87 lines
2.4 KiB
C
87 lines
2.4 KiB
C
/*
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* Compute the relative path needed to go from one Unix dir to another
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*
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* Copyright 2006 Alexandre Julliard
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
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*/
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#include "config.h"
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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/* determine where the destination path is located relative to the 'from' path */
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static const char *get_relative_path( const char *from, const char *dest, unsigned int *dotdots )
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{
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#define DIR_END(p) (*(p) == 0 || *(p) == '/')
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const char *start;
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/* a path of "." is equivalent to an empty path */
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if (!strcmp( from, "." )) from = "";
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*dotdots = 0;
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for (;;)
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{
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while (*from == '/') from++;
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while (*dest == '/') dest++;
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start = dest; /* save start of next path element */
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if (!*from) break;
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while (!DIR_END(from) && *from == *dest) { from++; dest++; }
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if (DIR_END(from) && DIR_END(dest)) continue;
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/* count remaining elements in 'from' */
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do
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{
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(*dotdots)++;
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while (!DIR_END(from)) from++;
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while (*from == '/') from++;
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}
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while (*from);
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break;
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}
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return start;
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#undef DIR_END
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}
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int main( int argc, char *argv[] )
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{
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const char *start;
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unsigned int dotdots = 0;
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if (argc != 3)
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{
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fprintf( stderr, "Usage: %s fromdir todir\n", argv[0] );
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exit(1);
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}
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start = get_relative_path( argv[1], argv[2], &dotdots );
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if (!start[0] && !dotdots) printf( ".\n" );
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else
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{
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while (dotdots)
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{
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printf( ".." );
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dotdots--;
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if (dotdots || start[0]) printf( "/" );
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}
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printf( "%s\n", start );
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}
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exit(0);
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}
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