From 811453d2fb29f5d584f1c2a31ccca9e2f8135e36 Mon Sep 17 00:00:00 2001
From: peter <petrel.harp@gmail.com>
Date: Wed, 2 Aug 2023 22:11:23 -0700
Subject: [PATCH] only have one edge table around

---
 c/tskit/tables.c | 37 +++++++++++++++++--------------------
 1 file changed, 17 insertions(+), 20 deletions(-)

diff --git a/c/tskit/tables.c b/c/tskit/tables.c
index c6107fb9ba..202c283c7d 100644
--- a/c/tskit/tables.c
+++ b/c/tskit/tables.c
@@ -12420,6 +12420,10 @@ forward_extend(tsk_table_collection_t *self, int direction)
     if (ret != 0) {
         goto out;
     }
+    ret = tsk_edge_table_clear(&self->edges);
+    if (ret != 0) {
+        goto out;
+    }
 
     ret = tsk_blkalloc_init(&edge_list_heap, 8192);
     if (ret != 0) {
@@ -12431,8 +12435,8 @@ forward_extend(tsk_table_collection_t *self, int direction)
         here = 0;
         sign = 1;
         sign_int = 1;
-        near_side = self->edges.left;
-        far_side = self->edges.right;
+        near_side = edges.left;
+        far_side = edges.right;
         tj = 0;
         tk = 0;
     } else {
@@ -12441,12 +12445,11 @@ forward_extend(tsk_table_collection_t *self, int direction)
         here = self->sequence_length;
         sign = -1;
         sign_int = -1;
-        near_side = self->edges.right;
-        far_side = self->edges.left;
+        near_side = edges.right;
+        far_side = edges.left;
         tj = M - 1;
         tk = M - 1;
     }
-    left = 0;
     edges_in_head = NULL;
     edges_in_tail = NULL;
     edges_out_head = NULL;
@@ -12470,8 +12473,8 @@ forward_extend(tsk_table_collection_t *self, int direction)
                 y->next = x;
             }
             edges_out_tail = x;
-            num_edges[self->edges.parent[O[tk]]] -= 1;
-            num_edges[self->edges.child[O[tk]]] -= 1;
+            num_edges[edges.parent[O[tk]]] -= 1;
+            num_edges[edges.child[O[tk]]] -= 1;
             tk += sign_int;
         }
         while (((tj < M) && (tj >= 0)) && (near_side[I[tj]] == here)) {
@@ -12488,8 +12491,8 @@ forward_extend(tsk_table_collection_t *self, int direction)
                 y->next = x;
             }
             edges_in_tail = x;
-            num_edges[self->edges.parent[I[tj]]] += 1;
-            num_edges[self->edges.child[I[tj]]] += 1;
+            num_edges[edges.parent[I[tj]]] += 1;
+            num_edges[edges.child[I[tj]]] += 1;
             tj += sign_int;
         }
         there = forwards ? self->sequence_length : 0;
@@ -12516,16 +12519,14 @@ forward_extend(tsk_table_collection_t *self, int direction)
                 for (ex2 = edges_out_head; ex2 != NULL; ex2 = ex2->next) {
                     if (!ex2->extended) {
                         e2 = ex2->edge;
-                        if ((self->edges.parent[e1] == self->edges.child[e2])
-                            && (num_edges[self->edges.child[e2]] == 0)) {
+                        if ((edges.parent[e1] == edges.child[e2])
+                            && (num_edges[edges.child[e2]] == 0)) {
                             for (ex_in = edges_in_head; ex_in != NULL;
                                  ex_in = ex_in->next) {
                                 e_in = ex_in->edge;
                                 if (sign * far_side[e_in] > sign * here) {
-                                    if ((self->edges.child[e1]
-                                            == self->edges.child[e_in])
-                                        && (self->edges.parent[e2]
-                                            == self->edges.parent[e_in])) {
+                                    if ((edges.child[e1] == edges.child[e_in])
+                                        && (edges.parent[e2] == edges.parent[e_in])) {
                                         ex1->extended = true;
                                         ex2->extended = true;
                                         ex_in->extended = true;
@@ -12538,7 +12539,7 @@ forward_extend(tsk_table_collection_t *self, int direction)
                                             edges.left[e2] = there;
                                             edges.right[e_in] = there;
                                         }
-                                        num_edges[self->edges.parent[e1]] += 2;
+                                        num_edges[edges.parent[e1]] += 2;
                                     }
                                 }
                             }
@@ -12552,10 +12553,6 @@ forward_extend(tsk_table_collection_t *self, int direction)
     }
 
     // done! write out new edge tables
-    ret = tsk_edge_table_clear(&self->edges);
-    if (ret != 0) {
-        goto out;
-    }
     for (tj = 0; tj < (tsk_id_t) edges.num_rows; tj++) {
         tsk_edge_table_get_row_unsafe(&edges, tj, &edge);
         if (edge.left < edge.right) {