/* $NetBSD: line.c,v 1.5 2003/10/13 14:34:25 agc Exp $ */
/*
* Copyright (c) 1988 Mark Nudelman
* Copyright (c) 1988, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
#ifndef lint
#if 0
static char sccsid[] = "@(#)line.c 8.1 (Berkeley) 6/6/93";
#else
__RCSID("$NetBSD: line.c,v 1.5 2003/10/13 14:34:25 agc Exp $");
#endif
#endif /* not lint */
/*
* Routines to manipulate the "line buffer".
* The line buffer holds a line of output as it is being built
* in preparation for output to the screen.
* We keep track of the PRINTABLE length of the line as it is being built.
*/
#include <sys/types.h>
#include <ctype.h>
#include "less.h"
#include "extern.h"
static char linebuf[1024]; /* Buffer which holds the current output line */
static char *curr; /* Pointer into linebuf */
static int column; /* Printable length, accounting for
backspaces, etc. */
/*
* A ridiculously complex state machine takes care of backspaces. The
* complexity arises from the attempt to deal with all cases, especially
* involving long lines with underlining, boldfacing or whatever. There
* are still some cases which will break it.
*
* There are four states:
* LN_NORMAL is the normal state (not in underline mode).
* LN_UNDERLINE means we are in underline mode. We expect to get
* either a sequence like "_\bX" or "X\b_" to continue
* underline mode, or anything else to end underline mode.
* LN_BOLDFACE means we are in boldface mode. We expect to get sequences
* like "X\bX\b...X\bX" to continue boldface mode, or anything
* else to end boldface mode.
* LN_UL_X means we are one character after LN_UNDERLINE
* (we have gotten the '_' in "_\bX" or the 'X' in "X\b_").
* LN_UL_XB means we are one character after LN_UL_X
* (we have gotten the backspace in "_\bX" or "X\b_";
* we expect one more ordinary character,
* which will put us back in state LN_UNDERLINE).
* LN_BO_X means we are one character after LN_BOLDFACE
* (we have gotten the 'X' in "X\bX").
* LN_BO_XB means we are one character after LN_BO_X
* (we have gotten the backspace in "X\bX";
* we expect one more 'X' which will put us back
* in LN_BOLDFACE).
*/
static int ln_state; /* Currently in normal/underline/bold/etc mode? */
#define LN_NORMAL 0 /* Not in underline, boldface or whatever mode */
#define LN_UNDERLINE 1 /* In underline, need next char */
#define LN_UL_X 2 /* In underline, got char, need \b */
#define LN_UL_XB 3 /* In underline, got char & \b, need one more */
#define LN_BOLDFACE 4 /* In boldface, need next char */
#define LN_BO_X 5 /* In boldface, got char, need \b */
#define LN_BO_XB 6 /* In boldface, got char & \b, need same char */
char *line; /* Pointer to the current line.
Usually points to linebuf. */
/*
* Rewind the line buffer.
*/
void
prewind()
{
line = curr = linebuf;
ln_state = LN_NORMAL;
column = 0;
}
/*
* Append a character to the line buffer.
* Expand tabs into spaces, handle underlining, boldfacing, etc.
* Returns 0 if ok, 1 if couldn't fit in buffer.
*/
#define NEW_COLUMN(addon) \
if (column + addon + (ln_state ? ue_width : 0) > sc_width) \
return(1); \
else \
column += addon
int
pappend(c)
int c;
{
if (c == '\0') {
/*
* Terminate any special modes, if necessary.
* Append a '\0' to the end of the line.
*/
switch (ln_state) {
case LN_UL_X:
curr[0] = curr[-1];
curr[-1] = UE_CHAR;
curr++;
break;
case LN_BO_X:
curr[0] = curr[-1];
curr[-1] = BE_CHAR;
curr++;
break;
case LN_UL_XB:
case LN_UNDERLINE:
*curr++ = UE_CHAR;
break;
case LN_BO_XB:
case LN_BOLDFACE:
*curr++ = BE_CHAR;
break;
}
ln_state = LN_NORMAL;
*curr = '\0';
return(0);
}
if (curr > linebuf + sizeof(linebuf) - 12)
/*
* Almost out of room in the line buffer.
* Don't take any chances.
* {{ Linebuf is supposed to be big enough that this
* will never happen, but may need to be made
* bigger for wide screens or lots of backspaces. }}
*/
return(1);
if (!bs_mode) {
/*
* Advance the state machine.
*/
switch (ln_state) {
case LN_NORMAL:
if (curr <= linebuf + 1
|| curr[-1] != (char)('H' | 0200))
break;
column -= 2;
if (c == curr[-2])
goto enter_boldface;
if (c == '_' || curr[-2] == '_')
goto enter_underline;
curr -= 2;
break;
enter_boldface:
/*
* We have "X\bX" (including the current char).
* Switch into boldface mode.
*/
column--;
if (column + bo_width + be_width + 1 >= sc_width)
/*
* Not enough room left on the screen to
* enter and exit boldface mode.
*/
return (1);
if (bo_width > 0 && curr > linebuf + 2
&& curr[-3] == ' ') {
/*
* Special case for magic cookie terminals:
* if the previous char was a space, replace
* it with the "enter boldface" sequence.
*/
curr[-3] = BO_CHAR;
column += bo_width-1;
} else {
curr[-1] = curr[-2];
curr[-2] = BO_CHAR;
column += bo_width;
curr++;
}
goto ln_bo_xb_case;
enter_underline:
/*
* We have either "_\bX" or "X\b_" (including
* the current char). Switch into underline mode.
*/
column--;
if (column + ul_width + ue_width + 1 >= sc_width)
/*
* Not enough room left on the screen to
* enter and exit underline mode.
*/
return (1);
if (ul_width > 0 &&
curr > linebuf + 2 && curr[-3] == ' ')
{
/*
* Special case for magic cookie terminals:
* if the previous char was a space, replace
* it with the "enter underline" sequence.
*/
curr[-3] = UL_CHAR;
column += ul_width-1;
} else
{
curr[-1] = curr[-2];
curr[-2] = UL_CHAR;
column += ul_width;
curr++;
}
goto ln_ul_xb_case;
/*NOTREACHED*/
case LN_UL_XB:
/*
* Termination of a sequence "_\bX" or "X\b_".
*/
if (c != '_' && curr[-2] != '_' && c == curr[-2])
{
/*
* We seem to have run on from underlining
* into boldfacing - this is a nasty fix, but
* until this whole routine is rewritten as a
* real DFA, ... well ...
*/
curr[0] = curr[-2];
curr[-2] = UE_CHAR;
curr[-1] = BO_CHAR;
curr += 2; /* char & non-existent backspace */
ln_state = LN_BO_XB;
goto ln_bo_xb_case;
}
ln_ul_xb_case:
if (c == '_')
c = curr[-2];
curr -= 2;
ln_state = LN_UNDERLINE;
break;
case LN_BO_XB:
/*
* Termination of a sequnce "X\bX".
*/
if (c != curr[-2] && (c == '_' || curr[-2] == '_'))
{
/*
* We seem to have run on from
* boldfacing into underlining.
*/
curr[0] = curr[-2];
curr[-2] = BE_CHAR;
curr[-1] = UL_CHAR;
curr += 2; /* char & non-existent backspace */
ln_state = LN_UL_XB;
goto ln_ul_xb_case;
}
ln_bo_xb_case:
curr -= 2;
ln_state = LN_BOLDFACE;
break;
case LN_UNDERLINE:
if (column + ue_width + bo_width + 1 + be_width >= sc_width)
/*
* We have just barely enough room to
* exit underline mode and handle a possible
* underline/boldface run on mixup.
*/
return (1);
ln_state = LN_UL_X;
break;
case LN_BOLDFACE:
if (c == '\b')
{
ln_state = LN_BO_XB;
break;
}
if (column + be_width + ul_width + 1 + ue_width >= sc_width)
/*
* We have just barely enough room to
* exit underline mode and handle a possible
* underline/boldface run on mixup.
*/
return (1);
ln_state = LN_BO_X;
break;
case LN_UL_X:
if (c == '\b')
ln_state = LN_UL_XB;
else
{
/*
* Exit underline mode.
* We have to shuffle the chars a bit
* to make this work.
*/
curr[0] = curr[-1];
curr[-1] = UE_CHAR;
column += ue_width;
if (ue_width > 0 && curr[0] == ' ')
/*
* Another special case for magic
* cookie terminals: if the next
* char is a space, replace it
* with the "exit underline" sequence.
*/
column--;
else
curr++;
ln_state = LN_NORMAL;
}
break;
case LN_BO_X:
if (c == '\b')
ln_state = LN_BO_XB;
else
{
/*
* Exit boldface mode.
* We have to shuffle the chars a bit
* to make this work.
*/
curr[0] = curr[-1];
curr[-1] = BE_CHAR;
column += be_width;
if (be_width > 0 && curr[0] == ' ')
/*
* Another special case for magic
* cookie terminals: if the next
* char is a space, replace it
* with the "exit boldface" sequence.
*/
column--;
else
curr++;
ln_state = LN_NORMAL;
}
break;
}
}
if (c == '\t') {
/*
* Expand a tab into spaces.
*/
do {
NEW_COLUMN(1);
} while ((column % tabstop) != 0);
*curr++ = '\t';
return (0);
}
if (c == '\b') {
if (ln_state == LN_NORMAL)
NEW_COLUMN(2);
else
column--;
*curr++ = ('H' | 0200);
return(0);
}
if (CONTROL_CHAR(c)) {
/*
* Put a "^X" into the buffer. The 0200 bit is used to tell
* put_line() to prefix the char with a ^. We don't actually
* put the ^ in the buffer because we sometimes need to move
* chars around, and such movement might separate the ^ from
* its following character.
*/
NEW_COLUMN(2);
*curr++ = (CARAT_CHAR(c) | 0200);
return(0);
}
/*
* Ordinary character. Just put it in the buffer.
*/
NEW_COLUMN(1);
*curr++ = c;
return (0);
}
/*
* Analogous to forw_line(), but deals with "raw lines":
* lines which are not split for screen width.
* {{ This is supposed to be more efficient than forw_line(). }}
*/
off_t
forw_raw_line(curr_pos)
off_t curr_pos;
{
char *p;
int c;
off_t new_pos;
if (curr_pos == NULL_POSITION || ch_seek(curr_pos) ||
(c = ch_forw_get()) == EOI)
return (NULL_POSITION);
p = linebuf;
for (;;)
{
if (c == '\n' || c == EOI)
{
new_pos = ch_tell();
break;
}
if (p >= &linebuf[sizeof(linebuf)-1])
{
/*
* Overflowed the input buffer.
* Pretend the line ended here.
* {{ The line buffer is supposed to be big
* enough that this never happens. }}
*/
new_pos = ch_tell() - 1;
break;
}
*p++ = c;
c = ch_forw_get();
}
*p = '\0';
line = linebuf;
return (new_pos);
}
/*
* Analogous to back_line(), but deals with "raw lines".
* {{ This is supposed to be more efficient than back_line(). }}
*/
off_t
back_raw_line(curr_pos)
off_t curr_pos;
{
char *p;
int c;
off_t new_pos;
if (curr_pos == NULL_POSITION || curr_pos <= (off_t)0 ||
ch_seek(curr_pos-1))
return (NULL_POSITION);
p = &linebuf[sizeof(linebuf)];
*--p = '\0';
for (;;)
{
c = ch_back_get();
if (c == '\n')
{
/*
* This is the newline ending the previous line.
* We have hit the beginning of the line.
*/
new_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.
*/
new_pos = (off_t)0;
break;
}
if (p <= linebuf)
{
/*
* Overflowed the input buffer.
* Pretend the line ended here.
*/
new_pos = ch_tell() + 1;
break;
}
*--p = c;
}
line = p;
return (new_pos);
}