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authorGeoffrey Keating <geoffk@geoffk.org>2005-06-21 00:28:25 +0000
committerGeoffrey Keating <geoffk@geoffk.org>2005-06-21 00:28:25 +0000
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Index: include/ChangeLog
2005-06-20 Geoffrey Keating <geoffk@apple.com> * libiberty.h (strverscmp): Prototype. Index: libiberty/ChangeLog 2005-06-20 Geoffrey Keating <geoffk@apple.com> * strverscmp.c: New. * Makefile.in (CFILES): Add strverscmp.c. (CONFIGURED_OFILES): Add strverscmp.o. (strverscmp.o): New rule. (stamp-functions): Add $(srcdir) to files in source directory. * configure.ac (funcs): Add strverscmp. (AC_CHECK_FUNCS): Add strverscmp. * configure: Regenerate. * functions.texi: Regenerate.
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+/* Compare strings while treating digits characters numerically.
+ Copyright (C) 1997, 2002, 2005 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., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 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;
+ }
+}