Eliminate copies of encoded image data

third_party/WebKit/Source/platform/image-decoders/SkDataSegmentReader.cpp

Index: third_party/WebKit/Source/platform/image-decoders/SkDataSegmentReader.cpp
diff --git a/third_party/WebKit/Source/platform/image-decoders/SkDataSegmentReader.cpp b/third_party/WebKit/Source/platform/image-decoders/SkDataSegmentReader.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..9df19bba3245c358860453a96850c07f339a7712
--- /dev/null
+++ b/third_party/WebKit/Source/platform/image-decoders/SkDataSegmentReader.cpp
@@ -0,0 +1,32 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "SkDataSegmentReader.h"
+
+namespace blink {
+
+SkDataSegmentReader::SkDataSegmentReader(PassRefPtr<SkData> data)
+: m_data(skia::AdoptRef(data.leakRef())) {}
+
+size_t SkDataSegmentReader::size() const
+{
+    return m_data->size();
+}
+
+size_t SkDataSegmentReader::getSomeData(const char*& data, size_t position) const
+{
+    if (position >= m_data->size())
+        return 0;
+
+    data = reinterpret_cast<const char*>(m_data->bytes() + position);

[Peter Kasting, 2016/03/23 02:42:59]

I'm sort of tempted to suggest using uint8_t* everywhere here like SkData
already does but I think that would probably touch a huge number of places.

Bring on std::byte in C++17...

[scroggo_chromium, 2016/03/24 13:59:46]

Haha +1!

+    return m_data->size() - position;
+}
+
+PassRefPtr<SkData> SkDataSegmentReader::getAsSkData() const
+{
+    return m_data.get();
+}
+
+} // namespace blink
+