InputByteStream.h

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/*
 *    This file is part of dvi2bitmap.
 *    Copyright 1999--2002, Council for the Central Laboratory of the Research Councils
 *    
 *    This program is part of the Starlink Software Distribution: see
 *    http://www.starlink.ac.uk 
 *
 *    dvi2bitmap is free software; you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License as published by
 *    the Free Software Foundation; either version 2 of the License, or
 *    (at your option) any later version.
 *
 *    dvi2bitmap is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with dvi2bitmap; if not, write to the Free Software
 *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 *    The General Public License is distributed along with this
 *    program in the file LICENCE.
 *
 *    Author: Norman Gray <norman@astro.gla.ac.uk>
 *    $Id: InputByteStream.h,v 1.28 2004/11/04 20:32:28 nxg Exp $
 */


#ifndef INPUT_BYTE_STREAM_HEADER_READ
#define INPUT_BYTE_STREAM_HEADER_READ 1

#include <Byte.h>
#include <DviError.h>
#include <verbosity.h>

#include <string>

class InputByteStreamError : public DviError {
 public:
    InputByteStreamError(string s) : DviError(s) { }
};

class InputByteStream {

 public:
    InputByteStream(int fileno)
            throw (InputByteStreamError);
    InputByteStream(string srcspec)
            throw (InputByteStreamError);
    ~InputByteStream();

    bool eof();
    virtual void close();
    Byte getByte(void)
            throw (InputByteStreamError);
    const Byte *getBlock(unsigned int length)
            throw (InputByteStreamError);
    void skip (unsigned int)
            throw (InputByteStreamError);

    signed int getSIU(int)
            throw (InputByteStreamError);
    signed int getSIS(int)
            throw (InputByteStreamError);
    unsigned int getUIU(int)
            throw (InputByteStreamError);
    /*
     * static getUIU reads from an array, rather than the file (ie,
     * it's really nothing to do with InputByteStream, but it's here
     * for consistency.
     */
    static unsigned int getUIU(int, const Byte *)
            throw (InputByteStreamError);
    static void setDefaultBufferSize(unsigned int length);
    static inline void verbosity (const verbosities level) {
        verbosity_ = level;
    }
    static verbosities getVerbosity(void) { return verbosity_; };

 protected:
    InputByteStream();
    bool bindToFileDescriptor(int fileno,
                              string filename="",
                              int bufsize=0,
                              bool fillBufferAndClose=false,
                              bool assertIsSeekable=false)
            throw (InputByteStreamError);
    int openSourceSpec(string srcspec)
            throw (InputByteStreamError);
    int getFD(void) const { return fd_; }
    void bufferSeek(unsigned int pos)
            throw (InputByteStreamError);
    void reloadBuffer(void);

 private:
    int fd_;                    /* file descriptor of handled file/pipe */
    int mappedfd_;              /* saved file descriptor of mapped file */
    string fname_;              /* name of file, or string rep'n of fd */
    Byte *buf_;                 /* buffer */
    size_t buflen_;             /* size of buffer */
    Byte *p_;                   /* current position in buffer */
    Byte *eob_;                 /* end of buffer */
    bool eof_;                  /* true on end of file (note this is from
                                   the client's point of view, not the class's:
                                   if we have `preloaded' a file, the
                                   underlying file will be closed, but there
                                   will still be more to read from the 
                                   stream) */
    void read_buf_(void)
            throw (InputByteStreamError);
    size_t certainly_read_(int fd, Byte *b, size_t len)
            throw (InputByteStreamError);

    static verbosities verbosity_;
    static unsigned int default_buffer_length_;
};

#endif /* INPUT_BYTE_STREAM_HEADER_READ */

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