src/client/keyboardBuffer.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <string.h>
   4 #include <assert.h>
   5 #include <SDL.h>
   6
   7 #include "keyboardBuffer.h"
   8
   9 static keyboardBuffer_t *keyboardBuffer = NULL;
  10
  11 static SDL_keysym emptyKey;
  12
  13 /*
  14  * Key buffer initialization
  15  * the parameter sets the number of keys
  16  */
  17 void keyboard_buffer_init(int size)
  18 {
  19         assert(size > 0);
  20         assert(keyboardBuffer == NULL);
  21
  22         keyboardBuffer = malloc(sizeof(keyboardBuffer_t));
  23         assert(keyboardBuffer != NULL);
  24         memset(keyboardBuffer, 0, sizeof(keyboardBuffer_t));
  25
  26         keyboardBuffer->buff = malloc(size * sizeof(SDL_keysym));
  27         assert(keyboardBuffer->buff != NULL);
  28         memset(keyboardBuffer->buff, 0, size * sizeof(SDL_keysym));
  29
  30         keyboardBuffer->begin = 0;
  31         keyboardBuffer->end = 0;
  32         keyboardBuffer->count = 0;
  33         keyboardBuffer->size = size;
  34
  35         emptyKey.sym = SDLK_UNKNOWN;
  36 }
  37
  38 /*
  39  * Empty the buffer
  40  */
  41 void keyboard_buffer_clear()
  42 {
  43         assert(keyboardBuffer != NULL);
  44
  45         keyboardBuffer->begin = 0;
  46         keyboardBuffer->end = 0;
  47         keyboardBuffer->count = 0;
  48         memset(keyboardBuffer->buff, 0, keyboardBuffer->size * sizeof(SDL_keysym));
  49 }
  50
  51 /*
  52  * Adds key to the end of the buffer. If the buffer is overrun,
  53  * an error is printed to stderr and the key is dropped.
  54  */
  55 bool_t keyboard_buffer_push(SDL_keysym key)
  56 {
  57         assert(keyboardBuffer != NULL);
  58
  59         if (keyboardBuffer->count >= keyboardBuffer->size) {
  60                 error("Keyboard buffer overrun - dropping the key [%02x]", key.sym);
  61                 return FALSE;
  62         }
  63
  64         keyboardBuffer->buff[keyboardBuffer->end] = key;
  65
  66         keyboardBuffer->end++;
  67         if (keyboardBuffer->end >= keyboardBuffer->size) {
  68                 keyboardBuffer->end = 0;
  69         }
  70
  71         keyboardBuffer->count++;
  72
  73         return TRUE;
  74 }
  75
  76 /*
  77  * Takes out first key from the buffer and returns it. If the buffer is empty,
  78  * an error is printed to stderr and SDLK_UNKNOWN is returned.
  79  */
  80 SDL_keysym keyboard_buffer_pop()
  81 {
  82         assert(keyboardBuffer != NULL);
  83
  84         if (keyboardBuffer->count <= 0) {
  85                 error("Keyboard buffer underrun");
  86                 return emptyKey;
  87         }
  88
  89         SDL_keysym key = keyboardBuffer->buff[keyboardBuffer->begin];
  90         keyboardBuffer->buff[keyboardBuffer->begin] = emptyKey;
  91
  92         keyboardBuffer->begin++;
  93
  94         if (keyboardBuffer->begin >= keyboardBuffer->size) {
  95                 keyboardBuffer->begin = 0;
  96         }
  97
  98         keyboardBuffer->count--;
  99
 100         return key;
 101 }
 102
 103 /*
 104  * The buffer size
 105  */
 106 int keyboard_buffer_get_size()
 107 {
 108         assert(keyboardBuffer != NULL);
 109         return keyboardBuffer->size;
 110 }
 111
 112 /*
 113  * Number of keys in the buffer
 114  */
 115 int keyboard_buffer_get_count()
 116 {
 117         assert(keyboardBuffer != NULL);
 118         return keyboardBuffer->count;
 119 }
 120
 121
 122 bool_t keyboard_buffer_is_any_key()
 123 {
 124         return keyboard_buffer_get_count() > 0 ? TRUE : FALSE;
 125 }
 126
 127 /*
 128  * Frees the buffer. If it is not empty, information
 129  * about filling is prined to stderr first.
 130  */
 131 void keyboard_buffer_quit()
 132 {
 133         assert(keyboardBuffer != NULL);
 134
 135         if (keyboardBuffer->count > 0) {
 136                 warning("Shutting down non-empty keyboard buffer");
 137         }
 138
 139         free(keyboardBuffer->buff);
 140         free(keyboardBuffer);
 141         keyboardBuffer = NULL;
 142 }