From 002fc568de07eae5f75e16846d4f2e68c0926748 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=89milie=20Feral?= <emilie.feral@numworks.com>
Date: Mon, 20 Nov 2017 16:15:41 +0100
Subject: [PATCH] [poincare] Fix division by zero

Change-Id: I644b70b58e6c2610681141158892668afc5a9c58
---
 poincare/src/arithmetic.cpp         | 3 +++
 poincare/src/division_quotient.cpp  | 3 +++
 poincare/src/division_remainder.cpp | 3 +++
 poincare/test/simplify_easy.cpp     | 2 ++
 4 files changed, 11 insertions(+)

diff --git a/poincare/src/arithmetic.cpp b/poincare/src/arithmetic.cpp
index 2d8df4bde..f5fe302d1 100644
--- a/poincare/src/arithmetic.cpp
+++ b/poincare/src/arithmetic.cpp
@@ -6,6 +6,9 @@ namespace Poincare {
 const Integer Arithmetic::k_primorial32("525896479052627740771371797072411912900610967452630");
 
 Integer Arithmetic::LCM(const Integer * a, const Integer * b) {
+  if (a->isZero() || b->isZero()) {
+    return Integer(0);
+  }
   Integer signResult = Integer::Division(Integer::Multiplication(*a, *b), GCD(a,b)).quotient;
   signResult.setNegative(false);
   return signResult;
diff --git a/poincare/src/division_quotient.cpp b/poincare/src/division_quotient.cpp
index 7f36ba10e..7565ba3e1 100644
--- a/poincare/src/division_quotient.cpp
+++ b/poincare/src/division_quotient.cpp
@@ -50,6 +50,9 @@ Expression * DivisionQuotient::shallowReduce(Context& context, AngleUnit angleUn
 
   Integer a = r0->numerator();
   Integer b = r1->numerator();
+  if (b.isZero()) {
+    return replaceWith(new Undefined(), true); // TODO: new Infinite(a.isNegative())
+  }
   Integer result = Integer::Division(a, b).quotient;
   return replaceWith(new Rational(result), true);
 }
diff --git a/poincare/src/division_remainder.cpp b/poincare/src/division_remainder.cpp
index 02caf8997..bac5e2760 100644
--- a/poincare/src/division_remainder.cpp
+++ b/poincare/src/division_remainder.cpp
@@ -50,6 +50,9 @@ Expression * DivisionRemainder::shallowReduce(Context& context, AngleUnit angleU
 
   Integer a = r0->numerator();
   Integer b = r1->numerator();
+  if (b.isZero()) {
+    return replaceWith(new Undefined(), true); // TODO: new Infinite(a.isNegative())
+  }
   Integer result = Integer::Division(a, b).remainder;
   return replaceWith(new Rational(result), true);
 }
diff --git a/poincare/test/simplify_easy.cpp b/poincare/test/simplify_easy.cpp
index 4c991296a..c33f81c2e 100644
--- a/poincare/test/simplify_easy.cpp
+++ b/poincare/test/simplify_easy.cpp
@@ -136,9 +136,11 @@ QUIZ_CASE(poincare_simplify_easy) {
   assert_parsed_expression_simplify_to("ceil(-1.3)", "-1");
   assert_parsed_expression_simplify_to("conj(1/2)", "1/2");
   assert_parsed_expression_simplify_to("quo(19,3)", "6");
+  assert_parsed_expression_simplify_to("quo(19,0)", "undef");
   assert_parsed_expression_simplify_to("quo(-19,3)", "-7");
   assert_parsed_expression_simplify_to("rem(19,3)", "1");
   assert_parsed_expression_simplify_to("rem(-19,3)", "2");
+  assert_parsed_expression_simplify_to("rem(19,0)", "undef");
   assert_parsed_expression_simplify_to("99!", "933262154439441526816992388562667004907159682643816214685929638952175999932299156089414639761565182862536979208272237582511852109168640000000000000000000000");
   assert_parsed_expression_simplify_to("floor(-1.3)", "-2");
   assert_parsed_expression_simplify_to("frac(-1.3)", "0.7");