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// Standard C
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
// System
#include <unistd.h>
// zlib
#include <zlib.h>
enum { BUFFER_SIZE = 8192 };
static void
usage(void)
{
(void) fprintf(stderr, "stream [-d] infile outfile\n");
}
static void
error(const char *msg)
{
perror(msg);
exit(EXIT_FAILURE);
}
void
do_compress(const char *in_name, const char *out_name, int compress_level)
{
FILE *in_file = fopen(in_name, "rb");
if ( in_file == NULL ) {
error("fopen() on in_file failed");
}
char mode[10];
(void) snprintf(mode, sizeof mode, "wb%d", compress_level);
gzFile out_file = gzopen(out_name, mode);
if ( out_file == NULL ) {
(void) fclose(in_file);
error("gzopen() on out_file failed");
}
unsigned char buffer[BUFFER_SIZE];
size_t bytes_read = 0;
while ( (bytes_read = fread(buffer, 1, BUFFER_SIZE, in_file)) != 0 ) {
gzfwrite(buffer, 1, bytes_read, out_file);
}
(void) fclose(in_file);
gzclose(out_file);
}
void
do_uncompress(const char *in_name, const char *out_name)
{
gzFile in_file = gzopen(in_name, "rb");
if ( in_file == NULL ) {
error("gzopen() on in_file failed");
}
FILE *out_file = fopen(out_name, "wb");
if ( out_file == NULL ) {
(void) gzclose(in_file);
error("fopen() on out_file failed");
}
unsigned char buffer[BUFFER_SIZE];
size_t bytes_read = 0;
while ( (bytes_read = gzfread(buffer, 1, BUFFER_SIZE, in_file)) != 0 ) {
(void) fwrite(buffer, 1, bytes_read, out_file);
}
gzclose(in_file);
(void) fclose(out_file);
}
int
main(int argc, char *argv[])
{
enum {
COMPRESSION_STD = 5,
COMPRESSION_BEST = 9
};
int decompress = 0;
int compress_level = COMPRESSION_STD;
int opt = 0;
while ( (opt = getopt(argc, argv, "dl")) != -1 ) {
switch ( opt ) {
case 'd':
decompress = 1;
break;
case 'l':
compress_level = COMPRESSION_BEST;
break;
case '?':
default:
usage();
return EXIT_SUCCESS;
}
}
argc -= optind;
argv += optind;
if ( argc != 2 ) {
usage();
return EXIT_FAILURE;
}
if ( !decompress ) {
do_compress(argv[0], argv[1], compress_level);
}
else {
do_uncompress(argv[0], argv[1]);
}
return EXIT_SUCCESS;
}
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