Merged Ito and put it in the BU namespace. I should probably clean up the

formatting on the comments, some of the lines wrap, but I'm not too worried
about it right now.  I also fixed up the doxygen config and build.conf files
so that everything is building nice and smooth now.

1 files changed, 231 insertions, 0 deletions

diff --git a/src/itoqueue.h b/src/itoqueue.h
new file mode 100644
index 0000000..322698d
--- /dev/null
+++ b/src/itoqueue.h
@@ -0,0 +1,231 @@
+#ifndef ITO_QUEUE_H
+#define ITO_QUEUE_H
+
+#include <pthread.h>
+
+#include "itomutex.h"
+#include "itocondition.h"
+
+namespace Bu
+{
+        /**
+         * A thread-safe queue class.  This class is a very simple queue with some cool
+         * extra functionality for use with the Ito system.  The main extra that it
+         * provides is the option to either dequeue without blocking, with infinite
+         * blocking, or with timed blocking, which will return a value if something is
+         * enqueued within the specified time limit, or NULL if the time limit is
+         * exceded.
+         *@author Mike Buland
+         */
+        template <class T>
+        class ItoQueue
+        {
+        private:
+                /**
+                 * Helper struct.  Keeps track of linked-list items for the queue data.
+                 */
+                typedef struct Item
+                {
+                        T pData;
+                        Item *pNext;
+                } Item;
+
+        public:
+                /**
+                 * Construct an empty queue.
+                 */
+                ItoQueue() :
+                        pStart( NULL ),
+                        pEnd( NULL ),
+                        nSize( 0 )
+                {
+                }
+                
+                /**
+                 * Destroy the queue.  This function will simply free all contained
+                 * structures.  If you stored pointers in the queue, this will lose the
+                 * pointers without cleaning up the memory they pointed to.  Make sure
+                 * you're queue is empty before allowing it to be destroyed!
+                 */
+                ~ItoQueue()
+                {
+                        Item *pCur = pStart;
+                        while( pCur )
+                        {
+                                Item *pTmp = pCur->pNext;
+                                delete pCur;
+                                pCur = pTmp;
+                        }
+                }
+
+                /**
+                 * Enqueue a pieces of data.  The new data will go at the end of the queue,
+                 * and unless another piece of data is enqueued, will be the last piece of
+                 * data to be dequeued.
+                 *@param pData The data to enqueue.  If this is not a primitive data type
+                 * it's probably best to use a pointer type.
+                 */
+                void enqueue( T pData )
+                {
+                        mOperate.lock();
+
+                        if( pStart == NULL )
+                        {
+                                pStart = pEnd = new Item;
+                                pStart->pData = pData;
+                                pStart->pNext = NULL;
+                                nSize++;
+                        }
+                        else
+                        {
+                                pEnd->pNext = new Item;
+                                pEnd = pEnd->pNext;
+                                pEnd->pData = pData;
+                                pEnd->pNext = NULL;
+                                nSize++;
+                        }
+
+                        cBlock.signal();
+                
+                        mOperate.unlock();
+                }
+
+                /**
+                 * Dequeue the first item from the queue.  This function can operate in two
+                 * different modes, blocking and non-blocking.  In non-blocking mode it will
+                 * return immediately weather there was data in the queue or not.  If there
+                 * was data it will remove it from the queue and return it to the caller.
+                 * In blocking mode it will block forever wating for data to be enqueued.
+                 * When data finally is enqueued this function will return immediately with
+                 * the new data.  The only way this function should ever return a null in
+                 * blocking mode is if the calling thread was cancelled.  It's probably a
+                 * good idea to check for NULL return values even if you use blocking, just
+                 * to be on the safe side.
+                 *@param bBlock Set to true to enable blocking, leave as false to work in
+                 * non-blocking mode.
+                 *@returns The next piece of data in the queue, or NULL if no data was in
+                 * the queue.
+                 */
+                T dequeue( bool bBlock=false )
+                {
+                        mOperate.lock();
+                        if( pStart == NULL )
+                        {
+                                mOperate.unlock();
+
+                                if( bBlock )
+                                {
+                                        cBlock.lock();
+
+                                        while( pStart == NULL )
+                                                cBlock.wait();
+                                
+                                        T tmp = dequeue( false );
+                                        
+                                        cBlock.unlock();
+                                        return tmp;
+
+                                }
+
+                                return NULL;
+                        }
+                        else
+                        {
+                                T pTmp = pStart->pData;
+                                Item *pDel = pStart;
+                                pStart = pStart->pNext;
+                                delete pDel;
+                                nSize--;
+                        
+                                mOperate.unlock();
+                                return pTmp;
+                        }
+                }
+
+                /**
+                 * Operates just like the other dequeue function in blocking mode with one
+                 * twist.  This function will block for at most nSec seconds and nUSec
+                 * micro-seconds.  If the timer is up and no data is available, this will
+                 * just return NULL.  If data is enqueued before the timeout expires, it
+                 * will dequeue and exit immediately.
+                 *@param nSec The number of seconds to wait, max.
+                 *@param nUSec The number of micro-seconds to wait, max.
+                 *@returns The next piece of data in the queue, or NULL if the timeout was
+                 * exceeded.
+                 */
+                T dequeue( int nSec, int nUSec )
+                {
+                        mOperate.lock();
+                        if( pStart == NULL )
+                        {
+                                mOperate.unlock();
+
+                                cBlock.lock();
+                                
+                                cBlock.wait( nSec, nUSec );
+
+                                if( pStart == NULL )
+                                {
+                                        cBlock.unlock();
+                                        return NULL;
+                                }
+                        
+                                mOperate.lock();
+                                T pTmp = pStart->pData;
+                                Item *pDel = pStart;
+                                pStart = pStart->pNext;
+                                delete pDel;
+                                nSize--;
+                                mOperate.unlock();
+                                        
+                                cBlock.unlock();
+                                return pTmp;
+                        }
+                        else
+                        {
+                                T pTmp = pStart->pData;
+                                Item *pDel = pStart;
+                                pStart = pStart->pNext;
+                                delete pDel;
+                                nSize--;
+                        
+                                mOperate.unlock();
+                                return pTmp;
+                        }
+                }
+
+                /**
+                 * Checks to see if the queue has data in it or not.  Note that there is no
+                 * function to determine the length of the queue.  This data isn't kept
+                 * track of.  If you really need to know, fix this.
+                 *@returns True if the queue is empty, false if it has data in it.
+                 */
+                bool isEmpty()
+                {
+                        mOperate.lock();
+                        bool bEmpty = (pStart == NULL );
+                        mOperate.unlock();
+
+                        return bEmpty;
+                }
+
+                long getSize()
+                {
+                        mOperate.lock();
+                        long nRet = nSize;
+                        mOperate.unlock();
+
+                        return nRet;
+                }
+
+        private:
+                Item *pStart;   /**< The start of the queue, the next element to dequeue. */
+                Item *pEnd;             /**< The end of the queue, the last element to dequeue. */
+                long nSize;             /**< The number of items in the queue. */
+
+                ItoMutex mOperate;      /**< The master mutex, used on all operations. */
+                ItoCondition cBlock;    /**< The condition for blocking dequeues. */
+        };
+}
+
+#endif