[svn r5] Initial commit. Most things are very rough.

dmd/stringtable.c

@@ -0,0 +1,139 @@
+
+// Copyright (c) 1999-2006 by Digital Mars
+// All Rights Reserved
+// written by Walter Bright
+// www.digitalmars.com
+// License for redistribution is by either the Artistic License
+// in artistic.txt, or the GNU General Public License in gnu.txt.
+// See the included readme.txt for details.
+
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+#include "root.h"
+#include "mem.h"
+#include "dchar.h"
+#include "lstring.h"
+#include "stringtable.h"
+
+StringTable::StringTable(unsigned size)
+{
+    table = (void **)mem.calloc(size, sizeof(void *));
+    tabledim = size;
+    count = 0;
+}
+
+StringTable::~StringTable()
+{
+    unsigned i;
+
+    // Zero out dangling pointers to help garbage collector.
+    // Should zero out StringEntry's too.
+    for (i = 0; i < count; i++)
+	table[i] = NULL;
+
+    mem.free(table);
+    table = NULL;
+}
+
+struct StringEntry
+{
+    StringEntry *left;
+    StringEntry *right;
+    hash_t hash;
+
+    StringValue value;
+
+    static StringEntry *alloc(const dchar *s, unsigned len);
+};
+
+StringEntry *StringEntry::alloc(const dchar *s, unsigned len)
+{
+    StringEntry *se;
+
+    se = (StringEntry *) mem.calloc(1,sizeof(StringEntry) - sizeof(Lstring) + Lstring::size(len));
+    se->value.lstring.length = len;
+    se->hash = Dchar::calcHash(s,len);
+    memcpy(se->value.lstring.string, s, len * sizeof(dchar));
+    return se;
+}
+
+void **StringTable::search(const dchar *s, unsigned len)
+{
+    hash_t hash;
+    unsigned u;
+    int cmp;
+    StringEntry **se;
+
+    //printf("StringTable::search(%p,%d)\n",s,len);
+    hash = Dchar::calcHash(s,len);
+    u = hash % tabledim;
+    se = (StringEntry **)&table[u];
+    //printf("\thash = %d, u = %d\n",hash,u);
+    while (*se)
+    {
+	cmp = (*se)->hash - hash;
+	if (cmp == 0)
+	{
+	    cmp = (*se)->value.lstring.len() - len;
+	    if (cmp == 0)
+	    {
+		cmp = Dchar::memcmp(s,(*se)->value.lstring.toDchars(),len);
+		if (cmp == 0)
+		    break;
+	    }
+	}
+	if (cmp < 0)
+	    se = &(*se)->left;
+	else
+	    se = &(*se)->right;
+    }
+    //printf("\treturn %p, %p\n",se, (*se));
+    return (void **)se;
+}
+
+StringValue *StringTable::lookup(const dchar *s, unsigned len)
+{   StringEntry *se;
+
+    se = *(StringEntry **)search(s,len);
+    if (se)
+	return &se->value;
+    else
+	return NULL;
+}
+
+StringValue *StringTable::update(const dchar *s, unsigned len)
+{   StringEntry **pse;
+    StringEntry *se;
+
+    pse = (StringEntry **)search(s,len);
+    se = *pse;
+    if (!se)			// not in table: so create new entry
+    {
+	se = StringEntry::alloc(s, len);
+	*pse = se;
+    }
+    return &se->value;
+}
+
+StringValue *StringTable::insert(const dchar *s, unsigned len)
+{   StringEntry **pse;
+    StringEntry *se;
+
+    pse = (StringEntry **)search(s,len);
+    se = *pse;
+    if (se)
+	return NULL;		// error: already in table
+    else
+    {
+	se = StringEntry::alloc(s, len);
+	*pse = se;
+    }
+    return &se->value;
+}
+
+
+
+