external/ibm-public/postfix/dist/src/util/dir_forest.c

   1 /*      $NetBSD$        */
   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 }