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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. #include <fifo.h>
  31.  
  32. #define KBD_BUFFER_SIZE 128
  33.  
  34. FIFO_INITIALIZE_STATIC(buffer, char, KBD_BUFFER_SIZE);
  35. fifo_count_t buffer_items;
  36.  
  37. void key_buffer_free(void)
  38. {
  39.     buffer_items = 0;
  40.     buffer.head = buffer.tail = 0;
  41. }
  42.  
  43. void key_buffer_init(void)
  44. {
  45.     key_buffer_free();
  46. }
  47.  
  48. /**
  49.  * @return empty buffer space
  50.  */
  51. int key_buffer_available(void)
  52. {
  53.     return KBD_BUFFER_SIZE - buffer_items;
  54. }
  55.  
  56. void key_buffer_push(char key)
  57. {
  58.     /* TODO: somebody may wait for key */
  59.     if (buffer_items < KBD_BUFFER_SIZE) {
  60.         fifo_push(buffer, key);
  61.         buffer_items++;
  62.     }
  63. }
  64.  
  65. /** Pop character from buffer.
  66.  * @param c
  67.  * @return zero on empty buffer, nonzero else
  68.  */
  69. int key_buffer_pop(char *c)
  70. {
  71.     if (buffer_items > 0) {
  72.         buffer_items--;
  73.         *c = fifo_pop(buffer);
  74.         return 1;
  75.     }
  76.     return 0;
  77. }
  78.  
  79.  
  80.