wy__rdbuf.h

一个不错

/* Copyright is licensed under GNU LGPL.                 by I.J.Wang 2005

   This header file is included in wy_uty.h

   Documentation: wy__rdbuf.3wy
*/
#ifndef WY__RDBUF_H__
#define WY__RDBUF_H__
#include "wybyteflow.h"

// Known problem: 
//       WyByteFlow regf("some_regular_file",O_RDONLY);
//
//       void f(WyByteFlow& bf) {
//         Wy__RdBuf rdq(bf);
//         dynamic_cast<WyRegFile&>(bf).set_pos(0);
//         WyByteFlow tmp(bf);
//         tmp.read(...);       // read pos could be random (not specified)
//       }
//
class Wy__RdBuf {
    WyByteFlow* _fptr;  // pointer to the WyByteFlow object to read data from
    WyStr _rqbuf;       // read buffer
    size_t _cidx;       // starting index for the next getdata output
    size_t _dtsize;     // data transfer size ('count' for read)
    unsigned int _lgch; // the char for unget (last get char)

    // [Syn] Initialize member _dtsize suitable for reading bf
    //
    // [Ret] Ok
    //       Wym_EBADF       Object is not valid for the operation
    //       Wym_ENOMEM      Not enough memory
    //
    WyRet _init_dtsize(const WyByteFlow& bf);

    // [Internal] For Wy_AtDestroy
    //
    // [Throw] Reply
    //       Wym_EBADF       Object is not valid for the operation
    //       Wym_ENOMEM      Not enough memory
    //
    static void _set_dtsize(Wy__RdBuf& rdq,size_t size); // For Wy_AtDestroy

    // Hidden
    Wy__RdBuf(const Wy__RdBuf& bf);
    const Wy__RdBuf& operator=(const Wy__RdBuf& rhs);
    bool operator==(const Wy__RdBuf& rhs) const;
    bool operator!=(const Wy__RdBuf& rhs) const;
   
  public:
    static const char class_name[];
    WY_THROW_REPLY;

    // bf can't be O_NONBLOCK
    //
    explicit  // no implicit conversion
    Wy__RdBuf(WyByteFlow* bfp);

    ~Wy__RdBuf() WY__TSPC();

    WyByteFlow* rf_ptr(void) const WY__TSPC();

    WyCSeg data(void) const WY__TSPC();

    // bf can't be O_NONBLOCK
    //
    WyRet reset(WyByteFlow*);

    WyRet getch(char& chr);
    WyRet getdata(WyCSeg& peek, size_t count);
    WyRet getdata(WyCSeg& peek, size_t count, char term);
    WyRet unget(void);
    void flush(size_t count);

    size_t _rdsize(void) const WY__TSPC();
    void _rdsize(size_t) WY__TSPC();
    WyRet _feed(void);
    WyRet _feed(size_t nbytes);
};

#endif