1 // Stream based logging mechanism.
3 // Written by Bernie Bright, 1998
5 // Copyright (C) 1998 Bernie Bright - bbright@c031.aone.net.au
7 // This library is free software; you can redistribute it and/or
8 // modify it under the terms of the GNU Library General Public
9 // License as published by the Free Software Foundation; either
10 // version 2 of the License, or (at your option) any later version.
12 // This library is distributed in the hope that it will be useful,
13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 // Library General Public License for more details.
17 // You should have received a copy of the GNU Library General Public
18 // License along with this library; if not, write to the
19 // Free Software Foundation, Inc., 59 Temple Place - Suite 330,
20 // Boston, MA 02111-1307, USA.
32 #include <simgear/compiler.h>
34 #ifdef FG_HAVE_STD_INCLUDES
38 # include <iostream.h>
39 # include <simgear/fg_traits.hxx>
42 #include <simgear/debug/debug_types.h>
44 #ifndef FG_HAVE_NATIVE_SGI_COMPILERS
45 FG_USING_STD(streambuf);
46 FG_USING_STD(ostream);
52 FG_USING_STD(iostream);
58 // 1. Change output destination. Done.
59 // 2. Make logbuf thread safe.
60 // 3. Read environment for default debugClass and debugPriority.
63 //-----------------------------------------------------------------------------
65 // logbuf is an output-only streambuf with the ability to disable sets of
66 // messages at runtime. Only messages with priority >= logbuf::logPriority
67 // and debugClass == logbuf::logClass are output.
69 class logbuf : public streambuf
73 #ifndef FG_HAVE_STD_INCLUDES
74 typedef char_traits<char> traits_type;
75 typedef char_traits<char>::int_type int_type;
76 typedef char_traits<char>::pos_type pos_type;
77 typedef char_traits<char>::off_type off_type;
79 // logbuf( streambuf* sb ) : sbuf(sb) {}
83 // Is logging enabled?
84 bool enabled() { return logging_enabled; }
86 // Set the logging level of subsequent messages.
87 void set_log_state( fgDebugClass c, fgDebugPriority p );
89 // Set the global logging level.
90 static void set_log_level( fgDebugClass c, fgDebugPriority p );
93 void set_sb( streambuf* sb );
97 inline virtual int sync();
98 int_type overflow( int ch );
99 // int xsputn( const char* s, istreamsize n );
103 // The streambuf used for actual output. Defaults to cerr.rdbuf().
104 static streambuf* sbuf;
106 static bool logging_enabled;
107 static fgDebugClass logClass;
108 static fgDebugPriority logPriority;
113 logbuf( const logbuf& );
114 void operator= ( const logbuf& );
120 #ifdef FG_HAVE_STD_INCLUDES
121 return sbuf->pubsync();
128 logbuf::set_log_state( fgDebugClass c, fgDebugPriority p )
130 logging_enabled = ((c & logClass) != 0 && p >= logPriority);
133 inline logbuf::int_type
134 logbuf::overflow( int c )
136 return logging_enabled ? sbuf->sputc(c) : (EOF == 0 ? 1: 0);
139 //-----------------------------------------------------------------------------
141 // logstream manipulator for setting the log level of a message.
145 loglevel( fgDebugClass c, fgDebugPriority p )
146 : logClass(c), logPriority(p) {}
148 fgDebugClass logClass;
149 fgDebugPriority logPriority;
152 //-----------------------------------------------------------------------------
154 // A helper class that ensures a streambuf and ostream are constructed and
155 // destroyed in the correct order. The streambuf must be created before the
156 // ostream but bases are constructed before members. Thus, making this class
157 // a private base of logstream, declared to the left of ostream, we ensure the
158 // correct order of construction and destruction.
160 struct logstream_base
162 // logstream_base( streambuf* sb ) : lbuf(sb) {}
168 //-----------------------------------------------------------------------------
172 class logstream : private logstream_base, public ostream
175 // The default is to send messages to cerr.
176 logstream( ostream& out )
177 // : logstream_base(out.rdbuf()),
179 ostream(&lbuf) { lbuf.set_sb(out.rdbuf());}
181 void set_output( ostream& out ) { lbuf.set_sb( out.rdbuf() ); }
183 // Set the global log class and priority level.
184 void setLogLevels( fgDebugClass c, fgDebugPriority p );
186 // Output operator to capture the debug level and priority of a message.
187 inline ostream& operator<< ( const loglevel& l );
191 logstream::operator<< ( const loglevel& l )
193 lbuf.set_log_state( l.logClass, l.logPriority );
197 //-----------------------------------------------------------------------------
199 // Return the one and only logstream instance.
200 // We use a function instead of a global object so we are assured that cerr
201 // has been initialised.
206 static logstream logstrm( cerr );
211 # define FG_LOG(C,P,M)
212 #elif defined( __MWERKS__ )
213 # define FG_LOG(C,P,M) ::fglog() << ::loglevel(C,P) << M << std::endl
215 # define FG_LOG(C,P,M) fglog() << loglevel(C,P) << M << endl
218 #endif // _LOGSTREAM_H