/*
* Copyright (C) 1984-2023 Mark Nudelman
*
* You may distribute under the terms of either the GNU General Public
* License or the Less License, as specified in the README file.
*
* For more information, see the README file.
*/
/*
* High level routines dealing with getting lines of input
* from the file being viewed.
*
* When we speak of "lines" here, we mean PRINTABLE lines;
* lines processed with respect to the screen width.
* We use the term "raw line" to refer to lines simply
* delimited by newlines; not processed with respect to screen width.
*/
#include "less.h"
extern int squeeze;
extern int hshift;
extern int quit_if_one_screen;
extern int sigs;
extern int ignore_eoi;
extern int status_col;
extern int wordwrap;
extern POSITION start_attnpos;
extern POSITION end_attnpos;
#if HILITE_SEARCH
extern int hilite_search;
extern int size_linebuf;
extern int show_attn;
#endif
/*
* Set the status column.
* base Position of first char in line.
* disp First visible char.
* Different than base_pos if line is shifted.
* edisp Last visible char.
* eol End of line. Normally the newline.
* Different than edisp if line is chopped.
*/
static void init_status_col(POSITION base_pos, POSITION disp_pos, POSITION edisp_pos, POSITION eol_pos)
{
int hl_before = (chop_line() && disp_pos != NULL_POSITION) ?
is_hilited_attr(base_pos, disp_pos, TRUE, NULL) : 0;
int hl_after = (chop_line()) ?
is_hilited_attr(edisp_pos, eol_pos, TRUE, NULL) : 0;
int attr;
char ch;
/*
* Get the next line.
* A "current" position is passed and a "new" position is returned.
* The current position is the position of the first character of
* a line. The new position is the position of the first character
* of the NEXT line. The line obtained is the line starting at curr_pos.
*/
public POSITION forw_line_seg(POSITION curr_pos, int skipeol, int rscroll, int nochop)
{
POSITION base_pos;
POSITION new_pos;
POSITION edisp_pos;
int c;
int blankline;
int endline;
int chopped;
int backchars;
POSITION wrap_pos;
int skipped_leading;
get_forw_line:
if (curr_pos == NULL_POSITION)
{
null_line();
return (NULL_POSITION);
}
#if HILITE_SEARCH
if (hilite_search == OPT_ONPLUS || is_filtering() || status_col)
{
/*
* If we are ignoring EOI (command F), only prepare
* one line ahead, to avoid getting stuck waiting for
* slow data without displaying the data we already have.
* If we're not ignoring EOI, we *could* do the same, but
* for efficiency we prepare several lines ahead at once.
*/
prep_hilite(curr_pos, curr_pos + 3*size_linebuf,
ignore_eoi ? 1 : -1);
curr_pos = next_unfiltered(curr_pos);
}
#endif
if (ch_seek(curr_pos))
{
null_line();
return (NULL_POSITION);
}
/*
* Step back to the beginning of the line.
*/
base_pos = curr_pos;
for (;;)
{
if (ABORT_SIGS())
{
null_line();
return (NULL_POSITION);
}
c = ch_back_get();
if (c == EOI)
break;
if (c == '\n')
{
(void) ch_forw_get();
break;
}
--base_pos;
}
/*
* Read forward again to the position we should start at.
*/
prewind();
plinestart(base_pos);
(void) ch_seek(base_pos);
new_pos = base_pos;
while (new_pos < curr_pos)
{
if (ABORT_SIGS())
{
null_line();
return (NULL_POSITION);
}
c = ch_forw_get();
backchars = pappend(c, new_pos);
new_pos++;
if (backchars > 0)
{
pshift_all();
if (wordwrap && (c == ' ' || c == '\t'))
{
do
{
new_pos++;
c = ch_forw_get();
} while (c == ' ' || c == '\t');
backchars = 1;
}
new_pos -= backchars;
while (--backchars >= 0)
(void) ch_back_get();
}
}
(void) pflushmbc();
pshift_all();
/*
* Read the first character to display.
*/
c = ch_forw_get();
if (c == EOI)
{
null_line();
return (NULL_POSITION);
}
blankline = (c == '\n' || c == '\r');
wrap_pos = NULL_POSITION;
skipped_leading = FALSE;
/*
* Read each character in the line and append to the line buffer.
*/
chopped = FALSE;
for (;;)
{
if (ABORT_SIGS())
{
null_line();
return (NULL_POSITION);
}
if (c == '\n' || c == EOI)
{
/*
* End of the line.
*/
backchars = pflushmbc();
new_pos = ch_tell();
if (backchars > 0 && (nochop || !chop_line()) && hshift == 0)
{
new_pos -= backchars + 1;
endline = FALSE;
} else
endline = TRUE;
edisp_pos = new_pos;
break;
}
if (c != '\r')
blankline = 0;
/*
* Append the char to the line and get the next char.
*/
backchars = pappend(c, ch_tell()-1);
if (backchars > 0)
{
/*
* The char won't fit in the line; the line
* is too long to print in the screen width.
* End the line here.
*/
if (skipeol)
{
/* Read to end of line. */
edisp_pos = ch_tell();
do
{
if (ABORT_SIGS())
{
null_line();
return (NULL_POSITION);
}
c = ch_forw_get();
} while (c != '\n' && c != EOI);
new_pos = ch_tell();
endline = TRUE;
quit_if_one_screen = FALSE;
chopped = TRUE;
} else
{
if (!wordwrap)
new_pos = ch_tell() - backchars;
else
{
/*
* We're word-wrapping, so go back to the last space.
* However, if it's the space itself that couldn't fit,
* simply ignore it and any subsequent spaces.
*/
if (c == ' ' || c == '\t')
{
do
{
new_pos = ch_tell();
c = ch_forw_get();
} while (c == ' ' || c == '\t');
if (c == '\r')
c = ch_forw_get();
if (c == '\n')
new_pos = ch_tell();
} else if (wrap_pos == NULL_POSITION)
new_pos = ch_tell() - backchars;
else
{
new_pos = wrap_pos;
loadc();
}
}
endline = FALSE;
}
break;
}
if (wordwrap)
{
if (c == ' ' || c == '\t')
{
if (skipped_leading)
{
wrap_pos = ch_tell();
savec();
}
} else
skipped_leading = TRUE;
}
c = ch_forw_get();
}
#if HILITE_SEARCH
if (blankline && show_attn)
{
/* Add spurious space to carry possible attn hilite. */
pappend(' ', ch_tell()-1);
}
#endif
pdone(endline, rscroll && chopped, 1);
#if HILITE_SEARCH
if (is_filtered(base_pos))
{
/*
* We don't want to display this line.
* Get the next line.
*/
curr_pos = new_pos;
goto get_forw_line;
}
if (status_col)
init_status_col(base_pos, line_position(), edisp_pos, new_pos);
#endif
if (squeeze && blankline)
{
/*
* This line is blank.
* Skip down to the last contiguous blank line
* and pretend it is the one which we are returning.
*/
while ((c = ch_forw_get()) == '\n' || c == '\r')
if (ABORT_SIGS())
{
null_line();
return (NULL_POSITION);
}
if (c != EOI)
(void) ch_back_get();
new_pos = ch_tell();
}
/*
* Get the previous line.
* A "current" position is passed and a "new" position is returned.
* The current position is the position of the first character of
* a line. The new position is the position of the first character
* of the PREVIOUS line. The line obtained is the one starting at new_pos.
*/
public POSITION back_line(POSITION curr_pos)
{
POSITION base_pos;
POSITION new_pos;
POSITION edisp_pos;
POSITION begin_new_pos;
int c;
int endline;
int chopped;
int backchars;
POSITION wrap_pos;
int skipped_leading;
if (squeeze)
{
/*
* Find out if the "current" line was blank.
*/
(void) ch_forw_get(); /* Skip the newline */
c = ch_forw_get(); /* First char of "current" line */
(void) ch_back_get(); /* Restore our position */
(void) ch_back_get();
if (c == '\n' || c == '\r')
{
/*
* The "current" line was blank.
* Skip over any preceding blank lines,
* since we skipped them in forw_line().
*/
while ((c = ch_back_get()) == '\n' || c == '\r')
if (ABORT_SIGS())
{
null_line();
return (NULL_POSITION);
}
if (c == EOI)
{
null_line();
return (NULL_POSITION);
}
(void) ch_forw_get();
}
}
/*
* Scan backwards until we hit the beginning of the line.
*/
for (;;)
{
if (ABORT_SIGS())
{
null_line();
return (NULL_POSITION);
}
c = ch_back_get();
if (c == '\n')
{
/*
* This is the newline ending the previous line.
* We have hit the beginning of the line.
*/
base_pos = ch_tell() + 1;
break;
}
if (c == EOI)
{
/*
* We have hit the beginning of the file.
* This must be the first line in the file.
* This must, of course, be the beginning of the line.
*/
base_pos = ch_tell();
break;
}
}
/*
* Now scan forwards from the beginning of this line.
* We keep discarding "printable lines" (based on screen width)
* until we reach the curr_pos.
*
* {{ This algorithm is pretty inefficient if the lines
* are much longer than the screen width,
* but I don't know of any better way. }}
*/
new_pos = base_pos;
if (ch_seek(new_pos))
{
null_line();
return (NULL_POSITION);
}
endline = FALSE;
prewind();
plinestart(new_pos);
loop:
wrap_pos = NULL_POSITION;
skipped_leading = FALSE;
begin_new_pos = new_pos;
(void) ch_seek(new_pos);
chopped = FALSE;
for (;;)
{
c = ch_forw_get();
if (c == EOI || ABORT_SIGS())
{
null_line();
return (NULL_POSITION);
}
new_pos++;
if (c == '\n')
{
backchars = pflushmbc();
if (backchars > 0 && !chop_line() && hshift == 0)
{
backchars++;
goto shift;
}
endline = TRUE;
edisp_pos = new_pos;
break;
}
backchars = pappend(c, ch_tell()-1);
if (backchars > 0)
{
/*
* Got a full printable line, but we haven't
* reached our curr_pos yet. Discard the line
* and start a new one.
*/
if (chop_line() || hshift > 0)
{
endline = TRUE;
chopped = TRUE;
quit_if_one_screen = FALSE;
edisp_pos = new_pos;
break;
}
shift:
if (!wordwrap)
{
pshift_all();
new_pos -= backchars;
} else
{
if (c == ' ' || c == '\t')
{
for (;;)
{
c = ch_forw_get();
if (c == ' ' || c == '\t')
new_pos++;
else
{
if (c == '\r')
{
c = ch_forw_get();
if (c == '\n')
new_pos++;
}
if (c == '\n')
new_pos++;
break;
}
}
if (new_pos >= curr_pos)
break;
pshift_all();
} else
{
pshift_all();
if (wrap_pos == NULL_POSITION)
new_pos -= backchars;
else
new_pos = wrap_pos;
}
}
goto loop;
}
if (wordwrap)
{
if (c == ' ' || c == '\t')
{
if (skipped_leading)
wrap_pos = new_pos;
} else
skipped_leading = TRUE;
}
if (new_pos >= curr_pos)
{
edisp_pos = new_pos;
break;
}
}
pdone(endline, chopped, 0);
#if HILITE_SEARCH
if (is_filtered(base_pos))
{
/*
* We don't want to display this line.
* Get the previous line.
*/
curr_pos = begin_new_pos;
goto get_back_line;
}
if (status_col)
init_status_col(base_pos, line_position(), edisp_pos, new_pos);
#endif
return (begin_new_pos);
}
/*
* Set attnpos.
*/
public void set_attnpos(POSITION pos)
{
int c;
if (pos != NULL_POSITION)
{
if (ch_seek(pos))
return;
for (;;)
{
c = ch_forw_get();
if (c == EOI)
break;
if (c == '\n' || c == '\r')
{
(void) ch_back_get();
break;
}
pos++;
}
end_attnpos = pos;
for (;;)
{
c = ch_back_get();
if (c == EOI || c == '\n' || c == '\r')
break;
pos--;
}
}
start_attnpos = pos;
}
