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1339 | cejka | 1 | /* |
2 | * Copyright (C) 2006 Josef Cejka |
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3 | * All rights reserved. |
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4 | * |
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5 | * Redistribution and use in source and binary forms, with or without |
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6 | * modification, are permitted provided that the following conditions |
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7 | * are met: |
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8 | * |
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9 | * - Redistributions of source code must retain the above copyright |
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10 | * notice, this list of conditions and the following disclaimer. |
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11 | * - Redistributions in binary form must reproduce the above copyright |
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12 | * notice, this list of conditions and the following disclaimer in the |
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13 | * documentation and/or other materials provided with the distribution. |
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14 | * - The name of the author may not be used to endorse or promote products |
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15 | * derived from this software without specific prior written permission. |
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16 | * |
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17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
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18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
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19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
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20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
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21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
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22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
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26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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27 | */ |
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28 | |||
29 | #include <key_buffer.h> |
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1392 | palkovsky | 30 | #include <libadt/fifo.h> |
1339 | cejka | 31 | |
1344 | cejka | 32 | #define KBD_BUFFER_SIZE 128 /**< Size of buffer for pressed keys */ |
1339 | cejka | 33 | |
1344 | cejka | 34 | FIFO_INITIALIZE_STATIC(buffer, char, KBD_BUFFER_SIZE); /**< Fifo for storing pressed keys */ |
35 | fifo_count_t buffer_items; /**< Counter of used items for prevent fifo overflow */ |
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1339 | cejka | 36 | |
1344 | cejka | 37 | /** Clear key buffer. |
38 | */ |
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1339 | cejka | 39 | void key_buffer_free(void) |
40 | { |
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41 | buffer_items = 0; |
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42 | buffer.head = buffer.tail = 0; |
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43 | } |
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44 | |||
1344 | cejka | 45 | /** Key buffer initialization. |
46 | * |
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47 | */ |
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1339 | cejka | 48 | void key_buffer_init(void) |
49 | { |
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50 | key_buffer_free(); |
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51 | } |
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52 | |||
1344 | cejka | 53 | /** Get free space in buffer. |
54 | * This function is useful for processing some scancodes that are translated |
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55 | * to more than one character. |
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1339 | cejka | 56 | * @return empty buffer space |
57 | */ |
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58 | int key_buffer_available(void) |
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59 | { |
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60 | return KBD_BUFFER_SIZE - buffer_items; |
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61 | } |
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62 | |||
1344 | cejka | 63 | /** |
64 | * @return nonzero, if buffer is not empty. |
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65 | */ |
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66 | int key_buffer_empty(void) |
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67 | { |
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68 | return (buffer_items == 0); |
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69 | } |
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70 | |||
71 | /** Push key to key buffer. |
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72 | * If buffer is full, character is ignored. |
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73 | * @param key code of stored key |
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74 | */ |
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1339 | cejka | 75 | void key_buffer_push(char key) |
76 | { |
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77 | if (buffer_items < KBD_BUFFER_SIZE) { |
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78 | fifo_push(buffer, key); |
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79 | buffer_items++; |
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80 | } |
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81 | } |
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82 | |||
83 | /** Pop character from buffer. |
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1344 | cejka | 84 | * @param c pointer to space where to store character from buffer. |
1339 | cejka | 85 | * @return zero on empty buffer, nonzero else |
86 | */ |
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87 | int key_buffer_pop(char *c) |
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88 | { |
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89 | if (buffer_items > 0) { |
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90 | buffer_items--; |
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91 | *c = fifo_pop(buffer); |
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92 | return 1; |
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93 | } |
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94 | return 0; |
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95 | } |
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96 | |||
97 |