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The C Users' Group Library 1994 August
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wc-cdrom-cusersgrouplibrary-1994-08.iso
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v_11_07
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1993-04-28
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122 lines
// MSTREAM.CPP
// Defines the classes required to
// access a secondary monitor for
// debugging.
#ifdef _Windows
#include <windows.h>
extern WORD _B000H; // pointer to global selector
#else
#include <dos.h>
#endif
#include "mstream.h"
#define CPL 80 // Characters Per Line
#define LPP 25 // Lines Per Page
#define ATTR 0x700 // white on black character attribute
mstreambuf::mstreambuf(char* s, int n) : streambuf(s,n)
{
setp(base(),ebuf()); // Initialize the put pointers
if ( screen == 0 ) { // screen pointer needs to be initialized
#ifdef _Windows // Windows will use the predefined global selector
screen = (unsigned int far*) MAKELONG( 0, &_B000H );
#else // DOS will point directly to the MDA memory area
screen = (unsigned int far*) MK_FP( 0xB000, 0 );
#endif
// first time thru we clear the screen
for ( int i = 0; i < (CPL*LPP); i++ )
screen[i] = ' ' + ATTR;
column = row = 0; // reset the current screen character position
}
}
mstreambuf::~mstreambuf()
{
sync(); // flush the put buffer before we leave.
}
void
mstreambuf::newline()
// This routine generates a new line on the mda monitor. It will scroll
// all of the lines on the screen up one line and erases the bottom line
// if it needs it.
{
column = 0; // reset the current column position
row++; // increment the current row pointer
if ( row == LPP ) { // are we at the bottom of the screen?
// move lines 2 thru 25 (LPP) up one line
_fmovmem( &screen[CPL], &screen[0], (CPL*(LPP-1))*2 );
// clear the last line
for ( int i = CPL*(LPP-1); i < (CPL*LPP); i++ )
screen[i] = ATTR + ' ';
row--; // decrement the current row pointer
}
}
int
mstreambuf::overflow( int nChar )
// This routine empties the put
// area and consumes the "nChar"
// character if it is not EOF.
{
sync(); // flush the buffer
if ( nChar != EOF ) // is there a character to consume?
return sputc( nChar ); // store it in the put area, returning the results
else
return 0; // return success otherwise
}
int
mstreambuf::sync()
// This routine flushes the put area.
{
int count = out_waiting(); // get the number of characters in the put area
if ( count ) {
for ( int i=0; i< count; i++ ) {
char c = pbase()[i]; // get each character and send to mda
if ( column == CPL ) // are we at the end of the line?
newline(); // then generate a CR/LF
if ( c == '\n' ) // is the character a CR/LF?
newline(); // then generate a CR/LF here as well
else // send character and attribute to monitor
screen[(CPL*row) + column++] = c + ATTR;
}
setp(base(),ebuf()); // reset the put area pointers
}
return 0;
}
mstream::mstream() : ostream()
// The class constructor. It will
// create a new streambuf using the
// classes character buffer.
{
strbuf = new mstreambuf(msgs,bsize);
// do the actual initialization and associate
// strbuf with ostream
ostream::init(strbuf);
// set flag so that the stream to be flushed after
// each insertion
setf(ios::unitbuf);
}
mstream::~mstream()
// The class destructor.
{
delete strbuf; // delete the streambuf used by the class.
}
// static class member allocation.
// This allocates space and initializes.
unsigned int far* mstreambuf::screen=0; // mda screen memory area
int mstreambuf::column=0; // current screen column position
int mstreambuf::row=0; // current screen line position
#ifndef __DLL__
mstream mout; // create a global instance of mstream for everyone to use.
#endif