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/*
* Copyright (c) 2019, 2025, Oracle and/or its affiliates.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License, version 2.0,
* as published by the Free Software Foundation.
*
* This program is designed to work with certain software (including
* but not limited to OpenSSL) that is licensed under separate terms,
* as designated in a particular file or component or in included license
* documentation. The authors of MySQL hereby grant you an additional
* permission to link the program and your derivative works with the
* separately licensed software that they have either included with
* the program or referenced in the documentation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License, version 2.0, for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef PLUGIN_X_PROTOCOL_STREAM_COMPRESSION_COMPRESSION_ALGORITHM_ZLIB_H_
#define PLUGIN_X_PROTOCOL_STREAM_COMPRESSION_COMPRESSION_ALGORITHM_ZLIB_H_
#include <memory>
#include <utility>
#include "my_dbug.h" // NOLINT(build/include_subdir)
#include "zlib.h" // NOLINT(build/include_subdir)
#include "plugin/x/protocol/stream/compression/compression_algorithm_interface.h"
namespace protocol {
class Compression_algorithm_zlib : public Compression_algorithm_interface {
public:
explicit Compression_algorithm_zlib(const int32_t level) {
m_stream.zalloc = Z_NULL;
m_stream.zfree = Z_NULL;
m_stream.opaque = Z_NULL;
m_stream.avail_in = 0;
m_stream.avail_out = 0;
m_stream.next_in = Z_NULL;
m_stream.next_out = Z_NULL;
deflateInit(&m_stream, level);
}
~Compression_algorithm_zlib() override { deflateEnd(&m_stream); }
void set_pledged_source_size(const int /*src_size*/) override {}
void set_input(uint8_t *in_ptr, const int in_size) override {
m_stream.avail_in = in_size;
m_stream.next_in = in_ptr;
m_flush_finished = false;
}
bool compress(uint8_t *out_ptr, int *out_size) override {
DBUG_TRACE;
if (m_stream.avail_in) return compress_impl(out_ptr, out_size, false);
*out_size = 0;
return true;
}
bool flush(uint8_t *out_ptr, int *out_size) override {
DBUG_TRACE;
if (m_flush_finished) {
*out_size = 0;
return true;
}
if (m_stream.avail_in) return compress(out_ptr, out_size);
const auto result = compress_impl(out_ptr, out_size, true);
if (0 != m_stream.avail_out) m_flush_finished = true;
return result;
}
static int32_t get_level_min() { return Z_BEST_SPEED; }
static int32_t get_level_max() { return Z_BEST_COMPRESSION; }
private:
bool compress_impl(uint8_t *out_ptr, int *out_size, const bool flush) {
DBUG_TRACE;
const int backup_out_size = *out_size;
m_stream.avail_out = backup_out_size;
m_stream.next_out = out_ptr;
do {
DBUG_LOG("debug", "deflate(in_size:" << m_stream.avail_in << ", out_size:"
<< m_stream.avail_out << ")");
const auto result = deflate(&m_stream, flush ? Z_SYNC_FLUSH : Z_NO_FLUSH);
if (Z_OK != result) {
DBUG_LOG("debug",
"deflate(out_size:"
<< m_stream.avail_out << ", in_size:" << m_stream.avail_in
<< ") returned an error, executed with " << result);
return false;
}
DBUG_LOG("debug", "should retry deflate(in_size:"
<< m_stream.avail_in
<< ", out_size:" << m_stream.avail_out << ")");
} while (!flush && (0 != m_stream.avail_out && 0 != m_stream.avail_in));
*out_size = backup_out_size - static_cast<int>(m_stream.avail_out);
return true;
}
bool m_flush_finished = false;
z_stream m_stream;
};
} // namespace protocol
#endif // PLUGIN_X_PROTOCOL_STREAM_COMPRESSION_COMPRESSION_ALGORITHM_ZLIB_H_
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