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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. #include <key_buffer.h>
  30.  
  31. /** Clear key buffer.
  32.  */
  33. void keybuffer_free(keybuffer_t *keybuffer)
  34. {
  35.  
  36.     keybuffer->items = 0;
  37.     keybuffer->head = keybuffer->tail = keybuffer->items = 0;
  38. }
  39.  
  40. /** Key buffer initialization.
  41.  *
  42.  */
  43. void keybuffer_init(keybuffer_t *keybuffer)
  44. {
  45.     keybuffer_free(keybuffer);
  46. }
  47.  
  48. /** Get free space in buffer.
  49.  * This function is useful for processing some scancodes that are translated
  50.  * to more than one character.
  51.  * @return empty buffer space
  52.  */
  53. int keybuffer_available(keybuffer_t *keybuffer)
  54. {
  55.     return KEYBUFFER_SIZE - keybuffer->items;
  56. }
  57.  
  58. /**
  59.  * @return nonzero, if buffer is not empty.
  60.  */
  61. int keybuffer_empty(keybuffer_t *keybuffer)
  62. {
  63.     return (keybuffer->items == 0);
  64. }
  65.  
  66. /** Push key to key buffer.
  67.  * If buffer is full, character is ignored.
  68.  * @param key code of stored key
  69.  */
  70. void keybuffer_push(keybuffer_t *keybuffer, char key)
  71. {
  72.     if (keybuffer->items < KEYBUFFER_SIZE) {
  73.         keybuffer->fifo[keybuffer->tail = (keybuffer->tail + 1) < keybuffer->items ? (keybuffer->tail + 1) : 0] = (key);
  74.         keybuffer->items++;
  75.     }
  76. }
  77.  
  78. /** Pop character from buffer.
  79.  * @param c pointer to space where to store character from buffer.
  80.  * @return zero on empty buffer, nonzero else
  81.  */
  82. int keybuffer_pop(keybuffer_t *keybuffer, char *c)
  83. {
  84.     if (keybuffer->items > 0) {
  85.         keybuffer->items--;
  86.         *c = keybuffer->fifo[keybuffer->head = (keybuffer->head + 1) < keybuffer->items ? (keybuffer->head + 1) : 0];
  87.         return 1;
  88.     }
  89.     return 0;
  90. }
  91.  
  92.  
  93.