| #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]; |
| } |
