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Less
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output.c
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C/C++ Source or Header
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1987-06-15
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4KB
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250 lines
/*
* High level routines dealing with the output to the screen.
*/
#include "less.h"
public int errmsgs; /* Count of messages displayed by error() */
extern int sigs;
extern int sc_width, sc_height;
extern int ul_width, ue_width;
extern int so_width, se_width;
extern int bo_width, be_width;
extern int tabstop;
extern int twiddle;
extern int any_display;
extern char *line;
extern char *first_cmd;
/*
* Display the line which is in the line buffer.
*/
public void
put_line()
{
#ifdef AMIGA
register unsigned char *p;
#else
register char *p;
#endif
register int c;
register int column;
extern int auto_wrap, ignaw;
if (sigs)
/*
* Don't output if a signal is pending.
*/
return;
if (line == NULL)
line = (twiddle) ? "~" : "";
column = 0;
#ifdef AMIGA
for (p = (unsigned char *)line; *p != '\0'; p++)
#else
for (p = line; *p != '\0'; p++)
#endif
{
switch (c = *p)
{
case UL_CHAR:
ul_enter();
column += ul_width;
break;
case UE_CHAR:
ul_exit();
column += ue_width;
break;
case BO_CHAR:
bo_enter();
column += bo_width;
break;
case BE_CHAR:
bo_exit();
column += be_width;
break;
case '\t':
do
{
putchr(' ');
column++;
} while ((column % tabstop) != 0);
break;
case '\b':
putbs();
column--;
break;
default:
if (c & 0200)
{
/*
* Control characters arrive here as the
* normal character [carat_char(c)] with
* the 0200 bit set. See pappend().
*/
putchr('^');
putchr(c & 0177);
column += 2;
} else
{
putchr(c);
column++;
}
}
}
if (column < sc_width || !auto_wrap || ignaw)
putchr('\n');
}
/*
* Is a given character a "control" character?
* {{ ASCII DEPENDENT }}
*/
public int
control_char(c)
int c;
{
return (c < ' ' || c == '\177');
}
/*
* Return the printable character used to identify a control character
* (printed after a carat; e.g. '\3' => "^C").
* {{ ASCII DEPENDENT }}
*/
public int
carat_char(c)
int c;
{
return ((c == '\177') ? '?' : (c | 0100));
}
static char obuf[1024];
static char *ob = obuf;
/*
* Flush buffered output.
*/
public void
flush()
{
#ifdef AMIGA
extern struct FileHandle *tty;
extern nrow;
if (nrow == 0)
ttopen();
ttflush();
Write(tty, obuf, (long) ob-obuf);
#else
write(1, obuf, ob-obuf);
#endif
ob = obuf;
}
/*
* Discard buffered output.
*/
public void
dropout()
{
ob = obuf;
}
/*
* Output a character.
*/
public void
putchr(c)
int c;
{
if (ob >= &obuf[sizeof(obuf)])
flush();
*ob++ = c;
}
/*
* Output a string.
*/
public void
putstr(s)
register char *s;
{
while (*s != '\0')
putchr(*s++);
}
/*
* Output a message in the lower left corner of the screen
* and wait for carriage return.
*/
static char return_to_continue[] = " (press RETURN)";
public void
error(s)
char *s;
{
register int c;
static char buf[2];
errmsgs++;
if (!any_display)
{
/*
* Nothing has been displayed yet.
* Output this message on error output (file
* descriptor 2) and don't wait for a keystroke
* to continue.
*
* This has the desirable effect of producing all
* error messages on error output if standard output
* is directed to a file. It also does the same if
* we never produce any real output; for example, if
* the input file(s) cannot be opened. If we do
* eventually produce output, code in edit() makes
* sure these messages can be seen before they are
* overwritten or scrolled away.
*/
write(2, s, strlen(s));
write(2, "\n", 1);
return;
}
lower_left();
clear_eol();
so_enter();
putstr(s);
putstr(return_to_continue);
so_exit();
#if ONLY_RETURN
while ((c = getchr()) != '\n' && c != '\r')
bell();
#else
c = getchr();
if (c != '\n' && c != '\r' && c != ' ')
{
buf[0] = c;
first_cmd = buf;
}
#endif
lower_left();
if (strlen(s) + sizeof(return_to_continue) +
so_width + se_width + 1 > sc_width)
/*
* Printing the message has probably scrolled the screen.
* {{ Unless the terminal doesn't have auto margins,
* in which case we just hammered on the right margin. }}
*/
repaint();
flush();
}