lz4_streambuf.h

/*******************************************************************************
 * Copyright 2022 MINRES Technologies GmbH
 * SPDX-License-Identifier: Apache-2.0
 *******************************************************************************
 *
 *  Created on: May 7, 2022
 *      Author: eyck
 */
 
#ifndef _UTIL_LZ4_STREAMBUF_H_
#define _UTIL_LZ4_STREAMBUF_H_
 
#include <cassert>
#include <istream>
#include <lz4frame.h>
#include <ostream>
#include <streambuf>
#include <vector>
 
namespace util {
class lz4c_steambuf : public std::streambuf {
public:
    lz4c_steambuf(std::ostream& sink, size_t buf_size);
 
    ~lz4c_steambuf();
 
    void close();
 
    lz4c_steambuf(const lz4c_steambuf&) = delete;
    lz4c_steambuf(lz4c_steambuf&&) = delete;
    lz4c_steambuf& operator=(const lz4c_steambuf&) = delete;
    lz4c_steambuf& operator=(lz4c_steambuf&&) = delete;
 
private:
    int_type overflow(int_type ch) override;
 
    int_type sync() override;
 
    void compress_and_write();
 
    std::ostream& sink;
    std::vector<char> src_buf;
    std::vector<char> dest_buf;
    LZ4F_compressionContext_t ctx{nullptr};
    bool closed{false};
};
 
class lz4d_streambuf : public std::streambuf {
public:
    lz4d_streambuf(std::istream& source, size_t buf_size);
 
    ~lz4d_streambuf();
 
    int_type underflow() override;
 
    lz4d_streambuf(const lz4d_streambuf&) = delete;
    lz4d_streambuf(lz4d_streambuf&&) = delete;
    lz4d_streambuf& operator=(const lz4d_streambuf&) = delete;
    lz4d_streambuf& operator=(lz4d_streambuf&&) = delete;
 
private:
    std::istream& src_str;
    std::vector<char> src_buf;
    std::vector<char> dest_buf;
    size_t offset{0};
    size_t src_buf_size{0};
    LZ4F_decompressionContext_t ctx{nullptr};
};
 
} // namespace util
 
#endif /* _UTIL_LZ4_STREAMBUF_H_ */