cleaned up the Trie code a bit by unifying retrieval into one internal function

--HG--
extra : convert_revision : svn%3A39bc706e-5318-0410-9160-8a85361fbb7c/trunk%401390

core/sm_trie.cpp

@@ -107,13 +107,6 @@
  *    This would drastically speed up x_check*
  */
 
-enum NodeType
-{
-	Node_Unused = 0,		/* Node is not being used (sparse) */
-	Node_Arc,				/* Node is part of an arc and does not terminate */
-	Node_Term,				/* Node is a terminator */
-};
-
 struct TrieNode
 {
 	/**
@@ -303,7 +296,7 @@ void sm_trie_destroy(Trie *trie)
 	delete trie;
 }
 
-bool sm_trie_delete(Trie *trie, const char *key)
+TrieNode *sm_trie_internal_retrieve(Trie *trie, const char *key)
 {
 	unsigned int lastidx = 1;		/* the last node index */
 	unsigned int curidx;			/* current node index */
@@ -313,7 +306,7 @@ bool sm_trie_delete(Trie *trie, const char *key)
 
 	if (!*key)
 	{
-		return false;
+		return NULL;
 	}
 
 	/* Start traversing at the root node */
@@ -329,7 +322,7 @@ bool sm_trie_delete(Trie *trie, const char *key)
 		/* Check if this slot is supposed to be empty or is a collision */
 		if ((curidx > trie->baseSize) || node->mode == Node_Unused || node->parent != lastidx)
 		{
-			return false;
+			return NULL;
 		} else if (node->mode == Node_Term) {
 			char *term = &trie->stringtab[node->idx];
 			if (strcmp(keyptr, term) == 0)
@@ -340,59 +333,27 @@ bool sm_trie_delete(Trie *trie, const char *key)
 		lastidx = curidx;
 	} while (*keyptr != '\0');
 
-	assert(node != NULL);
+	return node;
+}
 
-	if (!node->valset)
+bool sm_trie_delete(Trie *trie, const char *key)
+{
+	TrieNode *node = sm_trie_internal_retrieve(trie, key);
+	if (!node || !node->valset)
 	{
 		return false;
 	}
 
-	node->valset = false;
 	node->value = NULL;
+	node->valset = false;
 
 	return true;
 }
 
 bool sm_trie_retrieve(Trie *trie, const char *key, void **value)
 {
-	unsigned int lastidx = 1;		/* the last node index */
+	TrieNode *node = sm_trie_internal_retrieve(trie, key);
-	unsigned int curidx;			/* current node index */
+	if (!node || !node->valset)
-	const char *keyptr = key;		/* input stream at current token */
-	TrieNode *node = NULL;			/* current node being processed */
-	TrieNode *base = trie->base;
-
-	if (!*key)
-	{
-		return false;
-	}
-
-	/* Start traversing at the root node */
-	do
-	{
-		/* Find where the next character is, then advance */
-		curidx = base[lastidx].idx;
-		node = &base[curidx];
-		curidx += charval(*keyptr);
-		node = &base[curidx];
-		keyptr++;
-
-		/* Check if this slot is supposed to be empty or is a collision */
-		if ((curidx > trie->baseSize) || node->mode == Node_Unused || node->parent != lastidx)
-		{
-			return false;
-		} else if (node->mode == Node_Term) {
-			char *term = &trie->stringtab[node->idx];
-			if (strcmp(keyptr, term) == 0)
-			{
-				break;
-			}
-		}
-		lastidx = curidx;
-	} while (*keyptr != '\0');
-
-	assert(node != NULL);
-
-	if (!node->valset)
 	{
 		return false;
 	}
@@ -405,7 +366,7 @@ bool sm_trie_retrieve(Trie *trie, const char *key, void **value)
 	return true;
 }
 
-bool sm_trie_add(Trie *trie, const char *key, void *value, bool replace_allowed)
+bool sm_trie_insert(Trie *trie, const char *key, void *value)
 {
 	unsigned int lastidx = 1;		/* the last node index */
 	unsigned int curidx;			/* current node index */
@@ -650,7 +611,7 @@ bool sm_trie_add(Trie *trie, const char *key, void *value, bool replace_allowed)
 				/* Do an initial browsing to make sure they're not the same string */
 				if (strcmp(keyptr, term) == 0)
 				{
-					if (!node->valset || replace_allowed)
+					if (!node->valset)
 					{
 						node->valset = true;
 						node->value = value;
@@ -830,7 +791,7 @@ bool sm_trie_add(Trie *trie, const char *key, void *value, bool replace_allowed)
 	 */
 	assert(node->mode == Node_Arc);
 
-	if (!node->valset || replace_allowed)
+	if (!node->valset)
 	{
 		/* Insert is only possible if we have no production */
 		node->valset = true;
@@ -841,12 +802,16 @@ bool sm_trie_add(Trie *trie, const char *key, void *value, bool replace_allowed)
 	return false;
 }
 
-bool sm_trie_insert(Trie *trie, const char *key, void *value)
-{
-	return sm_trie_add(trie, key, value, false);
-}
-
 bool sm_trie_replace(Trie *trie, const char *key, void *value)
 {
-	return sm_trie_add(trie, key, value, true);
+	TrieNode *node = sm_trie_internal_retrieve(trie, key);
+	if (!node)
+	{
+		return sm_trie_insert(trie, key, value);
+	}
+
+	node->value = value;
+	node->valset = true;
+
+	return true;
 }

core/sm_trie.h

@@ -34,6 +34,13 @@
 
 struct Trie;
 
+enum NodeType
+{
+	Node_Unused = 0,		/* Node is not being used (sparse) */
+	Node_Arc,				/* Node is part of an arc and does not terminate */
+	Node_Term,				/* Node is a terminator */
+};
+
 Trie *sm_trie_create();
 void sm_trie_destroy(Trie *trie);
 bool sm_trie_insert(Trie *trie, const char *key, void *value);