Gzipped file stream buffer class. More...
#include <zfstream.h>
Public Member Functions | |
gzfilebuf * | open (const char *name, int io_mode) |
gzfilebuf * | attach (int file_descriptor, int io_mode) |
gzfilebuf * | close () |
int | setcompressionlevel (int comp_level) |
int | setcompressionstrategy (int comp_strategy) |
int | is_open () const |
virtual streampos | seekoff (streamoff, ios::seek_dir, int) |
virtual int | sync () |
int | setcompression (int comp_level, int comp_strategy=Z_DEFAULT_STRATEGY) |
Set compression level and strategy on the fly. | |
bool | is_open () const |
Check if file is open. | |
gzfilebuf * | open (const char *name, std::ios_base::openmode mode) |
Open gzipped file. | |
gzfilebuf * | attach (int fd, std::ios_base::openmode mode) |
Attach to already open gzipped file. | |
gzfilebuf * | close () |
Close gzipped file. | |
Protected Member Functions | |
virtual int | underflow () |
virtual int | overflow (int=EOF) |
bool | open_mode (std::ios_base::openmode mode, char *c_mode) const |
Convert ios open mode int to mode string used by zlib. | |
virtual std::streamsize | showmanyc () |
Number of characters available in stream buffer. | |
virtual int_type | underflow () |
Fill get area from gzipped file. | |
virtual int_type | overflow (int_type c=traits_type::eof()) |
Write put area to gzipped file. | |
virtual std::streambuf * | setbuf (char_type *p, std::streamsize n) |
Installs external stream buffer. | |
virtual int | sync () |
Flush stream buffer to file. |
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.
Definition at line 8 of file zfstream.h.
gzfilebuf* attach | ( | int | fd, |
std::ios_base::openmode | mode | ||
) |
Attach to already open gzipped file.
fd | File descriptor. |
mode | Open mode flags. |
this
on success, NULL on failure. gzfilebuf* close | ( | ) |
Close gzipped file.
this
on success, NULL on failure. bool is_open | ( | ) | const [inline] |
gzfilebuf* open | ( | const char * | name, |
std::ios_base::openmode | mode | ||
) |
Open gzipped file.
name | File name. |
mode | Open mode flags. |
this
on success, NULL on failure. bool open_mode | ( | std::ios_base::openmode | mode, |
char * | c_mode | ||
) | const [protected] |
Convert ios open mode int to mode string used by zlib.
virtual int_type overflow | ( | int_type | c = traits_type::eof() ) |
[protected, virtual] |
Write put area to gzipped file.
c | Extra character to add to buffer contents. |
This actually writes characters in stream buffer to gzipped file. With unbuffered output this is done one character at a time.
virtual std::streambuf* setbuf | ( | char_type * | p, |
std::streamsize | n | ||
) | [protected, virtual] |
Installs external stream buffer.
p | Pointer to char buffer. |
n | Size of external buffer. |
this
on success, NULL on failure.Call setbuf(0,0) to enable unbuffered output.
int setcompression | ( | int | comp_level, |
int | comp_strategy = Z_DEFAULT_STRATEGY |
||
) |
Set compression level and strategy on the fly.
comp_level | Compression level (see zlib.h for allowed values) |
comp_strategy | Compression strategy (see zlib.h for allowed values) |
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).
virtual std::streamsize showmanyc | ( | ) | [protected, virtual] |
Number of characters available in stream buffer.
This indicates number of characters in get area of stream buffer. These characters can be read without accessing the gzipped file.
virtual int sync | ( | ) | [protected, virtual] |
Flush stream buffer to file.
This calls underflow(EOF) to do the job.
virtual int_type underflow | ( | ) | [protected, virtual] |
Fill get area from gzipped file.
This actually reads characters from gzipped file to stream buffer. Always buffered.