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-rw-r--r--lib/sh/spell.c212
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diff --git a/lib/sh/spell.c b/lib/sh/spell.c
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--- /dev/null
+++ b/lib/sh/spell.c
@@ -0,0 +1,212 @@
+/* spell.c -- spelling correction for pathnames. */
+
+/* Copyright (C) 2000-2020 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 3 of the License, 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. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#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>
+#if defined (HAVE_SYS_PARAM_H)
+#include <sys/param.h>
+#endif
+
+#include <stdio.h>
+
+#include <bashansi.h>
+#include <maxpath.h>
+#include <stdc.h>
+
+static int mindist PARAMS((char *, char *, char *));
+static int spdist PARAMS((char *, char *));
+
+/*
+ * `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;
+}
+
+char *
+dirspell (dirname)
+ char *dirname;
+{
+ int n;
+ char *guess;
+
+ n = (strlen (dirname) * 3 + 1) / 2 + 1;
+ guess = (char *)malloc (n);
+ if (guess == 0)
+ return 0;
+
+ switch (spname (dirname, guess))
+ {
+ case -1:
+ default:
+ free (guess);
+ return (char *)NULL;
+ case 0:
+ case 1:
+ return guess;
+ }
+}