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      1 /*	$NetBSD: dir_forest.c,v 1.1.1.1 2009/06/23 10:08:59 tron Exp $	*/
      2 
      3 /*++
      4 /* NAME
      5 /*	dir_forest 3
      6 /* SUMMARY
      7 /*	file name to directory forest
      8 /* SYNOPSIS
      9 /*	#include <dir_forest.h>
     10 /*
     11 /*	char	*dir_forest(buf, path, depth)
     12 /*	VSTRING *buf;
     13 /*	const char *path;
     14 /*	int	depth;
     15 /* DESCRIPTION
     16 /*	This module implements support for directory forests: a file
     17 /*	organization that introduces one or more levels of intermediate
     18 /*	subdirectories in order to reduce the number of files per directory.
     19 /*
     20 /*	dir_forest() maps a file basename to a directory forest and
     21 /*	returns the resulting string: file name "abcd" becomes "a/b/"
     22 /*	and so on. The number of subdirectory levels is adjustable.
     23 /*
     24 /*	Arguments:
     25 /* .IP buf
     26 /*	A buffer that is overwritten with the result. The result
     27 /*	ends in "/" and is null terminated. If a null pointer is
     28 /*	specified, the result is written to a private buffer that
     29 /*	is overwritten upon each call.
     30 /* .IP path
     31 /*	A null-terminated string of printable characters. Characters
     32 /*	special to the file system are not permitted.
     33 /*	The first subdirectory is named after the first character
     34 /*	in \fIpath\fR, and so on. When the path is shorter than the
     35 /*	desired number of subdirectory levels, directory names
     36 /*	of '_' (underscore) are used as replacement.
     37 /* .IP depth
     38 /*	The desired number of subdirectory levels.
     39 /* DIAGNOSTICS
     40 /*	Panic: interface violations. Fatal error: out of memory.
     41 /* LICENSE
     42 /* .ad
     43 /* .fi
     44 /*	The Secure Mailer license must be distributed with this software.
     45 /* AUTHOR(S)
     46 /*	Wietse Venema
     47 /*	IBM T.J. Watson Research
     48 /*	P.O. Box 704
     49 /*	Yorktown Heights, NY 10598, USA
     50 /*--*/
     51 
     52 /* System library. */
     53 
     54 #include <sys_defs.h>
     55 #include <ctype.h>
     56 
     57 /* Utility library. */
     58 
     59 #include "msg.h"
     60 #include "dir_forest.h"
     61 
     62 /* dir_forest - translate base name to directory forest */
     63 
     64 char   *dir_forest(VSTRING *buf, const char *path, int depth)
     65 {
     66     const char *myname = "dir_forest";
     67     static VSTRING *private_buf = 0;
     68     int     n;
     69     const char *cp;
     70     int     ch;
     71 
     72     /*
     73      * Sanity checks.
     74      */
     75     if (*path == 0)
     76 	msg_panic("%s: empty path", myname);
     77     if (depth < 1)
     78 	msg_panic("%s: depth %d", myname, depth);
     79 
     80     /*
     81      * Your buffer or mine?
     82      */
     83     if (buf == 0) {
     84 	if (private_buf == 0)
     85 	    private_buf = vstring_alloc(1);
     86 	buf = private_buf;
     87     }
     88 
     89     /*
     90      * Generate one or more subdirectory levels, depending on the pathname
     91      * contents. When the pathname is short, use underscores instead.
     92      * Disallow non-printable characters or characters that are special to
     93      * the file system.
     94      */
     95     VSTRING_RESET(buf);
     96     for (cp = path, n = 0; n < depth; n++) {
     97 	if ((ch = *cp) == 0) {
     98 	    ch = '_';
     99 	} else {
    100 	    if (!ISPRINT(ch) || ch == '.' || ch == '/')
    101 		msg_panic("%s: invalid pathname: %s", myname, path);
    102 	    cp++;
    103 	}
    104 	VSTRING_ADDCH(buf, ch);
    105 	VSTRING_ADDCH(buf, '/');
    106     }
    107     VSTRING_TERMINATE(buf);
    108 
    109     if (msg_verbose > 1)
    110 	msg_info("%s: %s -> %s", myname, path, vstring_str(buf));
    111     return (vstring_str(buf));
    112 }
    113