version 3.0

common/filter.h

@@ -0,0 +1,82 @@
+////////////////////////////////////////////////////////////////////////////////
+//                                                                            //
+// File:           filter.h                                                   //
+// Description:    base classes for chained data processors                   //
+// Project:        WANProxy XTech                                             //
+// Author:         Andreu Vidal Bramfeld-Software                             //
+// Last modified:  2015-04-01                                                 //
+//                                                                            //
+////////////////////////////////////////////////////////////////////////////////
+
+#ifndef	COMMON_FILTER_H
+#define	COMMON_FILTER_H
+
+#include <list>
+#include <common/log.h>
+#include <common/buffer.h>
+
+class Filter
+{
+private:
+   Filter* recipient_;
+   
+public:
+   Filter ()										{ recipient_ = 0; }
+   virtual ~Filter ()							{ }
+   
+   void chain (Filter* nxt)					{ recipient_ = nxt; }
+   virtual bool consume (Buffer& buf)		{ return produce (buf); }
+   virtual bool produce (Buffer& buf)		{ return (recipient_ && recipient_->consume (buf)); }
+   virtual void flush (int flg)				{ if (recipient_) recipient_->flush (flg); }
+};
+
+class CountFilter : public Filter 
+{
+private:
+   intmax_t& counter_;
+   
+public:
+   CountFilter (intmax_t& p) : counter_(p)	   { }
+   virtual bool consume (Buffer& buf)		      { counter_ += buf.length (); return produce (buf); }
+};
+
+class BufferedFilter : public Filter
+{
+protected:
+   LogHandle log_;
+   Buffer pending_;
+	bool flushing_;
+	int flush_flags_;
+	
+public:
+   BufferedFilter (const LogHandle& log) : log_ (log)   { flushing_ = 0; flush_flags_ = 0; }
+};
+
+class LogisticFilter : public BufferedFilter
+{
+protected:
+   Filter* upstream_;
+	
+public:
+   LogisticFilter (const LogHandle& log) : BufferedFilter (log)   { upstream_ = 0; }
+   void set_upstream (Filter* f)   { upstream_ = f; }
+};
+
+class FilterChain : public Filter
+{
+private:
+	std::list<Filter*> nodes_;
+	Filter* holder_;
+
+public:
+   FilterChain (Filter* f)			{ holder_ = f; }
+   virtual ~FilterChain ()			{ while (! nodes_.empty ()) { delete nodes_.front (); nodes_.pop_front (); }}
+  
+   void prepend (Filter* f)  		{ Filter* act = (nodes_.empty () ? holder_ : nodes_.front ()); 
+											  if (f && act) nodes_.push_front (f), chain (f), f->chain (act); }
+   void append (Filter* f)  		{ Filter* act = (nodes_.empty () ? this : nodes_.front ()); 
+											  if (f && act) nodes_.push_front (f), act->chain (f), f->chain (holder_); }
+   virtual void flush (int flg)	{ if (nodes_.empty ()) chain (holder_); Filter::flush (flg); }
+};
+
+#endif /* !COMMON_FILTER_H */