/*! * \file deque08.c * \brief * This file provides double ended queue capability based on a ring buffer * * Author: Christos Choutouridis AEM: 8997 * email : * */ #include "deque08.h" /* * ============= Private Queue API ============= */ static iterator_t _preInc(deque08_t *q, iterator_t* it) { return (++*it >= q->capacity) ? *it=0 : *it; } static iterator_t _preDec(deque08_t *q, iterator_t* it) { return (--*it < 0) ? *it=q->capacity-1 : *it; } static iterator_t _postInc(deque08_t *q, iterator_t* it) { iterator_t ret = *it; if (++*it >= q->capacity) *it=0; return ret; } static iterator_t _postDec(deque08_t *q, iterator_t* it) { iterator_t ret = *it; if (--*it < 0) *it=q->capacity-1; return ret; } /* * ============= Public Queue API ============= */ /* * Link and Glue functions */ void deque08_link_buffer (deque08_t *q, byte_t* buf) { q->m = buf; } /* * Set functions */ inline void deque08_set_capacity (deque08_t *q, size_t capacity) { q->capacity = capacity; } /* * User Functions */ /*! * \brief * Check if deque is full * \param q Which deque to check * \return * \arg 0 Not full * \arg 1 Full */ int deque08_is_full (deque08_t *q) { return (q->items == q->capacity) ? 1:0; } /*! * \brief * Check if deque is empty * \param q Which deque to check * \return * \arg 0 Not empty * \arg 1 Empty */ int deque08_is_empty (deque08_t *q) { return (q->items) ? 0:1; } /*! * \brief * Return the number of items on deque * \param q Which deque to check */ int deque08_size (deque08_t *q) { return q->items; } /*! * \brief * Discard all items in deque * \param q Which deque to check */ void deque08_flush (deque08_t *q) { deque08_init(q); } /*! * \brief * Initialize the queue * \param queue Which queue to init */ void deque08_init (deque08_t *q) { q->f = 0; q->r = -1; q->items =0; } /*! * \brief * This function push a byte in front of deque. * \param q Pointer to deque to use * \param b byte to push * \return * \arg 0 Full queue * \arg 1 Done */ int deque08_push_front (deque08_t *q, byte_t b) { if (deque08_is_full (q) == 1) //full queue return 0; q->m [_preDec (q, &q->f)] = b; ++q->items; return 1; } /*! * \brief * This function pops a byte from the front of the deque. * \param q Pointer to deque to use * \param b Pointer to byte to return * \return * \arg 0 Empty queue * \arg 1 Done */ int deque08_pop_front (deque08_t *q, byte_t *b) { if (deque08_is_empty (q) == 1) //empty queue return 0; *b = q->m [_postInc (q, &q->f)]; --q->items; return 1; } /*! * \brief * This function push a byte in the back of deque. * \param q Pointer to deque to use * \param b byte to push * \return * \arg 0 Full queue * \arg 1 Done */ int deque08_push_back (deque08_t *q, byte_t b) { if (deque08_is_full (q) == 1) //full queue return 0; q->m [_preInc (q, &q->r)] = b; ++q->items; return 1; } /*! * \brief * This function pops a byte from the back of the deque. * \param q Pointer to deque to use * \param b Pointer to byte to return * \return * \arg 0 Empty queue * \arg 1 Done */ int deque08_pop_back (deque08_t *q, byte_t *b) { if (deque08_is_empty (q) == 1) //empty queue return 0; *b = q->m [_postDec (q, &q->r)]; --q->items; return 1; } /*! * \brief * This function gives the last item in the back of deque. * \param q Pointer to deque to use * \param b Pointer to byte to return * \return * \arg 0 Empty queue * \arg 1 Done */ int deque08_back (deque08_t *q, byte_t *b) { if (deque08_is_empty (q) == 1) //empty queue return 0; *b = q->m [q->r]; return 1; } /*! * \brief * This function gives the first item in the front of deque. * \param q Pointer to deque to use * \param b Pointer to byte to return * \return * \arg 0 Empty queue * \arg 1 Done */ int deque08_front (deque08_t *q, byte_t *b) { if (deque08_is_empty (q) == 1) //empty queue return 0; *b = q->m [q->f]; return 1; }