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Annotation of 43BSDTahoe/new/notes/src/newspath.c, revision 1.1.1.1

1.1       root        1: #include       <stdio.h>
                      2: #include       "newsgate.h"
                      3: 
                      4: #ifdef RCSIDENT
                      5: static char *rcsid = "$Header: newspath.c,v 1.7 85/01/18 15:40:17 notes Rel $";
                      6: #endif RCSIDENT
                      7: 
                      8: 
                      9: /*
                     10:  *     char *getpath(dest) char *dest;
                     11:  *
                     12:  *     look in the routing tables for a path from here to that
                     13:  *     specified host.  Return the path.
                     14:  *     Return NULL if there is no such path.
                     15:  *
                     16:  *     The returned path is of the form:
                     17:  *             a!b!c!d!dest!           (note trailing !)
                     18:  *
                     19:  *     The path is saved in a static buffer so you have to save 
                     20:  *     it or it is destroyed in the next call.
                     21:  *
                     22:  *     A re-write of what Jeff Donnelly did a while back.
                     23:  *     Ray Essick
                     24:  *
                     25:  *     The routing table contains lines of the form:
                     26:  *     site<space>path
                     27:  *             site = destination site
                     28:  *             path = a!b!c!d!site!    (not trailing !)
                     29:  *
                     30:  *     Must be in alphabetical order since the search gives up
                     31:  *     after finding a site "after" the one we want!
                     32:  */
                     33: 
                     34: FILE * fopen ();
                     35: extern char *fgets ();
                     36: 
                     37: /*
                     38:  *     This entire routine is only called when EXPANDPATH is defined
                     39:  *     so we surround it with an ifdef to keep down the binary sizes
                     40:  *     when EXPANDPATH is not defined.
                     41:  */
                     42: #ifdef EXPANDPATH
                     43: char   *getpath (dest)
                     44: char   *dest;
                     45: {
                     46: 
                     47:     static char line[BUFSIZ];
                     48:     FILE * mapfile;
                     49:     register char  *p,
                     50:                    *path;
                     51: 
                     52: 
                     53:     if ((mapfile = fopen (PATHMAP, "r")) == NULL)
                     54:        return (NULL);                                  /* no file */
                     55: 
                     56:     while (fgets (line, BUFSIZ, mapfile) != NULL)
                     57:     {
                     58:        p = line;
                     59:        path = NULL;
                     60:        do
                     61:        {
                     62:            switch (*p)
                     63:            {
                     64:                case ' ': 
                     65:                case '\t':                              /* zap and mark path */
                     66:                    if (path == NULL)                   /* only once */
                     67:                    {
                     68:                        *p++ = '\0';
                     69:                        path = p;
                     70:                    }
                     71:                    else
                     72:                        p++;                            /* gotta move over it */
                     73:                    break;
                     74: 
                     75:                case '\n': 
                     76:                    *p = '\0';                          /* end of it all */
                     77:                    break;
                     78: 
                     79:                default: 
                     80:                    p++;
                     81:                    break;
                     82:            }
                     83:        }
                     84:        while (*p);                                     /* terminates after newline */
                     85:        if (strcmp (line, dest) == 0)                   /* matches */
                     86:        {
                     87:            break;                                      /* jump and return */
                     88:        }
                     89: 
                     90:        if (strcmp (line, dest) > 0)                    /* past it */
                     91:        {
                     92:            path = NULL;
                     93:            break;
                     94:        }
                     95:     }
                     96:     fclose (mapfile);                                  /* don't litter */
                     97:     return (path);                                     /* and our answer */
                     98: }
                     99: #endif EXPANDPATH

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