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- /* backupfile.c -- make Emacs style backup file names
- Copyright (C) 1990,1991,1992,1993,1995,1997 Free Software Foundation, Inc.
- This program 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.
- This program 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 this program; see the file COPYING.
- If not, write to the Free Software Foundation,
- 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
- /* Written by David MacKenzie <djm@gnu.ai.mit.edu>.
- Some algorithms adapted from GNU Emacs. */
- #if HAVE_CONFIG_H
- # include <config.h>
- #endif
- #include <argmatch.h>
- #include <backupfile.h>
- #include <stdio.h>
- #include <sys/types.h>
- #if HAVE_STRING_H
- # include <string.h>
- #else
- # include <strings.h>
- #endif
- #if HAVE_DIRENT_H
- # include <dirent.h>
- # define NLENGTH(direct) strlen ((direct)->d_name)
- #else
- # define dirent direct
- # define NLENGTH(direct) ((size_t) (direct)->d_namlen)
- # if HAVE_SYS_NDIR_H
- # include <sys/ndir.h>
- # endif
- # if HAVE_SYS_DIR_H
- # include <sys/dir.h>
- # endif
- # if HAVE_NDIR_H
- # include <ndir.h>
- # endif
- #endif
- #if CLOSEDIR_VOID
- /* Fake a return value. */
- # define CLOSEDIR(d) (closedir (d), 0)
- #else
- # define CLOSEDIR(d) closedir (d)
- #endif
- #if STDC_HEADERS
- # include <stdlib.h>
- #else
- char *malloc ();
- #endif
- #if HAVE_DIRENT_H || HAVE_NDIR_H || HAVE_SYS_DIR_H || HAVE_SYS_NDIR_H
- # define HAVE_DIR 1
- #else
- # define HAVE_DIR 0
- #endif
- #if HAVE_LIMITS_H
- # include <limits.h>
- #endif
- #ifndef CHAR_BIT
- #define CHAR_BIT 8
- #endif
- /* Upper bound on the string length of an integer converted to string.
- 302 / 1000 is ceil (log10 (2.0)). Subtract 1 for the sign bit;
- add 1 for integer division truncation; add 1 more for a minus sign. */
- #define INT_STRLEN_BOUND(t) ((sizeof (t) * CHAR_BIT - 1) * 302 / 1000 + 2)
- /* 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)
- #if D_INO_IN_DIRENT
- # define REAL_DIR_ENTRY(dp) ((dp)->d_ino != 0)
- #else
- # define REAL_DIR_ENTRY(dp) 1
- #endif
- /* Which type of backup file names are generated. */
- enum backup_type backup_type = none;
- /* The extension added to file names to produce a simple (as opposed
- to numbered) backup file name. */
- const char *simple_backup_suffix = ".orig";
- static int max_backup_version __BACKUPFILE_P ((const char *, const char *));
- static int version_number __BACKUPFILE_P ((const char *, const char *, size_t));
- /* Return the name of the new backup file for file FILE,
- allocated with malloc. Return 0 if out of memory.
- FILE must not end with a '/' unless it is the root directory.
- Do not call this function if backup_type == none. */
- char *
- find_backup_file_name (file)
- const char *file;
- {
- size_t backup_suffix_size_max;
- size_t file_len = strlen (file);
- size_t numbered_suffix_size_max = INT_STRLEN_BOUND (int) + 4;
- char *s;
- const char *suffix = simple_backup_suffix;
- /* Allow room for simple or `.~N~' backups. */
- backup_suffix_size_max = strlen (simple_backup_suffix) + 1;
- if (HAVE_DIR && backup_suffix_size_max < numbered_suffix_size_max)
- backup_suffix_size_max = numbered_suffix_size_max;
- s = malloc (file_len + backup_suffix_size_max + numbered_suffix_size_max);
- if (s)
- {
- strcpy (s, file);
- #if HAVE_DIR
- if (backup_type != simple)
- {
- int highest_backup;
- size_t dir_len = base_name (s) - s;
- strcpy (s + dir_len, ".");
- highest_backup = max_backup_version (file + dir_len, s);
- if (! (backup_type == numbered_existing && highest_backup == 0))
- {
- char *numbered_suffix = s + (file_len + backup_suffix_size_max);
- sprintf (numbered_suffix, ".~%d~", highest_backup + 1);
- suffix = numbered_suffix;
- }
- strcpy (s, file);
- }
- #endif /* HAVE_DIR */
- addext (s, suffix, '~');
- }
- return s;
- }
- #if HAVE_DIR
- /* Return the number of the highest-numbered backup file for file
- FILE in directory DIR. If there are no numbered backups
- of FILE in DIR, or an error occurs reading DIR, return 0.
- */
- static int
- max_backup_version (file, dir)
- const char *file;
- const char *dir;
- {
- DIR *dirp;
- struct dirent *dp;
- int highest_version;
- int this_version;
- size_t file_name_length;
- dirp = opendir (dir);
- if (!dirp)
- return 0;
- highest_version = 0;
- file_name_length = strlen (file);
- while ((dp = readdir (dirp)) != 0)
- {
- if (!REAL_DIR_ENTRY (dp) || NLENGTH (dp) < file_name_length + 4)
- continue;
- this_version = version_number (file, dp->d_name, file_name_length);
- if (this_version > highest_version)
- highest_version = this_version;
- }
- if (CLOSEDIR (dirp))
- return 0;
- return highest_version;
- }
- /* If BACKUP is a numbered backup of BASE, return its version number;
- otherwise return 0. BASE_LENGTH is the length of BASE.
- */
- static int
- version_number (base, backup, base_length)
- const char *base;
- const char *backup;
- size_t base_length;
- {
- int version;
- const char *p;
- version = 0;
- if (strncmp (base, backup, base_length) == 0
- && backup[base_length] == '.'
- && backup[base_length + 1] == '~')
- {
- for (p = &backup[base_length + 2]; ISDIGIT (*p); ++p)
- version = version * 10 + *p - '0';
- if (p[0] != '~' || p[1])
- version = 0;
- }
- return version;
- }
- #endif /* HAVE_DIR */
- static const char * const backup_args[] =
- {
- "never", "simple", "nil", "existing", "t", "numbered", 0
- };
- static const enum backup_type backup_types[] =
- {
- simple, simple, numbered_existing, numbered_existing, numbered, numbered
- };
- /* Return the type of backup indicated by VERSION.
- Unique abbreviations are accepted. */
- enum backup_type
- get_version (version)
- const char *version;
- {
- int i;
- if (version == 0 || *version == 0)
- return numbered_existing;
- i = argmatch (version, backup_args);
- if (i < 0)
- {
- invalid_arg ("version control type", version, i);
- exit (2);
- }
- return backup_types[i];
- }
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