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/*
* catcho - outputing text to the standard output
*
* Usage
* -----
* catcho [options]
*
* Options
* -------
* -m --mode MODE Set the initial text mode (Default: passthrough)
* -v --version Display program information and exit
* -V --verbose Duplicate stdout on stderr
*
* Modes
* -----
* passthru / passthrough / normal / n - Input is copied to output verbatim.
* null / z - Input is dropped.
* hb - Input (interpreted as hex) is compressed to bytes on the output.
* bh - The opposite of hb.
* ib - Input (interpreted as bit-bytes) is compressed to bytes on the output.
* bi - The opposite of ib.
*
* Append 'f' to any mode (eg: bhf): Input is interpreted as '\n'-delimited
* filenames. File contents are filtered based on mode and sent to output.
*
* Switching modes
* ---------------
* When catcho receives signal SIGINT (ctrl-C from the terminal, for example),
* any pending input/output is flushed and catcho then interprets the input
* as a mode name terminated by a '\n'. Once the input provides a string\n,
* it switches the desired mode and input processing resumes.
*
* Exiting catcho
* --------------
* Since SIGINT is used for mode switching, the 'normal' way to terminate
* catcho is by sending it an End-Of-File byte on its input. (ctrl-D on your
* terminal)
*/
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <getopt.h>
#include <signal.h>
#define LAST_STR_CHAR(s) (s[strlen(s)-1])
/* modes */
enum mode
{
N,
Z,
HB,
BH,
IB,
BI
};
/* global state */
static enum mode current_mode = N;
static int current_mode_f = 0;
static int current_verbose = 0;
static size_t ccfwrite(const void *ptr, size_t size, size_t nmemb)
{
size_t ret;
ret = fwrite(ptr, size, nmemb, stdout);
if (current_verbose)
fwrite(ptr, size, nmemb, stderr);
return ret;
}
static void sigint(int sig)
{
(void)sig;
ccfwrite("in signal handler\n", 18, 1);
}
static int set_mode(const char *mode)
{
if (!mode)
return 0;
if (!strcmp(mode, "passthru") || // these don't support 'f' suffix
!strcmp(mode, "passthrough") ||
!strcmp(mode, "normal"))
{
current_mode = N;
current_mode_f = 0;
}
else if (!strcmp(mode, "null")) // this doesn't support 'f' suffix
{
current_mode = Z;
current_mode_f = 0;
}
else if (!strncmp(mode, "n", 1))
{
current_mode = N;
current_mode_f = (LAST_STR_CHAR(mode) == 'f');
}
else if (!strncmp(mode, "z", 1))
{
current_mode = Z;
current_mode_f = (LAST_STR_CHAR(mode) == 'f');
}
else if (!strncmp(mode, "hb", 2))
{
current_mode = HB;
current_mode_f = (LAST_STR_CHAR(mode) == 'f');
}
else if (!strncmp(mode, "bh", 2))
{
current_mode = BH;
current_mode_f = (LAST_STR_CHAR(mode) == 'f');
}
else if (!strncmp(mode, "ib", 2))
{
current_mode = IB;
current_mode_f = (LAST_STR_CHAR(mode) == 'f');
}
else if (!strncmp(mode, "bi", 2))
{
current_mode = BI;
current_mode_f = (LAST_STR_CHAR(mode) == 'f');
}
else
{
fprintf(stderr, "Mode string '%s' not recognized\n", mode);
return 0;
}
return 1;
}
void show_version(const char *name)
{
printf("%s version 1.0\n", name);
}
int main(int argc, char **argv)
{
/*
* handling command-line arguments:
* i'm going to leave opterr alone (defaults to non-zero)
* \this causes getopt to print its own error messages to
* stderr if things go wrong, which is fine.
*/
const char *shortopts = "m:vV";
const struct option longopts[] = {
{ "mode", required_argument, NULL, 'm' },
{ "version", no_argument, NULL, 'v' },
{ "verbose", no_argument, NULL, 'V' },
{ NULL, 0, NULL, 0 }
};
int opt;
while ((opt = getopt_long(argc, argv, shortopts, longopts, NULL)) != -1)
{
switch (opt)
{
case '?':
return 1;
case 'm':
if (!set_mode(optarg))
return 1;
break;
case 'v':
show_version(argv[0]);
return 0;
case 'V':
current_verbose = 1;
break;
}
}
/* setup signals (mode switch) */
signal(SIGINT, &sigint);
char memes[4];
fread(memes, 4, 1, stdin);
switch (current_mode)
{
case N: printf("NORMAL\n"); break;
case Z: printf("NULL\n"); break;
case HB: printf("hex to bytes\n"); break;
case BH: printf("bytes to hex\n"); break;
case IB: printf("bits to bytes\n"); break;
case BI: printf("bytes to bits\n"); break;
}
printf("file mode: %i\n", current_mode_f);
printf("verbose mode: %i\n", current_verbose);
return 0;
}
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