| 1 | /* |
| 2 | * This file is part of DisOrder |
| 3 | * Copyright (C) 2005, 2007 Richard Kettlewell |
| 4 | * |
| 5 | * This program is free software; you can redistribute it and/or modify |
| 6 | * it under the terms of the GNU General Public License as published by |
| 7 | * the Free Software Foundation; either version 2 of the License, or |
| 8 | * (at your option) any later version. |
| 9 | * |
| 10 | * This program is distributed in the hope that it will be useful, but |
| 11 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 13 | * General Public License for more details. |
| 14 | * |
| 15 | * You should have received a copy of the GNU General Public License |
| 16 | * along with this program; if not, write to the Free Software |
| 17 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 |
| 18 | * USA |
| 19 | */ |
| 20 | /** @file lib/filepart.c |
| 21 | * @brief Filename parsing |
| 22 | */ |
| 23 | |
| 24 | #include "common.h" |
| 25 | |
| 26 | #include "filepart.h" |
| 27 | #include "mem.h" |
| 28 | |
| 29 | /** @brief Parse a filename |
| 30 | * @param path Filename to parse |
| 31 | * @param Where to put directory name, or NULL |
| 32 | * @param Where to put basename, or NULL |
| 33 | */ |
| 34 | static void parse_filename(const char *path, |
| 35 | char **dirnamep, |
| 36 | char **basenamep) { |
| 37 | const char *s, *e = path + strlen(path); |
| 38 | |
| 39 | /* Strip trailing slashes. We never take these into account. */ |
| 40 | while(e > path && e[-1] == '/') |
| 41 | --e; |
| 42 | if(e == path) { |
| 43 | /* The path is empty or contains only slashes */ |
| 44 | if(*path) { |
| 45 | if(dirnamep) |
| 46 | *dirnamep = xstrdup("/"); |
| 47 | if(basenamep) |
| 48 | *basenamep = xstrdup("/"); |
| 49 | } else { |
| 50 | if(dirnamep) |
| 51 | *dirnamep = xstrdup(""); |
| 52 | if(basenamep) |
| 53 | *basenamep = xstrdup(""); |
| 54 | } |
| 55 | } else { |
| 56 | /* The path isn't empty and has more than just slashes. e therefore now |
| 57 | * points at the end of the basename. */ |
| 58 | s = e; |
| 59 | while(s > path && s[-1] != '/') |
| 60 | --s; |
| 61 | /* Now s points at the start of the basename */ |
| 62 | if(basenamep) |
| 63 | *basenamep = xstrndup(s, e - s); |
| 64 | if(s > path) { |
| 65 | --s; |
| 66 | /* s must now be pointing at a '/' before the basename */ |
| 67 | assert(*s == '/'); |
| 68 | while(s > path && s[-1] == '/') |
| 69 | --s; |
| 70 | /* Now s must be pointing at the last '/' after the dirname */ |
| 71 | assert(*s == '/'); |
| 72 | if(s == path) { |
| 73 | /* If we reached the start we must be at the root */ |
| 74 | if(dirnamep) |
| 75 | *dirnamep = xstrdup("/"); |
| 76 | } else { |
| 77 | /* There's more than just the root here */ |
| 78 | if(dirnamep) |
| 79 | *dirnamep = xstrndup(path, s - path); |
| 80 | } |
| 81 | } else { |
| 82 | /* There wasn't a slash */ |
| 83 | if(dirnamep) |
| 84 | *dirnamep = xstrdup("."); |
| 85 | } |
| 86 | } |
| 87 | } |
| 88 | |
| 89 | /** @brief Return the directory part of @p path |
| 90 | * @param path Path to parse |
| 91 | * @return Directory part of @p path |
| 92 | * |
| 93 | * Extracts the directory part of @p path. This is a simple lexical |
| 94 | * transformation and no canonicalization is performed. The result will only |
| 95 | * ever end "/" if it is the root directory. The result will be "." if there |
| 96 | * is no directory part. |
| 97 | */ |
| 98 | char *d_dirname(const char *path) { |
| 99 | char *d = 0; |
| 100 | |
| 101 | parse_filename(path, &d, 0); |
| 102 | assert(d != 0); |
| 103 | return d; |
| 104 | } |
| 105 | |
| 106 | /** @brief Return the basename part of @p path |
| 107 | * @param Path to parse |
| 108 | * @return Base part of @p path |
| 109 | * |
| 110 | * Extracts the base part of @p path. This is a simple lexical transformation |
| 111 | * and no canonicalization is performed. The result is always newly allocated |
| 112 | * even if compares equal to @p path. |
| 113 | */ |
| 114 | char *d_basename(const char *path) { |
| 115 | char *b = 0; |
| 116 | |
| 117 | parse_filename(path, 0, &b); |
| 118 | assert(b != 0); |
| 119 | return b; |
| 120 | } |
| 121 | |
| 122 | /** @brief Find the extension part of @p path |
| 123 | * @param path Path to parse |
| 124 | * @return Start of extension in @p path, or NULL |
| 125 | * |
| 126 | * The return value points into @p path and points at the "." at the start of |
| 127 | * the path. If the basename has no extension the result is NULL. Extensions |
| 128 | * are assumed to only contain the ASCII digits and letters. |
| 129 | * |
| 130 | * See also extension(). |
| 131 | */ |
| 132 | static const char *find_extension(const char *path) { |
| 133 | const char *q = path + strlen(path); |
| 134 | |
| 135 | while(q > path && strchr("abcdefghijklmnopqrstuvwxyz" |
| 136 | "ABCDEFGHIJKLMNOPQRSTUVWXYZ" |
| 137 | "0123456789", *q)) |
| 138 | --q; |
| 139 | return *q == '.' ? q : 0; |
| 140 | } |
| 141 | |
| 142 | /** @brief Strip the extension from @p path |
| 143 | * @param path Path to parse |
| 144 | * @return @p path with extension removed, or @p path |
| 145 | * |
| 146 | * The extension is defined exactly as for find_extension(). The result might |
| 147 | * or might not point into @p path. |
| 148 | */ |
| 149 | const char *strip_extension(const char *path) { |
| 150 | const char *q = find_extension(path); |
| 151 | |
| 152 | return q ? xstrndup(path, q - path) : path; |
| 153 | } |
| 154 | |
| 155 | /** @brief Find the extension part of @p path |
| 156 | * @param path Path to parse |
| 157 | * @return Start of extension in @p path, or "" |
| 158 | * |
| 159 | * The return value may points into @p path and if so points at the "." at the |
| 160 | * start of the path. If the basename has no extension the result is "". |
| 161 | * Extensions are assumed to only contain the ASCII digits and letters. |
| 162 | * |
| 163 | * See also find_extension(). |
| 164 | */ |
| 165 | const char *extension(const char *path) { |
| 166 | const char *q = find_extension(path); |
| 167 | |
| 168 | return q ? q : ""; |
| 169 | } |
| 170 | |
| 171 | /* |
| 172 | Local Variables: |
| 173 | c-basic-offset:2 |
| 174 | comment-column:40 |
| 175 | fill-column:79 |
| 176 | indent-tabs-mode:nil |
| 177 | End: |
| 178 | */ |