hash.cc

   1 /*
   2  * Copyright (c) 2000, Red Hat, Inc.
   3  *
   4  *     This program is free software; you can redistribute it and/or modify
   5  *     it under the terms of the GNU General Public License as published by
   6  *     the Free Software Foundation; either version 2 of the License, or
   7  *     (at your option) any later version.
   8  *
   9  *     A copy of the GNU General Public License can be found at
  10  *     http://www.gnu.org/
  11  *
  12  * Written by DJ Delorie <dj@cygnus.com>
  13  *
  14  */
  15
  16 /* Simple hash class for install.cc */
  17
  18 #if 0
  19 static const char *cvsid =
  20   "\n%%% $Id$\n";
  21 #endif
  22
  23 #include <stdlib.h>
  24 #include <string.h>
  25
  26 #include "hash.h"
  27
  28 class hash_internals
  29 {
  30 public:
  31   char **keys;
  32   int numkeys;
  33   int maxkeys;
  34   int prev_index;
  35 };
  36
  37 hash::hash ()
  38 {
  39   h = new hash_internals;
  40   h->numkeys = 0;
  41   h->maxkeys = 10;
  42   h->keys = (char **) malloc (h->maxkeys * sizeof (char *));
  43   h->prev_index = 0;
  44 }
  45
  46 hash::~hash ()
  47 {
  48   free (h->keys);
  49   delete h;
  50 }
  51
  52
  53 void
  54 hash::add (char const *string)
  55 {
  56   int i;
  57   for (i = 0; i < h->numkeys; i++)
  58     if (strcmp (h->keys[i], string) == 0)
  59       return;
  60   if (h->numkeys >= h->maxkeys)
  61     {
  62       h->maxkeys += 10;
  63       h->keys = (char **) realloc (h->keys, h->maxkeys * sizeof (char *));
  64     }
  65
  66   h->keys[h->numkeys] = new char[strlen(string) + 1];
  67   strcpy (h->keys[h->numkeys], string);
  68   h->numkeys++;
  69 }
  70
  71
  72 int
  73 hash::has (char const *string)
  74 {
  75   int i;
  76   for (i = 0; i < h->numkeys; i++)
  77     if (strcmp (h->keys[i], string) == 0)
  78       return 1;
  79   return 0;
  80 }
  81
  82 char *
  83 hash::enumerate (char const *prev)
  84 {
  85   if (prev == 0)
  86     h->prev_index = -1;
  87   h->prev_index++;
  88   if (h->prev_index >= h->numkeys)
  89     return 0;
  90   return h->keys[h->prev_index];
  91 }
  92
  93 static int
  94 rev_len (const void *va, const void *vb)
  95 {
  96   char *a = *(char **) va;
  97   char *b = *(char **) vb;
  98   return strcmp (b, a);
  99 }
 100
 101 void
 102 hash::reverse_sort ()
 103 {
 104   qsort (h->keys, h->numkeys, sizeof (h->keys[0]), rev_len);
 105 }