--- src/fsearch_string_utils.c.orig 2022-08-17 17:50:25 UTC +++ src/fsearch_string_utils.c @@ -164,3 +164,91 @@ fsearch_string_starts_with_interval(char *str, char ** *end_ptr = str; return false; } + +/* Compare strings while treating digits characters numerically. + Copyright (C) 1997-2022 Free Software Foundation, Inc. + Contributed by Jean-François Bignolles , + 1997. */ + +#include + +/* states: S_N: normal, S_I: comparing integral part, S_F: comparing + fractional parts, S_Z: idem but with leading Zeroes only */ +#define S_N 0x0 +#define S_I 0x3 +#define S_F 0x6 +#define S_Z 0x9 + +/* result_type: CMP: return diff; LEN: compare using len_diff/diff */ +#define CMP 2 +#define LEN 3 + +/* Compare S1 and S2 as strings holding indices/version numbers, + returning less than, equal to, or greater than zero if S1 is less + than, equal to, or greater than S2. */ + +int +strverscmp (const char *s1, const char *s2) +{ + const unsigned char *p1 = (const unsigned char *) s1; + const unsigned char *p2 = (const unsigned char *) s2; + + /* Symbol(s) 0 [1-9] others + Transition (10) 0 (01) d (00) x */ + static const uint_least8_t next_state[] = + { + /* state x d 0 */ + /* S_N */ S_N, S_I, S_Z, + /* S_I */ S_N, S_I, S_I, + /* S_F */ S_N, S_F, S_F, + /* S_Z */ S_N, S_F, S_Z + }; + + static const int_least8_t result_type[] = + { + /* state x/x x/d x/0 d/x d/d d/0 0/x 0/d 0/0 */ + + /* S_N */ CMP, CMP, CMP, CMP, LEN, CMP, CMP, CMP, CMP, + /* S_I */ CMP, -1, -1, +1, LEN, LEN, +1, LEN, LEN, + /* S_F */ CMP, CMP, CMP, CMP, CMP, CMP, CMP, CMP, CMP, + /* S_Z */ CMP, +1, +1, -1, CMP, CMP, -1, CMP, CMP + }; + + if (p1 == p2) + return 0; + + unsigned char c1 = *p1++; + unsigned char c2 = *p2++; + /* Hint: '0' is a digit too. */ + int state = S_N + ((c1 == '0') + (isdigit (c1) != 0)); + + int diff; + while ((diff = c1 - c2) == 0) + { + if (c1 == '\0') + return diff; + + state = next_state[state]; + c1 = *p1++; + c2 = *p2++; + state += (c1 == '0') + (isdigit (c1) != 0); + } + + state = result_type[state * 3 + (((c2 == '0') + (isdigit (c2) != 0)))]; + + switch (state) + { + case CMP: + return diff; + + case LEN: + while (isdigit (*p1++)) + if (!isdigit (*p2++)) + return 1; + + return isdigit (*p2) ? -1 : diff; + + default: + return state; + } +}