engine/stringbucket.c

   1 /*
   2     stringbucket.c - MaLa stringbucket handling
   3
   4   Copyright (C) 2004, 2005, Christian Thaeter <chth@gmx.net>
   5
   6   This program is free software; you can redistribute it and/or modify
   7   it under the terms of the GNU General Public License version 2 as
   8   published by the Free Software Foundation.
   9
  10   This program is distributed in the hope that it will be useful,
  11   but WITHOUT ANY WARRANTY; without even the implied warranty of
  12   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13   GNU General Public License for more details.
  14
  15   You should have received a copy of the GNU General Public License
  16   along with this program; if not, contact me.
  17
  18 */
  19 \f
  20 #define _GNU_SOURCE
  21
  22 #include <stdlib.h>
  23 #include <search.h>
  24 #include "stringbucket.h"
  25 #include "strings.h"
  26
  27
  28 void mala_stringbucket_init (MalaStringBucket bucket,
  29                              mala_string_cmp_fn cmpfn,
  30                              void (*freefn)(void*))
  31 {
  32   bucket->bucket = NULL;
  33   bucket->cmpfn = cmpfn;
  34   bucket->freefn = freefn;
  35   bucket->destroying = 0;
  36 }
  37
  38
  39 static void
  40 twalk_stringdata_destroy (const void *nodep,
  41                           const VISIT which,
  42                           const int depth)
  43 {
  44   (void) depth;
  45   (void) which;
  46   mala_string_data_free (*(MalaString_ref)nodep);
  47 }
  48
  49
  50 void
  51 mala_stringbucket_erase (MalaStringBucket bucket)
  52 {
  53   bucket->destroying = 1;
  54
  55   /* it makes the string destructor a bit easier when we destroy data on a single pass */
  56   twalk (bucket->bucket, twalk_stringdata_destroy);
  57
  58   tdestroy (bucket->bucket, (void(*)(void*)) mala_string_free);
  59   bucket->bucket = NULL;
  60   bucket->destroying = 0;
  61 }
  62
  63
  64 int
  65 mala_stringbucket_exists_cstr (MalaStringBucket bucket, const char * cstr)
  66 {
  67   mala_string tmp = MALA_STRING_AUTO (cstr);
  68   return !!tfind (&tmp, &bucket->bucket, bucket->cmpfn);
  69 }
  70
  71 /*
  72  * remove string from bucket
  73  */
  74 MalaString
  75 mala_stringbucket_string_remove (MalaString_ref self)
  76 {
  77   MALA_ASSERT(self);
  78
  79   if (!(*self)->bucket)
  80     return *self;
  81
  82   /* self is the last reference in the bucket */
  83   if ((*self)->refcnt <= 8)
  84     {
  85       if ((*self)->user && (*self)->bucket->freefn)
  86         (*self)->bucket->freefn ((*self)->user);
  87       (*self)->user = NULL;
  88
  89       tdelete (*self, &(*self)->bucket->bucket, (*self)->bucket->cmpfn);
  90       (*self)->bucket = NULL;
  91
  92       /* buckets counted as reference too */
  93       (*self)->refcnt -= 4;
  94
  95       return *self;
  96     }
  97   else
  98     {
  99       /* make a new string */
 100       (*self)->refcnt -= 4;
 101       return *self = mala_string_new ((*self)->str, NULL);
 102     }
 103 }
 104
 105
 106 MalaString
 107 mala_stringbucket_insert (MalaStringBucket bucket, MalaString_ref s)
 108 {
 109   MalaString_ref loc;
 110
 111   /* no bucket */
 112   if (!bucket)
 113     return *s;
 114
 115   /* already in this bucket */
 116   if (bucket && (*s)->bucket == bucket)
 117     return *s;
 118
 119   /* in another bucket, remove it */
 120   if ((*s)->bucket)
 121     {
 122       mala_stringbucket_string_remove (s);
 123     }
 124
 125   /*create in bucket*/
 126   mala_string tmp = MALA_STRING_AUTO ((*s)->str);
 127
 128   /*create in bucket*/
 129   loc = (MalaString_ref) tsearch (&tmp, &bucket->bucket, bucket->cmpfn);
 130   if (!loc)
 131     return NULL;
 132
 133   if (*loc == &tmp)
 134     {
 135       /*not in bucket*/
 136       (*s)->bucket = bucket;
 137       *loc = *s;
 138     }
 139   else
 140     {
 141       /*string already in bucket*/
 142       mala_string_free (*s);
 143       *s = *loc;
 144     }
 145   (*s)->refcnt += 4;
 146   return *s;
 147 }
 148
 149
 150
 151 /*
 152 // Local Variables:
 153 // mode: C
 154 // c-file-style: "gnu"
 155 // End:
 156 // arch-tag: 84fbd8ab-4e90-4d04-ab70-d9b955dde41c
 157 // end_of_file
 158 */