X-Git-Url: https://codewiz.org/gitweb?a=blobdiff_plain;f=bertos%2Fmware%2Ffifobuf.h;h=73f6c14e9c088f9d711386c3de0919c4c11d09c9;hb=e5174304054e26cd8f3cd1f9980871c20c07fc46;hp=7fb06b63fc25f718cb7d3f62a61d2389f60f53d1;hpb=0ef8c662a0beafedbf4bc7a85067395a3b569598;p=bertos.git diff --git a/bertos/mware/fifobuf.h b/bertos/mware/fifobuf.h index 7fb06b63..73f6c14e 100644 --- a/bertos/mware/fifobuf.h +++ b/bertos/mware/fifobuf.h @@ -1,361 +1 @@ -/** - * \file - * - * - * \version $Id$ - * - * \author Bernardo Innocenti - * - * \brief General pourpose FIFO buffer implemented with a ring buffer - * - * \li \c begin points to the first buffer element; - * \li \c end points to the last buffer element (unlike the STL convention); - * \li \c head points to the element to be extracted next; - * \li \c tail points to the location following the last insertion; - * \li when any of the pointers advances beyond \c end, it is reset - * back to \c begin. - * - * \code - * - * +-----------------------------------+ - * | empty | valid data | empty | - * +-----------------------------------+ - * ^ ^ ^ ^ - * begin head tail end - * - * \endcode - * - * The buffer is EMPTY when \c head and \c tail point to the same location: - * \code head == tail \endcode - * - * The buffer is FULL when \c tail points to the location immediately - * after \c head: - * \code tail == head - 1 \endcode - * - * The buffer is also FULL when \c tail points to the last buffer - * location and head points to the first one: - * \code head == begin && tail == end \endcode - */ - -#ifndef MWARE_FIFO_H -#define MWARE_FIFO_H - -#include -#include -#include - -typedef struct FIFOBuffer -{ - unsigned char * volatile head; - unsigned char * volatile tail; - unsigned char *begin; - unsigned char *end; -} FIFOBuffer; - - -#define ASSERT_VALID_FIFO(fifo) \ - ATOMIC( \ - ASSERT((fifo)->head >= (fifo)->begin); \ - ASSERT((fifo)->head <= (fifo)->end); \ - ASSERT((fifo)->tail >= (fifo)->begin); \ - ASSERT((fifo)->tail <= (fifo)->end); \ - ) - - -/** - * Check whether the fifo is empty - * - * \note Calling fifo_isempty() is safe while a concurrent - * execution context is calling fifo_push() or fifo_pop() - * only if the CPU can atomically update a pointer - * (which the AVR and other 8-bit processors can't do). - * - * \sa fifo_isempty_locked - */ -INLINE bool fifo_isempty(const FIFOBuffer *fb) -{ - //ASSERT_VALID_FIFO(fb); - return fb->head == fb->tail; -} - - -/** - * Check whether the fifo is full - * - * \note Calling fifo_isfull() is safe while a concurrent - * execution context is calling fifo_pop() and the - * CPU can update a pointer atomically. - * It is NOT safe when the other context calls - * fifo_push(). - * This limitation is not usually problematic in a - * consumer/producer scenario because the - * fifo_isfull() and fifo_push() are usually called - * in the producer context. - */ -INLINE bool fifo_isfull(const FIFOBuffer *fb) -{ - //ASSERT_VALID_FIFO(fb); - return - ((fb->head == fb->begin) && (fb->tail == fb->end)) - || (fb->tail == fb->head - 1); -} - - -/** - * Push a character on the fifo buffer. - * - * \note Calling \c fifo_push() on a full buffer is undefined. - * The caller must make sure the buffer has at least - * one free slot before calling this function. - * - * \note It is safe to call fifo_pop() and fifo_push() from - * concurrent contexts, unless the CPU can't update - * a pointer atomically (which the AVR and other 8-bit - * processors can't do). - * - * \sa fifo_push_locked - */ -INLINE void fifo_push(FIFOBuffer *fb, unsigned char c) -{ -#ifdef __MWERKS__ -#pragma interrupt called -#endif - //ASSERT_VALID_FIFO(fb); - - /* Write at tail position */ - *(fb->tail) = c; - - if (UNLIKELY(fb->tail == fb->end)) - /* wrap tail around */ - fb->tail = fb->begin; - else - /* Move tail forward */ - fb->tail++; -} - - -/** - * Pop a character from the fifo buffer. - * - * \note Calling \c fifo_pop() on an empty buffer is undefined. - * The caller must make sure the buffer contains at least - * one character before calling this function. - * - * \note It is safe to call fifo_pop() and fifo_push() from - * concurrent contexts. - */ -INLINE unsigned char fifo_pop(FIFOBuffer *fb) -{ -#ifdef __MWERKS__ -#pragma interrupt called -#endif - //ASSERT_VALID_FIFO(fb); - - if (UNLIKELY(fb->head == fb->end)) - { - /* wrap head around */ - fb->head = fb->begin; - return *(fb->end); - } - else - /* move head forward */ - return *(fb->head++); -} - - -/** - * Make the fifo empty, discarding all its current contents. - */ -INLINE void fifo_flush(FIFOBuffer *fb) -{ - //ASSERT_VALID_FIFO(fb); - fb->head = fb->tail; -} - - -#if CPU_REG_BITS >= CPU_BITS_PER_PTR - - /* - * 16/32bit CPUs that can update a pointer with a single write - * operation, no need to disable interrupts. - */ - #define fifo_isempty_locked(fb) fifo_isempty((fb)) - #define fifo_push_locked(fb, c) fifo_push((fb), (c)) - #define fifo_pop_locked(fb) fifo_pop((fb)) - #define fifo_flush_locked(fb) fifo_flush((fb)) - -#else /* CPU_REG_BITS < CPU_BITS_PER_PTR */ - - /** - * Similar to fifo_isempty(), but with stronger guarantees for - * concurrent access between user and interrupt code. - * - * \note This is actually only needed for 8-bit processors. - * - * \sa fifo_isempty() - */ - INLINE bool fifo_isempty_locked(const FIFOBuffer *fb) - { - bool result; - ATOMIC(result = fifo_isempty(fb)); - return result; - } - - - /** - * Similar to fifo_push(), but with stronger guarantees for - * concurrent access between user and interrupt code. - * - * \note This is actually only needed for 8-bit processors. - * - * \sa fifo_push() - */ - INLINE void fifo_push_locked(FIFOBuffer *fb, unsigned char c) - { - ATOMIC(fifo_push(fb, c)); - } - - /* Probably not really needed, but hard to prove. */ - INLINE unsigned char fifo_pop_locked(FIFOBuffer *fb) - { - unsigned char c; - ATOMIC(c = fifo_pop(fb)); - return c; - } - - /** - * Similar to fifo_flush(), but with stronger guarantees for - * concurrent access between user and interrupt code. - * - * \note This is actually only needed for 8-bit processors. - * - * \sa fifo_flush() - */ - INLINE void fifo_flush_locked(FIFOBuffer *fb) - { - ATOMIC(fifo_flush(fb)); - } - -#endif /* CPU_REG_BITS < BITS_PER_PTR */ - - -/** - * Thread safe version of fifo_isfull() - */ -INLINE bool fifo_isfull_locked(const FIFOBuffer *_fb) -{ - bool result; - ATOMIC(result = fifo_isfull(_fb)); - return result; -} - - -/** - * FIFO Initialization. - */ -INLINE void fifo_init(FIFOBuffer *fb, unsigned char *buf, size_t size) -{ - /* FIFO buffers have a known bug with 1-byte buffers. */ - ASSERT(size > 1); - - fb->head = fb->tail = fb->begin = buf; - fb->end = buf + size - 1; -} - -/** - * \return Lenght of the FIFOBuffer \a fb. - */ -INLINE size_t fifo_len(FIFOBuffer *fb) -{ - return fb->end - fb->begin; -} - - -#if 0 - -/* - * UNTESTED: if uncommented, to be moved in fifobuf.c - */ -void fifo_pushblock(FIFOBuffer *fb, unsigned char *block, size_t len) -{ - size_t freelen; - - /* Se c'e' spazio da tail alla fine del buffer */ - if (fb->tail >= fb->head) - { - freelen = fb->end - fb->tail + 1; - - /* C'e' abbastanza spazio per scrivere tutto il blocco? */ - if (freelen < len) - { - /* Scrivi quello che entra fino alla fine del buffer */ - memcpy(fb->tail, block, freelen); - block += freelen; - len -= freelen; - fb->tail = fb->begin; - } - else - { - /* Scrivi tutto il blocco */ - memcpy(fb->tail, block, len); - fb->tail += len; - return; - } - } - - for(;;) - { - while (!(freelen = fb->head - fb->tail - 1)) - Delay(FIFO_POLLDELAY); - - /* C'e' abbastanza spazio per scrivere tutto il blocco? */ - if (freelen < len) - { - /* Scrivi quello che entra fino alla fine del buffer */ - memcpy(fb->tail, block, freelen); - block += freelen; - len -= freelen; - fb->tail += freelen; - } - else - { - /* Scrivi tutto il blocco */ - memcpy(fb->tail, block, len); - fb->tail += len; - return; - } - } -} -#endif - -#endif /* MWARE_FIFO_H */ - +#include