Initial import of the CDE 2.1.30 sources from the Open Group.

cde/programs/dtmail/include/DtMail/Buffer.hh

@@ -0,0 +1,163 @@
+/*
+ *+SNOTICE
+ *
+ *
+ *      $XConsortium: Buffer.hh /main/4 1996/04/21 19:44:23 drk $
+ *
+ *      RESTRICTED CONFIDENTIAL INFORMATION:
+ *
+ *      The information in this document is subject to special
+ *      restrictions in a confidential disclosure agreement bertween
+ *      HP, IBM, Sun, USL, SCO and Univel.  Do not distribute this
+ *      document outside HP, IBM, Sun, USL, SCO, or Univel wihtout
+ *      Sun's specific written approval.  This documment and all copies
+ *      and derivative works thereof must be returned or destroyed at
+ *      Sun's request.
+ *
+ *      Copyright 1993 Sun Microsystems, Inc.  All rights reserved.
+ *
+ *+ENOTICE
+ */
+ 
+#ifndef _DTMAILBUFFER_HH
+#define _DTMAILBUFFER_HH
+
+#include <stdarg.h>
+
+// these classes are provided in order to have a logical array whose
+// size is not known at creation time.  The DtMailBuffer class
+// holds the data, and for the moment holds the only "write" operation
+// (which is append).  In addition, to be thread safe, there is
+// a separate class for reading, so that you can have separate
+// "seek points" in the read buffer in different procedures.
+
+class BufReader;
+
+class Buffer {
+
+
+    protected:
+	static const int defaultchunksize;
+
+    public:
+
+	Buffer();
+
+	// actually add data.  result is # of bytes written.  Can
+	// fail if underlying write fails, or if out of memory.
+	virtual int appendData(const char *user_buffer, int length) = 0;
+
+	// an interator function that gets called so that eventually
+	// the entire buffer has been passed through
+	typedef unsigned long (*CallBack)(const char *buffer, int len, va_list);
+	virtual unsigned long iterate(CallBack, ...) = 0;
+
+	// get a new reader object
+	virtual BufReader *getReader(void) = 0;
+
+	virtual int getSize(void) = 0;	// get total size of the buffer
+
+
+    protected:
+	virtual ~Buffer(void);
+    private:
+	Buffer(const Buffer&);		// try and avoid copies
+
+
+};
+
+// subsidiary classes
+class BufReader {
+    public:
+	// actually read data into a user specified buffer
+	virtual int getData(char *user_buffer, int length) = 0;
+	virtual ~BufReader(void);
+
+    protected:
+	BufReader();
+    private:
+	BufReader(const BufReader &);
+};
+
+
+class BufReaderMemory;
+class BufferMemory : public Buffer {
+
+    public:
+	class Chunk;
+	friend class BufReaderMemory;
+
+	BufferMemory(int chunksize);
+	BufferMemory();
+	virtual ~BufferMemory(void);
+
+	// actually add data.  result is # of bytes written.  Can
+	// fail if underlying write fails, or if out of memory.
+	virtual int appendData(const char *user_buffer, int length);
+
+	virtual unsigned long iterate(Buffer::CallBack, ...);
+
+	// get a new reader object
+	virtual BufReader *getReader(void);
+
+	virtual int getSize(void);      // get total size of the buffer
+
+    private:
+	class Chunk;
+
+	BufferMemory(const Buffer&);	// try and avoid copies
+	void initBuffer(int size);	// common constructor
+	int newChunk(int size);		// get a new data chunk
+
+	Chunk *_firstchunk;		// first chunk
+	Chunk *_lastchunk;		// last chunk
+	int _totalsize;			// total size in all buffers
+	int _chunksize;			// size to allocate new buffers
+
+	void *_mutex;
+
+	BufReaderMemory *_firstreader;	// linked list of readers
+
+
+    public:
+	// aux structure to hold data; no active functions
+	struct Chunk {
+	    struct Chunk *_nextchunk;	// next element in linked list
+	    char *_buffer;		// data buffer
+	    int _chunksize;		// allocated size of buffer
+	    int _currentend;		// current used space
+	};
+
+    // subsidiary classes
+};
+
+class BufReaderMemory : protected BufReader {
+    friend class BufferMemory;
+
+    public:
+	// actually read data into a user specified buffer
+	virtual int getData(char *user_buffer, int length);
+	virtual ~BufReaderMemory(void);
+
+    private:
+	BufReaderMemory(const BufReaderMemory &);
+	BufReaderMemory(BufferMemory *);
+
+	BufferMemory::Chunk *_currentchunk;
+	int _currentoffset;
+
+	BufferMemory *_buffer;
+	BufReaderMemory *_nextreader;	// maintain linked list of readers
+	BufReaderMemory *_prevreader;	// maintain linked list of readers
+};
+
+#endif // _DTMAILBUFFER_HH
+
+
+
+
+
+
+
+
+