//
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// Copyright (C) 2010 The Android Open Source Project
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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#include "update_engine/payload_generator/bzip.h"
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#include <bzlib.h>
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#include <stdlib.h>
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#include <algorithm>
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#include <limits>
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#include "update_engine/common/utils.h"
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namespace chromeos_update_engine {
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bool BzipCompress(const brillo::Blob& in, brillo::Blob* out) {
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TEST_AND_RETURN_FALSE(out);
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out->clear();
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if (in.size() == 0)
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return true;
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// We expect a compression ratio of about 35% with bzip2, so we start with
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// that much output space, which will then be doubled if needed.
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size_t buf_size = 40 + in.size() * 35 / 100;
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out->resize(buf_size);
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// Try increasing buffer size until it works
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for (;;) {
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if (buf_size > std::numeric_limits<uint32_t>::max())
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return false;
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uint32_t data_size = buf_size;
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int rc = BZ2_bzBuffToBuffCompress(
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reinterpret_cast<char*>(out->data()),
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&data_size,
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reinterpret_cast<char*>(const_cast<uint8_t*>(in.data())),
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in.size(),
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9, // Best compression
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0, // Silent verbosity
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0); // Default work factor
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TEST_AND_RETURN_FALSE(rc == BZ_OUTBUFF_FULL || rc == BZ_OK);
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if (rc == BZ_OK) {
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// we're done!
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out->resize(data_size);
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return true;
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}
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// Data didn't fit; double the buffer size.
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buf_size *= 2;
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out->resize(buf_size);
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}
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}
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} // namespace chromeos_update_engine
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