Switch SkCodec to int for counts and indices

This matches other Skia APIs. size_t was adopted from blink/
GIFImageReader.

Change-Id: Ic83e59f0942f597c4fb834e623acd9886ad483fe
Reviewed-on: https://skia-review.googlesource.com/13274
Reviewed-by: Mike Reed <reed@google.com>
Reviewed-by: Matt Sarett <msarett@google.com>
Reviewed-by: Chris Blume <cblume@google.com>
Commit-Queue: Leon Scroggins <scroggo@google.com>

2 files changed, 51 insertions, 43 deletions

diff --git a/third_party/gif/SkGifImageReader.cpp b/third_party/gif/SkGifImageReader.cpp
index 86768e301c..8c5cfa1ea8 100644
--- a/third_party/gif/SkGifImageReader.cpp
+++ b/third_party/gif/SkGifImageReader.cpp
@@ -202,7 +202,7 @@ bool SkGIFLZWContext::outputRow(const unsigned char* rowBegin)
 // Otherwise, decoding failed; returns false in this case, which will always cause the SkGifImageReader to set the "decode failed" flag.
 bool SkGIFLZWContext::doLZW(const unsigned char* block, size_t bytesInBlock)
 {
-    const size_t width = m_frameContext->width();
+    const int width = m_frameContext->width();
 
     if (rowIter == rowBuffer.end())
         return true;
@@ -306,14 +306,14 @@ bool SkGIFLZWContext::doLZW(const unsigned char* block, size_t bytesInBlock)
 }
 
 sk_sp<SkColorTable> SkGIFColorMap::buildTable(SkStreamBuffer* streamBuffer, SkColorType colorType,
-                                              size_t transparentPixel) const
+                                              int transparentPixel) const
 {
     if (!m_isDefined)
         return nullptr;
 
     const PackColorProc proc = choose_pack_color_proc(false, colorType);
     if (m_table && proc == m_packColorProc && m_transPixel == transparentPixel) {
-        SkASSERT(transparentPixel > (unsigned) m_table->count()
+        SkASSERT(transparentPixel == kNotFound || transparentPixel > m_table->count()
                 || m_table->operator[](transparentPixel) == SK_ColorTRANSPARENT);
         // This SkColorTable has already been built with the same transparent color and
         // packing proc. Reuse it.
@@ -331,7 +331,7 @@ sk_sp<SkColorTable> SkGIFColorMap::buildTable(SkStreamBuffer* streamBuffer, SkCo
     SkASSERT(m_colors <= SK_MAX_COLORS);
     const uint8_t* srcColormap = rawData->bytes();
     SkPMColor colorStorage[SK_MAX_COLORS];
-    for (size_t i = 0; i < m_colors; i++) {
+    for (int i = 0; i < m_colors; i++) {
         if (i == transparentPixel) {
             colorStorage[i] = SK_ColorTRANSPARENT;
         } else {
@@ -339,21 +339,21 @@ sk_sp<SkColorTable> SkGIFColorMap::buildTable(SkStreamBuffer* streamBuffer, SkCo
         }
         srcColormap += SK_BYTES_PER_COLORMAP_ENTRY;
     }
-    for (size_t i = m_colors; i < SK_MAX_COLORS; i++) {
+    for (int i = m_colors; i < SK_MAX_COLORS; i++) {
         colorStorage[i] = SK_ColorTRANSPARENT;
     }
     m_table = sk_sp<SkColorTable>(new SkColorTable(colorStorage, SK_MAX_COLORS));
     return m_table;
 }
 
-sk_sp<SkColorTable> SkGifImageReader::getColorTable(SkColorType colorType, size_t index) {
-    if (index >= m_frames.size()) {
+sk_sp<SkColorTable> SkGifImageReader::getColorTable(SkColorType colorType, int index) {
+    if (index < 0 || static_cast<size_t>(index) >= m_frames.size()) {
         return nullptr;
     }
 
     const SkGIFFrameContext* frameContext = m_frames[index].get();
     const SkGIFColorMap& localColorMap = frameContext->localColorMap();
-    const size_t transPix = frameContext->transparentPixel();
+    const int transPix = frameContext->transparentPixel();
     if (localColorMap.isDefined()) {
         return localColorMap.buildTable(&m_streamBuffer, colorType, transPix);
     }
@@ -385,7 +385,8 @@ bool SkGIFFrameContext::decode(SkStreamBuffer* streamBuffer, SkGifCodec* client,
     }
 
     // Some bad GIFs have extra blocks beyond the last row, which we don't want to decode.
-    while (m_currentLzwBlock < m_lzwBlocks.size() && m_lzwContext->hasRemainingRows()) {
+    while (static_cast<size_t>(m_currentLzwBlock) < m_lzwBlocks.size()
+           && m_lzwContext->hasRemainingRows()) {
         const auto& block = m_lzwBlocks[m_currentLzwBlock];
         const size_t len = block.blockSize;
 
@@ -411,7 +412,7 @@ bool SkGIFFrameContext::decode(SkStreamBuffer* streamBuffer, SkGifCodec* client,
 // Decode a frame.
 // This method uses SkGIFFrameContext:decode() to decode the frame; decoding error is reported to client as a critical failure.
 // Return true if decoding has progressed. Return false if an error has occurred.
-bool SkGifImageReader::decode(size_t frameIndex, bool* frameComplete)
+bool SkGifImageReader::decode(int frameIndex, bool* frameComplete)
 {
     SkGIFFrameContext* currentFrame = m_frames[frameIndex].get();
 
@@ -493,7 +494,7 @@ bool SkGifImageReader::parse(SkGifImageReader::SkGIFParseQuery query)
             m_screenWidth = GETINT16(currentComponent);
             m_screenHeight = GETINT16(currentComponent + 2);
 
-            const size_t globalColorMapColors = 2 << (currentComponent[4] & 0x07);
+            const int globalColorMapColors = 2 << (currentComponent[4] & 0x07);
 
             if ((currentComponent[4] & 0x80) && globalColorMapColors > 0) { /* global map */
                 m_globalColorMap.setNumColors(globalColorMapColors);
@@ -753,7 +754,7 @@ bool SkGifImageReader::parse(SkGifImageReader::SkGIFParseQuery query)
 
             const bool isLocalColormapDefined = SkToBool(currentComponent[8] & 0x80);
             // The three low-order bits of currentComponent[8] specify the bits per pixel.
-            const size_t numColors = 2 << (currentComponent[8] & 0x7);
+            const int numColors = 2 << (currentComponent[8] & 0x7);
             if (currentFrameIsFirstFrame()) {
                 if (hasTransparentPixel(0, isLocalColormapDefined, numColors)) {
                     m_firstFrameHasAlpha = true;
@@ -851,9 +852,10 @@ bool SkGifImageReader::parse(SkGifImageReader::SkGIFParseQuery query)
     return true;
 }
 
-bool SkGifImageReader::hasTransparentPixel(size_t i, bool isLocalColormapDefined,
-                                           size_t localColors) {
-    if (m_frames.size() <= i) {
+bool SkGifImageReader::hasTransparentPixel(int i, bool isLocalColormapDefined,
+                                           int localColors) {
+    SkASSERT(i >= 0);
+    if (m_frames.size() <= static_cast<size_t>(i)) {
         // This should only happen when parsing the first frame.
         SkASSERT(0 == i);
 
@@ -863,12 +865,17 @@ bool SkGifImageReader::hasTransparentPixel(size_t i, bool isLocalColormapDefined
         return !isLocalColormapDefined && m_globalColorMap.numColors() == 0;
     }
 
-    const size_t transparentPixel = m_frames[i]->transparentPixel();
+    const int transparentPixel = m_frames[i]->transparentPixel();
+    if (transparentPixel < 0) {
+        SkASSERT(SkGIFColorMap::kNotFound == transparentPixel);
+        return false;
+    }
+
     if (isLocalColormapDefined) {
         return transparentPixel < localColors;
     }
 
-    const size_t globalColors = m_globalColorMap.numColors();
+    const int globalColors = m_globalColorMap.numColors();
     if (!globalColors) {
         // No color table for this frame, so the frame is empty.
         // This is technically different from having a transparent
@@ -886,7 +893,7 @@ void SkGifImageReader::addFrameIfNecessary()
 {
     if (m_frames.empty() || m_frames.back()->isComplete()) {
         const size_t i = m_frames.size();
-        std::unique_ptr<SkGIFFrameContext> frame(new SkGIFFrameContext(i));
+        std::unique_ptr<SkGIFFrameContext> frame(new SkGIFFrameContext(static_cast<int>(i)));
         m_frames.push_back(std::move(frame));
     }
 }
@@ -909,7 +916,7 @@ static bool restore_bg(const SkGIFFrameContext& frame) {
 }
 
 void SkGifImageReader::setAlphaAndRequiredFrame(SkGIFFrameContext* frame) {
-    const size_t i = frame->frameId();
+    const int i = frame->frameId();
     if (0 == i) {
         frame->setHasAlpha(m_firstFrameHasAlpha);
         frame->setRequiredFrame(SkCodec::kNone);
@@ -933,7 +940,7 @@ void SkGifImageReader::setAlphaAndRequiredFrame(SkGIFFrameContext* frame) {
 
     const SkGIFFrameContext* prevFrame = m_frames[i - 1].get();
     while (prevFrame->getDisposalMethod() == SkCodecAnimation::RestorePrevious_DisposalMethod) {
-        const size_t prevId = prevFrame->frameId();
+        const int prevId = prevFrame->frameId();
         if (0 == prevId) {
             frame->setHasAlpha(true);
             frame->setRequiredFrame(SkCodec::kNone);
@@ -965,7 +972,7 @@ void SkGifImageReader::setAlphaAndRequiredFrame(SkGIFFrameContext* frame) {
     }
 
     while (frameRect.contains(prevFrameRect)) {
-        const size_t prevRequiredFrame = prevFrame->getRequiredFrame();
+        const int prevRequiredFrame = prevFrame->getRequiredFrame();
         if (prevRequiredFrame == SkCodec::kNone) {
             frame->setRequiredFrame(SkCodec::kNone);
             frame->setHasAlpha(true);
diff --git a/third_party/gif/SkGifImageReader.h b/third_party/gif/SkGifImageReader.h
index 9d69e48823..4667f7963f 100644
--- a/third_party/gif/SkGifImageReader.h
+++ b/third_party/gif/SkGifImageReader.h
@@ -148,7 +148,7 @@ struct SkGIFLZWBlock {
 
 class SkGIFColorMap final {
 public:
-    static constexpr size_t kNotFound = static_cast<size_t>(-1);
+    static constexpr int kNotFound = -1;
 
     SkGIFColorMap()
         : m_isDefined(false)
@@ -159,7 +159,7 @@ public:
     {
     }
 
-    void setNumColors(size_t colors) {
+    void setNumColors(int colors) {
         SkASSERT(!m_colors);
         SkASSERT(!m_position);
 
@@ -173,20 +173,20 @@ public:
         m_isDefined = true;
     }
 
-    size_t numColors() const { return m_colors; }
+    int numColors() const { return m_colors; }
 
     bool isDefined() const { return m_isDefined; }
 
     // Build RGBA table using the data stream.
     sk_sp<SkColorTable> buildTable(SkStreamBuffer*, SkColorType dstColorType,
-                                   size_t transparentPixel) const;
+                                   int transparentPixel) const;
 
 private:
     bool m_isDefined;
     size_t m_position;
-    size_t m_colors;
+    int m_colors;
     // Cached values. If these match on a new request, we can reuse m_table.
-    mutable size_t m_transPixel;
+    mutable int m_transPixel;
     mutable PackColorProc m_packColorProc;
     mutable sk_sp<SkColorTable> m_table;
 };
@@ -239,18 +239,18 @@ public:
     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; }
+    int transparentPixel() const { return m_transparentPixel; }
+    void setTransparentPixel(int pixel) { m_transparentPixel = pixel; }
     bool hasAlpha() const { return m_hasAlpha; }
     void setHasAlpha(bool alpha) { m_hasAlpha = alpha; }
     SkCodecAnimation::DisposalMethod getDisposalMethod() const { return m_disposalMethod; }
     void setDisposalMethod(SkCodecAnimation::DisposalMethod disposalMethod) { m_disposalMethod = disposalMethod; }
 
-    size_t getRequiredFrame() const {
+    int getRequiredFrame() const {
         SkASSERT(this->reachedStartOfData());
         return m_requiredFrame;
     }
-    void setRequiredFrame(size_t req) { m_requiredFrame = req; }
+    void setRequiredFrame(int req) { m_requiredFrame = req; }
 
     unsigned delayTime() const { return m_delayTime; }
     void setDelayTime(unsigned delay) { m_delayTime = delay; }
@@ -277,21 +277,21 @@ public:
     bool reachedStartOfData() const { return m_requiredFrame != kUninitialized; }
 
 private:
-    static constexpr size_t kUninitialized = static_cast<size_t>(-2);
+    static constexpr int kUninitialized = -2;
 
     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.
+    int m_transparentPixel; // Index of transparent pixel. Value is kNotFound if there is no transparent pixel.
     // Cached value, taking into account:
     // - m_transparentPixel
     // - frameRect
     // - previous required frame
     bool m_hasAlpha;
     SkCodecAnimation::DisposalMethod m_disposalMethod; // Restore to background, leave in place, etc.
-    size_t m_requiredFrame;
+    int m_requiredFrame;
     int m_dataSize;
 
     bool m_progressiveDisplay; // If true, do Haeberli interlace hack.
@@ -305,7 +305,7 @@ private:
 
     SkGIFColorMap m_localColorMap;
 
-    size_t m_currentLzwBlock;
+    int m_currentLzwBlock;
     bool m_isComplete;
     bool m_isHeaderDefined;
     bool m_isDataSizeDefined;
@@ -359,15 +359,15 @@ public:
     // 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);
+    bool decode(int frameIndex, bool* frameComplete);
 
-    size_t imagesCount() const
+    int imagesCount() const
     {
         // Report the first frame immediately, so the parser can stop when it
         // sees the size on a SizeQuery.
         const size_t frames = m_frames.size();
         if (frames <= 1) {
-            return frames;
+            return static_cast<int>(frames);
         }
 
         // This avoids counting an empty frame when the file is truncated (or
@@ -375,7 +375,7 @@ public:
         // possibly SkGIFImageHeader) but before reading the color table. This
         // ensures that we do not count a frame before we know its required
         // frame.
-        return m_frames.back()->reachedStartOfData() ? frames : frames - 1;
+        return static_cast<int>(m_frames.back()->reachedStartOfData() ? frames : frames - 1);
     }
     int loopCount() const {
         if (cLoopCountNotSeen == m_loopCount) {
@@ -389,9 +389,10 @@ public:
         return m_globalColorMap;
     }
 
-    const SkGIFFrameContext* frameContext(size_t index) const
+    const SkGIFFrameContext* frameContext(int index) const
     {
-        return index < m_frames.size() ? m_frames[index].get() : 0;
+        return index >= 0 && index < static_cast<int>(m_frames.size())
+                ? m_frames[index].get() : 0;
     }
 
     void clearDecodeState() {
@@ -401,7 +402,7 @@ public:
     }
 
     // Return the color table for frame index (which may be the global color table).
-    sk_sp<SkColorTable> getColorTable(SkColorType dstColorType, size_t index);
+    sk_sp<SkColorTable> getColorTable(SkColorType dstColorType, int index);
 
     bool firstFrameHasAlpha() const { return m_firstFrameHasAlpha; }
 
@@ -418,7 +419,7 @@ private:
     void setAlphaAndRequiredFrame(SkGIFFrameContext*);
     // This method is sometimes called before creating a SkGIFFrameContext, so it cannot rely
     // on SkGIFFrameContext::localColorMap().
-    bool hasTransparentPixel(size_t frameIndex, bool hasLocalColorMap, size_t localMapColors);
+    bool hasTransparentPixel(int frameIndex, bool hasLocalColorMap, int localMapColors);
     bool currentFrameIsFirstFrame() const
     {
         return m_frames.empty() || (m_frames.size() == 1u && !m_frames[0]->isComplete());