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  1. /*
  2.  * Copyright (C) 2006 Josef Cejka
  3.  * All rights reserved.
  4.  *
  5.  * Redistribution and use in source and binary forms, with or without
  6.  * modification, are permitted provided that the following conditions
  7.  * are met:
  8.  *
  9.  * - Redistributions of source code must retain the above copyright
  10.  *   notice, this list of conditions and the following disclaimer.
  11.  * - Redistributions in binary form must reproduce the above copyright
  12.  *   notice, this list of conditions and the following disclaimer in the
  13.  *   documentation and/or other materials provided with the distribution.
  14.  * - The name of the author may not be used to endorse or promote products
  15.  *   derived from this software without specific prior written permission.
  16.  *
  17.  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18.  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20.  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21.  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22.  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23.  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24.  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25.  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26.  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27.  */
  28.  
  29. /** @addtogroup kbdgen
  30.  * @brief   HelenOS generic uspace keyboard handler.
  31.  * @ingroup  kbd
  32.  * @{
  33.  */
  34. /** @file
  35.  */
  36. #include <key_buffer.h>
  37. #include <futex.h>
  38.  
  39. atomic_t keybuffer_futex = FUTEX_INITIALIZER;
  40.  
  41. /** Clear key buffer.
  42.  */
  43. void keybuffer_free(keybuffer_t *keybuffer)
  44. {
  45.     futex_down(&keybuffer_futex);
  46.     keybuffer->head = 0;
  47.     keybuffer->tail = 0;
  48.     keybuffer->items = 0;
  49.     futex_up(&keybuffer_futex);
  50. }
  51.  
  52. /** Key buffer initialization.
  53.  *
  54.  */
  55. void keybuffer_init(keybuffer_t *keybuffer)
  56. {
  57.     keybuffer_free(keybuffer);
  58. }
  59.  
  60. /** Get free space in buffer.
  61.  * This function is useful for processing some scancodes that are translated
  62.  * to more than one character.
  63.  * @return empty buffer space
  64.  */
  65. int keybuffer_available(keybuffer_t *keybuffer)
  66. {
  67.     return KEYBUFFER_SIZE - keybuffer->items;
  68. }
  69.  
  70. /**
  71.  * @return nonzero, if buffer is not empty.
  72.  */
  73. int keybuffer_empty(keybuffer_t *keybuffer)
  74. {
  75.     return (keybuffer->items == 0);
  76. }
  77.  
  78. /** Push key to key buffer.
  79.  * If buffer is full, character is ignored.
  80.  * @param key code of stored key
  81.  */
  82. void keybuffer_push(keybuffer_t *keybuffer, int key)
  83. {
  84.     futex_down(&keybuffer_futex);
  85.     if (keybuffer->items < KEYBUFFER_SIZE) {
  86.         keybuffer->fifo[keybuffer->tail] = key;
  87.         keybuffer->tail = (keybuffer->tail + 1) % KEYBUFFER_SIZE;
  88.         keybuffer->items++;
  89.     }
  90.     futex_up(&keybuffer_futex);
  91. }
  92.  
  93. /** Pop character from buffer.
  94.  * @param c pointer to space where to store character from buffer.
  95.  * @return zero on empty buffer, nonzero else
  96.  */
  97. int keybuffer_pop(keybuffer_t *keybuffer, int *c)
  98. {
  99.     futex_down(&keybuffer_futex);
  100.     if (keybuffer->items > 0) {
  101.         keybuffer->items--;
  102.         *c = (keybuffer->fifo[keybuffer->head]) ;
  103.         keybuffer->head = (keybuffer->head + 1) % KEYBUFFER_SIZE;
  104.         futex_up(&keybuffer_futex);
  105.         return 1;
  106.     }
  107.     futex_up(&keybuffer_futex);
  108.     return 0;
  109. }
  110.  
  111. /**
  112.  * @}
  113.  */
  114.  
  115.