source: asp3_tinet_ecnl_arm/trunk/musl-1.1.18/src/string/strverscmp.c@ 352

#define _GNU_SOURCE
#include <ctype.h>
#include <string.h>

int strverscmp(const char *l0, const char *r0)
{
        const unsigned char *l = (const void *)l0;
        const unsigned char *r = (const void *)r0;
        size_t i, dp, j;
        int z = 1;

        /* Find maximal matching prefix and track its maximal digit
         * suffix and whether those digits are all zeros. */
        for (dp=i=0; l[i]==r[i]; i++) {
                int c = l[i];
                if (!c) return 0;
                if (!isdigit(c)) dp=i+1, z=1;
                else if (c!='0') z=0;
        }

        if (l[dp]!='0' && r[dp]!='0') {
                /* If we're not looking at a digit sequence that began
                 * with a zero, longest digit string is greater. */
                for (j=i; isdigit(l[j]); j++)
                        if (!isdigit(r[j])) return 1;
                if (isdigit(r[j])) return -1;
        } else if (z && dp<i && (isdigit(l[i]) || isdigit(r[i]))) {
                /* Otherwise, if common prefix of digit sequence is
                 * all zeros, digits order less than non-digits. */
                return (unsigned char)(l[i]-'0') - (unsigned char)(r[i]-'0');
        }

        return l[i] - r[i];
}