From f9241bd7e6bc6cf7007e587bb9ac14f11dded0bf Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=89milie=20Feral?= <emilie.feral@numworks.com>
Date: Wed, 31 Jan 2018 13:32:14 +0100
Subject: [PATCH] [poincare] Decimal: writeTextInBuffer has to handle cases
 when the mantissa is too big to be serialize

---
 poincare/src/decimal.cpp                     | 14 +++++++++++---
 poincare/test/convert_expression_to_text.cpp |  2 ++
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/poincare/src/decimal.cpp b/poincare/src/decimal.cpp
index c81e7c199..0970c2550 100644
--- a/poincare/src/decimal.cpp
+++ b/poincare/src/decimal.cpp
@@ -125,17 +125,23 @@ int Decimal::writeTextInBuffer(char * buffer, int bufferSize, int numberOfSignif
     buffer[currentChar] = 0;
     return currentChar;
   }
+  char tempBuffer[200];
+  int mantissaLength = m_mantissa.writeTextInBuffer(tempBuffer, 200);
+  if (strcmp(tempBuffer, "undef") == 0) {
+    strlcpy(buffer, tempBuffer, bufferSize);
+    return mantissaLength;
+  }
   int nbOfDigitsInMantissaWithoutSign = numberOfDigitsInMantissaWithoutSign();
   int numberOfRequiredDigits = nbOfDigitsInMantissaWithoutSign > m_exponent ? nbOfDigitsInMantissaWithoutSign : m_exponent;
   numberOfRequiredDigits = m_exponent < 0 ? 1+nbOfDigitsInMantissaWithoutSign-m_exponent : numberOfRequiredDigits;
   /* Case 0: the number would be too long if we print it as a natural decimal */
   if (numberOfRequiredDigits > k_maxLength) {
     if (nbOfDigitsInMantissaWithoutSign == 1) {
-      currentChar +=m_mantissa.writeTextInBuffer(buffer, bufferSize);
+      currentChar += strlcpy(buffer, tempBuffer, bufferSize);
     } else {
       currentChar++;
       if (currentChar >= bufferSize-1) { return bufferSize-1; }
-      currentChar += m_mantissa.writeTextInBuffer(buffer+currentChar, bufferSize-currentChar);
+      currentChar += strlcpy(buffer+currentChar, tempBuffer, bufferSize-currentChar);
       int decimalMarkerPosition = 1;
       if (buffer[1] == '-') {
         decimalMarkerPosition++;
@@ -153,6 +159,8 @@ int Decimal::writeTextInBuffer(char * buffer, int bufferSize, int numberOfSignif
     return currentChar;
   }
   /* Case 2: Print a natural decimal number */
+  int deltaCharMantissa = m_exponent < 0 ? -m_exponent+1 : 0;
+  strlcpy(buffer+deltaCharMantissa, tempBuffer, bufferSize-deltaCharMantissa);
   if (m_mantissa.isNegative()) {
     buffer[currentChar++] = '-';
   }
@@ -176,7 +184,7 @@ int Decimal::writeTextInBuffer(char * buffer, int bufferSize, int numberOfSignif
     tempChar = buffer[currentChar];
     tempCharPosition = currentChar;
   }
-  currentChar += m_mantissa.writeTextInBuffer(buffer+currentChar, bufferSize-currentChar);
+  currentChar += mantissaLength;
   if (m_mantissa.isNegative()) { // replace the temp char back
     buffer[tempCharPosition] = tempChar;
   }
diff --git a/poincare/test/convert_expression_to_text.cpp b/poincare/test/convert_expression_to_text.cpp
index 74553c432..ab4e483d1 100644
--- a/poincare/test/convert_expression_to_text.cpp
+++ b/poincare/test/convert_expression_to_text.cpp
@@ -164,6 +164,8 @@ QUIZ_CASE(poincare_decimal_to_text) {
   assert_expression_prints_to(&e14, "9.99999999999995E-7");
   Decimal e15(0.0000009999999999999995);
   assert_expression_prints_to(&e15, "0.000001");
+  Decimal e16(0.0000009999999999901200121020102010201201201021099995);
+  assert_expression_prints_to(&e16, "9.9999999999012E-7");
 }
 
 QUIZ_CASE(poincare_complex_to_text) {