Pass String arguments by reference (#342)

Author: Rotzbua

README.md

@@ -231,19 +231,19 @@ void drawXbm(int16_t x, int16_t y, int16_t width, int16_t height, const uint8_t
 ## Text operations
 
 ``` C++
-void drawString(int16_t x, int16_t y, String text);
+void drawString(int16_t x, int16_t y, const String &text);
 
 // Draws a String with a maximum width at the given location.
 // If the given String is wider than the specified width
 // The text will be wrapped to the next line at a space or dash
-void drawStringMaxWidth(int16_t x, int16_t y, int16_t maxLineWidth, String text);
+void drawStringMaxWidth(int16_t x, int16_t y, int16_t maxLineWidth, const String &text);
 
 // Returns the width of the const char* with the current
 // font settings
 uint16_t getStringWidth(const char* text, uint16_t length);
 
 // Convencience method for the const char version
-uint16_t getStringWidth(String text);
+uint16_t getStringWidth(const String &text);
 
 // Specifies relative to which anchor point
 // the text is rendered. Available constants:

src/OLEDDisplay.cpp

@@ -606,7 +606,7 @@ void OLEDDisplay::drawStringInternal(int16_t xMove, int16_t yMove, char* text, u
 }
 
 
-void OLEDDisplay::drawString(int16_t xMove, int16_t yMove, String strUser) {
+void OLEDDisplay::drawString(int16_t xMove, int16_t yMove, const String &strUser) {
   uint16_t lineHeight = pgm_read_byte(fontData + HEIGHT_POS);
 
   // char* text must be freed!
@@ -644,7 +644,7 @@ void OLEDDisplay::drawStringf( int16_t x, int16_t y, char* buffer, String format
   drawString( x, y, buffer );
 }
 
-void OLEDDisplay::drawStringMaxWidth(int16_t xMove, int16_t yMove, uint16_t maxLineWidth, String strUser) {
+void OLEDDisplay::drawStringMaxWidth(int16_t xMove, int16_t yMove, uint16_t maxLineWidth, const String &strUser) {
   uint16_t firstChar  = pgm_read_byte(fontData + FIRST_CHAR_POS);
   uint16_t lineHeight = pgm_read_byte(fontData + HEIGHT_POS);
 
@@ -707,7 +707,7 @@ uint16_t OLEDDisplay::getStringWidth(const char* text, uint16_t length) {
   return max(maxWidth, stringWidth);
 }
 
-uint16_t OLEDDisplay::getStringWidth(String strUser) {
+uint16_t OLEDDisplay::getStringWidth(const String &strUser) {
   char* text = utf8ascii(strUser);
   uint16_t length = strlen(text);
   uint16_t width = getStringWidth(text, length);
@@ -1074,7 +1074,7 @@ void inline OLEDDisplay::drawInternal(int16_t xMove, int16_t yMove, int16_t widt
 }
 
 // You need to free the char!
-char* OLEDDisplay::utf8ascii(String str) {
+char* OLEDDisplay::utf8ascii(const String &str) {
   uint16_t k = 0;
   uint16_t length = str.length() + 1;
 

src/OLEDDisplay.h

@@ -243,22 +243,22 @@ class OLEDDisplay : public Stream {
     /* Text functions */
 
     // Draws a string at the given location
-    void drawString(int16_t x, int16_t y, String text);
+    void drawString(int16_t x, int16_t y, const String &text);
 
     // Draws a formatted string (like printf) at the given location
     void drawStringf(int16_t x, int16_t y, char* buffer, String format, ... );
 
     // Draws a String with a maximum width at the given location.
     // If the given String is wider than the specified width
     // The text will be wrapped to the next line at a space or dash
-    void drawStringMaxWidth(int16_t x, int16_t y, uint16_t maxLineWidth, String text);
+    void drawStringMaxWidth(int16_t x, int16_t y, uint16_t maxLineWidth, const String &text);
 
     // Returns the width of the const char* with the current
     // font settings
     uint16_t getStringWidth(const char* text, uint16_t length);
 
     // Convencience method for the const char version
-    uint16_t getStringWidth(String text);
+    uint16_t getStringWidth(const String &text);
 
     // Specifies relative to which anchor point
     // the text is rendered. Available constants:
@@ -378,7 +378,7 @@ class OLEDDisplay : public Stream {
     void sendInitCommands();
 
     // converts utf8 characters to extended ascii
-    char* utf8ascii(String s);
+    char* utf8ascii(const String &s);
 
     void inline drawInternal(int16_t xMove, int16_t yMove, int16_t width, int16_t height, const uint8_t *data, uint16_t offset, uint16_t bytesInData) __attribute__((always_inline));