menbedDisplayer.cpp

00001 #include "mbed.h"
00002 #include "include/menbedMenuMessage.h"
00003 #include "include/menbedDisplayer.h"
00004 
00005 MenbedDisplayer::MenbedDisplayer (MenbedDisplay *display) :
00006     display(display)
00007 {
00008 }
00009 
00010 
00011 void MenbedDisplayer::update (MenbedMenuMessage *menuMessage)
00012 {
00013     char *text = new char[display->getLineLength()+1];
00014 
00015     for (int i=0; i<display->getLines(); i++)
00016     {
00017         extractLine (menuMessage->text, i, text);
00018         display->writeLine (text, i);
00019     }
00020     
00021     // Print the up and down arrows if requested
00022     display->showUpArrow (menuMessage->showUpArrow);
00023     display->showDownArrow (menuMessage->showDownArrow);
00024     
00025     delete[] text;
00026 }
00027 
00028 
00029 void MenbedDisplayer::extractLine (char *catenatedText, uint8_t lineNum,
00030         char *extractedText)
00031 {
00032     char *subText, *endText;
00033     size_t bytesToCopy;
00034 
00035     extractedText[0] = '\0';
00036 
00037     // Return with just a blank line if the line number to be extracted exceeds
00038     // the number of lines in the menu
00039     if (lineNum > display->getLines() - 1)
00040         return;
00041 
00042     // We loop through the catenatedString finding each \n.  These \n
00043     // characters separate the substrings that we are trying to extract.
00044     subText = catenatedText;
00045     while (lineNum > 0)
00046     {
00047         subText = strchr (subText, '\n');
00048 
00049         // If the \n character was not found, the catenatedText string does not
00050         // contain enough \n-separated substrings.
00051         if (subText == (char *)NULL)
00052         {
00053             extractedText[0] = '\0';
00054             return;
00055         }
00056 
00057         // Increment the subText pointer because the strchr() command returned
00058         // a pointer to the \n character found, but next time through the loop
00059         // we want to find the next \n, not the same \n again.
00060         subText++;
00061         lineNum--;
00062     }
00063 
00064     // If there are strings following the one we are trying to extract, we
00065     // change the \n terminating the string to be extracted into a \0 so that
00066     // we can use the strlen function to determine the length of the string
00067     // we are trying to extract.  If there are no additional \n-separated
00068     // strings following the one we are attempting to extract, strlen should
00069     // work on subText without modification.
00070     if ((endText = strchr (subText, '\n')) != (char *)NULL)
00071         bytesToCopy = endText - subText + 1;
00072     else
00073         bytesToCopy = strlen(subText);
00074 
00075     // Copy the string found in the \n-separated substring number specified by
00076     // the lineNum parameter to the extracted string.
00077     strncpy (extractedText, subText, bytesToCopy);
00078 
00079     // Replace the \n at the end of extractedText string with a \0
00080     extractedText[bytesToCopy-1] = '\0';
00081 }