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// Copyright 2017 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifdef UNSAFE_BUFFERS_BUILD
// TODO(crbug.com/390223051): Remove C-library calls to fix the errors.
#pragma allow_unsafe_libc_calls
#endif
#ifndef COMPONENTS_ZUCCHINI_BUFFER_SINK_H_
#define COMPONENTS_ZUCCHINI_BUFFER_SINK_H_
#include <stdint.h>
#include <string.h>
#include <algorithm>
#include <iterator>
#include "base/check_op.h"
#include "components/zucchini/buffer_view.h"
namespace zucchini {
// BufferSink acts like an output stream with convenience methods to serialize
// data into a contiguous sequence of raw data. The underlying MutableBufferView
// emulates a cursor to track current write position, and guards against buffer
// overrun. Where applicable, BufferSink should be passed by pointer to maintain
// cursor progress across writes.
class BufferSink : public MutableBufferView {
public:
using iterator = MutableBufferView::iterator;
using MutableBufferView::MutableBufferView;
BufferSink() = default;
explicit BufferSink(MutableBufferView buffer);
BufferSink(const BufferSink&) = default;
BufferSink& operator=(BufferSink&&) = default;
// If sufficient space is available, writes the binary representation of
// |value| starting at the cursor, while advancing the cursor beyond the
// written region, and returns true. Otherwise returns false.
template <class T>
bool PutValue(const T& value) {
DCHECK_NE(begin(), nullptr);
if (Remaining() < sizeof(T))
return false;
::memcpy(begin(), &value, sizeof(T));
remove_prefix(sizeof(T));
return true;
}
// If sufficient space is available, writes the raw bytes [|first|, |last|)
// starting at the cursor, while advancing the cursor beyond the written
// region, and returns true. Otherwise returns false.
template <class It>
bool PutRange(It first, It last) {
static_assert(sizeof(typename std::iterator_traits<It>::value_type) ==
sizeof(uint8_t),
"value_type should fit in uint8_t");
DCHECK_NE(begin(), nullptr);
DCHECK(last >= first);
if (Remaining() < size_type(last - first))
return false;
std::copy(first, last, begin());
remove_prefix(last - first);
return true;
}
size_type Remaining() const { return size(); }
};
} // namespace zucchini
#endif // COMPONENTS_ZUCCHINI_BUFFER_SINK_H_
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