workbench/libs/mesa/src/gallium/auxiliary/util/u_fifo.h

   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
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  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,
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  21  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  22  * DEALINGS IN THE SOFTWARE.
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  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