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  1. /**************************************************************************
  2.  *
  3.  * Copyright © 2009 Jakob Bornecrantz
  4.  *
  5.  * Permission is hereby granted, free of charge, to any person obtaining a
  6.  * copy of this software and associated documentation files (the "Software"),
  7.  * to deal in the Software without restriction, including without limitation
  8.  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  9.  * and/or sell copies of the Software, and to permit persons to whom the
  10.  * Software is furnished to do so, subject to the following conditions:
  11.  *
  12.  * The above copyright notice and this permission notice (including the next
  13.  * paragraph) shall be included in all copies or substantial portions of the
  14.  * Software.
  15.  *
  16.  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17.  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18.  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  19.  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20.  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  21.  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  22.  * DEALINGS IN THE SOFTWARE.
  23.  *
  24.  **************************************************************************/
  25.  
  26. #ifndef U_FIFO_H
  27. #define U_FIFO_H
  28.  
  29. #include "util/u_memory.h"
  30.  
  31. struct util_fifo
  32. {
  33.    size_t head;
  34.    size_t tail;
  35.    size_t num;
  36.    size_t size;
  37. };
  38.  
  39. static INLINE struct util_fifo *
  40. u_fifo_create(size_t size)
  41. {
  42.    struct util_fifo *fifo;
  43.    fifo = MALLOC(sizeof(*fifo) + size * sizeof(void*));
  44.  
  45.    fifo->head = 0;
  46.    fifo->tail = 0;
  47.    fifo->num = 0;
  48.    fifo->size = size;
  49.  
  50.    return fifo;
  51. }
  52.  
  53. static INLINE boolean
  54. u_fifo_add(struct util_fifo *fifo, void *ptr)
  55. {
  56.    void **array = (void**)&fifo[1];
  57.    if (fifo->num >= fifo->size)
  58.       return FALSE;
  59.  
  60.    if (++fifo->head >= fifo->size)
  61.       fifo->head = 0;
  62.  
  63.    array[fifo->head] = ptr;
  64.  
  65.    ++fifo->num;
  66.  
  67.    return TRUE;
  68. }
  69.  
  70. static INLINE boolean
  71. u_fifo_pop(struct util_fifo *fifo, void **ptr)
  72. {
  73.    void **array = (void**)&fifo[1];
  74.  
  75.    if (!fifo->num)
  76.       return FALSE;
  77.  
  78.    if (++fifo->tail >= fifo->size)
  79.       fifo->tail = 0;
  80.  
  81.    *ptr = array[fifo->tail];
  82.  
  83.    ++fifo->num;
  84.  
  85.    return TRUE;
  86. }
  87.  
  88. static INLINE void
  89. u_fifo_destroy(struct util_fifo *fifo)
  90. {
  91.    FREE(fifo);
  92. }
  93.  
  94. #endif
  95.