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 #include <sys/cdefs.h> 20 __RCSID("$NetBSD: filenamecat.c,v 1.2 2016/05/17 14:00:09 christos Exp $"); 21 22 23 /* Written by Jim Meyering. */ 24 25 #ifdef HAVE_CONFIG_H 26 # include <config.h> 27 #endif 28 29 /* Specification. */ 30 #include "filenamecat.h" 31 32 #include <string.h> 33 34 #include "dirname.h" 35 #include "xalloc.h" 36 37 #if ! HAVE_MEMPCPY && ! defined mempcpy 38 # define mempcpy(D, S, N) ((void *) ((char *) memcpy (D, S, N) + (N))) 39 #endif 40 41 /* Return the longest suffix of F that is a relative file name. 42 If it has no such suffix, return the empty string. */ 43 44 static char const * 45 longest_relative_suffix (char const *f) 46 { 47 for (f += FILE_SYSTEM_PREFIX_LEN (f); ISSLASH (*f); f++) 48 continue; 49 return f; 50 } 51 52 /* Concatenate two file name components, DIR and ABASE, in 53 newly-allocated storage and return the result. 54 The resulting file name F is such that the commands "ls F" and "(cd 55 DIR; ls BASE)" refer to the same file, where BASE is ABASE with any 56 file system prefixes and leading separators removed. 57 Arrange for a directory separator if necessary between DIR and BASE 58 in the result, removing any redundant separators. 59 In any case, if BASE_IN_RESULT is non-NULL, set 60 *BASE_IN_RESULT to point to the copy of ABASE in the returned 61 concatenation. However, if ABASE begins with more than one slash, 62 set *BASE_IN_RESULT to point to the sole corresponding slash that 63 is copied into the result buffer. 64 65 Report an error if memory is exhausted. */ 66 67 char * 68 file_name_concat (char const *dir, char const *abase, char **base_in_result) 69 { 70 char const *dirbase = base_name (dir); 71 size_t dirbaselen = base_len (dirbase); 72 size_t dirlen = dirbase - dir + dirbaselen; 73 size_t needs_separator = (dirbaselen && ! ISSLASH (dirbase[dirbaselen - 1])); 74 75 char const *base = longest_relative_suffix (abase); 76 size_t baselen = strlen (base); 77 78 char *p_concat = xmalloc (dirlen + needs_separator + baselen + 1); 79 char *p; 80 81 p = mempcpy (p_concat, dir, dirlen); 82 *p = DIRECTORY_SEPARATOR; 83 p += needs_separator; 84 85 if (base_in_result) 86 *base_in_result = p - IS_ABSOLUTE_FILE_NAME (abase); 87 88 p = mempcpy (p, base, baselen); 89 *p = '\0'; 90 91 return p_concat; 92 } 93 94 #ifdef TEST_FILE_NAME_CONCAT 95 # include <stdlib.h> 96 # include <stdio.h> 97 int 98 main () 99 { 100 static char const *const tests[][3] = 101 { 102 {"a", "b", "a/b"}, 103 {"a/", "b", "a/b"}, 104 {"a/", "/b", "a/b"}, 105 {"a", "/b", "a/b"}, 106 107 {"/", "b", "/b"}, 108 {"/", "/b", "/b"}, 109 {"/", "/", "/"}, 110 {"a", "/", "a/"}, /* this might deserve a diagnostic */ 111 {"/a", "/", "/a/"}, /* this might deserve a diagnostic */ 112 {"a", "//b", "a/b"}, 113 }; 114 size_t i; 115 bool fail = false; 116 for (i = 0; i < sizeof tests / sizeof tests[0]; i++) 117 { 118 char *base_in_result; 119 char const *const *t = tests[i]; 120 char *res = file_name_concat (t[0], t[1], &base_in_result); 121 if (strcmp (res, t[2]) != 0) 122 { 123 printf ("got %s, expected %s\n", res, t[2]); 124 fail = true; 125 } 126 } 127 exit (fail ? EXIT_FAILURE : EXIT_SUCCESS); 128 } 129 #endif 130