fix rbt traversal.

lib/bcoin/rbt.js

@@ -479,24 +479,13 @@ RBT.prototype.snapshot = function snapshot() {
  */
 
 RBT.prototype.traverse = function traverse(test) {
-  var current = this.root;
-  var stack = [];
+  var current = this.min(this.root);
   var items = [];
 
-  for (;;) {
-    if (!current.isNull()) {
-      if (test(current))
-        items.push(current.copy());
-      stack.push(current);
-      current = current.left;
-      continue;
-    }
-
-    if (stack.length === 0)
-      break;
-
-    current = stack.pop();
-    current = current.right;
+  while (!current.isNull()) {
+    if (test(current))
+      items.push(current.copy());
+    current = this.successor(current);
   }
 
   return items;
@@ -519,8 +508,8 @@ RBT.prototype.dump = function dump() {
  */
 
 RBT.prototype.range = function range(gte, lte) {
-  var current = this.root;
-  var stack = [];
+  var root = this.root;
+  var current = SENTINEL;
   var items = [];
   var cmp;
 
@@ -530,63 +519,44 @@ RBT.prototype.range = function range(gte, lte) {
   if (typeof lte === 'string')
     lte = new Buffer(lte, 'ascii');
 
-  for (;;) {
-    if (!current.isNull()) {
-      cmp = this.rangeCompare(current.key, gte, lte);
+  if (gte) {
+    // Find the node closest to our gte key.
+    while (!root.isNull()) {
+      cmp = this.compare(gte, root.key);
+
       if (cmp === 0) {
-        items.push(current.copy());
-        stack.push(current);
+        current = root;
+        break;
       }
-      if (cmp <= 0)
-        current = current.left;
-      else
-        current = current.right;
-      continue;
+
+      if (cmp < 0) {
+        current = root;
+        root = root.left;
+      } else {
+        root = root.right;
+      }
+    }
+  } else {
+    // Descend into the left subtree.
+    current = this.min(root);
+  }
+
+  // Walk the tree in order.
+  while (!current.isNull()) {
+    if (lte) {
+      // Stop once we hit a key above our lte key.
+      cmp = this.compare(current.key, lte);
+      if (cmp > 0)
+        break;
     }
 
-    if (stack.length === 0)
-      break;
-
-    current = stack.pop();
-    current = current.right;
+    items.push(current.copy());
+    current = this.successor(current);
   }
 
   return items;
 };
 
-/**
- * Comparator for {@link RBT#range}.
- * @param {Buffer} key
- * @param {Buffer} gteKey
- * @param {Buffer} lteKey
- * @returns {Number}
- */
-
-RBT.prototype.rangeCompare = function rangeCompare(key, gteKey, lteKey) {
-  var gte, lte;
-
-  if (gteKey)
-    gte = this.compare(key, gteKey);
-  else
-    gte = 0;
-
-  if (lteKey)
-    lte = this.compare(key, lteKey);
-  else
-    lte = 0;
-
-  if (gte >= 0 && lte <= 0)
-    return 0;
-
-  if (lte > 0)
-    return -1;
-
-  if (gte < 0)
-    return 1;
-
-  assert(false);
-};
-
 /**
  * Open the database (leveldown method).
  * @param {Object?} options