Work on dict_compact routine.

[idzebra-moved-to-github.git] / dict / lookup.c

diff --git a/dict/lookup.c b/dict/lookup.c
index 0cb2260..b7dd51c 100644 (file)
--- a/dict/lookup.c
+++ b/dict/lookup.c
@@ -1,10 +1,35 @@
 /*
- * Copyright (C) 1994, Index Data I/S 
+ * Copyright (C) 1994-1999, Index Data
  * All rights reserved.
  * Sebastian Hammer, Adam Dickmeiss
  *
  * $Log: lookup.c,v $
- * Revision 1.1  1994-08-16 16:26:48  adam
+ * Revision 1.9  1999-02-02 14:50:25  adam
+ * Updated WIN32 code specific sections. Changed header.
+ *
+ * Revision 1.8  1998/03/05 08:17:24  adam
+ * Added a few comments - no code changed.
+ *
+ * Revision 1.7  1996/02/02 13:43:51  adam
+ * The public functions simply use char instead of Dict_char to represent
+ * search strings. Dict_char is used internally only.
+ *
+ * Revision 1.6  1995/12/11  09:04:50  adam
+ * Bug fix: the lookup/scan/lookgrep didn't handle empty dictionary.
+ *
+ * Revision 1.5  1995/09/04  09:09:15  adam
+ * String arg in lookup is const.
+ *
+ * Revision 1.4  1994/10/05  12:16:51  adam
+ * Pagesize is a resource now.
+ *
+ * Revision 1.3  1994/09/26  10:17:25  adam
+ * Minor changes.
+ *
+ * Revision 1.2  1994/09/16  15:39:14  adam
+ * Initial code of lookup - not tested yet.
+ *
+ * Revision 1.1  1994/08/16  16:26:48  adam
  * Added dict.
  *
  */
@@ -16,9 +41,81 @@
 
 #include <dict.h>
 
-int dict_lookup (Dict dict, Dict_char *p)
+static char *dict_look (Dict dict, const Dict_char *str)
+{
+    Dict_ptr ptr = 1;
+    int mid, lo, hi;
+    int cmp;
+    void *p;
+    short *indxp;
+    char *info;
+
+    dict_bf_readp (dict->dbf, ptr, &p);
+    mid = lo = 0;
+    hi = DICT_nodir(p)-1;
+    indxp = (short*) ((char*) p+DICT_pagesize(dict)-sizeof(short));    
+    while (lo <= hi)
+    {
+        mid = (lo+hi)/2;
+        if (indxp[-mid] > 0)
+        {
+            /* string (Dict_char *) DICT_EOS terminated */
+            /* unsigned char        length of information */
+            /* char *               information */
+            info = (char*)p + indxp[-mid];
+            cmp = dict_strcmp((Dict_char*) info, str);
+            if (!cmp)
+                return info+(dict_strlen ((Dict_char*) info)+1)
+                    *sizeof(Dict_char);
+        }
+        else
+        {
+            Dict_char dc;
+            Dict_ptr subptr;
+
+            /* Dict_ptr             subptr */
+            /* Dict_char            sub char */
+            /* unsigned char        length of information */
+            /* char *               information */
+            info = (char*)p - indxp[-mid];
+            memcpy (&dc, info+sizeof(Dict_ptr), sizeof(Dict_char));
+            cmp = dc- *str;
+            if (!cmp)
+            {
+                memcpy (&subptr, info, sizeof(Dict_ptr));
+                if (*++str == DICT_EOS)
+                {
+                    if (info[sizeof(Dict_ptr)+sizeof(Dict_char)])
+                        return info+sizeof(Dict_ptr)+sizeof(Dict_char);
+                    return NULL;
+                }
+                else
+                {
+                    if (subptr == 0)
+                        return NULL;
+                    ptr = subptr;
+                    dict_bf_readp (dict->dbf, ptr, &p);
+                    mid = lo = 0;
+                    hi = DICT_nodir(p)-1;
+                    indxp = (short*) ((char*) p+DICT_pagesize(dict)
+                                      -sizeof(short));
+                    continue;
+                }
+            }
+        }
+        if (cmp < 0)
+            lo = mid+1;
+        else
+            hi = mid-1;
+    }
+    return NULL;
+}
+
+char *dict_lookup (Dict dict, const char *p)
 {
-    return 0;
+    if (dict->head.last <= 1)
+        return NULL;
+    return dict_look (dict, (const Dict_char *) p);
 }