decompression_input_stream.h

/*
 * 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_DECOMPRESSION_INPUT_STREAM_H_
#definePLUGIN_X_PROTOCOL_STREAM_DECOMPRESSION_INPUT_STREAM_H_

#include"google/protobuf/io/zero_copy_stream.h"

#include"my_dbug.h"

#include"plugin/x/protocol/stream/compression/decompression_algorithm_interface.h"

namespaceprotocol {

classDecompression_input_stream
 : public google::protobuf::io::ZeroCopyInputStream {
public:
using ZeroCopyInputStream = google::protobuf::io::ZeroCopyInputStream;

public:
Decompression_input_stream(Decompression_algorithm_interface *algorithm,
 ZeroCopyInputStream *zero_copy_stream)
 : m_decompression_algorithm(algorithm), m_source(zero_copy_stream) {}

boolNext(constvoid **data, int *size) override {
 DBUG_TRACE;
constauto left = m_output_buffer_data_size - m_output_buffer_offset;

if (left > 0) {
 *data = m_output_buffer + m_output_buffer_offset;
 *size = left;

 m_output_buffer_offset = m_output_buffer_data_size;

DBUG_PRINT("info", ("Next(size:%i)=true", *size));
DBUG_DUMP("Decompression_input_stream-out", (constuint8_t *)*data,
 (int)*size);

returntrue;
 }

 m_all += m_output_buffer_offset;
if (!ReadCompressed()) {
returnfalse;
 }

returnNext(data, size);
 }

voidBackUp(int count) override {
 m_output_buffer_offset -= count;
DBUG_LOG("Decompression_input_stream::debug",
"BackUp(" << count << ") where m_output_buffer_offset:"
 << m_output_buffer_offset
 << ", m_output_buffer_data_size:"
 << m_output_buffer_data_size);
 }

boolSkip(int count) override {
DBUG_LOG("Decompression_input_stream::debug", "Skip(" << count << ")");
auto left = m_output_buffer_data_size - m_output_buffer_offset;

if (left >= count) {
 m_output_buffer_offset += count;
returntrue;
 }

 m_output_buffer_offset = m_output_buffer_data_size;
 m_all += m_output_buffer_offset;
if (!ReadCompressed()) returnfalse;

returnSkip(count - left);
 }

 google::protobuf::int64 ByteCount() constoverride {
return m_all + m_output_buffer_offset;
 }

private:
boolReadCompressed() {
 DBUG_TRACE;

if (m_decompression_algorithm->needs_input()) {
uint8_t *in_ptr;
int in_size;
if (!m_source->Next(
const_cast<constvoid **>(reinterpret_cast<void **>(&in_ptr)),
 &in_size))
returnfalse;

 m_decompression_algorithm->set_input(in_ptr, in_size);
 }

 m_output_buffer_offset = 0;
 m_output_buffer_data_size = sizeof(m_output_buffer);

return m_decompression_algorithm->decompress(m_output_buffer,
 &m_output_buffer_data_size);
 }

 Decompression_algorithm_interface *m_decompression_algorithm;
 ZeroCopyInputStream *m_source;

int64_t m_all = 0;
int64_t m_output_buffer_data_size = 0;
int64_t m_output_buffer_offset = 0;
uint8_t m_output_buffer[512];
};

} // namespace protocol

#endif// PLUGIN_X_PROTOCOL_STREAM_DECOMPRESSION_INPUT_STREAM_H_