Diff: tinyQ.h

Revision:

0:1ca47c273d0f

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tinyQ.h	Mon Jan 30 23:08:52 2012 +0000
@@ -0,0 +1,44 @@
+/** \defgroup tinyQ Tiny Queue
+ * Tiny Queues implements a 4 byte queue for iPhone events with just 1 byte of management overhead.
+ * Head and Tail pointers both inherently wrap at the end of the buffer and no bounds checking is 
+ * necesary IFF the buffer size is set as a power of 2 equal to the width of the pointers !!
+ * i.e head is 2 bits wide so the buffer must be 2^2 = 4 bytes deep.
+ * @{
+ */
+/** NOTE: Q_SIZE MUST be == 2 ^ widthof( tinyQ_t.head ) */
+#define Q_SIZE 256
+
+
+
+/** a tinyQ tracks a 4 byte queue with just 1 byte overhead */
+typedef struct
+{
+    unsigned int head:8;  ///< the bit depth MUST be that power of 2 that is the Q_SIZE
+    unsigned int tail:8;  ///< the bit depth MUST be that power of 2 that is the Q_SIZE
+    unsigned int fill:9;  ///< Must be 1 bit bigger than the head and tail pointers
+    char data[Q_SIZE];     ///< NOTE: Q_SIZE MUST be == 2 ^ widthof( tinyQ_t.head )
+}tinyQ_t;
+
+
+/**
+ * \brief Push an Accessibility Event onto our queue for sending to the iphone
+ * \param q pointer to our tinyQ_t
+ * \param c the Event to send to the iphone
+ * \return null if Q full,  1 on success
+ * \sa Qpop(), Qjump()
+ * \ingroup tinyQ
+ */
+int Qpush( tinyQ_t* q, char c );
+
+/**
+ * \brief Pop an Accessibility Event off our queue for sending to the iphone
+ * \param q pointer to our tinyQ_t
+ * \param c pointer to receive the Event
+ * \return null if Q empty, 1 on success
+ * \sa Qpop(), Qjump()
+ * \ingroup tinyQ
+ */
+int Qpop( tinyQ_t* q, char * c);
+
+int Qfree( tinyQ_t* q );
+void Qinit( tinyQ_t* q );
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