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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 | |
8 namespace blink { | |
9 | |
10 SegmentStream::SegmentStream() = default; | |
11 | |
12 SegmentStream::SegmentStream(SegmentStream&& rhs) | |
13 : reader_(std::move(rhs.reader_)), | |
14 position_(rhs.position_), | |
15 has_read_all_contents_(rhs.has_read_all_contents_), | |
16 is_cleared_(rhs.is_cleared_) {} | |
17 | |
18 SegmentStream& SegmentStream::operator=(SegmentStream&& rhs) { | |
19 reader_ = std::move(rhs.reader_); | |
20 position_ = rhs.position_; | |
21 has_read_all_contents_ = rhs.has_read_all_contents_; | |
22 is_cleared_ = rhs.is_cleared_; | |
23 | |
24 return *this; | |
25 } | |
26 | |
27 void SegmentStream::SetReader(WTF::PassRefPtr<SegmentReader> reader) { | |
28 reader_ = std::move(reader); | |
29 SetPositionState(position_); | |
30 } | |
31 | |
32 size_t SegmentStream::read(void* buffer, size_t size) { | |
33 if (is_cleared_) | |
34 return 0; | |
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 SetPositionState(position_ + bytes_advanced); | |
46 | |
47 return bytes_advanced; | |
48 } | |
49 | |
50 size_t SegmentStream::peek(void* buffer, size_t size) const { | |
51 if (is_cleared_) | |
52 return 0; | |
53 | |
54 size = std::min(size, reader_->size() - position_); | |
55 | |
56 size_t total_bytes_peeked = 0; | |
57 char* buffer_as_char_ptr = reinterpret_cast<char*>(buffer); | |
58 while (size) { | |
59 const char* segment = nullptr; | |
60 size_t bytes_peeked = | |
61 reader_->GetSomeData(segment, position_ + total_bytes_peeked); | |
62 if (!bytes_peeked) | |
63 break; | |
64 if (bytes_peeked > size) | |
65 bytes_peeked = size; | |
66 | |
67 memcpy(buffer_as_char_ptr, segment, bytes_peeked); | |
68 buffer_as_char_ptr += bytes_peeked; | |
69 size -= bytes_peeked; | |
70 total_bytes_peeked += bytes_peeked; | |
71 } | |
72 | |
73 return total_bytes_peeked; | |
74 } | |
75 | |
76 bool SegmentStream::rewind() { | |
77 SetPositionState(0); | |
78 return true; | |
79 } | |
80 | |
81 bool SegmentStream::seek(size_t position) { | |
82 SetPositionState(position); | |
83 return true; | |
84 } | |
85 | |
86 bool SegmentStream::move(long offset) { | |
87 DCHECK_GT(offset, 0); | |
scroggo_chromium
2017/08/08 19:39:25
In [1], vmpstr@ suggested that you "DCHECK absolut
cblume
2017/08/09 17:29:29
position_ is a size_t and can never be negative.
T
scroggo_chromium
2017/08/09 17:50:48
sgtm
| |
88 SetPositionState(position_ + offset); | |
89 return true; | |
90 } | |
91 | |
92 void SegmentStream::SetPositionState(size_t new_position) { | |
93 position_ = new_position; | |
94 if (reader_) { | |
95 const size_t reader_size = reader_->size(); | |
96 has_read_all_contents_ = position_ >= reader_size; | |
97 is_cleared_ = position_ > reader_size; | |
98 } else { | |
99 has_read_all_contents_ = true; | |
100 is_cleared_ = true; | |
101 } | |
102 } | |
103 | |
104 } // namespace blink | |
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