From 05452d0c45fdf2c00541a9db7a0923590a565646 Mon Sep 17 00:00:00 2001
From: Jiri Vlasak <hubacji1@fel.cvut.cz>
Date: Mon, 13 Jan 2020 09:36:05 +0100
Subject: [PATCH] Add perfect parking slot length computation

---
 api/bcar.h  |  6 ++++++
 src/bcar.cc | 20 ++++++++++++++++++++
 2 files changed, 26 insertions(+)

diff --git a/api/bcar.h b/api/bcar.h
index 836f725..716adab 100644
--- a/api/bcar.h
+++ b/api/bcar.h
@@ -77,6 +77,12 @@ class BicycleCar {
                 the rear (from the rear axle view) part of the car.
                 */
                 double orradi() const;
+                /*! \brief Return length of perfect parking slot.
+
+                The width of the slot is the same as the width of the
+                car.
+                */
+                double perfect_parking_slot_len() const;
                 /*! \brief Set maximum steering angle.
                 */
                 void set_max_steer();
diff --git a/src/bcar.cc b/src/bcar.cc
index a882488..a161a00 100644
--- a/src/bcar.cc
+++ b/src/bcar.cc
@@ -34,6 +34,26 @@ double BicycleCar::orradi() const
         return sqrt(pow(this->mtr() + this->w() / 2, 2) + pow(this->dr(), 2));
 }
 
+double BicycleCar::perfect_parking_slot_len() const
+{
+        // see Simon R. Blackburn *The Geometry of Perfect Parking*
+        // see https://www.ma.rhul.ac.uk/SRBparking
+        double r = this->ctc() / 2;
+        double l = this->wb();
+        double k = this->df() - this->wb();
+        double w = this->w();
+        return
+                this->l()
+                + sqrt(
+                        (r*r - l*l)
+                        + pow(l + k, 2)
+                        - pow(sqrt(r*r - l*l) - w, 2)
+                )
+                - l
+                - k
+        ;
+}
+
 void BicycleCar::set_max_steer()
 {
         this->st(asin(this->wb() / (10.82 / 2)));
-- 
2.39.2