hush/libbb/copy_file_chunk.c

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/* vi: set sw=4 ts=4: */
/*
* Utility routines.
*
* Copyright (C) tons of folks. Tracking down who wrote what
* isn't something I'm going to worry about... If you wrote something
* here, please feel free to acknowledge your work.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Based in part on code from sash, Copyright (c) 1999 by David I. Bell
* Permission has been granted to redistribute this code under the GPL.
*
*/
#include <stdio.h>
#include <sys/stat.h>
#include "libbb.h"
/* Copy CHUNKSIZE bytes (or until EOF if CHUNKSIZE equals -1) from SRC_FILE
* to DST_FILE. */
extern int copy_file_chunk(FILE *src_file, FILE *dst_file, unsigned long long chunksize)
{
size_t nread, nwritten, size;
char buffer[BUFSIZ];
while (chunksize != 0) {
if (chunksize > BUFSIZ)
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size = BUFSIZ;
else
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size = chunksize;
nread = fread (buffer, 1, size, src_file);
if (nread != size && ferror (src_file)) {
perror_msg ("read");
return -1;
} else if (nread == 0) {
if (chunksize != -1) {
error_msg ("Unable to read all data");
return -1;
}
return 0;
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}
nwritten = fwrite (buffer, 1, nread, dst_file);
if (nwritten != nread) {
if (ferror (dst_file))
perror_msg ("write");
else
error_msg ("Unable to write all data");
return -1;
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}
if (chunksize != -1)
chunksize -= nwritten;
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}
return 0;
}