1 // Stream based logging mechanism.
3 // Written by Bernie Bright, 1998
5 // Copyright (C) 1998 Bernie Bright - bbright@c031.aone.net.au
7 // This program is free software; you can redistribute it and/or
8 // modify it under the terms of the GNU General Public License as
9 // published by the Free Software Foundation; either version 2 of the
10 // License, or (at your option) any later version.
12 // This program is distributed in the hope that it will be useful, but
13 // WITHOUT ANY WARRANTY; without even the implied warranty of
14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 // General Public License for more details.
17 // You should have received a copy of the GNU General Public License
18 // along with this program; if not, write to the Free Software
19 // Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
31 #include <Include/compiler.h>
33 #ifdef FG_HAVE_STD_INCLUDES
37 # include <iostream.h>
38 # include "Include/fg_traits.hxx"
41 #include "debug_types.h"
43 #ifndef FG_HAVE_NATIVE_SGI_COMPILERS
44 FG_USING_STD(streambuf);
45 FG_USING_STD(ostream);
51 FG_USING_STD(iostream);
57 // 1. Change output destination. Done.
58 // 2. Make logbuf thread safe.
59 // 3. Read environment for default debugClass and debugPriority.
62 //-----------------------------------------------------------------------------
64 // logbuf is an output-only streambuf with the ability to disable sets of
65 // messages at runtime. Only messages with priority >= logbuf::logPriority
66 // and debugClass == logbuf::logClass are output.
68 class logbuf : public streambuf
72 #ifndef FG_HAVE_STD_INCLUDES
73 typedef char_traits<char> traits_type;
74 typedef char_traits<char>::int_type int_type;
75 typedef char_traits<char>::pos_type pos_type;
76 typedef char_traits<char>::off_type off_type;
78 // logbuf( streambuf* sb ) : sbuf(sb) {}
82 // Is logging enabled?
83 bool enabled() { return logging_enabled; }
85 // Set the logging level of subsequent messages.
86 void set_log_state( fgDebugClass c, fgDebugPriority p );
88 // Set the global logging level.
89 static void set_log_level( fgDebugClass c, fgDebugPriority p );
92 void set_sb( streambuf* sb );
96 inline virtual int sync();
97 int_type overflow( int ch );
98 // int xsputn( const char* s, istreamsize n );
102 // The streambuf used for actual output. Defaults to cerr.rdbuf().
103 static streambuf* sbuf;
105 static bool logging_enabled;
106 static fgDebugClass logClass;
107 static fgDebugPriority logPriority;
112 logbuf( const logbuf& );
113 void operator= ( const logbuf& );
119 #ifdef FG_HAVE_STD_INCLUDES
120 return sbuf->pubsync();
127 logbuf::set_log_state( fgDebugClass c, fgDebugPriority p )
129 logging_enabled = ((c & logClass) != 0 && p >= logPriority);
132 inline logbuf::int_type
133 logbuf::overflow( int c )
135 return logging_enabled ? sbuf->sputc(c) : (EOF == 0 ? 1: 0);
138 //-----------------------------------------------------------------------------
140 // logstream manipulator for setting the log level of a message.
144 loglevel( fgDebugClass c, fgDebugPriority p )
145 : logClass(c), logPriority(p) {}
147 fgDebugClass logClass;
148 fgDebugPriority logPriority;
151 //-----------------------------------------------------------------------------
153 // A helper class that ensures a streambuf and ostream are constructed and
154 // destroyed in the correct order. The streambuf must be created before the
155 // ostream but bases are constructed before members. Thus, making this class
156 // a private base of logstream, declared to the left of ostream, we ensure the
157 // correct order of construction and destruction.
159 struct logstream_base
161 // logstream_base( streambuf* sb ) : lbuf(sb) {}
167 //-----------------------------------------------------------------------------
171 class logstream : private logstream_base, public ostream
174 // The default is to send messages to cerr.
175 logstream( ostream& out )
176 // : logstream_base(out.rdbuf()),
178 ostream(&lbuf) { lbuf.set_sb(out.rdbuf());}
180 void set_output( ostream& out ) { lbuf.set_sb( out.rdbuf() ); }
182 // Set the global log class and priority level.
183 void setLogLevels( fgDebugClass c, fgDebugPriority p );
185 // Output operator to capture the debug level and priority of a message.
186 inline ostream& operator<< ( const loglevel& l );
190 logstream::operator<< ( const loglevel& l )
192 lbuf.set_log_state( l.logClass, l.logPriority );
196 //-----------------------------------------------------------------------------
198 // Return the one and only logstream instance.
199 // We use a function instead of a global object so we are assured that cerr
200 // has been initialised.
205 static logstream logstrm( cerr );
210 # define FG_LOG(C,P,M)
211 #elif defined( __MWERKS__ )
212 # define FG_LOG(C,P,M) ::fglog() << ::loglevel(C,P) << M << std::endl
214 # define FG_LOG(C,P,M) fglog() << loglevel(C,P) << M << endl
217 #endif // _LOGSTREAM_H