| /* Compare strings while treating digits characters numerically. |
| Copyright (C) 1997-2019 Free Software Foundation, Inc. |
| This file is part of the libiberty library. |
| Contributed by Jean-François Bignolles <bignolle@ecoledoc.ibp.fr>, 1997. |
| |
| Libiberty is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Lesser General Public |
| License as published by the Free Software Foundation; either |
| version 2.1 of the License, or (at your option) any later version. |
| |
| Libiberty 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 |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public |
| License along with the GNU C Library; if not, write to the Free |
| Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
| 02110-1301 USA. */ |
| |
| #include "libiberty.h" |
| #include "safe-ctype.h" |
| |
| /* |
| @deftypefun int strverscmp (const char *@var{s1}, const char *@var{s2}) |
| The @code{strverscmp} function compares the string @var{s1} against |
| @var{s2}, considering them as holding indices/version numbers. Return |
| value follows the same conventions as found in the @code{strverscmp} |
| function. In fact, if @var{s1} and @var{s2} contain no digits, |
| @code{strverscmp} behaves like @code{strcmp}. |
| |
| Basically, we compare strings normally (character by character), until |
| we find a digit in each string - then we enter a special comparison |
| mode, where each sequence of digits is taken as a whole. If we reach the |
| end of these two parts without noticing a difference, we return to the |
| standard comparison mode. There are two types of numeric parts: |
| "integral" and "fractional" (those begin with a '0'). The types |
| of the numeric parts affect the way we sort them: |
| |
| @itemize @bullet |
| @item |
| integral/integral: we compare values as you would expect. |
| |
| @item |
| fractional/integral: the fractional part is less than the integral one. |
| Again, no surprise. |
| |
| @item |
| fractional/fractional: the things become a bit more complex. |
| If the common prefix contains only leading zeroes, the longest part is less |
| than the other one; else the comparison behaves normally. |
| @end itemize |
| |
| @smallexample |
| strverscmp ("no digit", "no digit") |
| @result{} 0 // @r{same behavior as strcmp.} |
| strverscmp ("item#99", "item#100") |
| @result{} <0 // @r{same prefix, but 99 < 100.} |
| strverscmp ("alpha1", "alpha001") |
| @result{} >0 // @r{fractional part inferior to integral one.} |
| strverscmp ("part1_f012", "part1_f01") |
| @result{} >0 // @r{two fractional parts.} |
| strverscmp ("foo.009", "foo.0") |
| @result{} <0 // @r{idem, but with leading zeroes only.} |
| @end smallexample |
| |
| This function is especially useful when dealing with filename sorting, |
| because filenames frequently hold indices/version numbers. |
| @end deftypefun |
| |
| */ |
| |
| /* 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 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 Glibc 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; |
| 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; |
| } |
| } |