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]!='0' && r[dp]!='0') { 22 /* If we're not looking at a digit sequence that began 23 * with a zero, 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} 35