107 lines
3.4 KiB
C
107 lines
3.4 KiB
C
/* $NetBSD: path.c,v 1.5 2011/09/21 19:32:59 christos Exp $ */
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/*
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* Copyright (c) 1991 Carnegie Mellon University
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* All Rights Reserved.
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*
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* Permission to use, copy, modify and distribute this software and its
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* documentation is hereby granted, provided that both the copyright
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* notice and this permission notice appear in all copies of the
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* software, derivative works or modified versions, and any portions
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* thereof, and that both notices appear in supporting documentation.
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*
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* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
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* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
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* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
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*
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* Carnegie Mellon requests users of this software to return to
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*
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* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
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* School of Computer Science
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* Carnegie Mellon University
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* Pittsburgh PA 15213-3890
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*
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* any improvements or extensions that they make and grant Carnegie the rights
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* to redistribute these changes.
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*/
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/* path -- break filename into directory and file
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*
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* path (filename,direc,file);
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* char *filename,*direc,*file;
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* filename is input; direc and file are output (user-supplied).
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* file will not have any trailing /; direc might.
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*
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* Note these rules:
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* 1. trailing / are ignored (except as first character)
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* 2. x/y is x;y where y contains no / (x may contain /)
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* 3. /y is /;y where y contains no /
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* 4. y is .;y where y contains no /
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* 5. is .;. (null filename)
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* 6. / is /;. (the root directory)
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*
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* Algorithm is this:
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* 1. delete trailing / except in first position
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* 2. if any /, find last one; change to null; y++
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* else y = x; (x is direc; y is file)
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* 3. if y is null, y = .
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* 4. if x equals y, x = .
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* else if x is null, x = /
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*
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* HISTORY
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* 20-Nov-79 Steven Shafer (sas) at Carnegie-Mellon University
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* Copied verbatim from PDP-11. Still as messy as ever.
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* Some people have asked for a modification (I think that's a better
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* idea than a new routine) which will change the directory name
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* into an absolute pathname if it isn't one already. The change
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* involves doing a getwd() and prepending that if appropriate, with
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* a "/" in between that and the directory part of the path.
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* If you want to be cute, you can also resolve ".."s at that time.
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*
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*/
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#include "supcdefs.h"
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#include "supextern.h"
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void
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path(const char *original, char *direc, char *file)
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{
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char *y;
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/* x is direc */
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const char *p;
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/* copy and note the end */
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p = original;
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y = direc;
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while ((*y++ = *p++) != '\0'); /* copy string */
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/* y now points to first char after null */
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--y; /* y now points to null */
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--y; /* y now points to last char of string before
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* null */
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/* chop off trailing / except as first character */
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while (y > direc && *y == '/')
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--y; /* backpedal past / */
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/* y now points to char before first trailing / or null */
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*(++y) = 0; /* chop off end of string */
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/* y now points to null */
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/* find last /, if any. If found, change to null and bump y */
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while (y > direc && *y != '/')
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--y;
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/* y now points to / or direc. Note *direc may be / */
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if (*y == '/') {
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*y++ = 0;
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}
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/* find file name part */
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if (*y)
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strcpy(file, y);
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else
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strcpy(file, ".");
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/* find directory part */
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if (direc == y)
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strcpy(direc, ".");
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else if (*direc == 0)
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strcpy(direc, "/");
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/* else direc already has proper value */
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}
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