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scmd.c
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scmd.c
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/* Simple command line tool for snappy */
#include <fcntl.h>
#include <stdlib.h>
#include <errno.h>
#include <unistd.h>
#include <string.h>
#include <stdio.h>
#include "snappy.h"
#include "map.h"
#include "util.h"
enum { undef, compress, uncompress } mode = undef;
void usage(void)
{
fprintf(stderr,
"scmd [-c|-d] [-s] file [outfile]\n"
"-c compress\n"
"-d uncompress\n"
"-s print to standard output"
"Compress or uncompress file with snappy.\n"
"When no output file is specified write to file.snp\n");
exit(1);
}
int match_suffix(char *p, char *suf)
{
int suflen = strlen(suf);
int plen = strlen(p);
if (plen < suflen)
return 0;
char *s = p + plen - suflen;
return !strcmp(s, suf);
}
int open_output(char *name, char *oname, char **ofn)
{
int fd;
char *file;
if (oname) {
file = oname;
} else {
int len = strlen(name);
file = xmalloc(len + 6);
if (mode == compress)
snprintf(file, len + 6, "%s.snp", name);
else if (match_suffix(name, ".snp")) {
strcpy(file, name);
file[len - 4] = 0;
} else {
fprintf(stderr, "Please specify output name\n");
exit(1);
}
}
*ofn = file;
fd = open(file, O_WRONLY|O_CREAT|O_TRUNC, 0644);
if (fd < 0) {
fprintf(stderr, "Cannot create %s: %s\n", file,
strerror(errno));
exit(1);
}
return fd;
}
int main(int ac, char **av)
{
int opt;
int to_stdout = 0;
while ((opt = getopt(ac, av, "dcs")) != -1) {
switch (opt) {
case 'd':
mode = uncompress;
break;
case 'c':
mode = compress;
break;
case 's':
to_stdout = 1;
break;
default:
usage();
}
}
char *map;
size_t size;
if (!av[optind])
usage();
if (mode == undef) {
if (match_suffix(av[optind], ".snp"))
mode = uncompress;
else
mode = compress;
}
map = mapfile(av[optind], O_RDONLY, &size);
if (!map) {
fprintf(stderr, "Cannot open %s: %s\n", av[1], strerror(errno));
exit(1);
}
int err;
char *out;
size_t outlen;
if (mode == uncompress) {
err = snappy_uncompressed_length(map, size, &outlen);
} else {
outlen = snappy_max_compressed_length(size);
}
out = xmalloc(outlen);
struct snappy_env env;
if (mode == compress) {
snappy_init_env(&env);
err = snappy_compress(&env, map, size, out, &outlen);
} else
err = snappy_uncompress(map, size, out);
if (mode == compress) {
snappy_free_env(&env);
}
unmap_file(map, size);
if (err) {
fprintf(stderr, "Cannot process %s: %s\n", av[optind],
strerror(-err));
exit(1);
}
char *file;
int fd;
if (to_stdout) {
if(av[optind + 1])
usage();
fd = 1;
file = "<stdout>";
} else {
if (av[optind + 1] && av[optind + 2])
usage();
fd = open_output(av[optind], av[optind + 1], &file);
}
err = 0;
if (write(fd, out, outlen) != outlen) {
fprintf(stderr, "Cannot write to %s: %s\n",
file,
strerror(errno));
err = 1;
}
if (!to_stdout)
free(file);
free(out);
return err;
}