Prosper Van / xbeeCom

xbee communication for UWB quadcopter project Originally by Greg Abdo Forking to reduce impact of interrupt by moving packetbuilder out of the interrupt and letting be handled in the main loop

Fork of com by Prosper Van

queueChar/queueChar.cpp

Committer:
oprospero
Date:
2014-10-06
Revision:
17:acef0fb07510

File content as of revision 17:acef0fb07510:

/*************************** queue.cpp ***************************************/
/*                                                                           */
/*****************************************************************************/

#include "queueChar.h"

/***************************** constructor ***********************************/
/* Description:                                                              */
/*****************************************************************************/

queueChar::queueChar()
{
    front = 0;
    end = 0;
    lengthVar = 0;
    for (int i = 0; i < MAXQUEUECHARLENGTH; i++)
    {
        buffer[i] = 0;
    }
}

/******************************* distructor **********************************/
/* Description:                                                              */
/*****************************************************************************/

queueChar::~queueChar()
{
    clear();        // Clear the entire queue.
}

/*****************************************************************************/
/* Description:                                                              */
/* Accepts:                                                                  */
/* Returns:                                                                  */
/*****************************************************************************/

bool queueChar::isEmpty()
{
    bool empty = front == end;
    if (empty) lengthVar = 0;
    return empty;
}

/*****************************************************************************/
/* Description:                                                              */
/* Accepts:                                                                  */
/* Returns:                                                                  */
/*****************************************************************************/

void queueChar::clear()
{
    lengthVar = 0;
    front = 0;
    end = 0;
}

/*****************************************************************************/
/* Description:                                                              */
/* Accepts:                                                                  */
/* Returns:                                                                  */
/*****************************************************************************/

void queueChar::add( char data )
{
    buffer[front] = data;
    front = nextIndex(front);
    if (front == end)
        end = nextIndex(end);
    else
        lengthVar++;
}

/*****************************************************************************/
/* Description:                                                              */
/* Accepts:                                                                  */
/* Returns:                                                                  */
/*****************************************************************************/

char queueChar::pop()
{
    if (isEmpty())
        return 255;
    else
    {
        lengthVar--;
        char data = buffer[end];
        end = nextIndex(end);
        return data;
    }
}

/*****************************************************************************/
/* Description:                                                              */
/* Accepts:                                                                  */
/* Returns:                                                                  */
/*****************************************************************************/

char queueChar::peek()
{
//    return front;
    char data = buffer[end];
    return data;
}

/*****************************************************************************/
/* Description:                                                              */
/* Accepts:                                                                  */
/* Returns:                                                                  */
/*****************************************************************************/

char queueChar::length()
{
    short diff = front - end;
    if (diff < 0)
        diff += MAXQUEUECHARLENGTH;
//    diff = diff % MAXQUEUECHARLENGTH;
    return diff;
//    if (diff == lengthVar)
//        return lengthVar;
//    else
//        lengthVar = diff;
//        return 255;
}


char queueChar::nextIndex(char index)
{
    index++;
    if (index >= MAXQUEUECHARLENGTH)
        index = 0;
    return index;
}