Alignment/Geners/interface/CStringStream.hh - master - githubmirror/cmssw

Alignment/Geners/interface/CStringStream.hh
84 строки3 KB
Ivan Razumov
Add missing include
30 ноя 2023, 14:11
30 ноя 2023, 14:113d5c5ef
// Compressed string stream.
//
// Properties we need to have in this class:
//
// 1. Ability to use it as std::ostringstream for uncompressed writes.
//
// 2. Ability to use it as std::istringstream for uncompressed reads.
//
// 3. Ability to fill the compression buffer from an istream.
//
// 4. Ability to dump the compression buffer to an ostream.
//
// 5. Ability to convert data between compressed and uncompressed buffers.

#ifndef GENERS_CSTRINGSTREAM_HH_
#define GENERS_CSTRINGSTREAM_HH_

#include <iostream>
#include <vector>

#include <memory>
#include "Alignment/Geners/interface/CStringBuf.hh"
#include "Alignment/Geners/interface/ZlibHandle.hh"

namespace gs {
  class CStringStream : public std::basic_iostream<char> {
  public:
    enum CompressionMode { NOT_COMPRESSED = 0, ZLIB, BZIP2 };

    CStringStream(CompressionMode m, int compressionLevel, unsigned minSizeToCompress, unsigned bufSize);

    // Basic inspectors
    inline CompressionMode compressionMode() const { return mode_; }
    inline int compressionLevel() const { return compressionLevel_; }
    inline unsigned minSizeToCompress() const { return minSizeToCompress_; }
    inline std::size_t bufferSize() const { return comprBuf_.size(); }

    // "setCompressionMode" calls "reset" internally.
    // All unprocessed data will be lost.
    void setCompressionMode(CompressionMode m);

    // The sink must be set before calling "writeCompressed".
    // This is where the compressed data will be dumped.
    inline void setSink(std::ostream &os) { sink_ = &os; }

    // "writeCompressed" compresses the content of this stream
    // and dumps them to sink. The write pointer is repositioned
    // at the beginning of the stream. The compression mode is
    // returned (always NOT_COMPRESSED if the amount of data
    // was below "minSizeToCompress").
    CompressionMode writeCompressed();

    // Fill this stream from compressed data. Could be called
    // repetitively. Uncompressed data is appended at the end
    // (internal pointers are not reset).
    void readCompressed(std::istream &in, unsigned compressionCode, unsigned long long len);

    // Reposition both read and write pointers of the stream
    // at the beginning of the stream
    void reset();

    // Parse the compression mode. Returns "true" on success.
    static bool getCompressionModeByName(const char *name, CompressionMode *m);

    // String representation of the compression mode
    static std::string compressionModeName(CompressionMode m, bool useShortName = true);

    CStringStream(const CStringStream &) = delete;
    CStringStream &operator=(const CStringStream &) = delete;

  private:
    CStringBuf buf_;
    CompressionMode mode_;
    int compressionLevel_;
    unsigned minSizeToCompress_;
    std::vector<char> comprBuf_;
    std::vector<char> readBuf_;
    std::ostream *sink_;
    std::unique_ptr<ZlibInflateHandle> inflator_;
    std::unique_ptr<ZlibDeflateHandle> deflator_;
  };
}  // namespace gs

#endif  // GENERS_CSTRINGSTREAM_HH_