From 50a2ebfb1e98c702fe3cfed51056a547152586c6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Motiejus=20Jak=C5=A1tys?= <motiejus@uber.com>
Date: Thu, 18 Feb 2021 10:00:14 +0200
Subject: [PATCH] bends are arrays now

---
 IV/tests.sql | 9 +++++++--
 IV/wm.sql    | 8 +++++---
 2 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/IV/tests.sql b/IV/tests.sql
index 36bee92..6cbad3b 100644
--- a/IV/tests.sql
+++ b/IV/tests.sql
@@ -18,7 +18,12 @@ insert into figures (name, way) values ('fig3-1', ST_GeomFromText('LINESTRING(0
 insert into figures (name, way) values ('fig5', ST_GeomFromText('LINESTRING(0 39,19 52,27 77,26 104,41 115,49 115,65 103,65 75,53 45,63 15,91 0,91 0)'));
 
 do $$
+declare
+  bends geometry[];
 begin
-  perform assert_equals(3::bigint, (select count(1) from detect_bends((select way from figures where name='fig3'))));
-  perform assert_equals(3::bigint, (select count(1) from detect_bends((select way from figures where name='fig3-1'))));
+  perform assert_equals(3, array_length(detect_bends((select way from figures where name='fig3')), 1));
+  perform assert_equals(3, array_length(detect_bends((select way from figures where name='fig3-1')), 1));
+
+  select detect_bends((select way from figures where name='fig5')) into bends;
+  perform assert_equals(2, array_length(bends, 1));
 end $$ language plpgsql;
diff --git a/IV/wm.sql b/IV/wm.sql
index 5cd9bf8..92f8be1 100644
--- a/IV/wm.sql
+++ b/IV/wm.sql
@@ -1,14 +1,16 @@
 \set ON_ERROR_STOP on
 SET plpgsql.extra_errors TO 'all';
 
+drop function if exists detect_bends;
 -- detect_bends detects bends using the inflection angles. It does not do corrections.
-create or replace function detect_bends(line geometry) returns table(bend geometry) as $$
+create or replace function detect_bends(line geometry, OUT bends geometry[]) as $$
 declare
   pi real;
   p geometry;
   p1 geometry;
   p2 geometry;
   p3 geometry;
+  bend geometry;
   prev_sign int4;
   cur_sign int4;
 begin
@@ -27,7 +29,7 @@ begin
 
     if prev_sign + cur_sign = 0 then
       if bend is not null then
-        return next;
+        bends = bends || bend;
       end if;
       bend = st_makeline(p3, p2);
     end if;
@@ -38,7 +40,7 @@ begin
   -- to avoid that, return the last bend if the last accumulation has >3
   -- vertices.
   if (select count(1) from ((select st_dumppoints(bend) as a)) b) >= 3 then
-    return next;
+    bends = bends || bend;
   end if;
 end
 $$ language plpgsql;