i-bash/lib/sh/spell.c
2009-09-12 16:46:53 +00:00

186 lines
4.1 KiB
C

/* spell.c -- spelling correction for pathnames. */
/* Copyright (C) 2000 Free Software Foundation, Inc.
This file is part of GNU Bash, the Bourne Again SHell.
Bash 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 2, or (at your option) any later
version.
Bash 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 Bash; see the file COPYING. If not, write to the Free Software
Foundation, 59 Temple Place, Suite 330, Boston, MA 02111 USA. */
#include <config.h>
#if defined (HAVE_UNISTD_H)
# ifdef _MINIX
# include <sys/types.h>
# endif
# include <unistd.h>
#endif
#include <bashtypes.h>
#include <posixdir.h>
#include <posixstat.h>
#ifndef _MINIX
#include <sys/param.h>
#endif
#include <stdio.h>
#include <bashansi.h>
#include <maxpath.h>
static int mindist (), spdist ();
/*
* `spname' and its helpers are inspired by the code in "The UNIX
* Programming Environment", Kernighan & Pike, Prentice-Hall 1984,
* pages 209 - 213.
*/
/*
* `spname' -- return a correctly spelled filename
*
* int spname(char * oldname, char * newname)
* Returns: -1 if no reasonable match found
* 0 if exact match found
* 1 if corrected
* Stores corrected name in `newname'.
*/
int
spname(oldname, newname)
char *oldname;
char *newname;
{
char *op, *np, *p;
char guess[PATH_MAX + 1], best[PATH_MAX + 1];
op = oldname;
np = newname;
for (;;)
{
while (*op == '/') /* Skip slashes */
*np++ = *op++;
*np = '\0';
if (*op == '\0') /* Exact or corrected */
{
/* `.' is rarely the right thing. */
if (oldname[1] == '\0' && newname[1] == '\0' &&
oldname[0] != '.' && newname[0] == '.')
return -1;
return strcmp(oldname, newname) != 0;
}
/* Copy next component into guess */
for (p = guess; *op != '/' && *op != '\0'; op++)
if (p < guess + PATH_MAX)
*p++ = *op;
*p = '\0';
if (mindist(newname, guess, best) >= 3)
return -1; /* Hopeless */
/*
* Add to end of newname
*/
for (p = best; *np = *p++; np++)
;
}
}
/*
* Search directory for a guess
*/
static int
mindist(dir, guess, best)
char *dir;
char *guess;
char *best;
{
DIR *fd;
struct dirent *dp;
int dist, x;
dist = 3; /* Worst distance */
if (*dir == '\0')
dir = ".";
if ((fd = opendir(dir)) == NULL)
return dist;
while ((dp = readdir(fd)) != NULL)
{
/*
* Look for a better guess. If the new guess is as
* good as the current one, we take it. This way,
* any single character match will be a better match
* than ".".
*/
x = spdist(dp->d_name, guess);
if (x <= dist && x != 3)
{
strcpy(best, dp->d_name);
dist = x;
if (dist == 0) /* Exact match */
break;
}
}
(void)closedir(fd);
/* Don't return `.' */
if (best[0] == '.' && best[1] == '\0')
dist = 3;
return dist;
}
/*
* `spdist' -- return the "distance" between two names.
*
* int spname(char * oldname, char * newname)
* Returns: 0 if strings are identical
* 1 if two characters are transposed
* 2 if one character is wrong, added or deleted
* 3 otherwise
*/
static int
spdist(cur, new)
char *cur, *new;
{
while (*cur == *new)
{
if (*cur == '\0')
return 0; /* Exact match */
cur++;
new++;
}
if (*cur)
{
if (*new)
{
if (cur[1] && new[1] && cur[0] == new[1] && cur[1] == new[0] && strcmp (cur + 2, new + 2) == 0)
return 1; /* Transposition */
if (strcmp (cur + 1, new + 1) == 0)
return 2; /* One character mismatch */
}
if (strcmp(&cur[1], &new[0]) == 0)
return 2; /* Extra character */
}
if (*new && strcmp(cur, new + 1) == 0)
return 2; /* Missing character */
return 3;
}