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/*
* getopt.c
*
* Simple POSIX getopt(), no GNU extensions...
*/
#include <stdint.h>
#include <unistd.h>
#include <string.h>
char *optarg;
int optind = 1;
int opterr, optopt;
static const char *__optptr;
int getopt(int argc, char * const *argv, const char *optstring)
{
const char *carg = argv[optind];
const char *osptr;
int opt;
/* We don't actually need argc */
(void)argc;
/* First, eliminate all non-option cases */
if ( !carg || carg[0] != '-' || !carg[1] ) {
return -1;
}
if ( carg[1] == '-' && !carg[2] ) {
optind++;
return -1;
}
if ( (uintptr_t)(__optptr-carg) > (uintptr_t)strlen(carg) )
__optptr = carg+1; /* Someone frobbed optind, change to new opt. */
opt = *__optptr++;
if ( opt != ':' && (osptr = strchr(optstring, opt)) ) {
if ( osptr[1] == ':' ) {
if ( *__optptr ) {
/* Argument-taking option with attached argument */
optarg = (char *)__optptr;
optind++;
} else {
/* Argument-taking option with non-attached argument */
if ( argv[optind+1] ) {
optarg = (char *)argv[optind+1];
optind += 2;
} else {
/* Missing argument */
return (optstring[0] == ':') ? ':' : '?';
}
}
return opt;
} else {
/* Non-argument-taking option */
/* __optptr will remember the exact position to resume at */
if ( ! *__optptr )
optind++;
return opt;
}
} else {
/* Unknown option */
optopt = opt;
if ( ! *__optptr )
optind++;
return '?';
}
}
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