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#include <errno.h>
#include <stddef.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
static struct settings_s {
size_t fetchpos;
size_t fetchto;
char *filein;
char *fileout;
int mode;
} settings = {0};
static int parseargs(int argc, char **argv, struct settings_s * settings);
void printhelp(const char * const name);
int main(int argc, char **argv)
{
int ret = 0;
if ((ret = parseargs(argc, argv, &settings))) {
goto out;
}
out:
return ret;
}
static int parseargs(int argc, char **argv, struct settings_s * settings)
{
struct settings_s s = {0};
ssize_t i;
int ret = 0;
if (argc < 2) {
goto err;
}
for (i = 1; i < argc - 1; ++i) {
if (!(strcmp(argv[i], "--sort"))) {
s.mode = 0;
} else if (!(strcmp(argv[i], "--fetch"))) {
s.mode = 1;
} else if (!(strncmp(argv[i], "--position=", 11))) {
if (strlen(argv[i]) > 11) {
s.fetchpos = strtoul(argv[i] + 11, NULL, 10);
} else {
goto err;
}
} else if (!(strncmp(argv[i], "--num=", 6))) {
if (strlen(argv[i]) > 6) {
s.fetchto = strtoul(argv[i] + 11, NULL, 10);
} else {
goto err;
}
} else if (!(strncmp(argv[i], "--out=", 6))) {
if (strlen(argv[i]) > 6) {
s.fileout = argv[i] + 6;
} else {
goto err;
}
} else {
goto err;
}
}
if (!strncmp(argv[i], "--", 2)) {
goto err;
} else {
s.filein = argv[i];
}
*settings = s;
if (0) {
err:
ret = EINVAL;
printhelp(*argv);
}
return ret;
}
void printhelp(const char * const name)
{
printf( "This is a mergesort program and such\n"
"\n"
"usage:\t%s [options]\n FILE"
"\n"
"Options:\n"
" --sort sort mode (default)\n"
" --fetch fetch element\n"
" --position=<num> fetch element from position <num>\n"
" --num=<num> <num> of elements to fetch\n"
" --out=<name> write output to <name> file\n"
"\n"
"In case more than one same option is provided, the last one take precedence\n"
"\n",
name);
return;
}
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