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1ea316270f
compiler-time type checking, and also causes problems for targets where multiple incompatible calling conventions may be selected based on argument types. This change switches less(1) to ANSI prototypes. While there, we also remove use of "register", and attempt to use "const" a bit better now that the compiler can check argument types. Reviewed by: cem, emaste MFC after: 3 weeks Sponsored by: DARPA, AFRL Differential Revision: https://reviews.freebsd.org/D10152
461 lines
8.7 KiB
C
461 lines
8.7 KiB
C
/*
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* Copyright (C) 1984-2015 Mark Nudelman
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*
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* You may distribute under the terms of either the GNU General Public
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* License or the Less License, as specified in the README file.
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*
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* For more information, see the README file.
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*/
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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 "less.h"
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extern int squeeze;
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extern int chopline;
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extern int hshift;
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extern int quit_if_one_screen;
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extern int sigs;
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extern int ignore_eoi;
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extern int status_col;
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extern POSITION start_attnpos;
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extern POSITION end_attnpos;
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#if HILITE_SEARCH
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extern int hilite_search;
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extern int size_linebuf;
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#endif
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/*
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* Get the next line.
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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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*/
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public POSITION
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forw_line(POSITION curr_pos)
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{
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POSITION base_pos;
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POSITION new_pos;
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int c;
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int blankline;
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int endline;
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int backchars;
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get_forw_line:
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if (curr_pos == NULL_POSITION)
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{
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null_line();
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return (NULL_POSITION);
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}
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#if HILITE_SEARCH
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if (hilite_search == OPT_ONPLUS || is_filtering() || status_col)
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{
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/*
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* If we are ignoring EOI (command F), only prepare
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* one line ahead, to avoid getting stuck waiting for
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* slow data without displaying the data we already have.
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* If we're not ignoring EOI, we *could* do the same, but
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* for efficiency we prepare several lines ahead at once.
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*/
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prep_hilite(curr_pos, curr_pos + 3*size_linebuf,
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ignore_eoi ? 1 : -1);
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curr_pos = next_unfiltered(curr_pos);
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}
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#endif
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if (ch_seek(curr_pos))
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{
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null_line();
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return (NULL_POSITION);
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}
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/*
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* Step back to the beginning of the line.
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*/
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base_pos = curr_pos;
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for (;;)
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{
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if (ABORT_SIGS())
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{
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null_line();
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return (NULL_POSITION);
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}
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c = ch_back_get();
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if (c == EOI)
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break;
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if (c == '\n')
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{
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(void) ch_forw_get();
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break;
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}
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--base_pos;
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}
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/*
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* Read forward again to the position we should start at.
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*/
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prewind();
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plinenum(base_pos);
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(void) ch_seek(base_pos);
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new_pos = base_pos;
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while (new_pos < curr_pos)
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{
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if (ABORT_SIGS())
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{
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null_line();
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return (NULL_POSITION);
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}
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c = ch_forw_get();
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backchars = pappend(c, new_pos);
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new_pos++;
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if (backchars > 0)
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{
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pshift_all();
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new_pos -= backchars;
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while (--backchars >= 0)
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(void) ch_back_get();
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}
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}
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(void) pflushmbc();
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pshift_all();
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/*
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* Read the first character to display.
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*/
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c = ch_forw_get();
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if (c == EOI)
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{
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null_line();
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return (NULL_POSITION);
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}
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blankline = (c == '\n' || c == '\r');
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/*
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* Read each character in the line and append to the line buffer.
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*/
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for (;;)
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{
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if (ABORT_SIGS())
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{
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null_line();
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return (NULL_POSITION);
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}
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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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backchars = pflushmbc();
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new_pos = ch_tell();
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if (backchars > 0 && !chopline && hshift == 0)
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{
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new_pos -= backchars + 1;
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endline = FALSE;
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} else
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endline = TRUE;
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break;
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}
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if (c != '\r')
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blankline = 0;
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/*
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* Append the char to the line and get the next char.
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*/
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backchars = pappend(c, ch_tell()-1);
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if (backchars > 0)
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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 (chopline || hshift > 0)
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{
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do
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{
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if (ABORT_SIGS())
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{
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null_line();
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return (NULL_POSITION);
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}
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c = ch_forw_get();
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} while (c != '\n' && c != EOI);
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new_pos = ch_tell();
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endline = TRUE;
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quit_if_one_screen = FALSE;
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} else
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{
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new_pos = ch_tell() - backchars;
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endline = FALSE;
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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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pdone(endline, 1);
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#if HILITE_SEARCH
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if (is_filtered(base_pos))
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{
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/*
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* We don't want to display this line.
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* Get the next line.
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*/
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curr_pos = new_pos;
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goto get_forw_line;
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}
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if (status_col && is_hilited(base_pos, ch_tell()-1, 1, NULL))
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set_status_col('*');
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#endif
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if (squeeze && blankline)
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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' || c == '\r')
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if (ABORT_SIGS())
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{
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null_line();
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return (NULL_POSITION);
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}
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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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* 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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*/
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public POSITION
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back_line(POSITION curr_pos)
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{
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POSITION new_pos, begin_new_pos, base_pos;
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int c;
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int endline;
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int backchars;
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get_back_line:
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if (curr_pos == NULL_POSITION || curr_pos <= ch_zero())
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{
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null_line();
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return (NULL_POSITION);
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}
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#if HILITE_SEARCH
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if (hilite_search == OPT_ONPLUS || is_filtering() || status_col)
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prep_hilite((curr_pos < 3*size_linebuf) ?
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0 : curr_pos - 3*size_linebuf, curr_pos, -1);
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#endif
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if (ch_seek(curr_pos-1))
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{
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null_line();
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return (NULL_POSITION);
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}
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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' || c == '\r')
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{
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/*
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* The "current" line was blank.
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* Skip over any preceding 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' || c == '\r')
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if (ABORT_SIGS())
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{
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null_line();
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return (NULL_POSITION);
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}
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if (c == EOI)
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{
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null_line();
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return (NULL_POSITION);
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}
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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 (ABORT_SIGS())
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{
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null_line();
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return (NULL_POSITION);
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}
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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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base_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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base_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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new_pos = base_pos;
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if (ch_seek(new_pos))
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{
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null_line();
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return (NULL_POSITION);
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}
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endline = FALSE;
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prewind();
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plinenum(new_pos);
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loop:
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begin_new_pos = new_pos;
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(void) ch_seek(new_pos);
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do
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{
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c = ch_forw_get();
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if (c == EOI || ABORT_SIGS())
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{
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null_line();
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return (NULL_POSITION);
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}
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new_pos++;
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if (c == '\n')
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{
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backchars = pflushmbc();
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if (backchars > 0 && !chopline && hshift == 0)
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{
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backchars++;
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goto shift;
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}
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endline = TRUE;
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break;
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}
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backchars = pappend(c, ch_tell()-1);
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if (backchars > 0)
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{
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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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if (chopline || hshift > 0)
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{
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endline = TRUE;
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quit_if_one_screen = FALSE;
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break;
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}
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shift:
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pshift_all();
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while (backchars-- > 0)
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{
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(void) ch_back_get();
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new_pos--;
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}
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goto loop;
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}
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} while (new_pos < curr_pos);
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pdone(endline, 0);
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#if HILITE_SEARCH
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if (is_filtered(base_pos))
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{
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/*
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* We don't want to display this line.
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* Get the previous line.
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*/
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curr_pos = begin_new_pos;
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goto get_back_line;
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}
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if (status_col && curr_pos > 0 && is_hilited(base_pos, curr_pos-1, 1, NULL))
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set_status_col('*');
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#endif
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return (begin_new_pos);
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}
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/*
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* Set attnpos.
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*/
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public void
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set_attnpos(POSITION pos)
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{
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int c;
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if (pos != NULL_POSITION)
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{
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if (ch_seek(pos))
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return;
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for (;;)
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{
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c = ch_forw_get();
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if (c == EOI)
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break;
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if (c == '\n' || c == '\r')
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{
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(void) ch_back_get();
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break;
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}
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pos++;
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}
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end_attnpos = pos;
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for (;;)
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{
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c = ch_back_get();
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if (c == EOI || c == '\n' || c == '\r')
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break;
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pos--;
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}
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}
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start_attnpos = pos;
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}
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