20d6e5fe6e
of user keys (documentation pending). The only key whose semantics have changed is the capital 'N' key, which now performs a repeat-search in the opposite direction (just like in vi). This commit is a little bulkier than what I had originally planned. I'm not completely happy with the direction it went, but it's definately an improvement, and the alternative is to continue becoming irrelevant compared to GNU less. (Does anyone even _use_ /usr/bin/more these days?)
271 lines
6.9 KiB
C
271 lines
6.9 KiB
C
/*
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* Copyright (c) 1988 Mark Nudleman
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* Copyright (c) 1988, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef lint
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static char sccsid[] = "@(#)input.c 8.1 (Berkeley) 6/6/93";
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#endif /* not lint */
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#ifndef lint
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static const char rcsid[] =
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"$FreeBSD$";
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#endif /* not lint */
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/*
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* High level routines dealing with getting lines of input
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* from the file being viewed.
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*
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* When we speak of "lines" here, we mean PRINTABLE lines;
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* lines processed with respect to the screen width.
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* We use the term "raw line" to refer to lines simply
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* delimited by newlines; not processed with respect to screen width.
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*/
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#include <sys/types.h>
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#include "less.h"
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/* NOTE!: if (wraplines) assert (horiz_off == 0) */
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int horiz_off = 0; /* # characters scrolled off left of screen */
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int wraplines = 1; /* wrap lines around screen, yes or no */
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extern int squeeze;
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extern int sigs;
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extern char *line;
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off_t ch_tell();
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/*
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* Get the next printable line.
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*
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* A "current" position is passed and a "new" position is returned.
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* The current position is the position of the first character of
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* a line. The new position is the position of the first character
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* of the NEXT line. The line obtained is the line starting at curr_pos.
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* It is placed into the global line buffer ("line").
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*/
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off_t
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forw_line(curr_pos)
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off_t curr_pos;
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{
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off_t new_pos;
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register int c;
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if (curr_pos == NULL_POSITION || ch_seek(curr_pos))
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return (NULL_POSITION);
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c = ch_forw_get();
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if (c == EOI)
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return (NULL_POSITION);
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prewind();
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for (;;)
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{
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if (sigs)
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return (NULL_POSITION);
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if (c == '\n' || c == EOI)
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{
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/*
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* End of the line.
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*/
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new_pos = ch_tell();
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break;
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}
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/*
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* Append the char to the line and get the next char.
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* The pappend() will throw away any unimportant chars
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* (ie. not underlines or bolds) as per wraplines.
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*
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* XXX line.c needs to be rewritten...
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*/
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if (pappend(c))
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{
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/*
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* The char won't fit in the line; the line
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* is too long to print in the screen width.
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* End the line here.
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*/
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if (!wraplines) {
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/* Throw away left-over characters on line */
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c = ch_forw_get();
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while (c != '\n' && c != EOI)
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c = ch_forw_get();
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new_pos = ch_tell();
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} else {
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new_pos = ch_tell() - 1;
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}
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break;
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}
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c = ch_forw_get();
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}
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(void) pappend('\0');
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if (squeeze && *line == '\0')
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{
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/*
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* This line is blank.
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* Skip down to the last contiguous blank line
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* and pretend it is the one which we are returning.
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*/
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while ((c = ch_forw_get()) == '\n')
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if (sigs)
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return (NULL_POSITION);
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if (c != EOI)
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(void) ch_back_get();
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new_pos = ch_tell();
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}
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return (new_pos);
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}
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/*
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* Get the previous line.
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*
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* A "current" position is passed and a "new" position is returned.
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* The current position is the position of the first character of
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* a line. The new position is the position of the first character
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* of the PREVIOUS line. The line obtained is the one starting at new_pos.
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* It is placed into the global line buffer ("line").
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*/
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off_t
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back_line(curr_pos)
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off_t curr_pos;
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{
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off_t new_pos, begin_new_pos;
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int c;
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if (curr_pos == NULL_POSITION || curr_pos <= (off_t)0 ||
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ch_seek(curr_pos-1))
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return (NULL_POSITION);
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if (squeeze)
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{
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/*
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* Find out if the "current" line was blank.
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*/
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(void) ch_forw_get(); /* Skip the newline */
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c = ch_forw_get(); /* First char of "current" line */
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(void) ch_back_get(); /* Restore our position */
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(void) ch_back_get();
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if (c == '\n')
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{
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/*
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* The "current" line was blank.
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* Skip over any preceeding blank lines,
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* since we skipped them in forw_line().
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*/
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while ((c = ch_back_get()) == '\n')
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if (sigs)
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return (NULL_POSITION);
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if (c == EOI)
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return (NULL_POSITION);
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(void) ch_forw_get();
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}
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}
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/*
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* Scan backwards until we hit the beginning of the line.
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*/
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for (;;)
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{
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if (sigs)
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return (NULL_POSITION);
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c = ch_back_get();
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if (c == '\n')
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{
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/*
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* This is the newline ending the previous line.
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* We have hit the beginning of the line.
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*/
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new_pos = ch_tell() + 1;
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break;
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}
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if (c == EOI)
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{
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/*
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* We have hit the beginning of the file.
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* This must be the first line in the file.
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* This must, of course, be the beginning of the line.
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*/
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new_pos = ch_tell();
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break;
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}
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}
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/*
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* Now scan forwards from the beginning of this line.
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* We keep discarding "printable lines" (based on screen width)
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* until we reach the curr_pos.
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*
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* {{ This algorithm is pretty inefficient if the lines
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* are much longer than the screen width,
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* but I don't know of any better way. }}
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*/
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if (ch_seek(new_pos))
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return (NULL_POSITION);
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loop:
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begin_new_pos = new_pos;
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prewind();
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do
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{
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c = ch_forw_get();
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if (c == EOI || sigs)
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return (NULL_POSITION);
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new_pos++;
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if (c == '\n')
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break;
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if (pappend(c))
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{
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if (wraplines) {
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/*
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* Got a full printable line, but we haven't
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* reached our curr_pos yet. Discard the line
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* and start a new one.
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*/
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(void) pappend('\0');
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(void) ch_back_get();
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new_pos--;
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goto loop;
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} else
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break; /* Got everything we need */
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}
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} while (new_pos < curr_pos);
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(void) pappend('\0');
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return (begin_new_pos);
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}
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