1 files changed, 235 insertions, 0 deletions
diff --git a/gnulib-local/lib/backupfile.c b/gnulib-local/lib/backupfile.c
new file mode 100644
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+++ b/gnulib-local/lib/backupfile.c
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+/* backupfile.c -- make Emacs style backup file names
+   Copyright (C) 1990-1999, 2000-2003, 2005-2006, 2012 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 3 of the License, 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.  If not, see <http://www.gnu.org/licenses/>.  */
+
+/* Written by David MacKenzie <djm@gnu.ai.mit.edu>.
+   Some algorithms adapted from GNU Emacs. */
+
+#include <config.h>
+
+#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>
+#endif
+
+#include <stdlib.h>
+
+#include "basename.h"
+
+#if HAVE_DIRENT_H
+# define HAVE_DIR 1
+#else
+# define HAVE_DIR 0
+#endif
+
+#include <limits.h>
+
+/* 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
+
+/* The extension added to file names to produce a simple (as opposed
+   to numbered) backup file name. */
+const char *simple_backup_suffix = "~";
+
+#if HAVE_DIR
+static int max_backup_version (const char *, const char *);
+static int version_number (const char *, const char *, size_t);
+#endif
+
+/* 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 (const char *file, enum backup_type backup_type)
+{
+  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 = (char *) 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 = basename (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 (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) || strlen (dp->d_name) < 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 (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[] =
+{
+  /* In a series of synonyms, present the most meaning full first, so
+     that argmatch_valid be more readable. */
+  "none", "off",
+  "simple", "never",
+  "existing", "nil",
+  "numbered", "t",
+  0
+};
+
+static const enum backup_type backup_types[] =
+{
+  none, none,
+  simple, simple,
+  numbered_existing, numbered_existing,
+  numbered, numbered
+};
+
+/* Return the type of backup specified by VERSION.
+   If VERSION is NULL or the empty string, return numbered_existing.
+   If VERSION is invalid or ambiguous, fail with a diagnostic appropriate
+   for the specified CONTEXT.  Unambiguous abbreviations are accepted.  */
+
+enum backup_type
+get_version (const char *context, const char *version)
+{
+  if (version == 0 || *version == 0)
+    return numbered_existing;
+  else
+    return XARGMATCH (context, version, backup_args, backup_types);
+}
+
+
+/* Return the type of backup specified by VERSION.
+   If VERSION is NULL, use the value of the envvar VERSION_CONTROL.
+   If the specified string is invalid or ambiguous, fail with a diagnostic
+   appropriate for the specified CONTEXT.
+   Unambiguous abbreviations are accepted.  */
+
+enum backup_type
+xget_version (const char *context, const char *version)
+{
+  if (version && *version)
+    return get_version (context, version);
+  else
+    return get_version ("$VERSION_CONTROL", getenv ("VERSION_CONTROL"));
+}