1/*******************************************************************************
2 * $Revision: 1.2 $
3 * $Date: 2001/09/11 06:19:36 $
4 * $Author: vyzo $
5 *
6 * Contents: A streambuf which uses the GNU readline library for line I/O
7 * (c) 2001 by Dimitris Vyzovitis [vyzo@media.mit.edu]
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
13 *
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
17 * General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public
20 * License along with this program; if not, write to the Free
21 * Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
22 * MA 02111-1307 USA
23 *
24 ******************************************************************************/
25
26#ifndef _READLINEBUF_H_
27#define _READLINEBUF_H_
28
29#include <iostream>
30#include <cstring>
31#include <cassert>
32#include <cstdlib>
33#include <cstdio>
34
35#include <readline/readline.h>
36#include <readline/history.h>
37
38#if (defined __GNUC__) && (__GNUC__ < 3)
39#include <streambuf.h>
40#else
41#include <streambuf>
42using std::streamsize;
43using std::streambuf;
44#endif
45
46class readlinebuf : public streambuf {
47public:
48#if (defined __GNUC__) && (__GNUC__ < 3)
49	typedef char char_type;
50	typedef int int_type;
51	typedef streampos pos_type;
52	typedef streamoff off_type;
53#endif
54	static const int_type eof = EOF; // this is -1
55	static const int_type not_eof = 0;
56
57private:
58	const char* prompt_;
59	bool history_;
60	char* line_;
61	int low_;
62	int high_;
63
64protected:
65
66	virtual int_type showmanyc() const { return high_ - low_; }
67
68	virtual streamsize xsgetn( char_type* buf, streamsize n ) {
69		int rd = n > (high_ - low_)? (high_ - low_) : n;
70		memcpy( buf, line_, rd );
71		low_ += rd;
72
73		if ( rd < n ) {
74			low_ = high_ = 0;
75			free( line_ ); // free( NULL ) is a noop
76			line_ = readline( prompt_ );
77			if ( line_ ) {
78				high_ = strlen( line_ );
79				if ( history_ && high_ ) add_history( line_ );
80				rd += xsgetn( buf + rd, n - rd );
81			}
82		}
83
84		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