625 lines
12 KiB
C
625 lines
12 KiB
C
/*
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* Copyright (C) 1984-2023 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 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 int wordwrap;
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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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extern int show_attn;
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#endif
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/*
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* Set the status column.
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* base Position of first char in line.
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* disp First visible char.
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* Different than base_pos if line is shifted.
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* edisp Last visible char.
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* eol End of line. Normally the newline.
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* Different than edisp if line is chopped.
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*/
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static void init_status_col(POSITION base_pos, POSITION disp_pos, POSITION edisp_pos, POSITION eol_pos)
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{
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int hl_before = (chop_line() && disp_pos != NULL_POSITION) ?
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is_hilited_attr(base_pos, disp_pos, TRUE, NULL) : 0;
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int hl_after = (chop_line()) ?
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is_hilited_attr(edisp_pos, eol_pos, TRUE, NULL) : 0;
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int attr;
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char ch;
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if (hl_before && hl_after)
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{
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attr = hl_after;
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ch = '=';
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} else if (hl_before)
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{
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attr = hl_before;
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ch = '<';
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} else if (hl_after)
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{
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attr = hl_after;
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ch = '>';
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} else
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{
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attr = is_hilited_attr(base_pos, eol_pos, TRUE, NULL);
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ch = '*';
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}
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if (attr)
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set_status_col(ch, attr);
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}
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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 forw_line_seg(POSITION curr_pos, int skipeol, int rscroll, int nochop)
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{
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POSITION base_pos;
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POSITION new_pos;
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POSITION edisp_pos;
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int c;
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int blankline;
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int endline;
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int chopped;
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int backchars;
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POSITION wrap_pos;
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int skipped_leading;
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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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plinestart(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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if (wordwrap && (c == ' ' || c == '\t'))
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{
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do
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{
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new_pos++;
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c = ch_forw_get();
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} while (c == ' ' || c == '\t');
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backchars = 1;
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}
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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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wrap_pos = NULL_POSITION;
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skipped_leading = FALSE;
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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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chopped = FALSE;
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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 && (nochop || !chop_line()) && 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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edisp_pos = new_pos;
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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 (skipeol)
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{
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/* Read to end of line. */
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edisp_pos = ch_tell();
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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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chopped = TRUE;
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} else
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{
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if (!wordwrap)
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new_pos = ch_tell() - backchars;
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else
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{
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/*
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* We're word-wrapping, so go back to the last space.
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* However, if it's the space itself that couldn't fit,
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* simply ignore it and any subsequent spaces.
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*/
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if (c == ' ' || c == '\t')
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{
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do
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{
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new_pos = ch_tell();
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c = ch_forw_get();
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} while (c == ' ' || c == '\t');
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if (c == '\r')
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c = ch_forw_get();
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if (c == '\n')
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new_pos = ch_tell();
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} else if (wrap_pos == NULL_POSITION)
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new_pos = ch_tell() - backchars;
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else
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{
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new_pos = wrap_pos;
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loadc();
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}
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}
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endline = FALSE;
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}
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break;
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}
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if (wordwrap)
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{
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if (c == ' ' || c == '\t')
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{
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if (skipped_leading)
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{
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wrap_pos = ch_tell();
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savec();
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}
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} else
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skipped_leading = TRUE;
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}
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c = ch_forw_get();
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}
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#if HILITE_SEARCH
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if (blankline && show_attn)
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{
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/* Add spurious space to carry possible attn hilite. */
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pappend(' ', ch_tell()-1);
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}
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#endif
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pdone(endline, rscroll && chopped, 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)
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init_status_col(base_pos, line_position(), edisp_pos, new_pos);
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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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public POSITION forw_line(POSITION curr_pos)
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{
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return forw_line_seg(curr_pos, (chop_line() || hshift > 0), TRUE, FALSE);
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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 back_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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POSITION edisp_pos;
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POSITION begin_new_pos;
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int c;
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int endline;
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int chopped;
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int backchars;
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POSITION wrap_pos;
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int skipped_leading;
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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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plinestart(new_pos);
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loop:
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wrap_pos = NULL_POSITION;
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skipped_leading = FALSE;
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begin_new_pos = new_pos;
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(void) ch_seek(new_pos);
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chopped = FALSE;
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for (;;)
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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 && !chop_line() && 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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edisp_pos = new_pos;
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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 (chop_line() || hshift > 0)
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{
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endline = TRUE;
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chopped = TRUE;
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quit_if_one_screen = FALSE;
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edisp_pos = new_pos;
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break;
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}
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shift:
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if (!wordwrap)
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{
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pshift_all();
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new_pos -= backchars;
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} else
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{
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if (c == ' ' || c == '\t')
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{
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for (;;)
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{
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c = ch_forw_get();
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if (c == ' ' || c == '\t')
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new_pos++;
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else
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{
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if (c == '\r')
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{
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c = ch_forw_get();
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if (c == '\n')
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new_pos++;
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}
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if (c == '\n')
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new_pos++;
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break;
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}
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}
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if (new_pos >= curr_pos)
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break;
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pshift_all();
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} else
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{
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pshift_all();
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if (wrap_pos == NULL_POSITION)
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new_pos -= backchars;
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else
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new_pos = wrap_pos;
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}
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}
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goto loop;
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}
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if (wordwrap)
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{
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if (c == ' ' || c == '\t')
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{
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if (skipped_leading)
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wrap_pos = new_pos;
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} else
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skipped_leading = TRUE;
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}
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if (new_pos >= curr_pos)
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{
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edisp_pos = new_pos;
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break;
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}
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}
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pdone(endline, chopped, 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)
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init_status_col(base_pos, line_position(), edisp_pos, new_pos);
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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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*/
|
|
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;
|
|
}
|