Diff: menbed/menbedDisplayer.cpp

Revision:

0:92357d1220f3

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/menbed/menbedDisplayer.cpp	Fri May 19 13:07:52 2017 +0000
@@ -0,0 +1,81 @@
+#include "mbed.h"
+#include "include/menbedMenuMessage.h"
+#include "include/menbedDisplayer.h"
+
+MenbedDisplayer::MenbedDisplayer (MenbedDisplay *display) :
+    display(display)
+{
+}
+
+
+void MenbedDisplayer::update (MenbedMenuMessage *menuMessage)
+{
+    char *text = new char[display->getLineLength()+1];
+
+    for (int i=0; i<display->getLines(); i++)
+    {
+        extractLine (menuMessage->text, i, text);
+        display->writeLine (text, i);
+    }
+    
+    // Print the up and down arrows if requested
+    display->showUpArrow (menuMessage->showUpArrow);
+    display->showDownArrow (menuMessage->showDownArrow);
+    
+    delete[] text;
+}
+
+
+void MenbedDisplayer::extractLine (char *catenatedText, uint8_t lineNum,
+        char *extractedText)
+{
+    char *subText, *endText;
+    size_t bytesToCopy;
+
+    extractedText[0] = '\0';
+
+    // Return with just a blank line if the line number to be extracted exceeds
+    // the number of lines in the menu
+    if (lineNum > display->getLines() - 1)
+        return;
+
+    // We loop through the catenatedString finding each \n.  These \n
+    // characters separate the substrings that we are trying to extract.
+    subText = catenatedText;
+    while (lineNum > 0)
+    {
+        subText = strchr (subText, '\n');
+
+        // If the \n character was not found, the catenatedText string does not
+        // contain enough \n-separated substrings.
+        if (subText == (char *)NULL)
+        {
+            extractedText[0] = '\0';
+            return;
+        }
+
+        // Increment the subText pointer because the strchr() command returned
+        // a pointer to the \n character found, but next time through the loop
+        // we want to find the next \n, not the same \n again.
+        subText++;
+        lineNum--;
+    }
+
+    // If there are strings following the one we are trying to extract, we
+    // change the \n terminating the string to be extracted into a \0 so that
+    // we can use the strlen function to determine the length of the string
+    // we are trying to extract.  If there are no additional \n-separated
+    // strings following the one we are attempting to extract, strlen should
+    // work on subText without modification.
+    if ((endText = strchr (subText, '\n')) != (char *)NULL)
+        bytesToCopy = endText - subText + 1;
+    else
+        bytesToCopy = strlen(subText);
+
+    // Copy the string found in the \n-separated substring number specified by
+    // the lineNum parameter to the extracted string.
+    strncpy (extractedText, subText, bytesToCopy);
+
+    // Replace the \n at the end of extractedText string with a \0
+    extractedText[bytesToCopy-1] = '\0';
+}