TeX 1995 July/TeX CD-ROM July 1995 (Disc 1)(Walnut Creek)(1995).ISO/tex-k/tex-k-archive.past/tex-k-archive.gz/tex-k-archive/[e-mail]_Tue Oct 12 15:54:44 1993.msg

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Date: Tue, 12 Oct 1993 14:54:44 +0100
From: Frank Jensen <[e-mail]>
Message-Id: <[e-mail]>
To: [e-mail]
Subject: Speed of (recursive) search in the Kpathsearch library


I'm sure most people have noticed the delay due to the recursive
search of subdirectories when TeX starts up.  [Our users certainly
have as they have started to make private copies of the style files
they need and abandon the search of the `global' style directories.]

At our site, we have in the TeX `inputs' directory approximately 1500
files distributed in 75 directories (and only very few of the ordinary
files are located in non-leaf directories).  And this hierarchy is
getting larger, not smaller.  This takes a noticable amount of time to
search despite the clever trick Karl uses to speed it up.

So I tried to see how much I could speed up the search by having a
precompiled list of all input files available in a directory
hierarchy.  I assumed this list to be a simple text file in the format
produced by the (GNU) `ls' command with option `-R', and that the file
would be located at the root of the hierarchy and named "ls-R".  And
IMO, the results are promising: the start up + search is (for all
practical purposes) instantaneous.

I only modified two files: `pathsearch.c' and `elt-dirs.c'.  [I have
appended diffs for the changes below.  I can of course supply complete
copies of the files, if needed.]  I only made the absolute minimum of
changes to make it work.  It hasn't been tuned: for example, the
"ls-R" file is read every time, we search for a file; it should only
be read the first time.

Anyway, I think something like this is worthwhile despite the need to
maintain an extra file.  What do you think?

---
Frank Jensen,   [e-mail]
Department of Mathematics and Computer Science
Aalborg University
DENMARK


*** pathsearch.c    Sat Sep 25 20:13:28 1993
--- pathsearch.c.new    Mon Oct 11 19:03:22 1993
***************
*** 18,23 ****
--- 18,26 ----

  #include <kpathsea/config.h>

+ #include <kpathsea/c-fopen.h>
+ #include <kpathsea/line.h>
+ #include <kpathsea/c-pathch.h>
  #include <kpathsea/absolute.h>
  #include <kpathsea/expand.h>
  #include <kpathsea/pathsearch.h>
***************
*** 58,76 ****
            XRETALLOC (potential, allocated, char);
          }

!       strcpy (potential, dir);
!       strcat (potential, name);

!       if (kpse_readable_file (potential))
!         { /* Found a file.  Maybe one is all the caller wants.  */
!           str_list_add (&ret, potential);
!           if (!search_all)
!             /* No need to terminate with NULL; the caller knows.  */
!             return ret;
!
!           /* Start new filename.  */
!           allocated = INIT_ALLOC;
!           potential = xmalloc (allocated);
          }
      }

--- 61,124 ----
            XRETALLOC (potential, allocated, char);
          }

!       if (IS_DIR_SEP (dir[dir_len - 2]))
!         { /* search "ls-R" file */
!       char file_name[1000]; /* arbitrary length */
!       string p = file_name + dir_len - 1, q = p;
!       FILE *ls_R_file;
!       char *l;
!
!       strcpy (file_name, dir);
!       strcpy (p, "ls-R");
!       ls_R_file = xfopen (file_name, FOPEN_R_MODE);
!       while ((l = read_line (ls_R_file)) != NULL)
!         {
!           int llen = strlen (l);
!
!           if (llen > 0)
!         if (l[llen - 1] == ':')
!           { /* new directory */
!             l[llen - 1] = DIR_SEP;
!             strcpy (p, l);
!             q = p + llen;
!           }
!             else if (strcmp (l, name) == 0)
!           { /* we expect a file to be found now */
!             strcpy (q, l);
!             if (kpse_readable_file (file_name)) /* just to check */
!               { /* Found a file; maybe one is all the caller wants. */
!               str_list_add (&ret, xstrdup (file_name));
!               if (!search_all)
!                 { /* No need to terminate with NULL;
!                  the caller knows. */
!                   free (l);
!                   strcpy (p, "ls-R");
!                   xfclose (ls_R_file, file_name);
!                   return ret;
!                 }
!               }
!           }
!           free (l);
!         }
!       strcpy (p, "ls-R");
!       xfclose (ls_R_file, file_name);
!     }
!       else
!     {
!       strcpy (potential, dir);
!       strcat (potential, name);

!       if (kpse_readable_file (potential))
!         { /* Found a file.  Maybe one is all the caller wants.  */
!           str_list_add (&ret, potential);
!           if (!search_all)
!         /* No need to terminate with NULL; the caller knows.  */
!         return ret;
!
!           /* Start new filename.  */
!           allocated = INIT_ALLOC;
!           potential = xmalloc (allocated);
!         }
          }
      }

*** elt-dirs.c    Wed Aug  4 01:42:20 1993
--- elt-dirs.c.new    Mon Oct 11 19:15:14 1993
***************
*** 224,231 ****
            /* If two consecutive directory separators, find subdirectories.  */
            if (IS_DIR_SEP (dir[1]))
              {
!               do_subdir (str_list_ptr, elt, dir - elt + 1, dir + 2);
!               found_special = true;
              }

            /* If /?, make following component optional.  */
--- 224,237 ----
            /* If two consecutive directory separators, find subdirectories.  */
            if (IS_DIR_SEP (dir[1]))
              {
!           char ls_R[1000]; /* arbitrary length */
!           strncpy (ls_R, elt, dir - elt + 1);
!           strcpy (ls_R + (dir - elt + 1), "ls-R");
!           if (!kpse_readable_file (ls_R))
!         {
!           do_subdir (str_list_ptr, elt, dir - elt + 1, dir + 2);
!           found_special = true;
!             }
              }

            /* If /?, make following component optional.  */