2 * $OpenBSD: backupfile.c,v 1.18 2004/08/05 21:47:24 deraadt Exp $
3 * $DragonFly: src/usr.bin/patch/backupfile.c,v 1.3 2006/04/10 08:11:43 joerg Exp $
7 * backupfile.c -- make Emacs style backup file names Copyright (C) 1990 Free
8 * Software Foundation, Inc.
10 * This program is free software; you can redistribute it and/or modify it
11 * without restriction.
13 * This program is distributed in the hope that it will be useful, but WITHOUT
14 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 * FITNESS FOR A PARTICULAR PURPOSE.
19 * David MacKenzie <djm@ai.mit.edu>. Some algorithms adapted from GNU Emacs.
30 #include "backupfile.h"
33 #define ISDIGIT(c) (isascii ((unsigned char)c) && isdigit ((unsigned char)c))
35 /* Which type of backup file names are generated. */
36 enum backup_type backup_type
= none
;
39 * The extension added to file names to produce a simple (as opposed to
40 * numbered) backup file name.
42 const char *simple_backup_suffix
= "~";
44 static char *concat(const char *, const char *);
45 static char *make_version_name(const char *, int);
46 static int max_backup_version(const char *, const char *);
47 static int version_number(const char *, const char *, int);
48 static int argmatch(const char *, const char **);
49 static void invalid_arg(const char *, const char *, int);
52 * Return the name of the new backup file for file FILE, allocated with
53 * malloc. Return 0 if out of memory. FILE must not end with a '/' unless it
54 * is the root directory. Do not call this function if backup_type == none.
57 find_backup_file_name(const char *file
)
59 char *dir
, *base_versions
, *tmp_file
;
62 if (backup_type
== simple
)
63 return concat(file
, simple_backup_suffix
);
64 tmp_file
= strdup(file
);
67 base_versions
= concat(basename(tmp_file
), ".~");
69 if (base_versions
== NULL
)
71 tmp_file
= strdup(file
);
72 if (tmp_file
== NULL
) {
76 dir
= dirname(tmp_file
);
82 highest_backup
= max_backup_version(base_versions
, dir
);
85 if (backup_type
== numbered_existing
&& highest_backup
== 0)
86 return concat(file
, simple_backup_suffix
);
87 return make_version_name(file
, highest_backup
+ 1);
91 * Return the number of the highest-numbered backup file for file FILE in
92 * directory DIR. If there are no numbered backups of FILE in DIR, or an
93 * error occurs reading DIR, return 0. FILE should already have ".~" appended
97 max_backup_version(const char *file
, const char *dir
)
101 int highest_version
, this_version
, file_name_length
;
108 file_name_length
= strlen(file
);
110 while ((dp
= readdir(dirp
)) != NULL
) {
111 if (dp
->d_namlen
<= file_name_length
)
114 this_version
= version_number(file
, dp
->d_name
, file_name_length
);
115 if (this_version
> highest_version
)
116 highest_version
= this_version
;
119 return highest_version
;
123 * Return a string, allocated with malloc, containing "FILE.~VERSION~".
124 * Return 0 if out of memory.
127 make_version_name(const char *file
, int version
)
131 if (asprintf(&backup_name
, "%s.~%d~", file
, version
) == -1)
137 * If BACKUP is a numbered backup of BASE, return its version number;
138 * otherwise return 0. BASE_LENGTH is the length of BASE. BASE should
139 * already have ".~" appended to it.
142 version_number(const char *base
, const char *backup
, int base_length
)
148 if (!strncmp(base
, backup
, base_length
) && ISDIGIT(backup
[base_length
])) {
149 for (p
= &backup
[base_length
]; ISDIGIT(*p
); ++p
)
150 version
= version
* 10 + *p
- '0';
151 if (p
[0] != '~' || p
[1])
158 * Return the newly-allocated concatenation of STR1 and STR2. If out of
162 concat(const char *str1
, const char *str2
)
166 if (asprintf(&newstr
, "%s%s", str1
, str2
) == -1)
172 * If ARG is an unambiguous match for an element of the null-terminated array
173 * OPTLIST, return the index in OPTLIST of the matched element, else -1 if it
174 * does not match any element or -2 if it is ambiguous (is a prefix of more
178 argmatch(const char *arg
, const char **optlist
)
180 int i
; /* Temporary index in OPTLIST. */
181 size_t arglen
; /* Length of ARG. */
182 int matchind
= -1; /* Index of first nonexact match. */
183 int ambiguous
= 0; /* If nonzero, multiple nonexact match(es). */
185 arglen
= strlen(arg
);
187 /* Test all elements for either exact match or abbreviated matches. */
188 for (i
= 0; optlist
[i
]; i
++) {
189 if (!strncmp(optlist
[i
], arg
, arglen
)) {
190 if (strlen(optlist
[i
]) == arglen
)
191 /* Exact match found. */
193 else if (matchind
== -1)
194 /* First nonexact match found. */
197 /* Second nonexact match found. */
208 * Error reporting for argmatch. KIND is a description of the type of entity
209 * that was being matched. VALUE is the invalid value that was given. PROBLEM
210 * is the return value from argmatch.
213 invalid_arg(const char *kind
, const char *value
, int problem
)
215 fprintf(stderr
, "patch: ");
217 fprintf(stderr
, "invalid");
218 else /* Assume -2. */
219 fprintf(stderr
, "ambiguous");
220 fprintf(stderr
, " %s `%s'\n", kind
, value
);
223 static const char *backup_args
[] = {
224 "never", "simple", "nil", "existing", "t", "numbered", 0
227 static enum backup_type backup_types
[] = {
228 simple
, simple
, numbered_existing
,
229 numbered_existing
, numbered
, numbered
233 * Return the type of backup indicated by VERSION. Unique abbreviations are
237 get_version(const char *version
)
241 if (version
== NULL
|| *version
== '\0')
242 return numbered_existing
;
243 i
= argmatch(version
, backup_args
);
245 return backup_types
[i
];
246 invalid_arg("version control type", version
, i
);