diff options
Diffstat (limited to 'src/gl/strverscmp.c')
| -rw-r--r-- | src/gl/strverscmp.c | 112 |
1 files changed, 112 insertions, 0 deletions
diff --git a/src/gl/strverscmp.c b/src/gl/strverscmp.c new file mode 100644 index 0000000..c484349 --- /dev/null +++ b/src/gl/strverscmp.c @@ -0,0 +1,112 @@ +/* Compare strings while treating digits characters numerically. + Copyright (C) 1997-2021 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Jean-François Bignolles <bignolle@ecoledoc.ibp.fr>, 1997. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU General Public + License as published by the Free Software Foundation; either + version 3 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + General Public License for more details. + + You should have received a copy of the GNU General Public + License along with the GNU C Library; if not, see + <https://www.gnu.org/licenses/>. */ + +#ifndef _LIBC +# include <libc-config.h> +# define __strverscmp strverscmp +#endif + +#include <stdint.h> +#include <string.h> +#include <ctype.h> + +/* 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 (for more info, see the texinfo doc). +*/ + +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; + } +} +libc_hidden_def (__strverscmp) +weak_alias (__strverscmp, strverscmp) |