// Copyright 2017 The Chromium OS Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#include "puffin/src/bit_writer.h"
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#include <algorithm>
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#include "puffin/src/logging.h"
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namespace puffin {
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bool BufferBitWriter::WriteBits(size_t nbits, uint32_t bits) {
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TEST_AND_RETURN_FALSE(((out_size_ - index_) * 8) - out_holder_bits_ >= nbits);
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TEST_AND_RETURN_FALSE(nbits <= sizeof(bits) * 8);
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while (nbits > 0) {
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while (out_holder_bits_ >= 8) {
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out_buf_[index_++] = out_holder_ & 0x000000FF;
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out_holder_ >>= 8;
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out_holder_bits_ -= 8;
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}
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while (out_holder_bits_ < 24 && nbits > 0) {
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out_holder_ |= (bits & 0x000000FF) << out_holder_bits_;
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auto min = std::min(nbits, static_cast<size_t>(8));
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out_holder_bits_ += min;
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bits >>= min;
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nbits -= min;
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}
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}
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return true;
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}
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bool BufferBitWriter::WriteBytes(
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size_t nbytes,
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const std::function<bool(uint8_t* buffer, size_t count)>& read_fn) {
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TEST_AND_RETURN_FALSE(((out_size_ - index_) * 8) - out_holder_bits_ >=
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(nbytes * 8));
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TEST_AND_RETURN_FALSE(out_holder_bits_ % 8 == 0);
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TEST_AND_RETURN_FALSE(Flush());
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TEST_AND_RETURN_FALSE(read_fn(&out_buf_[index_], nbytes));
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index_ += nbytes;
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return true;
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}
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bool BufferBitWriter::WriteBoundaryBits(uint8_t bits) {
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return WriteBits((8 - (out_holder_bits_ & 7)) & 7, bits);
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}
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bool BufferBitWriter::Flush() {
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TEST_AND_RETURN_FALSE(WriteBoundaryBits(0));
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while (out_holder_bits_ > 0) {
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out_buf_[index_++] = out_holder_ & 0x000000FF;
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out_holder_ >>= 8;
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out_holder_bits_ -= 8;
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}
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return true;
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}
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size_t BufferBitWriter::Size() const {
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return index_;
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}
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} // namespace puffin
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