Re: Log class problems

["Ilya A. Volynets-Evenbakh" <ilya@total-knowledge.com>]

OK.
Take a look at
http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/classstd_1_1basic__streambuf.html#std_1_1basic__streambufb3

See what base class version of overflow does...


Alexey Parshin wrote:

>Since the attachment doesn't work - sending it directly
>
>//#include "stdafx.h"
>#include <iostream>
>#include <strstream>
>
>using namespace std;
>
>class CLogStreamBuf : public streambuf {
>   iostream *m_parent;
>   char     *m_start;
>   char     *m_end;
>   char     *m_buffer;
>protected:
>   virtual int_type overflow(int_type c);
>   virtual streamsize xsputn(const char_type* s, streamsize n);
>public:
>   CLogStreamBuf() {
>       m_buffer = new char[16];
>       setbuf(m_buffer,16);
>   }
>   ~CLogStreamBuf() {
>       cout << "Destructor" << endl;
>       delete m_buffer;
>   }
>};
>
>class CLog : public iostream {
>   CLogStreamBuf m_buffer;
>public:
>   CLog() : iostream(&m_buffer),ios(0) {}
>   ~CLog() { flush(); }
>};
>
>streambuf::int_type CLogStreamBuf::overflow(streambuf::int_type c) {
>   int bytes = pptr() - pbase();
>   cout << "in overflow, char = '" << char(c) << "' " << c << " - was " <<
>bytes << " bytes" << endl;
>   streambuf::int_type rc = streambuf::overflow(c);
>   return rc;
>}
>
>streamsize CLogStreamBuf::xsputn(const char_type* s, streamsize n) {
>   int bytes = pptr() - pbase();
>   char *buff = new char[n+1];
>   strncpy(buff,s,n); buff[n] = 0;
>   cout << "in xsputn, str = " << buff << " - was " << bytes << " bytes" <<
>endl;
>   delete buff;
>   streamsize rc = streambuf::xsputn(s,n);
>
>   while ( sgetc() != EOF )  {
>      char ch = sbumpc();
>      //if (ch == 10) cout << endl;
>      //else
>      if (ch >= 10)
>         cout << ch;
>   }
>   return rc;
>}
>
>int main(int argc,char *argv[]) {
>   CLog cl;
>   for (unsigned i = 0; i < 4; i++)
>      cl << "line" << i << " " << 12345 << " out " << endl << endl;
>}
>
>
>
>--
>Alexey Parshin,
>http://www.sptk.net
>
>  
>

-- 
Ilya A. Volynets-Evenbakh
Total Knowledge. CTO
http://www.total-knowledge.com