/*
* Copyright (c) Meta Platforms, Inc. and affiliates.
* All rights reserved.
*
* This source code is licensed under both the BSD-style license (found in the
* LICENSE file in the root directory of this source tree) and the GPLv2 (found
* in the COPYING file in the root directory of this source tree).
*/
#include "SkippableFrame.h"
#include "mem.h"
#include "utils/Range.h"

#include <cstdio>

using namespace pzstd;

SkippableFrame::SkippableFrame(std::uint32_t size) : frameSize_(size) {
 MEM_writeLE32(data_.data(), kSkippableFrameMagicNumber);
 MEM_writeLE32(data_.data() + 4, kFrameContentsSize);
 MEM_writeLE32(data_.data() + 8, frameSize_);
}

/* static */ std::size_t SkippableFrame::tryRead(ByteRange bytes) {
 if (bytes.size() < SkippableFrame::kSize ||
     MEM_readLE32(bytes.begin()) != kSkippableFrameMagicNumber ||
     MEM_readLE32(bytes.begin() + 4) != kFrameContentsSize) {
   return 0;
 }
 return MEM_readLE32(bytes.begin() + 8);
}