GzipFileWriter.hpp

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#ifndef BYTEME_GZIP_FILE_WRITER_HPP
#define BYTEME_GZIP_FILE_WRITER_HPP
 
#include <stdexcept>
#include <vector>
#include <string>
#include "Writer.hpp"
 
namespace byteme {
 
class GzipFileWriter : public Writer {
public:
    GzipFileWriter(const char* path, int compression_level = 6, size_t buffer_size = 65536) : my_gzfile(path, "wb") {
        if (gzbuffer(my_gzfile.handle, buffer_size)) {
            throw std::runtime_error("failed to set the Gzip compression buffer");
        }
        if (gzsetparams(my_gzfile.handle, compression_level, Z_DEFAULT_STRATEGY) != Z_OK) {
            throw std::runtime_error("failed to set the Gzip compression parameters");
        }
    }
 
    GzipFileWriter(const std::string& path, int compression_level = 6, size_t buffer_size = 65536) : GzipFileWriter(path.c_str(), compression_level, buffer_size) {}
 
public:
    using Writer::write;
 
    void write(const unsigned char* buffer, size_t n) {
        if (n) {
            size_t ok = gzwrite(my_gzfile.handle, buffer, n);
            if (ok != n) {
                throw std::runtime_error("failed to write to the Gzip-compressed file");
            }
        }
    }
 
    void finish() {
        my_gzfile.closed = true;
        if (gzclose(my_gzfile.handle) != Z_OK) {
            throw std::runtime_error("failed to close the Gzip-compressed file after writing");
        }
    }
 
private:
    SelfClosingGzFile my_gzfile;
};
 
}
 
#endif