1 files changed, 136 insertions, 0 deletions
diff --git a/mpeglib/lib/input/simpleRingBuffer.h b/mpeglib/lib/input/simpleRingBuffer.h
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+++ b/mpeglib/lib/input/simpleRingBuffer.h
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+/*
+  a thread safe ring buffer without dependencies
+  Copyright (C) 1999  Martin Vogt
+
+  This program is free software; you can redistribute it and/or modify
+  it under the terms of the GNU Library General Public License as published by
+  the Free Software Foundation.
+
+  For more information look at the file COPYRIGHT in this package
+
+ */
+
+
+
+
+#ifndef _SIMPLERINGBUFFER_H
+#define _SIMPLERINGBUFFER_H
+
+#include "../util/abstract/abs_thread.h"
+
+extern "C" {
+  #include <stdio.h>
+}
+
+/** 
+   Note to parameter minLinBufSize in Constructor:
+   <p>
+   If the fillgrade is sufficient we can delivier at least
+   this amount of bytes with one "fill"
+   (If the fillgrade is not suffficient we can only deliever fillgrade)
+   This values adresses the problem that a ring buffer cannot
+   deliever linear memory the whole time(eg. if you read near the
+   upper end)
+   <p>
+   If the requested Buffersize by the device is smaller than
+   this number you can be sure that you get exactly
+   your preferred buffersize. not more not less.(but
+   only if the fillgrade allows this)
+*/
+
+
+
+
+class SimpleRingBuffer {
+
+
+ public:
+
+  SimpleRingBuffer(int ringBufferSize, int minLinBufferSize);
+  virtual ~SimpleRingBuffer();
+
+  // Writer thread can call these:
+
+  int getWriteArea(char* &ptr,int &size);
+  void forwardWritePtr(int bytes);
+  int waitForSpace(int minSpace);
+  void exitWaitForSpace();
+  void setCanWaitForSpace(int lCanWaitForSpace);
+  
+  
+  // Reader thread these:
+ 
+  void forwardReadPtr(int bytes);
+  int getReadArea(char* &ptr,int &size);
+  int waitForData(int minData);
+  void exitWaitForData();
+  void setCanWaitForData(int lCanWaitForData);
+  int getCanWaitForData();
+
+
+  // and the lockPos
+  void forwardLockPtr(int bytes);
+
+
+  // both:
+
+  int getFillgrade();       // return how much buffer between reader/writer
+  void emptyBuffer();    // frees the space between them
+  int getFreeRead();
+  int getFreeWrite();
+
+  int getSize();
+  int getReadBytes();
+  int getWriteBytes();
+
+  // make sure that no one calls getReadArea/getWriteArea
+  void resizeBuffer(int changeSize);
+ private:
+  void updateCanWrite();
+  void updateCanRead();
+
+  int size;
+  
+  int lockgrade;
+  int fillgrade;
+  
+  char* readPos;
+  char* writePos;
+  char* lockPos;
+
+  char* startPos;
+
+  char* lastPos;
+  char* eofPos;
+  int canWrite;
+  int canRead;
+
+  int waitMinData;
+  int waitMinSpace;
+
+  abs_thread_mutex_t mut;
+  abs_thread_cond_t dataCond;
+  abs_thread_cond_t spaceCond;
+  
+  int insertBlock;
+  int readBlock;
+  int linAvail;
+
+  char* minLinBuf;
+  int minLinBufSize;
+  int lWaitForData;
+  int lWaitForSpace;
+
+  // statistic purpose:
+  int readBytes;
+  int writeBytes;
+
+  int lCanWaitForSpace;
+  int lCanWaitForData;
+  int instance;
+};
+
+#endif
+
+  
+