init/lib/src/strexpand.c

56 lines
894 B
C

#include <string.h>
#include <stdlib.h>
#include <ctype.h>
#include "util.h"
char *strexpand(const char *inp, size_t argc, const char *const *argv)
{
char *out, *dst;
const char *ptr;
size_t i, len;
ptr = inp;
len = 0;
while (*ptr != '\0') {
if (ptr[0] == '%' && isdigit(ptr[1])) {
i = ptr[1] - '0';
if (i < argc)
len += strlen(argv[i]);
ptr += 2;
} else if (ptr[0] == '%' && ptr[1] == '%') {
ptr += 2;
len += 1;
} else {
++ptr;
++len;
}
}
out = calloc(1, len + 1);
if (out == NULL)
return NULL;
dst = out;
while (*inp != '\0') {
if (inp[0] == '%' && isdigit(inp[1])) {
i = inp[1] - '0';
if (i < argc) {
len = strlen(argv[i]);
memcpy(dst, argv[i], len);
dst += len;
}
inp += 2;
} else if (inp[0] == '%' && inp[1] == '%') {
*(dst++) = '%';
inp += 2;
} else {
*(dst++) = *(inp++);
}
}
return out;
}