Chris BAYLEY
/
SPI-2-USB
Dump SPI from input to pc.serial
tinyQ.h
- Committer:
- cbayley
- Date:
- 2012-01-30
- Revision:
- 0:1ca47c273d0f
File content as of revision 0:1ca47c273d0f:
/** \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 );