From 3cedfb84e94d20f5cdf6313eec8dbca975850fec Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=89milie=20Feral?= <emilie.feral@numworks.com>
Date: Fri, 12 Oct 2018 09:37:53 +0200
Subject: [PATCH] [shared] StorageCartesianFunction: add a method
 derivativeNameWithArgument

---
 apps/shared/storage_cartesian_function.cpp | 13 +++++++++++++
 apps/shared/storage_cartesian_function.h   |  1 +
 2 files changed, 14 insertions(+)

diff --git a/apps/shared/storage_cartesian_function.cpp b/apps/shared/storage_cartesian_function.cpp
index 55db2760a..b70ff1249 100644
--- a/apps/shared/storage_cartesian_function.cpp
+++ b/apps/shared/storage_cartesian_function.cpp
@@ -46,6 +46,19 @@ StorageCartesianFunction StorageCartesianFunction::NewModel(Ion::Storage::Record
   return StorageCartesianFunction(Ion::Storage::sharedStorage()->recordNamed(nameBuffer));
 }
 
+int StorageCartesianFunction::derivativeNameWithArgument(char * buffer, size_t bufferSize, char arg) {
+  // Fill buffer with f(x). Keep one char for derivative sign.
+  int numberOfChars = nameWithArgument(buffer, bufferSize-1, arg);
+  assert(numberOfChars < bufferSize - 1);
+  char * lastChar = buffer+numberOfChars;
+  while (*(lastChar+1) != '(' && lastChar >= buffer) {
+    *(lastChar+1) = *lastChar;
+    lastChar--;
+  }
+  *lastChar = '\'';
+  return numberOfChars+1;
+}
+
 bool StorageCartesianFunction::displayDerivative() const {
   return recordData()->displayDerivative();
 }
diff --git a/apps/shared/storage_cartesian_function.h b/apps/shared/storage_cartesian_function.h
index a62d54e0f..e3d221e18 100644
--- a/apps/shared/storage_cartesian_function.h
+++ b/apps/shared/storage_cartesian_function.h
@@ -18,6 +18,7 @@ public:
   //bool operator!=(const StorageCartesianFunction & other) const { return !(*(static_cast<Record *>(this)) == static_cast<Record &>(other)); }
   bool displayDerivative() const;
   void setDisplayDerivative(bool display);
+  int derivativeNameWithArgument(char * buffer, size_t bufferSize, char arg);
   double approximateDerivative(double x, Poincare::Context * context) const;
   double sumBetweenBounds(double start, double end, Poincare::Context * context) const override;
   Poincare::Expression::Coordinate2D nextMinimumFrom(double start, double step, double max, Poincare::Context * context) const;