Add support for multiple frames in SkCodec

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