/*
* Copyright (C) 2006 Josef Cejka
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* - The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <key_buffer.h>
#include <fifo.h>
#define KBD_BUFFER_SIZE 128 /**< Size of buffer for pressed keys */
FIFO_INITIALIZE_STATIC(buffer, char, KBD_BUFFER_SIZE); /**< Fifo for storing pressed keys */
fifo_count_t buffer_items; /**< Counter of used items for prevent fifo overflow */
/** Clear key buffer.
*/
void key_buffer_free(void)
{
buffer_items = 0;
buffer.head = buffer.tail = 0;
}
/** Key buffer initialization.
*
*/
void key_buffer_init(void)
{
key_buffer_free();
}
/** Get free space in buffer.
* This function is useful for processing some scancodes that are translated
* to more than one character.
* @return empty buffer space
*/
int key_buffer_available(void)
{
return KBD_BUFFER_SIZE - buffer_items;
}
/**
* @return nonzero, if buffer is not empty.
*/
int key_buffer_empty(void)
{
return (buffer_items == 0);
}
/** Push key to key buffer.
* If buffer is full, character is ignored.
* @param key code of stored key
*/
void key_buffer_push(char key)
{
if (buffer_items < KBD_BUFFER_SIZE) {
fifo_push(buffer, key);
buffer_items++;
}
}
/** Pop character from buffer.
* @param c pointer to space where to store character from buffer.
* @return zero on empty buffer, nonzero else
*/
int key_buffer_pop(char *c)
{
if (buffer_items > 0) {
buffer_items--;
*c = fifo_pop(buffer);
return 1;
}
return 0;
}