFImageReader(SkStream* stream)
-        : m_client(nullptr)
-        , m_state(GIFType)
-        , m_bytesToConsume(6) // Number of bytes for GIF type, either "GIF87a" or "GIF89a".
-        , m_version(0)
-        , m_screenWidth(0)
-        , m_screenHeight(0)
-        , m_loopCount(cLoopCountNotSeen)
-        , m_streamBuffer(stream)
-        , m_parseCompleted(false)
-        , m_firstFrameHasAlpha(false)
-        , m_firstFrameSupportsIndex8(false)
-    {
-    }
-
-    ~GIFImageReader()
-    {
-    }
-
-    void setClient(SkGifCodec* client) { m_client = client; }
-
-    unsigned screenWidth() const { return m_screenWidth; }
-    unsigned screenHeight() const { return m_screenHeight; }
-
-    // Option to pass to parse(). All enums are negative, because a non-negative value is used to
-    // indicate that the Reader should parse up to and including the frame indicated.
-    enum GIFParseQuery {
-        // Parse enough to determine the size. Note that this parses the first frame's header,
-        // since we may decide to expand based on the frame's dimensions.
-        GIFSizeQuery        = -1,
-        // Parse to the end, so we know about all frames.
-        GIFFrameCountQuery  = -2,
-    };
-
-    // Parse incoming GIF data stream into internal data structures.
-    // Non-negative values are used to indicate to parse through that frame.
-    // Return true if parsing has progressed or there is not enough data.
-    // Return false if a fatal error is encountered.
-    bool parse(GIFParseQuery);
-
-    // Decode the frame indicated by frameIndex.
-    // frameComplete will be set to true if the frame is completely decoded.
-    // The method returns false if there is an error.
-    bool decode(size_t frameIndex, bool* frameComplete);
-
-    size_t imagesCount() const
-    {
-        if (m_frames.empty())
-            return 0;
-
-        // This avoids counting an empty frame when the file is truncated right after
-        // GIFControlExtension but before GIFImageHeader.
-        // FIXME: This extra complexity is not necessary and we should just report m_frames.size().
-        return m_frames.back()->isHeaderDefined() ? m_frames.size() : m_frames.size() - 1;
-    }
-    int loopCount() const { return m_loopCount; }
-
-    const GIFColorMap& globalColorMap() const
-    {
-        return m_globalColorMap;
-    }
-
-    const GIFFrameContext* frameContext(size_t index) const
-    {
-        return index < m_frames.size() ? m_frames[index].get() : 0;
-    }
-
-    void clearDecodeState() {
-        for (size_t index = 0; index < m_frames.size(); index++) {
-            m_frames[index]->clearDecodeState();
-        }
-    }
-
-    // Return the color table for frame index (which may be the global color table).
-    sk_sp<SkColorTable> getColorTable(SkColorType dstColorType, size_t index) const;
-
-    bool firstFrameHasAlpha() const { return m_firstFrameHasAlpha; }
-
-    bool firstFrameSupportsIndex8() const { return m_firstFrameSupportsIndex8; }
-
-private:
-    // Requires that one byte has been buffered into m_streamBuffer.
-    unsigned char getOneByte() const {
-        return reinterpret_cast<const unsigned char*>(m_streamBuffer.get())[0];
-    }
-
-    void addFrameIfNecessary();
-    bool currentFrameIsFirstFrame() const
-    {
-        return m_frames.empty() || (m_frames.size() == 1u && !m_frames[0]->isComplete());
-    }
-
-    // Unowned pointer
-    SkGifCodec* m_client;
-
-    // Parsing state machine.
-    GIFState m_state; // Current decoder master state.
-    size_t m_bytesToConsume; // Number of bytes to consume for next stage of parsing.
-
-    // Global (multi-image) state.
-    int m_version; // Either 89 for GIF89 or 87 for GIF87.
-    unsigned m_screenWidth; // Logical screen width & height.
-    unsigned m_screenHeight;
-    GIFColorMap m_globalColorMap;
-    int m_loopCount; // Netscape specific extension block to control the number of animation loops a GIF renders.
-
-    std::vector<std::unique_ptr<GIFFrameContext>> m_frames;
-
-    SkStreamBuffer m_streamBuffer;
-    bool m_parseCompleted;
-
-    // These values can be computed before we create a GIFFrameContext, so we
-    // store them here instead of on m_frames[0].
-    bool m_firstFrameHasAlpha;
-    bool m_firstFrameSupportsIndex8;
-};
-
-#endif