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| 1 // Copyright (c) 2017 The Chromium Authors. All rights reserved. |
| 2 // Use of this source code is governed by a BSD-style license that can be |
| 3 // found in the LICENSE file. |
| 4 |
| 5 #include "platform/image-decoders/SegmentStream.h" |
| 6 #include <utility> |
| 7 #include "platform/image-decoders/SegmentReader.h" |
| 8 |
| 9 namespace blink { |
| 10 |
| 11 SegmentStream::SegmentStream() = default; |
| 12 |
| 13 SegmentStream::SegmentStream(SegmentStream&& rhs) |
| 14 : reader_(std::move(rhs.reader_)), position_(rhs.position_) {} |
| 15 |
| 16 SegmentStream& SegmentStream::operator=(SegmentStream&& rhs) { |
| 17 reader_ = std::move(rhs.reader_); |
| 18 position_ = rhs.position_; |
| 19 |
| 20 return *this; |
| 21 } |
| 22 |
| 23 SegmentStream::~SegmentStream() = default; |
| 24 |
| 25 void SegmentStream::SetReader(WTF::RefPtr<SegmentReader> reader) { |
| 26 reader_ = std::move(reader); |
| 27 } |
| 28 |
| 29 bool SegmentStream::IsCleared() const { |
| 30 return !reader_ || position_ > reader_->size(); |
| 31 } |
| 32 |
| 33 size_t SegmentStream::read(void* buffer, size_t size) { |
| 34 DCHECK(!IsCleared()); |
| 35 |
| 36 size = std::min(size, reader_->size() - position_); |
| 37 |
| 38 size_t bytes_advanced = 0; |
| 39 if (!buffer) { // skipping, not reading |
| 40 bytes_advanced = size; |
| 41 } else { |
| 42 bytes_advanced = peek(buffer, size); |
| 43 } |
| 44 |
| 45 position_ += bytes_advanced; |
| 46 |
| 47 return bytes_advanced; |
| 48 } |
| 49 |
| 50 size_t SegmentStream::peek(void* buffer, size_t size) const { |
| 51 DCHECK(!IsCleared()); |
| 52 |
| 53 size = std::min(size, reader_->size() - position_); |
| 54 |
| 55 size_t total_bytes_peeked = 0; |
| 56 char* buffer_as_char_ptr = reinterpret_cast<char*>(buffer); |
| 57 while (size) { |
| 58 const char* segment = nullptr; |
| 59 size_t bytes_peeked = |
| 60 reader_->GetSomeData(segment, position_ + total_bytes_peeked); |
| 61 if (!bytes_peeked) |
| 62 break; |
| 63 if (bytes_peeked > size) |
| 64 bytes_peeked = size; |
| 65 |
| 66 memcpy(buffer_as_char_ptr, segment, bytes_peeked); |
| 67 buffer_as_char_ptr += bytes_peeked; |
| 68 size -= bytes_peeked; |
| 69 total_bytes_peeked += bytes_peeked; |
| 70 } |
| 71 |
| 72 return total_bytes_peeked; |
| 73 } |
| 74 |
| 75 bool SegmentStream::isAtEnd() const { |
| 76 return !reader_ || position_ >= reader_->size(); |
| 77 } |
| 78 |
| 79 bool SegmentStream::rewind() { |
| 80 position_ = 0; |
| 81 return true; |
| 82 } |
| 83 |
| 84 bool SegmentStream::seek(size_t position) { |
| 85 position_ = position; |
| 86 return true; |
| 87 } |
| 88 |
| 89 bool SegmentStream::move(long offset) { |
| 90 DCHECK_GT(offset, 0); |
| 91 position_ += offset; |
| 92 return true; |
| 93 } |
| 94 |
| 95 size_t SegmentStream::getLength() const { |
| 96 if (reader_) |
| 97 return reader_->size(); |
| 98 |
| 99 return 0; |
| 100 } |
| 101 |
| 102 } // namespace blink |
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