Avoid getLength in ico decoder.

src/images/SkImageDecoder_libbmp.cpp

 
 /*
  * Copyright 2007 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #include "bmpdecoderhelper.h"
@@ skipping 74 matching lines @@
     int height() const { return fHeight; }
     const uint8_t* rgb() const { return fRGB.begin(); }
 
 private:
     SkTDArray<uint8_t> fRGB;
     int fWidth;
     int fHeight;
     bool fJustBounds;
 };
 
+// Defined in SkImageDecoder.cpp
+extern size_t copy_stream_to_storage(SkAutoMalloc* storage, SkStream* stream);

[djsollen, 2013/08/19 16:57:20]

why not make it a protected method on SkImageDecoder or better yet in some
utility file (.h/.cpp combo) so that we don't have to extern it here.

[scroggo, 2013/08/19 18:45:55]

Done.

+
 bool SkBMPImageDecoder::onDecode(SkStream* stream, SkBitmap* bm, Mode mode) {
     // First read the entire stream, so that all of the data can be passed to
     // the BmpDecoderHelper.
 
-    // Byte length of all of the data.
-    size_t length;
     // Allocated space used to hold the data.
     SkAutoMalloc storage;
-
-    if (stream->hasLength()) {
-        length = stream->getLength();
-        void* dst = storage.reset(length);
-        if (stream->read(dst, length) != length) {
-            return false;
-        }
-    } else {
-        SkDynamicMemoryWStream tempStream;
-        // Arbitrary buffer size.
-        const size_t bufferSize = 256 * 1024; // 256 KB
-        char buffer[bufferSize];
-        length = 0;
-        do {
-            size_t bytesRead = stream->read(buffer, bufferSize);
-            tempStream.write(buffer, bytesRead);
-            length += bytesRead;
-            SkASSERT(tempStream.bytesWritten() == length);
-        } while (!stream->isAtEnd());
-        void* dst = storage.reset(length);
-        tempStream.copyTo(dst);
+    // Byte length of all of the data.
+    const size_t length = copy_stream_to_storage(&storage, stream);
+    if (0 == length) {
+        return 0;
     }
 
     const bool justBounds = SkImageDecoder::kDecodeBounds_Mode == mode;
     SkBmpDecoderCallback callback(justBounds);
 
     // Now decode the BMP into callback's rgb() array [r,g,b, r,g,b, ...]
     {
         image_codec::BmpDecoderHelper helper;
         const int max_pixels = 16383*16383; // max width*height
         if (!helper.DecodeImage((const char*)storage.get(), length,
@@ skipping 39 matching lines @@
     const int dstHeight = sampler.scaledHeight();
     const uint8_t* srcRow = callback.rgb();
 
     srcRow += sampler.srcY0() * srcRowBytes;
     for (int y = 0; y < dstHeight; y++) {
         sampler.next(srcRow);
         srcRow += sampler.srcDY() * srcRowBytes;
     }
     return true;
 }