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Diffstat (limited to 'string/strverscmp.c')
| -rw-r--r-- | string/strverscmp.c | 111 |
1 files changed, 111 insertions, 0 deletions
diff --git a/string/strverscmp.c b/string/strverscmp.c new file mode 100644 index 0000000000..388df75dfd --- /dev/null +++ b/string/strverscmp.c @@ -0,0 +1,111 @@ +/* Compare strings while treating digits characters numerically. + Copyright (C) 1997 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 Library General Public License as + published by the Free Software Foundation; either version 2 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 + Library General Public License for more details. + + You should have received a copy of the GNU Library General Public + License along with the GNU C Library; see the file COPYING.LIB. If not, + write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. */ + +#include <string.h> +#include <ctype.h> + +/* states: S_N: normal, S_I: comparing integral part, S_F: comparing + Fractionnal parts, S_Z: idem but with leading Zeroes only */ +#define S_N 0x0 +#define S_I 0x4 +#define S_F 0x8 +#define S_Z 0xC + +/* 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 (s1, s2) + const char *s1; + const char *s2; +{ + const unsigned char *p1 = (const unsigned char *) s1; + const unsigned char *p2 = (const unsigned char *) s2; + unsigned char c1, c2; + int state; + int diff; + + /* Symbol(s) 0 [1-9] others (padding) + Transition (10) 0 (01) d (00) x (11) - */ + static const unsigned int next_state[] = + { + /* state x d 0 - */ + /* S_N */ S_N, S_I, S_Z, S_N, + /* S_I */ S_N, S_I, S_I, S_I, + /* S_F */ S_N, S_F, S_F, S_F, + /* S_Z */ S_N, S_F, S_Z, S_Z + }; + + static const int result_type[] = + { + /* state x/x x/d x/0 x/- d/x d/d d/0 d/- + 0/x 0/d 0/0 0/- -/x -/d -/0 -/- */ + + /* S_N */ CMP, CMP, CMP, CMP, CMP, LEN, CMP, CMP, + CMP, CMP, CMP, CMP, CMP, CMP, CMP, CMP, + /* S_I */ CMP, -1, -1, CMP, +1, LEN, LEN, CMP, + +1, LEN, LEN, CMP, CMP, CMP, CMP, CMP, + /* S_F */ CMP, CMP, CMP, CMP, CMP, LEN, CMP, CMP, + CMP, CMP, CMP, CMP, CMP, CMP, CMP, CMP, + /* S_Z */ CMP, +1, +1, CMP, -1, CMP, CMP, CMP, + -1, CMP, CMP, CMP + }; + + if (p1 == p2) + return 0; + + c1 = *p1++; + c2 = *p2++; + /* Hint: '0' is a digit too. */ + state = S_N | (c1 == '0') + (isdigit (c1) != 0); + + while ((diff = c1 - c2) == 0 && c1 != '\0') + { + state = next_state[state]; + c1 = *p1++; + c2 = *p2++; + state |= (c1 == '0') + (isdigit (c1) != 0); + } + + state = result_type[state << 2 | ((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; + } +} |