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