1#define _GNU_SOURCE
2#include <ctype.h>
3#include <string.h>
4
5int strverscmp(const char *l0, const char *r0)
6{
7 const unsigned char *l = (const void *)l0;
8 const unsigned char *r = (const void *)r0;
9 size_t i, dp, j;
10 int z = 1;
11
12 /* Find maximal matching prefix and track its maximal digit
13 * suffix and whether those digits are all zeros. */
14 for (dp=i=0; l[i]==r[i]; i++) {
15 int c = l[i];
16 if (!c) return 0;
17 if (!isdigit(c)) dp=i+1, z=1;
18 else if (c!='0') z=0;
19 }
20
21 if (l[dp]-'1'<9U && r[dp]-'1'<9U) {
22 /* If we're looking at non-degenerate digit sequences starting
23 * with nonzero digits, longest digit string is greater. */
24 for (j=i; isdigit(l[j]); j++)
25 if (!isdigit(r[j])) return 1;
26 if (isdigit(r[j])) return -1;
27 } else if (z && dp<i && (isdigit(l[i]) || isdigit(r[i]))) {
28 /* Otherwise, if common prefix of digit sequence is
29 * all zeros, digits order less than non-digits. */
30 return (unsigned char)(l[i]-'0') - (unsigned char)(r[i]-'0');
31 }
32
33 return l[i] - r[i];
34}