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

queue/queue.cpp@22:0e8e22f161ff, 2014-11-02 (annotated)

Committer:
oprospero
Date:
Sun Nov 02 19:18:11 2014 +0000
Revision:
22:0e8e22f161ff
Parent:
16:89695823d407 
Clean up

Who changed what in which revision?

UserRevisionLine numberNew contents of line
oprospero 0:26a151d2c6db 1 /*************************** queue.cpp ***************************************/
oprospero 0:26a151d2c6db 2 /* */
oprospero 0:26a151d2c6db 3 /* Authers: Oanh Tran, Ling Lei, Sihao Xie, Greg Abdo. */
oprospero 0:26a151d2c6db 4 /* Date: February 23, 2013 */
oprospero 0:26a151d2c6db 5 /* Version: 1.0 */
oprospero 0:26a151d2c6db 6 /* */
oprospero 0:26a151d2c6db 7 /* The queue is used to stack StructureItem in order with a FILO */
oprospero 0:26a151d2c6db 8 /*arrangement. */
oprospero 0:26a151d2c6db 9 /*****************************************************************************/
oprospero 0:26a151d2c6db 10
oprospero 0:26a151d2c6db 11 #include "queue.h"
oprospero 0:26a151d2c6db 12
oprospero 0:26a151d2c6db 13 /***************************** constructor ***********************************/
oprospero 0:26a151d2c6db 14 /* Description: */
oprospero 0:26a151d2c6db 15 /*****************************************************************************/
oprospero 0:26a151d2c6db 16
oprospero 0:26a151d2c6db 17 queue::queue()
oprospero 0:26a151d2c6db 18 {
oprospero 0:26a151d2c6db 19 front = NULL; // Set front to NULL at the start.
oprospero 0:26a151d2c6db 20 }
oprospero 0:26a151d2c6db 21
oprospero 0:26a151d2c6db 22 /******************************* distructor **********************************/
oprospero 0:26a151d2c6db 23 /* Description: */
oprospero 0:26a151d2c6db 24 /*****************************************************************************/
oprospero 0:26a151d2c6db 25
oprospero 0:26a151d2c6db 26 queue::~queue()
oprospero 0:26a151d2c6db 27 {
oprospero 0:26a151d2c6db 28 clear(); // Clear the entire queue.
oprospero 0:26a151d2c6db 29 }
oprospero 0:26a151d2c6db 30
oprospero 0:26a151d2c6db 31 /*****************************************************************************/
oprospero 0:26a151d2c6db 32 /* Description: */
oprospero 0:26a151d2c6db 33 /* Accepts: */
oprospero 0:26a151d2c6db 34 /* Returns: */
oprospero 0:26a151d2c6db 35 /*****************************************************************************/
oprospero 0:26a151d2c6db 36
oprospero 0:26a151d2c6db 37 bool queue::isEmpty()
oprospero 0:26a151d2c6db 38 {
oprospero 0:26a151d2c6db 39 // Is the queue empty?
oprospero 0:26a151d2c6db 40 if( front == NULL ) // Check the front pointer.
oprospero 0:26a151d2c6db 41 return true; // Queue is empty, return true.
oprospero 0:26a151d2c6db 42 return false; // There is atleast one item, not empty.
oprospero 0:26a151d2c6db 43 }
oprospero 0:26a151d2c6db 44
oprospero 0:26a151d2c6db 45 /*****************************************************************************/
oprospero 0:26a151d2c6db 46 /* Description: */
oprospero 0:26a151d2c6db 47 /* Accepts: */
oprospero 0:26a151d2c6db 48 /* Returns: */
oprospero 0:26a151d2c6db 49 /*****************************************************************************/
oprospero 0:26a151d2c6db 50
oprospero 0:26a151d2c6db 51 void queue::clear()
oprospero 0:26a151d2c6db 52 {
oprospero 0:26a151d2c6db 53 // Is the list already empty?
oprospero 0:26a151d2c6db 54 if( isEmpty() ) // Check for an empty list.
oprospero 0:26a151d2c6db 55 return; // List is empty, don't need to do anything.
oprospero 0:26a151d2c6db 56
oprospero 0:26a151d2c6db 57 queueNode * current = front; // Create node to help step through list.
oprospero 0:26a151d2c6db 58 queueNode * placeHold = front; // Create node to keep place of delete.
oprospero 0:26a151d2c6db 59
oprospero 0:26a151d2c6db 60 // As long as were not at the end, keep stepping to the next node.
oprospero 0:26a151d2c6db 61 while( current != NULL)
oprospero 0:26a151d2c6db 62 {
oprospero 0:26a151d2c6db 63 placeHold = current->next; // Hold where we have to go.
oprospero 0:26a151d2c6db 64 delete current; // Delete the node.
oprospero 0:26a151d2c6db 65 current = placeHold; // Set current to the next node.
oprospero 0:26a151d2c6db 66 }
oprospero 0:26a151d2c6db 67
oprospero 0:26a151d2c6db 68 front = NULL; // Reset the front to NULL;
oprospero 0:26a151d2c6db 69 length = 0;
oprospero 0:26a151d2c6db 70 }
oprospero 0:26a151d2c6db 71
oprospero 0:26a151d2c6db 72 /*****************************************************************************/
oprospero 0:26a151d2c6db 73 /* Description: */
oprospero 0:26a151d2c6db 74 /* Accepts: */
oprospero 0:26a151d2c6db 75 /* Returns: */
oprospero 0:26a151d2c6db 76 /*****************************************************************************/
oprospero 0:26a151d2c6db 77
oprospero 0:26a151d2c6db 78 void queue::add( short * item )
oprospero 0:26a151d2c6db 79 {
oprospero 0:26a151d2c6db 80 // Were we passed an invalid object somehow?
oprospero 0:26a151d2c6db 81 if( item == NULL ) // Check for NULL
oprospero 0:26a151d2c6db 82 return; // If so, return.
oprospero 0:26a151d2c6db 83
oprospero 0:26a151d2c6db 84 if( queueLength() > MAXQUEUELENGTH )
oprospero 8:951c71c71b2d 85 delete pop();
oprospero 0:26a151d2c6db 86
oprospero 0:26a151d2c6db 87 queueNode * newNode = new queueNode( item ); // Create the new node.
oprospero 0:26a151d2c6db 88
oprospero 0:26a151d2c6db 89 if( isEmpty() )
oprospero 0:26a151d2c6db 90 front = newNode; // Set front to the new node.
oprospero 0:26a151d2c6db 91 else
oprospero 0:26a151d2c6db 92 {
oprospero 0:26a151d2c6db 93 queueNode *temp = front;
oprospero 0:26a151d2c6db 94 while( temp->next != NULL )
oprospero 0:26a151d2c6db 95 temp = temp->next;
oprospero 0:26a151d2c6db 96
oprospero 0:26a151d2c6db 97 temp->next = newNode;
oprospero 0:26a151d2c6db 98 }
oprospero 0:26a151d2c6db 99 length++;
oprospero 0:26a151d2c6db 100 }
oprospero 0:26a151d2c6db 101
oprospero 0:26a151d2c6db 102 /*****************************************************************************/
oprospero 0:26a151d2c6db 103 /* Description: */
oprospero 0:26a151d2c6db 104 /* Accepts: */
oprospero 0:26a151d2c6db 105 /* Returns: */
oprospero 0:26a151d2c6db 106 /*****************************************************************************/
oprospero 0:26a151d2c6db 107
oprospero 0:26a151d2c6db 108 short * queue::pop()
oprospero 0:26a151d2c6db 109 {
oprospero 0:26a151d2c6db 110 // Is the list already empty?
oprospero 0:26a151d2c6db 111 if( isEmpty() ) // Check for an empty list.
oprospero 0:26a151d2c6db 112 return NULL; // List is empty, don't need to do anything.
oprospero 0:26a151d2c6db 113
oprospero 0:26a151d2c6db 114 short* dataHold = front->data; // Keep track of what were returning.
oprospero 0:26a151d2c6db 115 queueNode * oldNode = front; // Save the old node to be deleted
oprospero 0:26a151d2c6db 116 front = front->next; // Set front to next object.
oprospero 16:89695823d407 117
oprospero 0:26a151d2c6db 118 delete oldNode; // Delete the front node.
oprospero 0:26a151d2c6db 119 length--; // Remove one from the length.
oprospero 0:26a151d2c6db 120 return dataHold; // return the stuctureItem.
oprospero 0:26a151d2c6db 121 }
oprospero 0:26a151d2c6db 122
oprospero 0:26a151d2c6db 123 /*****************************************************************************/
oprospero 0:26a151d2c6db 124 /* Description: */
oprospero 0:26a151d2c6db 125 /* Accepts: */
oprospero 0:26a151d2c6db 126 /* Returns: */
oprospero 0:26a151d2c6db 127 /*****************************************************************************/
oprospero 0:26a151d2c6db 128
oprospero 0:26a151d2c6db 129 short * queue::peek()
oprospero 0:26a151d2c6db 130 {
oprospero 0:26a151d2c6db 131 if( front != NULL )
oprospero 0:26a151d2c6db 132 return front->data;
oprospero 0:26a151d2c6db 133
oprospero 0:26a151d2c6db 134 return NULL;
oprospero 0:26a151d2c6db 135 }
oprospero 0:26a151d2c6db 136
oprospero 0:26a151d2c6db 137 /*****************************************************************************/
oprospero 0:26a151d2c6db 138 /* Description: */
oprospero 0:26a151d2c6db 139 /* Accepts: */
oprospero 0:26a151d2c6db 140 /* Returns: */
oprospero 0:26a151d2c6db 141 /*****************************************************************************/
oprospero 0:26a151d2c6db 142
oprospero 0:26a151d2c6db 143 short queue::queueLength()
oprospero 0:26a151d2c6db 144 {
oprospero 0:26a151d2c6db 145 return length;
oprospero 0:26a151d2c6db 146 }