Upstream Android modifications to the image encoders/decoders.

src/images/SkImageDecoder_libwebp.cpp

Index: src/images/SkImageDecoder_libwebp.cpp
diff --git a/src/images/SkImageDecoder_libwebp.cpp b/src/images/SkImageDecoder_libwebp.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..d4e40c0cd7834a49023e32b43892c895b0e251a7
--- /dev/null
+++ b/src/images/SkImageDecoder_libwebp.cpp
@@ -0,0 +1,595 @@
+/*
+ * Copyright 2010, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "SkImageDecoder.h"
+#include "SkImageEncoder.h"
+#include "SkColorPriv.h"
+#include "SkScaledBitmapSampler.h"
+#include "SkStream.h"
+#include "SkTemplates.h"
+#include "SkUtils.h"
+#include "SkTScopedPtr.h"
+
+// A WebP decoder only, on top of (subset of) libwebp
+// For more information on WebP image format, and libwebp library, see:
+//   http://code.google.com/speed/webp/
+//   http://www.webmproject.org/code/#libwebp_webp_image_decoder_library
+//   http://review.webmproject.org/gitweb?p=libwebp.git
+
+#include <stdio.h>
+extern "C" {
+// If moving libwebp out of skia source tree, path for webp headers must be
+// updated accordingly. Here, we enforce using local copy in webp sub-directory.
+#include "webp/decode.h"
+#include "webp/encode.h"
+}
+
+#ifdef ANDROID
+#include <cutils/properties.h>
+
+// Key to lookup the size of memory buffer set in system property
+static const char KEY_MEM_CAP[] = "ro.media.dec.webp.memcap";
+#endif
+
+// this enables timing code to report milliseconds for a decode
+//#define TIME_DECODE
+
+//////////////////////////////////////////////////////////////////////////
+//////////////////////////////////////////////////////////////////////////
+
+// Define VP8 I/O on top of Skia stream
+
+//////////////////////////////////////////////////////////////////////////
+//////////////////////////////////////////////////////////////////////////
+

[robertphillips, 2013/03/13 13:55:14]

k prefix? g prefix?

+static const size_t WEBP_VP8_HEADER_SIZE = 64;
+static const size_t WEBP_IDECODE_BUFFER_SZ = (1 << 16);
+
+// Parse headers of RIFF container, and check for valid Webp (VP8) content.
+static bool webp_parse_header(SkStream* stream, int* width, int* height, int* alpha) {
+    unsigned char buffer[WEBP_VP8_HEADER_SIZE];
+    const uint32_t contentSize = stream->getLength();
+    const size_t len = stream->read(buffer, WEBP_VP8_HEADER_SIZE);
+    const uint32_t read_bytes =
+            (contentSize < WEBP_VP8_HEADER_SIZE) ? contentSize : WEBP_VP8_HEADER_SIZE;
+    if (len != read_bytes) {
+        return false; // can't read enough
+    }
+
+    WebPBitstreamFeatures features;
+    VP8StatusCode status = WebPGetFeatures(buffer, read_bytes, &features);
+    if (VP8_STATUS_OK != status) {
+        return false; // Invalid WebP file.
+    }
+    *width = features.width;
+    *height = features.height;
+    *alpha = features.has_alpha;
+
+    // sanity check for image size that's about to be decoded.
+    {
+        Sk64 size;
+        size.setMul(*width, *height);
+        if (size.isNeg() || !size.is32()) {
+            return false;
+        }
+        // now check that if we are 4-bytes per pixel, we also don't overflow
+        if (size.get32() > (0x7FFFFFFF >> 2)) {
+            return false;
+        }
+    }
+    return true;
+}
+
+class SkWEBPImageDecoder: public SkImageDecoder {
+public:
+    SkWEBPImageDecoder() {
+        fInputStream = NULL;
+        fOrigWidth = 0;
+        fOrigHeight = 0;
+        fHasAlpha = 0;
+    }
+    virtual ~SkWEBPImageDecoder() {
+        SkSafeUnref(fInputStream);
+    }
+
+    virtual Format getFormat() const SK_OVERRIDE {
+        return kWEBP_Format;
+    }
+
+protected:
+    virtual bool onBuildTileIndex(SkStream *stream, int *width, int *height) SK_OVERRIDE;
+    virtual bool onDecodeRegion(SkBitmap* bitmap, const SkIRect& rect) SK_OVERRIDE;
+    virtual bool onDecode(SkStream* stream, SkBitmap* bm, Mode) SK_OVERRIDE;
+
+private:

[robertphillips, 2013/03/13 13:55:14]

members first?

+    bool setDecodeConfig(SkBitmap* decodedBitmap, int width, int height);
+    SkStream* fInputStream;
+    int fOrigWidth;
+    int fOrigHeight;

[robertphillips, 2013/03/13 13:55:14]

should fHasAlpha be a bool?

+    int fHasAlpha;
+
+    typedef SkImageDecoder INHERITED;
+};
+
+//////////////////////////////////////////////////////////////////////////
+
+#ifdef TIME_DECODE
+
+#include "SkTime.h"
+
+class AutoTimeMillis {
+public:
+    AutoTimeMillis(const char label[]) :
+        fLabel(label) {
+        if (NULL == fLabel) {
+            fLabel = "";
+        }
+        fNow = SkTime::GetMSecs();
+    }
+    ~AutoTimeMillis() {
+        SkDebugf("---- Time (ms): %s %d\n", fLabel, SkTime::GetMSecs() - fNow);
+    }
+private:
+    const char* fLabel;
+    SkMSec fNow;
+};
+
+#endif
+
+///////////////////////////////////////////////////////////////////////////////
+
+// This guy exists just to aid in debugging, as it allows debuggers to just
+// set a break-point in one place to see all error exists.
+static bool return_false(const SkBitmap& bm, const char msg[]) {
+    SkDEBUGF(("libwebp error %s [%d %d]", msg, bm.width(), bm.height()));
+    return false; // must always return false
+}
+

[robertphillips, 2013/03/13 13:55:14]

bool hasAlpha?

+static WEBP_CSP_MODE webp_decode_mode(const SkBitmap* decodedBitmap, int hasAlpha) {
+    WEBP_CSP_MODE mode = MODE_LAST;
+    SkBitmap::Config config = decodedBitmap->config();
+    // For images that have alpha, choose appropriate color mode (MODE_rgbA,
+    // MODE_rgbA_4444) that pre-multiplies RGB pixel values with transparency
+    // factor (alpha).

[robertphillips, 2013/03/13 13:55:14]

constant on LHS

+    if (config == SkBitmap::kARGB_8888_Config) {
+      mode = hasAlpha ? MODE_rgbA : MODE_RGBA;
+    } else if (config == SkBitmap::kARGB_4444_Config) {
+      mode = hasAlpha ? MODE_rgbA_4444 : MODE_RGBA_4444;
+    } else if (config == SkBitmap::kRGB_565_Config) {
+      mode = MODE_RGB_565;
+    }
+    SkASSERT(MODE_LAST != mode);
+    return mode;
+}
+
+// Incremental WebP image decoding. Reads input buffer of 64K size iteratively
+// and decodes this block to appropriate color-space as per config object.
+static bool webp_idecode(SkStream* stream, WebPDecoderConfig* config) {
+    WebPIDecoder* idec = WebPIDecode(NULL, 0, config);
+    if (NULL == idec) {
+        WebPFreeDecBuffer(&config->output);
+        return false;
+    }
+
+    stream->rewind();
+    const uint32_t contentSize = stream->getLength();
+    const uint32_t readBufferSize = (contentSize < WEBP_IDECODE_BUFFER_SZ) ?

[robertphillips, 2013/03/13 13:55:14]

remove spaces?

+                                       contentSize : WEBP_IDECODE_BUFFER_SZ;
+    SkAutoMalloc srcStorage(readBufferSize);
+    unsigned char* input = (uint8_t*)srcStorage.get();
+    if (NULL == input) {
+        WebPIDelete(idec);
+        WebPFreeDecBuffer(&config->output);
+        return false;
+    }
+
+    uint32_t bytesRemaining = contentSize;
+    while (bytesRemaining > 0) {
+        const uint32_t bytesToRead = (bytesRemaining < WEBP_IDECODE_BUFFER_SZ) ?
+                                      bytesRemaining : WEBP_IDECODE_BUFFER_SZ;
+        const size_t bytesRead = stream->read(input, bytesToRead);
+        if (0 == bytesRead) {
+            break;
+        }
+
+        VP8StatusCode status = WebPIAppend(idec, input, bytesRead);
+        if (VP8_STATUS_OK == status || VP8_STATUS_SUSPENDED == status) {
+            bytesRemaining -= bytesRead;
+        } else {
+            break;
+        }
+    }
+    srcStorage.free();
+    WebPIDelete(idec);
+    WebPFreeDecBuffer(&config->output);
+

[robertphillips, 2013/03/13 13:55:14]

return bytesRemaining <= 0;?

+    if (bytesRemaining > 0) {
+        return false;
+    } else {
+        return true;
+    }
+}
+
+static bool webp_get_config_resize(WebPDecoderConfig* config,
+                                   SkBitmap* decodedBitmap,
+                                   int width, int height, int hasAlpha) {
+    WEBP_CSP_MODE mode = webp_decode_mode(decodedBitmap, hasAlpha);
+    if (MODE_LAST == mode) {
+        return false;
+    }
+
+    if (0 == WebPInitDecoderConfig(config)) {
+        return false;
+    }
+
+    config->output.colorspace = mode;
+    config->output.u.RGBA.rgba = (uint8_t*)decodedBitmap->getPixels();
+    config->output.u.RGBA.stride = decodedBitmap->rowBytes();
+    config->output.u.RGBA.size = decodedBitmap->getSize();
+    config->output.is_external_memory = 1;
+
+    if (width != decodedBitmap->width() || height != decodedBitmap->height()) {
+        config->options.use_scaling = 1;
+        config->options.scaled_width = decodedBitmap->width();
+        config->options.scaled_height = decodedBitmap->height();
+    }
+
+    return true;
+}
+
+static bool webp_get_config_resize_crop(WebPDecoderConfig* config,
+                                        SkBitmap* decodedBitmap,

[robertphillips, 2013/03/13 13:55:14]

bool hasAlpha?

+                                        const SkIRect& region, int hasAlpha) {
+
+    if (!webp_get_config_resize(config, decodedBitmap, region.width(),
+                                region.height(), hasAlpha)) {
+      return false;
+    }
+
+    config->options.use_cropping = 1;
+    config->options.crop_left = region.fLeft;
+    config->options.crop_top = region.fTop;
+    config->options.crop_width = region.width();
+    config->options.crop_height = region.height();
+
+    return true;
+}
+
+bool SkWEBPImageDecoder::setDecodeConfig(SkBitmap* decodedBitmap,
+                                         int width, int height) {
+    SkBitmap::Config config = this->getPrefConfig(k32Bit_SrcDepth, fHasAlpha);
+
+    // YUV converter supports output in RGB565, RGBA4444 and RGBA8888 formats.
+    if (fHasAlpha) {
+        if (config != SkBitmap::kARGB_4444_Config) {
+            config = SkBitmap::kARGB_8888_Config;
+        }
+    } else {
+        if (config != SkBitmap::kRGB_565_Config &&
+            config != SkBitmap::kARGB_4444_Config) {
+            config = SkBitmap::kARGB_8888_Config;
+        }
+    }
+
+    if (!this->chooseFromOneChoice(config, width, height)) {
+        return false;
+    }
+
+    decodedBitmap->setConfig(config, width, height, 0);
+
+    decodedBitmap->setIsOpaque(!fHasAlpha);
+
+    return true;
+}
+
+bool SkWEBPImageDecoder::onBuildTileIndex(SkStream* stream,
+                                          int *width, int *height) {
+    int origWidth, origHeight, hasAlpha;
+    if (!webp_parse_header(stream, &origWidth, &origHeight, &hasAlpha)) {
+        return false;
+    }
+
+    stream->rewind();
+    *width = origWidth;
+    *height = origHeight;
+
+    SkRefCnt_SafeAssign(this->fInputStream, stream);
+    this->fOrigWidth = origWidth;
+    this->fOrigHeight = origHeight;
+    this->fHasAlpha = hasAlpha;
+
+    return true;
+}
+
+static bool is_config_compatible(const SkBitmap& bitmap) {
+    SkBitmap::Config config = bitmap.config();
+    return config == SkBitmap::kARGB_4444_Config ||
+           config == SkBitmap::kRGB_565_Config ||
+           config == SkBitmap::kARGB_8888_Config;
+}
+
+bool SkWEBPImageDecoder::onDecodeRegion(SkBitmap* decodedBitmap,
+                                        const SkIRect& region) {
+    SkIRect rect = SkIRect::MakeWH(fOrigWidth, fOrigHeight);
+
+    if (!rect.intersect(region)) {
+        // If the requested region is entirely outsides the image, return false
+        return false;
+    }
+
+    const int sampleSize = this->getSampleSize();
+    SkScaledBitmapSampler sampler(rect.width(), rect.height(), sampleSize);
+    const int width = sampler.scaledWidth();
+    const int height = sampler.scaledHeight();
+
+    // The image can be decoded directly to decodedBitmap if
+    //   1. the region is within the image range
+    //   2. bitmap's config is compatible
+    //   3. bitmap's size is same as the required region (after sampled)
+    bool directDecode = (rect == region) &&
+                        (decodedBitmap->isNull() ||
+                         (is_config_compatible(*decodedBitmap) &&
+                         (decodedBitmap->width() == width) &&
+                         (decodedBitmap->height() == height)));
+    SkTScopedPtr<SkBitmap> adb;
+    SkBitmap *bitmap = decodedBitmap;
+
+    if (!directDecode) {
+        // allocates a temp bitmap
+        bitmap = new SkBitmap;
+        adb.reset(bitmap);
+    }
+
+    if (bitmap->isNull()) {
+        if (!setDecodeConfig(bitmap, width, height)) {
+            return false;
+        }
+        // alloc from native heap if it is a temp bitmap. (prevent GC)
+        bool allocResult = (bitmap == decodedBitmap)
+                               ? allocPixelRef(bitmap, NULL)
+                               : bitmap->allocPixels();
+        if (!allocResult) {
+            return return_false(*decodedBitmap, "allocPixelRef");
+        }
+    } else {
+        // This is also called in setDecodeConfig in above block.
+        // i.e., when bitmap->isNull() is true.
+        if (!chooseFromOneChoice(bitmap->config(), width, height)) {
+            return false;
+        }
+    }
+
+    SkAutoLockPixels alp(*bitmap);
+    WebPDecoderConfig config;
+    if (!webp_get_config_resize_crop(&config, bitmap, rect, fHasAlpha)) {
+        return false;
+    }
+
+    // Decode the WebP image data stream using WebP incremental decoding for
+    // the specified cropped image-region.
+    if (!webp_idecode(this->fInputStream, &config)) {
+        return false;
+    }
+
+    if (!directDecode) {
+        cropBitmap(decodedBitmap, bitmap, sampleSize, region.x(), region.y(),
+                   region.width(), region.height(), rect.x(), rect.y());
+    }
+    return true;
+}
+
+bool SkWEBPImageDecoder::onDecode(SkStream* stream, SkBitmap* decodedBitmap,
+                                  Mode mode) {
+#ifdef TIME_DECODE
+    AutoTimeMillis atm("WEBP Decode");
+#endif
+
+    int origWidth, origHeight, hasAlpha;
+    if (!webp_parse_header(stream, &origWidth, &origHeight, &hasAlpha)) {
+        return false;
+    }

[robertphillips, 2013/03/13 13:55:14]

remove this->?

+    this->fHasAlpha = hasAlpha;
+
+    const int sampleSize = this->getSampleSize();
+    SkScaledBitmapSampler sampler(origWidth, origHeight, sampleSize);
+
+    // If only bounds are requested, done
+    if (SkImageDecoder::kDecodeBounds_Mode == mode) {

[robertphillips, 2013/03/13 13:55:14]

just "return setDecodeConfig"?

+        if (!setDecodeConfig(decodedBitmap, sampler.scaledWidth(),
+                             sampler.scaledHeight())) {
+            return false;
+        }
+        return true;
+    }
+
+    // No Bitmap reuse supported for this format
+    if (!decodedBitmap->isNull()) {
+        return false;
+    }
+    if (!setDecodeConfig(decodedBitmap, sampler.scaledWidth(),
+                         sampler.scaledHeight())) {
+        return false;
+    }
+
+    if (!this->allocPixelRef(decodedBitmap, NULL)) {
+        return return_false(*decodedBitmap, "allocPixelRef");
+    }
+
+    SkAutoLockPixels alp(*decodedBitmap);
+
+    WebPDecoderConfig config;
+    if (!webp_get_config_resize(&config, decodedBitmap, origWidth, origHeight,
+                                hasAlpha)) {
+        return false;
+    }
+
+    // Decode the WebP image data stream using WebP incremental decoding.
+    return webp_idecode(stream, &config);
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+typedef void (*ScanlineImporter)(const uint8_t* in, uint8_t* out, int width,
+                                 const SkPMColor* SK_RESTRICT ctable);
+
+static void ARGB_8888_To_RGB(const uint8_t* in, uint8_t* rgb, int width,
+                             const SkPMColor*) {
+  const uint32_t* SK_RESTRICT src = (const uint32_t*)in;
+  for (int i = 0; i < width; ++i) {
+      const uint32_t c = *src++;
+      rgb[0] = SkGetPackedR32(c);
+      rgb[1] = SkGetPackedG32(c);
+      rgb[2] = SkGetPackedB32(c);
+      rgb += 3;
+  }
+}
+
+static void RGB_565_To_RGB(const uint8_t* in, uint8_t* rgb, int width,
+                           const SkPMColor*) {
+  const uint16_t* SK_RESTRICT src = (const uint16_t*)in;
+  for (int i = 0; i < width; ++i) {
+      const uint16_t c = *src++;
+      rgb[0] = SkPacked16ToR32(c);
+      rgb[1] = SkPacked16ToG32(c);
+      rgb[2] = SkPacked16ToB32(c);
+      rgb += 3;
+  }
+}
+
+static void ARGB_4444_To_RGB(const uint8_t* in, uint8_t* rgb, int width,
+                             const SkPMColor*) {
+  const SkPMColor16* SK_RESTRICT src = (const SkPMColor16*)in;
+  for (int i = 0; i < width; ++i) {
+      const SkPMColor16 c = *src++;
+      rgb[0] = SkPacked4444ToR32(c);
+      rgb[1] = SkPacked4444ToG32(c);
+      rgb[2] = SkPacked4444ToB32(c);
+      rgb += 3;
+  }
+}
+
+static void Index8_To_RGB(const uint8_t* in, uint8_t* rgb, int width,
+                          const SkPMColor* SK_RESTRICT ctable) {
+  const uint8_t* SK_RESTRICT src = (const uint8_t*)in;
+  for (int i = 0; i < width; ++i) {
+      const uint32_t c = ctable[*src++];
+      rgb[0] = SkGetPackedR32(c);
+      rgb[1] = SkGetPackedG32(c);
+      rgb[2] = SkGetPackedB32(c);
+      rgb += 3;
+  }
+}
+
+static ScanlineImporter ChooseImporter(const SkBitmap::Config& config) {
+    switch (config) {
+        case SkBitmap::kARGB_8888_Config:
+            return ARGB_8888_To_RGB;
+        case SkBitmap::kRGB_565_Config:
+            return RGB_565_To_RGB;
+        case SkBitmap::kARGB_4444_Config:
+            return ARGB_4444_To_RGB;
+        case SkBitmap::kIndex8_Config:
+            return Index8_To_RGB;
+        default:
+            return NULL;
+    }
+}
+

[robertphillips, 2013/03/13 13:55:14]

Should this return a bool?

+static int stream_writer(const uint8_t* data, size_t data_size,
+                         const WebPPicture* const picture) {
+  SkWStream* const stream = (SkWStream*)picture->custom_ptr;
+  return stream->write(data, data_size) ? 1 : 0;
+}
+
+class SkWEBPImageEncoder : public SkImageEncoder {
+protected:
+    virtual bool onEncode(SkWStream* stream, const SkBitmap& bm, int quality) SK_OVERRIDE;
+
+private:
+    typedef SkImageEncoder INHERITED;
+};
+
+bool SkWEBPImageEncoder::onEncode(SkWStream* stream, const SkBitmap& bm,
+                                  int quality) {
+    const SkBitmap::Config config = bm.getConfig();

[robertphillips, 2013/03/13 13:55:14]

scanlineImport?

+    const ScanlineImporter scanline_import = ChooseImporter(config);
+    if (NULL == scanline_import) {
+        return false;
+    }
+
+    SkAutoLockPixels alp(bm);
+    SkAutoLockColors ctLocker;
+    if (NULL == bm.getPixels()) {
+        return false;
+    }
+

[robertphillips, 2013/03/13 13:55:14]

webpConfig?

+    WebPConfig webp_config;
+    if (!WebPConfigPreset(&webp_config, WEBP_PRESET_DEFAULT, quality)) {
+        return false;
+    }
+
+    WebPPicture pic;
+    WebPPictureInit(&pic);
+    pic.width = bm.width();
+    pic.height = bm.height();
+    pic.writer = stream_writer;
+    pic.custom_ptr = (void*)stream;
+
+    const SkPMColor* colors = ctLocker.lockColors(bm);
+    const uint8_t* src = (uint8_t*)bm.getPixels();
+    const int rgbStride = pic.width * 3;
+
+    // Import (for each scanline) the bit-map image (in appropriate color-space)
+    // to RGB color space.
+    uint8_t* rgb = new uint8_t[rgbStride * pic.height];
+    for (int y = 0; y < pic.height; ++y) {
+        scanline_import(src + y * bm.rowBytes(), rgb + y * rgbStride,
+                        pic.width, colors);
+    }
+
+    bool ok = WebPPictureImportRGB(&pic, rgb, rgbStride);
+    delete[] rgb;
+
+    ok = ok && WebPEncode(&webp_config, &pic);
+    WebPPictureFree(&pic);
+
+    return ok;
+}
+
+
+///////////////////////////////////////////////////////////////////////////////
+DEFINE_DECODER_CREATOR(WEBPImageDecoder);
+DEFINE_ENCODER_CREATOR(WEBPImageEncoder);
+///////////////////////////////////////////////////////////////////////////////
+
+#include "SkTRegistry.h"
+
+static SkImageDecoder* sk_libwebp_dfactory(SkStream* stream) {
+    int width, height, hasAlpha;
+    if (!webp_parse_header(stream, &width, &height, &hasAlpha)) {
+        return NULL;
+    }
+
+    // Magic matches, call decoder
+    return SkNEW(SkWEBPImageDecoder);
+}
+
+static SkImageEncoder* sk_libwebp_efactory(SkImageEncoder::Type t) {
+      return (SkImageEncoder::kWEBP_Type == t) ? SkNEW(SkWEBPImageEncoder) : NULL;
+}
+
+static SkTRegistry<SkImageDecoder*, SkStream*> gDReg(sk_libwebp_dfactory);
+static SkTRegistry<SkImageEncoder*, SkImageEncoder::Type> gEReg(sk_libwebp_efactory);