Projects/USBtoSerial/Lib/RingBuff.c

   1 /*
   2              LUFA Library
   3      Copyright (C) Dean Camera, 2010.
   4
   5   dean [at] fourwalledcubicle [dot] com
   6       www.fourwalledcubicle.com
   7 */
   8
   9 /*
  10   Copyright 2010  Dean Camera (dean [at] fourwalledcubicle [dot] com)
  11
  12   Permission to use, copy, modify, distribute, and sell this
  13   software and its documentation for any purpose is hereby granted
  14   without fee, provided that the above copyright notice appear in
  15   all copies and that both that the copyright notice and this
  16   permission notice and warranty disclaimer appear in supporting
  17   documentation, and that the name of the author not be used in
  18   advertising or publicity pertaining to distribution of the
  19   software without specific, written prior permission.
  20
  21   The author disclaim all warranties with regard to this
  22   software, including all implied warranties of merchantability
  23   and fitness.  In no event shall the author be liable for any
  24   special, indirect or consequential damages or any damages
  25   whatsoever resulting from loss of use, data or profits, whether
  26   in an action of contract, negligence or other tortious action,
  27   arising out of or in connection with the use or performance of
  28   this software.
  29 */
  30
  31 #include "RingBuff.h"
  32
  33 void Buffer_Initialize(RingBuff_t* const Buffer)
  34 {
  35         BUFF_ATOMIC_BLOCK
  36         {
  37                 Buffer->InPtr    = (RingBuff_Data_t*)&Buffer->Buffer;
  38                 Buffer->OutPtr   = (RingBuff_Data_t*)&Buffer->Buffer;
  39                 Buffer->Elements = 0;
  40         }
  41 }
  42
  43 void Buffer_StoreElement(RingBuff_t* const Buffer, RingBuff_Data_t Data)
  44 {
  45         BUFF_ATOMIC_BLOCK
  46         {
  47         #if defined(BUFF_DROPOLD)
  48                 if (Buffer->Elements == BUFF_LENGTH)
  49                 {
  50                         Buffer->OutPtr++;
  51
  52                         if (Buffer->OutPtr == &Buffer->Buffer[BUFF_LENGTH])
  53                           Buffer->OutPtr = (RingBuff_Data_t*)&Buffer->Buffer;
  54                 }
  55                 else
  56                 {
  57                         Buffer->Elements++;
  58                 }
  59         #elif defined(BUFF_DROPNEW)
  60                 if (Buffer->Elements == BUFF_LENGTH)
  61                   return;
  62
  63                   Buffer->Elements++;
  64         #elif defined(BUFF_NODROPCHECK)
  65                   Buffer->Elements++;
  66         #endif
  67
  68                 *(Buffer->InPtr) = Data;
  69                 Buffer->InPtr++;
  70
  71                 if (Buffer->InPtr == &Buffer->Buffer[BUFF_LENGTH])
  72                   Buffer->InPtr = (RingBuff_Data_t*)&Buffer->Buffer;
  73         }
  74 }
  75
  76 RingBuff_Data_t Buffer_GetElement(RingBuff_t* const Buffer)
  77 {
  78         RingBuff_Data_t BuffData;
  79
  80         BUFF_ATOMIC_BLOCK
  81         {
  82 #if defined(BUFF_EMPTYRETURNSZERO)
  83                 if (!(Buffer->Elements))
  84                   return 0;
  85 #elif !defined(BUFF_NOEMPTYCHECK)
  86         #error No empty buffer check behavior specified.
  87 #endif
  88
  89                 BuffData = *(Buffer->OutPtr);
  90
  91                 Buffer->OutPtr++;
  92                 Buffer->Elements--;
  93
  94                 if (Buffer->OutPtr == &Buffer->Buffer[BUFF_LENGTH])
  95                   Buffer->OutPtr = (RingBuff_Data_t*)&Buffer->Buffer;
  96         }
  97
  98         return BuffData;
  99 }
 100
 101 #if defined(BUFF_USEPEEK)
 102 RingBuff_Data_t Buffer_PeekElement(const RingBuff_t* const Buffer)
 103 {
 104         RingBuff_Data_t BuffData;
 105
 106         BUFF_ATOMIC_BLOCK
 107         {
 108 #if defined(BUFF_EMPTYRETURNSZERO)
 109                 if (!(Buffer->Elements))
 110                   return 0;
 111 #elif !defined(BUFF_NOEMPTYCHECK)
 112         #error No empty buffer check behavior specified.
 113 #endif
 114
 115                 BuffData = *(Buffer->OutPtr);
 116         }
 117
 118         return BuffData;
 119 }
 120 #endif