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Diffstat (limited to 'compat/zlib/contrib/iostream3/zfstream.h')
| -rw-r--r-- | compat/zlib/contrib/iostream3/zfstream.h | 466 |
1 files changed, 466 insertions, 0 deletions
diff --git a/compat/zlib/contrib/iostream3/zfstream.h b/compat/zlib/contrib/iostream3/zfstream.h new file mode 100644 index 0000000..8574479 --- /dev/null +++ b/compat/zlib/contrib/iostream3/zfstream.h @@ -0,0 +1,466 @@ +/* + * A C++ I/O streams interface to the zlib gz* functions + * + * by Ludwig Schwardt <schwardt@sun.ac.za> + * original version by Kevin Ruland <kevin@rodin.wustl.edu> + * + * This version is standard-compliant and compatible with gcc 3.x. + */ + +#ifndef ZFSTREAM_H +#define ZFSTREAM_H + +#include <istream> // not iostream, since we don't need cin/cout +#include <ostream> +#include "zlib.h" + +/*****************************************************************************/ + +/** + * @brief Gzipped file stream buffer class. + * + * This class implements basic_filebuf for gzipped files. It doesn't yet support + * seeking (allowed by zlib but slow/limited), putback and read/write access + * (tricky). Otherwise, it attempts to be a drop-in replacement for the standard + * file streambuf. +*/ +class gzfilebuf : public std::streambuf +{ +public: + // Default constructor. + gzfilebuf(); + + // Destructor. + virtual + ~gzfilebuf(); + + /** + * @brief Set compression level and strategy on the fly. + * @param comp_level Compression level (see zlib.h for allowed values) + * @param comp_strategy Compression strategy (see zlib.h for allowed values) + * @return Z_OK on success, Z_STREAM_ERROR otherwise. + * + * Unfortunately, these parameters cannot be modified separately, as the + * previous zfstream version assumed. Since the strategy is seldom changed, + * it can default and setcompression(level) then becomes like the old + * setcompressionlevel(level). + */ + int + setcompression(int comp_level, + int comp_strategy = Z_DEFAULT_STRATEGY); + + /** + * @brief Check if file is open. + * @return True if file is open. + */ + bool + is_open() const { return (file != NULL); } + + /** + * @brief Open gzipped file. + * @param name File name. + * @param mode Open mode flags. + * @return @c this on success, NULL on failure. + */ + gzfilebuf* + open(const char* name, + std::ios_base::openmode mode); + + /** + * @brief Attach to already open gzipped file. + * @param fd File descriptor. + * @param mode Open mode flags. + * @return @c this on success, NULL on failure. + */ + gzfilebuf* + attach(int fd, + std::ios_base::openmode mode); + + /** + * @brief Close gzipped file. + * @return @c this on success, NULL on failure. + */ + gzfilebuf* + close(); + +protected: + /** + * @brief Convert ios open mode int to mode string used by zlib. + * @return True if valid mode flag combination. + */ + bool + open_mode(std::ios_base::openmode mode, + char* c_mode) const; + + /** + * @brief Number of characters available in stream buffer. + * @return Number of characters. + * + * This indicates number of characters in get area of stream buffer. + * These characters can be read without accessing the gzipped file. + */ + virtual std::streamsize + showmanyc(); + + /** + * @brief Fill get area from gzipped file. + * @return First character in get area on success, EOF on error. + * + * This actually reads characters from gzipped file to stream + * buffer. Always buffered. + */ + virtual int_type + underflow(); + + /** + * @brief Write put area to gzipped file. + * @param c Extra character to add to buffer contents. + * @return Non-EOF on success, EOF on error. + * + * This actually writes characters in stream buffer to + * gzipped file. With unbuffered output this is done one + * character at a time. + */ + virtual int_type + overflow(int_type c = traits_type::eof()); + + /** + * @brief Installs external stream buffer. + * @param p Pointer to char buffer. + * @param n Size of external buffer. + * @return @c this on success, NULL on failure. + * + * Call setbuf(0,0) to enable unbuffered output. + */ + virtual std::streambuf* + setbuf(char_type* p, + std::streamsize n); + + /** + * @brief Flush stream buffer to file. + * @return 0 on success, -1 on error. + * + * This calls underflow(EOF) to do the job. + */ + virtual int + sync(); + +// +// Some future enhancements +// +// virtual int_type uflow(); +// virtual int_type pbackfail(int_type c = traits_type::eof()); +// virtual pos_type +// seekoff(off_type off, +// std::ios_base::seekdir way, +// std::ios_base::openmode mode = std::ios_base::in|std::ios_base::out); +// virtual pos_type +// seekpos(pos_type sp, +// std::ios_base::openmode mode = std::ios_base::in|std::ios_base::out); + +private: + /** + * @brief Allocate internal buffer. + * + * This function is safe to call multiple times. It will ensure + * that a proper internal buffer exists if it is required. If the + * buffer already exists or is external, the buffer pointers will be + * reset to their original state. + */ + void + enable_buffer(); + + /** + * @brief Destroy internal buffer. + * + * This function is safe to call multiple times. It will ensure + * that the internal buffer is deallocated if it exists. In any + * case, it will also reset the buffer pointers. + */ + void + disable_buffer(); + + /** + * Underlying file pointer. + */ + gzFile file; + + /** + * Mode in which file was opened. + */ + std::ios_base::openmode io_mode; + + /** + * @brief True if this object owns file descriptor. + * + * This makes the class responsible for closing the file + * upon destruction. + */ + bool own_fd; + + /** + * @brief Stream buffer. + * + * For simplicity this remains allocated on the free store for the + * entire life span of the gzfilebuf object, unless replaced by setbuf. + */ + char_type* buffer; + + /** + * @brief Stream buffer size. + * + * Defaults to system default buffer size (typically 8192 bytes). + * Modified by setbuf. + */ + std::streamsize buffer_size; + + /** + * @brief True if this object owns stream buffer. + * + * This makes the class responsible for deleting the buffer + * upon destruction. + */ + bool own_buffer; +}; + +/*****************************************************************************/ + +/** + * @brief Gzipped file input stream class. + * + * This class implements ifstream for gzipped files. Seeking and putback + * is not supported yet. +*/ +class gzifstream : public std::istream +{ +public: + // Default constructor + gzifstream(); + + /** + * @brief Construct stream on gzipped file to be opened. + * @param name File name. + * @param mode Open mode flags (forced to contain ios::in). + */ + explicit + gzifstream(const char* name, + std::ios_base::openmode mode = std::ios_base::in); + + /** + * @brief Construct stream on already open gzipped file. + * @param fd File descriptor. + * @param mode Open mode flags (forced to contain ios::in). + */ + explicit + gzifstream(int fd, + std::ios_base::openmode mode = std::ios_base::in); + + /** + * Obtain underlying stream buffer. + */ + gzfilebuf* + rdbuf() const + { return const_cast<gzfilebuf*>(&sb); } + + /** + * @brief Check if file is open. + * @return True if file is open. + */ + bool + is_open() { return sb.is_open(); } + + /** + * @brief Open gzipped file. + * @param name File name. + * @param mode Open mode flags (forced to contain ios::in). + * + * Stream will be in state good() if file opens successfully; + * otherwise in state fail(). This differs from the behavior of + * ifstream, which never sets the state to good() and therefore + * won't allow you to reuse the stream for a second file unless + * you manually clear() the state. The choice is a matter of + * convenience. + */ + void + open(const char* name, + std::ios_base::openmode mode = std::ios_base::in); + + /** + * @brief Attach to already open gzipped file. + * @param fd File descriptor. + * @param mode Open mode flags (forced to contain ios::in). + * + * Stream will be in state good() if attach succeeded; otherwise + * in state fail(). + */ + void + attach(int fd, + std::ios_base::openmode mode = std::ios_base::in); + + /** + * @brief Close gzipped file. + * + * Stream will be in state fail() if close failed. + */ + void + close(); + +private: + /** + * Underlying stream buffer. + */ + gzfilebuf sb; +}; + +/*****************************************************************************/ + +/** + * @brief Gzipped file output stream class. + * + * This class implements ofstream for gzipped files. Seeking and putback + * is not supported yet. +*/ +class gzofstream : public std::ostream +{ +public: + // Default constructor + gzofstream(); + + /** + * @brief Construct stream on gzipped file to be opened. + * @param name File name. + * @param mode Open mode flags (forced to contain ios::out). + */ + explicit + gzofstream(const char* name, + std::ios_base::openmode mode = std::ios_base::out); + + /** + * @brief Construct stream on already open gzipped file. + * @param fd File descriptor. + * @param mode Open mode flags (forced to contain ios::out). + */ + explicit + gzofstream(int fd, + std::ios_base::openmode mode = std::ios_base::out); + + /** + * Obtain underlying stream buffer. + */ + gzfilebuf* + rdbuf() const + { return const_cast<gzfilebuf*>(&sb); } + + /** + * @brief Check if file is open. + * @return True if file is open. + */ + bool + is_open() { return sb.is_open(); } + + /** + * @brief Open gzipped file. + * @param name File name. + * @param mode Open mode flags (forced to contain ios::out). + * + * Stream will be in state good() if file opens successfully; + * otherwise in state fail(). This differs from the behavior of + * ofstream, which never sets the state to good() and therefore + * won't allow you to reuse the stream for a second file unless + * you manually clear() the state. The choice is a matter of + * convenience. + */ + void + open(const char* name, + std::ios_base::openmode mode = std::ios_base::out); + + /** + * @brief Attach to already open gzipped file. + * @param fd File descriptor. + * @param mode Open mode flags (forced to contain ios::out). + * + * Stream will be in state good() if attach succeeded; otherwise + * in state fail(). + */ + void + attach(int fd, + std::ios_base::openmode mode = std::ios_base::out); + + /** + * @brief Close gzipped file. + * + * Stream will be in state fail() if close failed. + */ + void + close(); + +private: + /** + * Underlying stream buffer. + */ + gzfilebuf sb; +}; + +/*****************************************************************************/ + +/** + * @brief Gzipped file output stream manipulator class. + * + * This class defines a two-argument manipulator for gzofstream. It is used + * as base for the setcompression(int,int) manipulator. +*/ +template<typename T1, typename T2> + class gzomanip2 + { + public: + // Allows insertor to peek at internals + template <typename Ta, typename Tb> + friend gzofstream& + operator<<(gzofstream&, + const gzomanip2<Ta,Tb>&); + + // Constructor + gzomanip2(gzofstream& (*f)(gzofstream&, T1, T2), + T1 v1, + T2 v2); + private: + // Underlying manipulator function + gzofstream& + (*func)(gzofstream&, T1, T2); + + // Arguments for manipulator function + T1 val1; + T2 val2; + }; + +/*****************************************************************************/ + +// Manipulator function thunks through to stream buffer +inline gzofstream& +setcompression(gzofstream &gzs, int l, int s = Z_DEFAULT_STRATEGY) +{ + (gzs.rdbuf())->setcompression(l, s); + return gzs; +} + +// Manipulator constructor stores arguments +template<typename T1, typename T2> + inline + gzomanip2<T1,T2>::gzomanip2(gzofstream &(*f)(gzofstream &, T1, T2), + T1 v1, + T2 v2) + : func(f), val1(v1), val2(v2) + { } + +// Insertor applies underlying manipulator function to stream +template<typename T1, typename T2> + inline gzofstream& + operator<<(gzofstream& s, const gzomanip2<T1,T2>& m) + { return (*m.func)(s, m.val1, m.val2); } + +// Insert this onto stream to simplify setting of compression level +inline gzomanip2<int,int> +setcompression(int l, int s = Z_DEFAULT_STRATEGY) +{ return gzomanip2<int,int>(&setcompression, l, s); } + +#endif // ZFSTREAM_H |