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/* $Id: gzip_stream.c,v 1.4 2003/09/30 15:22:53 mjw Exp $ */
/*
* Copyright (C) 2003 Hewlett-Packard Company.
*
* This library is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/** @file
* An IOStream implementation using zlib gzFile to provide
* compression and decompression.
*/
#ifndef __KERNEL__
#include <stdio.h>
#include <stdlib.h>
#include "zlib.h"
#include "allocate.h"
#include "gzip_stream.h"
static int gzip_read(IOStream *s, void *buf, size_t n);
static int gzip_write(IOStream *s, const void *buf, size_t n);
static int gzip_error(IOStream *s);
static int gzip_close(IOStream *s);
static void gzip_free(IOStream *s);
static int gzip_flush(IOStream *s);
/** Methods used by a gzFile* IOStream. */
static const IOMethods gzip_methods = {
read: gzip_read,
write: gzip_write,
error: gzip_error,
close: gzip_close,
free: gzip_free,
flush: gzip_flush,
};
/** Get the underlying gzFile*.
*
* @param s gzip stream
* @return the stream s wraps
*/
static inline gzFile get_gzfile(IOStream *s){
return (gzFile)s->data;
}
/** Write to the underlying stream.
*
* @param stream destination
* @param buf data
* @param n number of bytes to write
* @return number of bytes written
*/
static int gzip_write(IOStream *s, const void *buf, size_t n){
return gzwrite(get_gzfile(s), (void*)buf, n);
}
/** Read from the underlying stream.
*
* @param stream input
* @param buf where to put input
* @param n number of bytes to read
* @return number of bytes read
*/
static int gzip_read(IOStream *s, void *buf, size_t n){
return gzread(get_gzfile(s), buf, n);
}
/** Flush the underlying stream.
*
* @param s gzip stream
* @return 0 on success, error code otherwise
*/
static int gzip_flush(IOStream *s){
//return gzflush(get_gzfile(s), Z_NO_FLUSH);
return gzflush(get_gzfile(s), Z_SYNC_FLUSH);
//return gzflush(get_gzfile(s), Z_FULL_FLUSH);
}
/** Check if a stream has an error.
*
* @param s gzip stream
* @return 1 if has an error, 0 otherwise
*/
static int gzip_error(IOStream *s){
int err;
gzFile *gz = get_gzfile(s);
gzerror(gz, &err);
return (err == Z_ERRNO ? 1 /* ferror(gzfile(gz)) */ : err);
}
/** Close a gzip stream.
*
* @param s gzip stream to close
* @return result of the close
*/
static int gzip_close(IOStream *s){
return gzclose(get_gzfile(s));
}
/** Free a gzip stream.
*
* @param s gzip stream
*/
static void gzip_free(IOStream *s){
// Do nothing - fclose does it all?
}
/** Create an IOStream for a gzip stream.
*
* @param f stream to wrap
* @return new IOStream using f for i/o
*/
IOStream *gzip_stream_new(gzFile *f){
IOStream *io = ALLOCATE(IOStream);
if(io){
io->methods = &gzip_methods;
io->data = (void*)f;
}
return io;
}
/** IOStream version of fopen().
*
* @param file name of the file to open
* @param flags giving the mode to open in (as for fopen())
* @return new stream for the open file, or NULL if failed
*/
IOStream *gzip_stream_fopen(const char *file, const char *flags){
IOStream *io = NULL;
gzFile *fgz;
fgz = gzopen(file, flags);
if(fgz){
io = gzip_stream_new(fgz);
if(!io){
gzclose(fgz);
//free(fgz); // gzclose frees ?
}
}
return io;
}
/** IOStream version of fdopen().
*
* @param fd file descriptor
* @param flags giving the mode to open in (as for fdopen())
* @return new stream for the open file, or NULL if failed
*/
IOStream *gzip_stream_fdopen(int fd, const char *flags){
IOStream *io = NULL;
gzFile *fgz;
fgz = gzdopen(fd, flags);
if(fgz){
io = gzip_stream_new(fgz);
}
return io;
}
#endif
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