WatermelonModders
111 lines
3.5 KiB
C
111 lines
3.5 KiB
C
/**
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* Copyright 2011 Bump Technologies, Inc. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without modification, are
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* permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice, this list of
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* conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice, this list
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* of conditions and the following disclaimer in the documentation and/or other materials
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* provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY BUMP TECHNOLOGIES, INC. ``AS IS'' AND ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
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* FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL BUMP TECHNOLOGIES, INC. OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
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* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
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* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* The views and conclusions contained in the software and documentation are those of the
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* authors and should not be interpreted as representing official policies, either expressed
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* or implied, of Bump Technologies, Inc.
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*
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**/
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#include "ringbuffer.h"
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#include <assert.h>
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/* Initialize a ringbuffer structure to empty */
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void ringbuffer_init(ringbuffer *rb) {
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rb->head = &rb->slots[0];
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rb->tail = &rb->slots[0];
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rb->used = 0;
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int x;
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for (x=0; x<RING_SLOTS; x++)
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rb->slots[x].next = &(rb->slots[(x + 1) % RING_SLOTS]);
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}
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/** READ FUNCTIONS **/
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/* Return a char * that represents the current unconsumed buffer */
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char * ringbuffer_read_next(ringbuffer *rb, int * length) {
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assert(rb->used);
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*length = rb->head->left;
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return rb->head->ptr;
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}
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/* Mark consumption of only part of the read head buffer */
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void ringbuffer_read_skip(ringbuffer *rb, int length) {
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assert(rb->used);
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rb->head->ptr += length;
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rb->head->left -= length;
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}
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/* Pop a consumed (fully read) head from the buffer */
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void ringbuffer_read_pop(ringbuffer *rb) {
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assert(rb->used);
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rb->head = rb->head->next;
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rb->used--;
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}
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/** WRITE FUNCTIONS **/
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/* Return the tail ptr (current target of new writes) */
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char * ringbuffer_write_ptr(ringbuffer *rb) {
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assert(rb->used < RING_SLOTS);
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return rb->tail->data;
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}
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/* Mark the tail appended for `length` bytes, and move the cursor
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* to the next slot */
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void ringbuffer_write_append(ringbuffer *rb, int length) {
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assert(rb->used < RING_SLOTS);
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rb->used++;
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rb->tail->ptr = rb->tail->data;
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rb->tail->left = length;
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rb->tail = rb->tail->next;
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}
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/** RING STATE FUNCTIONS **/
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/* Used size of the ringbuffer */
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int ringbuffer_size(ringbuffer *rb) {
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return rb->used;
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}
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/* Used size of the ringbuffer */
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int ringbuffer_capacity(ringbuffer *rb) {
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(void) rb;
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return RING_SLOTS;
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}
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/* Is the ringbuffer completely empty (implies: no data to be written) */
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int ringbuffer_is_empty(ringbuffer *rb) {
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return rb->used == 0;
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}
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/* Is the ringbuffer completely full (implies: no more data should be read) */
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int ringbuffer_is_full(ringbuffer *rb) {
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return rb->used == RING_SLOTS;
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}
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