mirror of
https://git.FreeBSD.org/src.git
synced 2024-12-23 11:18:54 +00:00
242 lines
6.1 KiB
C
242 lines
6.1 KiB
C
/*
|
|
* Copyright (c) 1988 Mark Nudleman
|
|
* 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. All advertising materials mentioning features or use of this software
|
|
* must display the following acknowledgement:
|
|
* This product includes software developed by the University of
|
|
* California, Berkeley and its contributors.
|
|
* 4. 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.
|
|
*/
|
|
|
|
#ifndef lint
|
|
static char sccsid[] = "@(#)input.c 8.1 (Berkeley) 6/6/93";
|
|
#endif /* not lint */
|
|
|
|
/*
|
|
* 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 <sys/types.h>
|
|
#include <less.h>
|
|
|
|
extern int squeeze;
|
|
extern int sigs;
|
|
extern char *line;
|
|
|
|
off_t ch_tell();
|
|
|
|
/*
|
|
* 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.
|
|
*/
|
|
off_t
|
|
forw_line(curr_pos)
|
|
off_t curr_pos;
|
|
{
|
|
off_t new_pos;
|
|
register int c;
|
|
|
|
if (curr_pos == NULL_POSITION || ch_seek(curr_pos))
|
|
return (NULL_POSITION);
|
|
|
|
c = ch_forw_get();
|
|
if (c == EOI)
|
|
return (NULL_POSITION);
|
|
|
|
prewind();
|
|
for (;;)
|
|
{
|
|
if (sigs)
|
|
return (NULL_POSITION);
|
|
if (c == '\n' || c == EOI)
|
|
{
|
|
/*
|
|
* End of the line.
|
|
*/
|
|
new_pos = ch_tell();
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* Append the char to the line and get the next char.
|
|
*/
|
|
if (pappend(c))
|
|
{
|
|
/*
|
|
* The char won't fit in the line; the line
|
|
* is too long to print in the screen width.
|
|
* End the line here.
|
|
*/
|
|
new_pos = ch_tell() - 1;
|
|
break;
|
|
}
|
|
c = ch_forw_get();
|
|
}
|
|
(void) pappend('\0');
|
|
|
|
if (squeeze && *line == '\0')
|
|
{
|
|
/*
|
|
* 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')
|
|
if (sigs)
|
|
return (NULL_POSITION);
|
|
if (c != EOI)
|
|
(void) ch_back_get();
|
|
new_pos = ch_tell();
|
|
}
|
|
|
|
return (new_pos);
|
|
}
|
|
|
|
/*
|
|
* 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.
|
|
*/
|
|
off_t
|
|
back_line(curr_pos)
|
|
off_t curr_pos;
|
|
{
|
|
off_t new_pos, begin_new_pos;
|
|
int c;
|
|
|
|
if (curr_pos == NULL_POSITION || curr_pos <= (off_t)0 ||
|
|
ch_seek(curr_pos-1))
|
|
return (NULL_POSITION);
|
|
|
|
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')
|
|
{
|
|
/*
|
|
* The "current" line was blank.
|
|
* Skip over any preceeding blank lines,
|
|
* since we skipped them in forw_line().
|
|
*/
|
|
while ((c = ch_back_get()) == '\n')
|
|
if (sigs)
|
|
return (NULL_POSITION);
|
|
if (c == EOI)
|
|
return (NULL_POSITION);
|
|
(void) ch_forw_get();
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Scan backwards until we hit the beginning of the line.
|
|
*/
|
|
for (;;)
|
|
{
|
|
if (sigs)
|
|
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.
|
|
*/
|
|
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 = 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. }}
|
|
*/
|
|
if (ch_seek(new_pos))
|
|
return (NULL_POSITION);
|
|
loop:
|
|
begin_new_pos = new_pos;
|
|
prewind();
|
|
|
|
do
|
|
{
|
|
c = ch_forw_get();
|
|
if (c == EOI || sigs)
|
|
return (NULL_POSITION);
|
|
new_pos++;
|
|
if (c == '\n')
|
|
break;
|
|
if (pappend(c))
|
|
{
|
|
/*
|
|
* Got a full printable line, but we haven't
|
|
* reached our curr_pos yet. Discard the line
|
|
* and start a new one.
|
|
*/
|
|
(void) pappend('\0');
|
|
(void) ch_back_get();
|
|
new_pos--;
|
|
goto loop;
|
|
}
|
|
} while (new_pos < curr_pos);
|
|
|
|
(void) pappend('\0');
|
|
|
|
return (begin_new_pos);
|
|
}
|