/*
* 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.
*/
/** @addtogroup kbdgen
* @brief HelenOS generic uspace keyboard handler.
* @ingroup kbd
* @{
*/
/** @file
*/
#include <key_buffer.h>
#include <futex.h>
atomic_t keybuffer_futex = FUTEX_INITIALIZER;
/** Clear key buffer.
*/
void keybuffer_free(keybuffer_t *keybuffer)
{
futex_down(&keybuffer_futex);
keybuffer->head = 0;
keybuffer->tail = 0;
keybuffer->items = 0;
futex_up(&keybuffer_futex);
}
/** Key buffer initialization.
*
*/
void keybuffer_init(keybuffer_t *keybuffer)
{
keybuffer_free(keybuffer);
}
/** 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 keybuffer_available(keybuffer_t *keybuffer)
{
return KEYBUFFER_SIZE - keybuffer->items;
}
/**
* @return nonzero, if buffer is not empty.
*/
int keybuffer_empty(keybuffer_t *keybuffer)
{
return (keybuffer->items == 0);
}
/** Push key to key buffer.
* If buffer is full, character is ignored.
* @param key code of stored key
*/
void keybuffer_push(keybuffer_t *keybuffer, int key)
{
futex_down(&keybuffer_futex);
if (keybuffer->items < KEYBUFFER_SIZE) {
keybuffer->fifo[keybuffer->tail] = key;
keybuffer->tail = (keybuffer->tail + 1) % KEYBUFFER_SIZE;
keybuffer->items++;
}
futex_up(&keybuffer_futex);
}
/** Pop character from buffer.
* @param c pointer to space where to store character from buffer.
* @return zero on empty buffer, nonzero else
*/
int keybuffer_pop(keybuffer_t *keybuffer, int *c)
{
futex_down(&keybuffer_futex);
if (keybuffer->items > 0) {
keybuffer->items--;
*c = (keybuffer->fifo[keybuffer->head]) ;
keybuffer->head = (keybuffer->head + 1) % KEYBUFFER_SIZE;
futex_up(&keybuffer_futex);
return 1;
}
futex_up(&keybuffer_futex);
return 0;
}
/**
* @}
*/