CircularBuffer.h

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00001 //===========================================================================
00002 //Copyright (C) 2003, 2004 Zentaro Kavanagh
00003 //
00004 //Redistribution and use in source and binary forms, with or without
00005 //modification, are permitted provided that the following conditions
00006 //are met:
00007 //
00008 //- Redistributions of source code must retain the above copyright
00009 //  notice, this list of conditions and the following disclaimer.
00010 //
00011 //- Redistributions in binary form must reproduce the above copyright
00012 //  notice, this list of conditions and the following disclaimer in the
00013 //  documentation and/or other materials provided with the distribution.
00014 //
00015 //- Neither the name of Zentaro Kavanagh nor the names of contributors 
00016 //  may be used to endorse or promote products derived from this software 
00017 //  without specific prior written permission.
00018 //
00019 //THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
00020 //``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
00021 //LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
00022 //PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE ORGANISATION OR
00023 //CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
00024 //EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
00025 //PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
00026 //PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
00027 //LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
00028 //NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
00029 //SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
00030 //===========================================================================
00031 #pragma once
00032 #include <libOOOgg/dllstuff.h>
00033 #include <libOOOgg/IFIFOBuffer.h>
00034 
00035 
00036 //Empty Buffer
00037 //==============
00038 //
00039 //              <--------------- Buffer Size -------------------->
00040 //      
00041 //              0123456789 123456789 123456789 123456789 123456789*
00042 //      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
00043 //      R
00044 //              W
00045 //
00046 //
00047 //              0123456789 123456789 123456789 123456789 123456789*
00048 //      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
00049 //                                                                      R
00050 //                                                                      W
00051 //
00052 //When R = W Buffer is empty
00053 //
00054 //              when R = W:     available bytes = 0
00055 //              when R = W: space left = buffer size
00057 
00058 //Full Buffer
00059 //===========
00060 //
00061 //
00062 //
00063 //              <--------------- Buffer Size -------------------->
00064 //      
00065 //              0123456789 123456789 123456789 123456789 123456789*
00066 //      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
00067 //                               R
00068 //                                                              W
00069 //
00070 //
00071 //              <--------------- Buffer Size -------------------->
00072 //      
00073 //              0123456789 123456789 123456789 123456789 123456789*
00074 //      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
00075 //      R
00076 //                                                                                        W
00077 //
00078 //Buffer is full when R = (W + 1) MOD (bufferSize + 1)
00079 //
00080 //              when    R = (W + 1) MOD (bufferSize + 1):               available bytes = buffer size
00081 //              when    R = (W + 1) MOD (bufferSize + 1):               space left  = 0
00082 //
00083 //
00084 //      
00085 //
00087 
00088 //Partial Buffers
00089 //===============
00090 //
00091 //Case 1
00092 //======
00093 //
00094 //
00095 //              <--------------- Buffer Size -------------------->
00096 //      
00097 //              0123456789 123456789 123456789 123456789 123456789*
00098 //      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
00099 //                                                                         R
00100 //                                                                                          W
00101 //
00102 //
00103 //              when W > R:             available bytes                                                         =       W - R
00104 //              when W > R:             space left = buffer size - available bytes      =       buffer size + R - W
00105 //
00106 //
00107 //Case 2
00108 //======
00109 //
00110 //
00111 //              <--------------- Buffer Size -------------------->
00112 //                                1                     2                 3                     4
00113 //              0123456789 123456789 123456789 123456789 123456789*
00114 //      XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
00115 //                                                      R
00116 //              W
00117 //
00118 //              when R > W:                     available bytes                                                                 =       buffer size + 1 - R + W
00119 //              when R > W:                     space left = buffer size - available bytes              =       R - W - 1
00120 //              
00121 //
00122 //
00123 //
00124 //
00125 
00126 class LIBOOOGG_API CircularBuffer
00127         :       public IFIFOBuffer
00128 {
00129 public:
00131         CircularBuffer(unsigned long inBufferSize);
00132         virtual ~CircularBuffer(void);
00133 
00135         virtual unsigned long read(unsigned char* outData, unsigned long inBytesToRead);
00136 
00138         virtual unsigned long write(const unsigned char* inData, unsigned long inBytesToWrite);
00139 
00141         virtual unsigned long numBytesAvail();
00142 
00144         virtual unsigned long spaceLeft();
00145 
00147         virtual void reset();
00148 
00149 protected:
00150         unsigned long mBufferSize;
00151         unsigned long mReadPtr;
00152         unsigned long mWritePtr;
00153 
00154         void bufASSERT(bool inBool) {   if (!inBool) throw 0; };
00155         unsigned char* mBuffer;
00156 
00157 private:
00158         CircularBuffer& operator=(const CircularBuffer& other);  /* Don't assign me */
00159         CircularBuffer(const CircularBuffer& other); /* Don't copy me */
00160 };

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