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/* Compare strings while treating digits characters numerically.
Copyright (C) 1997, 2000 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Jean-Francois 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. */
#if HAVE_CONFIG_H
# include <config.h>
#endif
#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 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
/* ISDIGIT differs from isdigit, as follows:
- Its arg may be any int or unsigned int; it need not be an unsigned char.
- It's guaranteed to evaluate its argument exactly once.
- It's typically faster.
Posix 1003.2-1992 section 2.5.2.1 page 50 lines 1556-1558 says that
only '0' through '9' are digits. Prefer ISDIGIT to isdigit unless
it's important to use the locale's definition of `digit' even when the
host does not conform to Posix. */
#define ISDIGIT(c) ((unsigned) (c) - '0' <= 9)
/* 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;
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;
}
}
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