Index: third_party/WebKit/Source/platform/image-decoders/SegmentStream.cpp |
diff --git a/third_party/WebKit/Source/platform/image-decoders/SegmentStream.cpp b/third_party/WebKit/Source/platform/image-decoders/SegmentStream.cpp |
new file mode 100644 |
index 0000000000000000000000000000000000000000..c5cf2e7dcb6a46f642eb0878f7c210286e8464fc |
--- /dev/null |
+++ b/third_party/WebKit/Source/platform/image-decoders/SegmentStream.cpp |
@@ -0,0 +1,107 @@ |
+// Copyright (c) 2017 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 "platform/image-decoders/SegmentStream.h" |
+ |
+namespace blink { |
+ |
+SegmentStream::SegmentStream() |
+ : reader_(), |
+ position_(0), |
+ has_read_all_contents_(true), |
+ is_cleared_(true) {} |
+ |
+void SegmentStream::SetReader(SegmentReader* reader, |
+ bool all_contents_received) { |
scroggo_chromium
2017/04/17 20:04:56
It looks like this parameter is unused.
cblume
2017/04/20 03:42:26
Done.
scroggo_chromium
2017/04/21 20:09:31
You've commented out the parameter, but why not re
cblume
2017/04/21 23:47:38
Oops. Thought it was part of an interface we were
|
+ reader_ = reader; |
+ if (reader) { |
+ has_read_all_contents_ = reader->size() == position_; |
scroggo_chromium
2017/04/17 20:04:56
If the position > reader->size(), should has_read_
cblume
2017/04/20 03:42:26
Done.
|
+ is_cleared_ = position_ > reader_->size(); |
+ } else { |
+ has_read_all_contents_ = true; |
+ is_cleared_ = true; |
+ } |
+} |
+ |
+size_t SegmentStream::read(void* buffer, size_t size) { |
+ if (is_cleared_) |
+ return 0; |
+ |
+ size = std::min(size, reader_->size() - position_); |
+ |
+ size_t bytes_advanced = 0; |
+ if (!buffer) { // skipping, not reading |
+ bytes_advanced = size; |
+ } else { |
+ bytes_advanced = peek(buffer, size); |
+ } |
+ |
+ position_ += bytes_advanced; |
+ has_read_all_contents_ = position_ == reader_->size(); |
+ |
+ return bytes_advanced; |
+} |
+ |
+size_t SegmentStream::peek(void* buffer, size_t size) const { |
+ if (is_cleared_) |
+ return 0; |
+ |
+ size = std::min(size, reader_->size() - position_); |
+ |
+ size_t peek_position = position_; |
+ size_t total_bytes_peeked = 0; |
+ char* buffer_as_char_ptr = reinterpret_cast<char*>(buffer); |
+ while (size) { |
+ const char* segment = nullptr; |
+ size_t bytes_peeked = reader_->GetSomeData(segment, peek_position); |
+ if (!bytes_peeked) |
+ break; |
+ if (bytes_peeked > size) |
+ bytes_peeked = size; |
+ |
+ memcpy(buffer_as_char_ptr, segment, bytes_peeked); |
+ buffer_as_char_ptr += bytes_peeked; |
+ size -= bytes_peeked; |
+ total_bytes_peeked += bytes_peeked; |
+ peek_position += bytes_peeked; |
+ } |
+ |
+ return total_bytes_peeked; |
+} |
+ |
+bool SegmentStream::rewind() { |
+ position_ = 0; |
+ has_read_all_contents_ = true; |
scroggo_chromium
2017/04/17 20:04:56
Why is this set to true? Should this be in an "els
cblume
2017/04/20 03:42:26
Done.
|
+ if (reader_) |
+ has_read_all_contents_ = position_ == reader_->size(); |
+ |
+ return true; |
+} |
+ |
+bool SegmentStream::seek(size_t position) { |
+ has_read_all_contents_ = true; |
scroggo_chromium
2017/04/17 20:04:56
Similarly, why did this get set to true?
cblume
2017/04/20 03:42:26
Done.
|
+ if (reader_) { |
+ position = std::min(position, reader_->size()); |
+ has_read_all_contents_ = position == reader_->size(); |
scroggo_chromium
2017/04/17 20:04:56
This gets repeated a lot. Maybe add an inlined met
cblume
2017/04/20 03:42:26
Done.
|
+ } |
+ position_ = position; |
scroggo_chromium
2017/04/17 20:04:56
It seems odd to me that we correct position if the
cblume
2017/04/20 03:42:26
I agree.
We cannot correct without a reader. So my
scroggo_chromium
2017/04/21 20:09:31
Maybe add a comment?
cblume
2017/04/21 23:47:38
Done.
|
+ |
+ return true; |
+} |
+ |
+bool SegmentStream::move(long offset) { |
+ long absolute_position = position_ + offset; |
+ |
+ // clamp inside the bounds of the buffer size |
+ absolute_position = std::max(absolute_position, 0l); |
+ absolute_position = |
+ std::min(static_cast<size_t>(absolute_position), reader_->size()); |
+ |
+ position_ = absolute_position; |
+ has_read_all_contents_ = position_ == reader_->size(); |
+ |
+ return true; |
+} |
+ |
+} // namespace blink |