/* 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>#elsechar *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 intmax_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 intversion_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_typeget_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];}