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1 | /* |
2 | * Copyright (c) Meta Platforms, Inc. and affiliates. |
3 | * All rights reserved. |
4 | * |
5 | * This source code is licensed under both the BSD-style license (found in the |
6 | * LICENSE file in the root directory of this source tree) and the GPLv2 (found |
7 | * in the COPYING file in the root directory of this source tree). |
8 | */ |
9 | #include "SkippableFrame.h" |
10 | #include "mem.h" |
11 | #include "utils/Range.h" |
12 | |
13 | #include <cstdio> |
14 | |
15 | using namespace pzstd; |
16 | |
17 | SkippableFrame::SkippableFrame(std::uint32_t size) : frameSize_(size) { |
18 | MEM_writeLE32(data_.data(), kSkippableFrameMagicNumber); |
19 | MEM_writeLE32(data_.data() + 4, kFrameContentsSize); |
20 | MEM_writeLE32(data_.data() + 8, frameSize_); |
21 | } |
22 | |
23 | /* static */ std::size_t SkippableFrame::tryRead(ByteRange bytes) { |
24 | if (bytes.size() < SkippableFrame::kSize || |
25 | MEM_readLE32(bytes.begin()) != kSkippableFrameMagicNumber || |
26 | MEM_readLE32(bytes.begin() + 4) != kFrameContentsSize) { |
27 | return 0; |
28 | } |
29 | return MEM_readLE32(bytes.begin() + 8); |
30 | } |