setting up parent and child.

include/r3.h

@@ -66,7 +66,11 @@ struct _node {
 struct _edge {
     char * pattern;
     int    pattern_len;
+
+    /* the child node */
     node * child;
+    /* the parent node */
+    node * parent;
     uint64_t         hits;
     float            score;
     bool             has_slug:1;

src/edge.c

@@ -29,6 +29,7 @@ edge * r3_edge_create(char * pattern, int pattern_len, node * child) {
     e->pattern = pattern;
     e->pattern_len = pattern_len;
     e->child = child;
+    e->parent = NULL;
 
     // update childs parent edge
     child->parent_edge = e;
@@ -61,8 +62,10 @@ node * r3_edge_branch(edge *e, int dl) {
 
     // the suffix edge of the leaf
     new_child = r3_tree_create(3);
-    s1_len = e->pattern_len - dl;
-    e1 = r3_edge_create(zstrndup(s1, s1_len), s1_len, new_child);
+    s1_len    = e->pattern_len - dl;
+
+    /* create the parent edge of new child */
+    e1        = r3_edge_create(zstrndup(s1, s1_len), s1_len, new_child);
 
     // Migrate the child edges to the new edge we just created.
     for ( int i = 0 ; i < tmp_edge_len ; i++ ) {

src/node.c

@@ -129,6 +129,8 @@ void r3_node_append_edge(node *n, edge *e) {
             n->edges = p;
         }
     }
+    // when append new edge, we update the parent node of the edge.
+    e->parent = n;
     n->edges[ n->edge_len++ ] = e;
 }
 
@@ -557,6 +559,10 @@ void r3_tree_dump(node * n, int level) {
         printf(" regexp:%s", n->combined_pattern);
     }
 
+    if ( n->parent_edge ) {
+        printf(" belongs to edge:%p", n->parent_edge);
+    }
+
     printf(" endpoint:%d", n->endpoint);
 
     if (n->data) {

tests/bench_str.csv

@@ -445,3 +445,5 @@
 1400685490,13185955.87
 1400748100,12609470.07
 1400748288,13317009.48
+1400748727,12973679.22
+1400748826,12902583.84