readlinebuf.h revision 119610 
196462Sru/*******************************************************************************
296462Sru * $Revision: 1.2 $
396462Sru * $Date: 2001/09/11 06:19:36 $
496462Sru * $Author: vyzo $
596462Sru *
696462Sru * Contents: A streambuf which uses the GNU readline library for line I/O
7156813Sru * (c) 2001 by Dimitris Vyzovitis [vyzo@media.mit.edu]
8155264Sru *
996462Sru * This program is free software; you can redistribute it and/or modify
1096462Sru * it under the terms of the GNU General Public License as published by
1196668Sru * the Free Software Foundation; either version 2 of the License, or
1296462Sru * (at your option) any later version.
1396668Sru *
1496462Sru * This program is distributed in the hope that it will be useful,
1596462Sru * but WITHOUT ANY WARRANTY; without even the implied warranty of
1696462Sru * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
1796668Sru * General Public License for more details.
1896462Sru *
1996668Sru * You should have received a copy of the GNU General Public
2096462Sru * License along with this program; if not, write to the Free
2196462Sru * Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
2296462Sru * MA 02111-1307 USA
2396462Sru *
2496462Sru ******************************************************************************/
2596462Sru
2696462Sru#ifndef _READLINEBUF_H_
2796462Sru#define _READLINEBUF_H_
2896462Sru
2996462Sru#include <iostream>
3096462Sru#include <cstring>
3196462Sru#include <cassert>
3296462Sru#include <cstdlib>
3396462Sru#include <cstdio>
3496462Sru
3596462Sru#include <readline/readline.h>
3696462Sru#include <readline/history.h>
3796462Sru
3896462Sru#if (defined __GNUC__) && (__GNUC__ < 3)
3996462Sru#include <streambuf.h>
4096462Sru#else
4196462Sru#include <streambuf>
4296668Sruusing std::streamsize;
4396462Sruusing std::streambuf;
4496462Sru#endif
4596462Sru
4696462Sruclass readlinebuf : public streambuf {
4796462Srupublic:
4896462Sru#if (defined __GNUC__) && (__GNUC__ < 3)
4996462Sru	typedef char char_type;
5096462Sru	typedef int int_type;
5196462Sru	typedef streampos pos_type;
5296462Sru	typedef streamoff off_type;
5396668Sru#endif
5496462Sru	static const int_type eof = EOF; // this is -1
5596462Sru	static const int_type not_eof = 0;
5696462Sru
5796462Sruprivate:
5896462Sru	const char* prompt_;
5996462Sru	bool history_;
6096462Sru	char* line_;
6196462Sru	int low_;
6296462Sru	int high_;
6396462Sru
64144893Shartiprotected:
6596462Sru
6696462Sru	virtual int_type showmanyc() const { return high_ - low_; }
6796462Sru
6896668Sru	virtual streamsize xsgetn( char_type* buf, streamsize n ) {
6996462Sru		int rd = n > (high_ - low_)? (high_ - low_) : n;
7096462Sru		memcpy( buf, line_, rd );
7196462Sru		low_ += rd;
7296462Sru
7396462Sru		if ( rd < n ) {
7496462Sru			low_ = high_ = 0;
7596462Sru			free( line_ ); // free( NULL ) is a noop
7696462Sru			line_ = readline( prompt_ );
7796462Sru			if ( line_ ) {
7896462Sru				high_ = strlen( line_ );
79144893Sharti				if ( history_ && high_ ) add_history( line_ );
8096668Sru				rd += xsgetn( buf + rd, n - rd );
8196668Sru			}
8299343Sru		}
83155264Sru
84156813Sru		return rd;
85	}
86
87	virtual int_type underflow() {
88		if ( high_ == low_ ) {
89			low_ = high_ = 0;
90			free( line_ ); // free( NULL ) is a noop
91			line_ = readline( prompt_ );
92			if ( line_ ) {
93				high_ = strlen( line_ );
94				if ( history_ && high_ ) add_history( line_ );
95			}
96		}
97
98		if ( low_ < high_ ) return line_[low_];
99		else return eof;
100	}
101
102	virtual int_type uflow() {
103		int_type c = underflow();
104		if ( c != eof ) ++low_;
105		return c;
106	}
107
108	virtual int_type pbackfail( int_type c = eof ) {
109		if ( low_ > 0 )	--low_;
110		else if ( c != eof ) {
111			if ( high_ > 0 ) {
112				char* nl = (char*)realloc( line_, high_ + 1 );
113				if ( nl ) {
114					line_ = (char*)memcpy( nl + 1, line_, high_ );
115					high_ += 1;
116					line_[0] = char( c );
117				} else return eof;
118			} else {
119				assert( !line_ );
120				line_ = (char*)malloc( sizeof( char ) );
121				*line_ = char( c );
122				high_ = 1;
123			}
124		} else return eof;
125
126		return not_eof;
127	}
128
129public:
130	readlinebuf( const char* prompt = NULL, bool history = true )
131		: prompt_( prompt ), history_( history ),
132		  line_( NULL ), low_( 0 ), high_( 0 ) {
133		setbuf( 0, 0 );
134	}
135
136
137};
138
139#endif
140