From 54e38c692a94b52b8c7ee37bb50089f759905eae Mon Sep 17 00:00:00 2001
From: Corentin Le Molgat <corentinl@google.com>
Date: Thu, 27 Dec 2018 16:47:59 +0100
Subject: [PATCH] .Net: Add support for delegate function as TransitCallback
 (Fix #997)

---
 .../constraint_solver/csharp/SolverHelper.cs   |  3 +++
 ortools/constraint_solver/csharp/routing.i     | 11 +++++++++++
 .../constraint_solver/csharp/routing_types.i   | 18 ++++++++++++++++++
 3 files changed, 32 insertions(+)

diff --git a/ortools/constraint_solver/csharp/SolverHelper.cs b/ortools/constraint_solver/csharp/SolverHelper.cs
index d2ac15e88f..87fc0af371 100644
--- a/ortools/constraint_solver/csharp/SolverHelper.cs
+++ b/ortools/constraint_solver/csharp/SolverHelper.cs
@@ -15,6 +15,9 @@ namespace Google.OrTools.ConstraintSolver {
 using System;
 using System.Collections.Generic;
 
+public delegate long TransitCallback(long FromIndex, long ToIndex);
+public delegate long UnaryTransitCallback(long FromIndex);
+
 public partial class Solver : IDisposable {
   public IntVar[] MakeIntVarArray(int count, long min, long max) {
     IntVar[] array = new IntVar[count];
diff --git a/ortools/constraint_solver/csharp/routing.i b/ortools/constraint_solver/csharp/routing.i
index 2ffc876aaf..f2d1c85f86 100644
--- a/ortools/constraint_solver/csharp/routing.i
+++ b/ortools/constraint_solver/csharp/routing.i
@@ -77,6 +77,17 @@ class RoutingSearchParameters;
     self->AddVectorDimension(values.data(), capacity,
                              fix_start_cumul_to_zero, name);
   }
+
+ int RegisterTransitCallback(operations_research::TransitCallback c) {
+   return $self->RegisterTransitCallback([c](int64 i, int64 j) {
+       return (*c)(i, j);
+       });
+ }
+ int RegisterUnaryTransitCallback(operations_research::UnaryTransitCallback c) {
+   return $self->RegisterUnaryTransitCallback([c](int64 i) {
+       return (*c)(i);
+       });
+ }
 }
 
 %rename("%(camelcase)s", %$isfunction) "";
diff --git a/ortools/constraint_solver/csharp/routing_types.i b/ortools/constraint_solver/csharp/routing_types.i
index af0e2ae985..8f2f9f6bbb 100644
--- a/ortools/constraint_solver/csharp/routing_types.i
+++ b/ortools/constraint_solver/csharp/routing_types.i
@@ -77,3 +77,21 @@ DEFINE_INDEX_TYPE(operations_research::RoutingDisjunctionIndex);
 DEFINE_INDEX_TYPE(operations_research::RoutingVehicleClassIndex);
 
 %include "ortools/constraint_solver/routing_types.h"
+
+%{
+namespace operations_research {
+ typedef int64 (*TransitCallback)(int64, int64);
+ typedef int64 (*UnaryTransitCallback)(int64);
+}  // namespace operations_research
+%}
+
+%define %DEFINE_CALLBACK(TYPE, CSTYPE)
+  %typemap(ctype) TYPE, TYPE& "void*"
+  %typemap(in) TYPE  %{ $1 = (TYPE)$input; %}
+  %typemap(in) TYPE& %{ $1 = (TYPE*)&$input; %}
+  %typemap(imtype, out="IntPtr") TYPE, TYPE& "CSTYPE"
+  %typemap(cstype, out="IntPtr") TYPE, TYPE& "CSTYPE"
+  %typemap(csin) TYPE, TYPE& "$csinput"
+%enddef
+%DEFINE_CALLBACK(operations_research::TransitCallback, TransitCallback)
+%DEFINE_CALLBACK(operations_research::UnaryTransitCallback, UnaryTransitCallback)