1 /* Concatenate two arbitrary file names. 2 3 Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005 Free 4 Software Foundation, Inc. 5 6 This program is free software; you can redistribute it and/or modify 7 it under the terms of the GNU General Public License as published by 8 the Free Software Foundation; either version 2, or (at your option) 9 any later version. 10 11 This program is distributed in the hope that it will be useful, 12 but WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 GNU General Public License for more details. 15 16 You should have received a copy of the GNU General Public License 17 along with this program; if not, write to the Free Software Foundation, 18 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ 19 20 /* Written by Jim Meyering. */ 21 22 #ifdef HAVE_CONFIG_H 23 # include <config.h> 24 #endif 25 26 /* Specification. */ 27 #include "filenamecat.h" 28 29 #include <string.h> 30 31 #include "dirname.h" 32 #include "xalloc.h" 33 34 #if ! HAVE_MEMPCPY && ! defined mempcpy 35 # define mempcpy(D, S, N) ((void *) ((char *) memcpy (D, S, N) + (N))) 36 #endif 37 38 /* Return the longest suffix of F that is a relative file name. 39 If it has no such suffix, return the empty string. */ 40 41 static char const * 42 longest_relative_suffix (char const *f) 43 { 44 for (f += FILE_SYSTEM_PREFIX_LEN (f); ISSLASH (*f); f++) 45 continue; 46 return f; 47 } 48 49 /* Concatenate two file name components, DIR and ABASE, in 50 newly-allocated storage and return the result. 51 The resulting file name F is such that the commands "ls F" and "(cd 52 DIR; ls BASE)" refer to the same file, where BASE is ABASE with any 53 file system prefixes and leading separators removed. 54 Arrange for a directory separator if necessary between DIR and BASE 55 in the result, removing any redundant separators. 56 In any case, if BASE_IN_RESULT is non-NULL, set 57 *BASE_IN_RESULT to point to the copy of ABASE in the returned 58 concatenation. However, if ABASE begins with more than one slash, 59 set *BASE_IN_RESULT to point to the sole corresponding slash that 60 is copied into the result buffer. 61 62 Report an error if memory is exhausted. */ 63 64 char * 65 file_name_concat (char const *dir, char const *abase, char **base_in_result) 66 { 67 char const *dirbase = base_name (dir); 68 size_t dirbaselen = base_len (dirbase); 69 size_t dirlen = dirbase - dir + dirbaselen; 70 size_t needs_separator = (dirbaselen && ! ISSLASH (dirbase[dirbaselen - 1])); 71 72 char const *base = longest_relative_suffix (abase); 73 size_t baselen = strlen (base); 74 75 char *p_concat = xmalloc (dirlen + needs_separator + baselen + 1); 76 char *p; 77 78 p = mempcpy (p_concat, dir, dirlen); 79 *p = DIRECTORY_SEPARATOR; 80 p += needs_separator; 81 82 if (base_in_result) 83 *base_in_result = p - IS_ABSOLUTE_FILE_NAME (abase); 84 85 p = mempcpy (p, base, baselen); 86 *p = '\0'; 87 88 return p_concat; 89 } 90 91 #ifdef TEST_FILE_NAME_CONCAT 92 # include <stdlib.h> 93 # include <stdio.h> 94 int 95 main () 96 { 97 static char const *const tests[][3] = 98 { 99 {"a", "b", "a/b"}, 100 {"a/", "b", "a/b"}, 101 {"a/", "/b", "a/b"}, 102 {"a", "/b", "a/b"}, 103 104 {"/", "b", "/b"}, 105 {"/", "/b", "/b"}, 106 {"/", "/", "/"}, 107 {"a", "/", "a/"}, /* this might deserve a diagnostic */ 108 {"/a", "/", "/a/"}, /* this might deserve a diagnostic */ 109 {"a", "//b", "a/b"}, 110 }; 111 size_t i; 112 bool fail = false; 113 for (i = 0; i < sizeof tests / sizeof tests[0]; i++) 114 { 115 char *base_in_result; 116 char const *const *t = tests[i]; 117 char *res = file_name_concat (t[0], t[1], &base_in_result); 118 if (strcmp (res, t[2]) != 0) 119 { 120 printf ("got %s, expected %s\n", res, t[2]); 121 fail = true; 122 } 123 } 124 exit (fail ? EXIT_FAILURE : EXIT_SUCCESS); 125 } 126 #endif 127