719 lines
14 KiB
C
719 lines
14 KiB
C
/*
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* Copyright (C) 1984-2000 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 about less, or for information on how to
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* contact the author, see the README file.
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*/
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/*
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* Routines to manipulate the "line buffer".
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* The line buffer holds a line of output as it is being built
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* in preparation for output to the screen.
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*/
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#include "less.h"
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#define IS_CONT(c) (((c) & 0xC0) == 0x80)
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#define LINENUM_WIDTH 8 /* Chars to use for line number */
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/* Buffer which holds the current output line */
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public char linebuf[LINEBUF_SIZE];
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public int size_linebuf = sizeof(linebuf);
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public int cshift; /* Current left-shift of output line buffer */
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public int hshift; /* Desired left-shift of output line buffer */
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static char attr[LINEBUF_SIZE]; /* Extension of linebuf to hold attributes */
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static int curr; /* Index into linebuf */
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static int column; /* Printable length, accounting for
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backspaces, etc. */
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static int overstrike; /* Next char should overstrike previous char */
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static int is_null_line; /* There is no current line */
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static int lmargin; /* Left margin */
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static char pendc;
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static POSITION pendpos;
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static char *end_ansi_chars;
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static int do_append();
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extern int bs_mode;
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extern int tabstop;
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extern int linenums;
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extern int ctldisp;
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extern int twiddle;
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extern int binattr;
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extern int status_col;
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extern int auto_wrap, ignaw;
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extern int bo_s_width, bo_e_width;
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extern int ul_s_width, ul_e_width;
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extern int bl_s_width, bl_e_width;
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extern int so_s_width, so_e_width;
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extern int sc_width, sc_height;
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extern int utf_mode;
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extern POSITION start_attnpos;
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extern POSITION end_attnpos;
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/*
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* Initialize from environment variables.
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*/
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public void
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init_line()
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{
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end_ansi_chars = lgetenv("LESSANSIENDCHARS");
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if (end_ansi_chars == NULL || *end_ansi_chars == '\0')
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end_ansi_chars = "m";
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}
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/*
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* Rewind the line buffer.
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*/
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public void
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prewind()
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{
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curr = 0;
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column = 0;
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overstrike = 0;
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is_null_line = 0;
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pendc = '\0';
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lmargin = 0;
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if (status_col)
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lmargin += 1;
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if (linenums == OPT_ONPLUS)
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lmargin += LINENUM_WIDTH+1;
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}
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/*
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* Insert the line number (of the given position) into the line buffer.
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*/
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public void
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plinenum(pos)
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POSITION pos;
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{
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register int lno;
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register int i;
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if (linenums == OPT_ONPLUS)
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{
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/*
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* Get the line number and put it in the current line.
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* {{ Note: since find_linenum calls forw_raw_line,
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* it may seek in the input file, requiring the caller
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* of plinenum to re-seek if necessary. }}
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* {{ Since forw_raw_line modifies linebuf, we must
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* do this first, before storing anything in linebuf. }}
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*/
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lno = find_linenum(pos);
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}
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/*
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* Display a status column if the -J option is set.
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*/
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if (status_col)
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{
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linebuf[curr] = ' ';
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if (start_attnpos != NULL_POSITION &&
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pos >= start_attnpos && pos < end_attnpos)
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attr[curr] = AT_STANDOUT;
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else
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attr[curr] = 0;
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curr++;
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column++;
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}
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/*
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* Display the line number at the start of each line
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* if the -N option is set.
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*/
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if (linenums == OPT_ONPLUS)
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{
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sprintf(&linebuf[curr], "%*d", LINENUM_WIDTH, lno);
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column += LINENUM_WIDTH;
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for (i = 0; i < LINENUM_WIDTH; i++)
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attr[curr++] = 0;
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}
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/*
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* Append enough spaces to bring us to the lmargin.
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*/
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while (column < lmargin)
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{
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linebuf[curr] = ' ';
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attr[curr++] = AT_NORMAL;
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column++;
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}
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}
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/*
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*
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*/
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static int
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utf_len(char *s, int len)
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{
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int ulen = 0;
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while (*s != '\0' && len > 0)
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{
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if (!IS_CONT(*s))
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len--;
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s++;
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ulen++;
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}
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while (IS_CONT(*s))
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{
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s++;
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ulen++;
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}
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return (ulen);
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}
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/*
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* Shift the input line left.
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* This means discarding N printable chars at the start of the buffer.
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*/
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static void
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pshift(shift)
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int shift;
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{
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int i;
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int real_shift;
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if (shift > column - lmargin)
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shift = column - lmargin;
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if (shift > curr - lmargin)
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shift = curr - lmargin;
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if (!utf_mode)
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real_shift = shift;
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else
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{
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real_shift = utf_len(linebuf + lmargin, shift);
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if (real_shift > curr)
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real_shift = curr;
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}
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for (i = 0; i < curr - real_shift; i++)
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{
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linebuf[lmargin + i] = linebuf[lmargin + i + real_shift];
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attr[lmargin + i] = attr[lmargin + i + real_shift];
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}
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column -= shift;
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curr -= real_shift;
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cshift += shift;
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}
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/*
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* Return the printing width of the start (enter) sequence
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* for a given character attribute.
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*/
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static int
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attr_swidth(a)
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int a;
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{
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switch (a)
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{
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case AT_BOLD: return (bo_s_width);
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case AT_UNDERLINE: return (ul_s_width);
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case AT_BLINK: return (bl_s_width);
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case AT_STANDOUT: return (so_s_width);
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}
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return (0);
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}
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/*
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* Return the printing width of the end (exit) sequence
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* for a given character attribute.
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*/
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static int
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attr_ewidth(a)
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int a;
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{
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switch (a)
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{
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case AT_BOLD: return (bo_e_width);
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case AT_UNDERLINE: return (ul_e_width);
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case AT_BLINK: return (bl_e_width);
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case AT_STANDOUT: return (so_e_width);
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}
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return (0);
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}
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/*
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* Return the printing width of a given character and attribute,
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* if the character were added to the current position in the line buffer.
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* Adding a character with a given attribute may cause an enter or exit
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* attribute sequence to be inserted, so this must be taken into account.
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*/
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static int
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pwidth(c, a)
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int c;
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int a;
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{
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register int w;
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if (utf_mode && IS_CONT(c))
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return (0);
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if (c == '\b')
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/*
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* Backspace moves backwards one position.
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*/
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return (-1);
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if (control_char(c))
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/*
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* Control characters do unpredicatable things,
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* so we don't even try to guess; say it doesn't move.
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* This can only happen if the -r flag is in effect.
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*/
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return (0);
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/*
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* Other characters take one space,
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* plus the width of any attribute enter/exit sequence.
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*/
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w = 1;
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if (curr > 0 && attr[curr-1] != a)
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w += attr_ewidth(attr[curr-1]);
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if (a && (curr == 0 || attr[curr-1] != a))
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w += attr_swidth(a);
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return (w);
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}
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/*
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* Delete the previous character in the line buffer.
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*/
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static void
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backc()
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{
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curr--;
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column -= pwidth(linebuf[curr], attr[curr]);
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}
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/*
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* Are we currently within a recognized ANSI escape sequence?
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*/
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static int
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in_ansi_esc_seq()
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{
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int i;
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/*
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* Search backwards for either an ESC (which means we ARE in a seq);
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* or an end char (which means we're NOT in a seq).
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*/
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for (i = curr-1; i >= 0; i--)
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{
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if (linebuf[i] == ESC)
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return (1);
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if (strchr(end_ansi_chars, linebuf[i]) != NULL)
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return (0);
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}
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return (0);
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}
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/*
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* Append a character and attribute to the line buffer.
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*/
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static int
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storec(c, a, pos)
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int c;
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int a;
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POSITION pos;
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{
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register int w;
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#if HILITE_SEARCH
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if (is_hilited(pos, pos+1, 0))
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/*
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* This character should be highlighted.
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* Override the attribute passed in.
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*/
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a = AT_STANDOUT;
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#endif
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if (ctldisp == OPT_ONPLUS && in_ansi_esc_seq())
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w = 0;
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else
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w = pwidth(c, a);
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if (ctldisp != OPT_ON && column + w + attr_ewidth(a) > sc_width)
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/*
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* Won't fit on screen.
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*/
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return (1);
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if (curr >= sizeof(linebuf)-2)
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/*
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* Won't fit in line buffer.
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*/
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return (1);
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/*
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* Special handling for "magic cookie" terminals.
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* If an attribute enter/exit sequence has a printing width > 0,
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* and the sequence is adjacent to a space, delete the space.
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* We just mark the space as invisible, to avoid having too
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* many spaces deleted.
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* {{ Note that even if the attribute width is > 1, we
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* delete only one space. It's not worth trying to do more.
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* It's hardly worth doing this much. }}
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*/
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if (curr > 0 && a != AT_NORMAL &&
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linebuf[curr-1] == ' ' && attr[curr-1] == AT_NORMAL &&
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attr_swidth(a) > 0)
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{
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/*
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* We are about to append an enter-attribute sequence
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* just after a space. Delete the space.
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*/
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attr[curr-1] = AT_INVIS;
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column--;
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} else if (curr > 0 && attr[curr-1] != AT_NORMAL &&
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attr[curr-1] != AT_INVIS && c == ' ' && a == AT_NORMAL &&
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attr_ewidth(attr[curr-1]) > 0)
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{
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/*
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* We are about to append a space just after an
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* exit-attribute sequence. Delete the space.
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*/
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a = AT_INVIS;
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column--;
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}
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/* End of magic cookie handling. */
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linebuf[curr] = c;
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attr[curr] = a;
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column += w;
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return (0);
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}
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/*
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* Append a character to the line buffer.
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* Expand tabs into spaces, handle underlining, boldfacing, etc.
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* Returns 0 if ok, 1 if couldn't fit in buffer.
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*/
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public int
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pappend(c, pos)
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register int c;
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POSITION pos;
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{
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int r;
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if (pendc)
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{
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if (do_append(pendc, pendpos))
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/*
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* Oops. We've probably lost the char which
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* was in pendc, since caller won't back up.
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*/
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return (1);
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pendc = '\0';
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}
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if (c == '\r' && bs_mode == BS_SPECIAL)
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{
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/*
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* Don't put the CR into the buffer until we see
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* the next char. If the next char is a newline,
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* discard the CR.
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*/
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pendc = c;
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pendpos = pos;
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return (0);
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}
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r = do_append(c, pos);
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/*
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* If we need to shift the line, do it.
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* But wait until we get to at least the middle of the screen,
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* so shifting it doesn't affect the chars we're currently
|
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* pappending. (Bold & underline can get messed up otherwise.)
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*/
|
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if (cshift < hshift && column > sc_width / 2)
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pshift(hshift - cshift);
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return (r);
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}
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static int
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do_append(c, pos)
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int c;
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POSITION pos;
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{
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register char *s;
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register int a;
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#define STOREC(c,a) \
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if (storec((c),(a),pos)) return (1); else curr++
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if (c == '\b')
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{
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switch (bs_mode)
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{
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case BS_NORMAL:
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STOREC(c, AT_NORMAL);
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break;
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case BS_CONTROL:
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goto do_control_char;
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case BS_SPECIAL:
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if (curr == 0)
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break;
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backc();
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overstrike = 1;
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break;
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}
|
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} else if (overstrike)
|
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{
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/*
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* Overstrike the character at the current position
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* in the line buffer. This will cause either
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* underline (if a "_" is overstruck),
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* bold (if an identical character is overstruck),
|
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* or just deletion of the character in the buffer.
|
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*/
|
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overstrike = 0;
|
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if ((char)c == linebuf[curr])
|
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STOREC(linebuf[curr], AT_BOLD);
|
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else if (c == '_')
|
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STOREC(linebuf[curr], AT_UNDERLINE);
|
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else if (linebuf[curr] == '_')
|
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STOREC(c, AT_UNDERLINE);
|
|
else if (control_char(c))
|
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goto do_control_char;
|
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else
|
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STOREC(c, AT_NORMAL);
|
|
} else if (c == '\t')
|
|
{
|
|
/*
|
|
* Expand a tab into spaces.
|
|
*/
|
|
if (tabstop == 0)
|
|
tabstop = 1;
|
|
switch (bs_mode)
|
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{
|
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case BS_CONTROL:
|
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goto do_control_char;
|
|
case BS_NORMAL:
|
|
case BS_SPECIAL:
|
|
do
|
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{
|
|
STOREC(' ', AT_NORMAL);
|
|
} while (((column + cshift - lmargin) % tabstop) != 0);
|
|
break;
|
|
}
|
|
} else if (control_char(c))
|
|
{
|
|
do_control_char:
|
|
if (ctldisp == OPT_ON || (ctldisp == OPT_ONPLUS && c == ESC))
|
|
{
|
|
/*
|
|
* Output as a normal character.
|
|
*/
|
|
STOREC(c, AT_NORMAL);
|
|
} else
|
|
{
|
|
/*
|
|
* Convert to printable representation.
|
|
*/
|
|
s = prchar(c);
|
|
a = binattr;
|
|
|
|
/*
|
|
* Make sure we can get the entire representation
|
|
* of the character on this line.
|
|
*/
|
|
if (column + (int) strlen(s) +
|
|
attr_swidth(a) + attr_ewidth(a) > sc_width)
|
|
return (1);
|
|
|
|
for ( ; *s != 0; s++)
|
|
STOREC(*s, a);
|
|
}
|
|
} else
|
|
{
|
|
STOREC(c, AT_NORMAL);
|
|
}
|
|
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Terminate the line in the line buffer.
|
|
*/
|
|
public void
|
|
pdone(endline)
|
|
int endline;
|
|
{
|
|
if (pendc && (pendc != '\r' || !endline))
|
|
/*
|
|
* If we had a pending character, put it in the buffer.
|
|
* But discard a pending CR if we are at end of line
|
|
* (that is, discard the CR in a CR/LF sequence).
|
|
*/
|
|
(void) do_append(pendc, pendpos);
|
|
|
|
/*
|
|
* Make sure we've shifted the line, if we need to.
|
|
*/
|
|
if (cshift < hshift)
|
|
pshift(hshift - cshift);
|
|
|
|
/*
|
|
* Add a newline if necessary,
|
|
* and append a '\0' to the end of the line.
|
|
*/
|
|
if (column < sc_width || !auto_wrap || ignaw || ctldisp == OPT_ON)
|
|
{
|
|
linebuf[curr] = '\n';
|
|
attr[curr] = AT_NORMAL;
|
|
curr++;
|
|
}
|
|
linebuf[curr] = '\0';
|
|
attr[curr] = AT_NORMAL;
|
|
/*
|
|
* If we are done with this line, reset the current shift.
|
|
*/
|
|
if (endline)
|
|
cshift = 0;
|
|
}
|
|
|
|
/*
|
|
* Get a character from the current line.
|
|
* Return the character as the function return value,
|
|
* and the character attribute in *ap.
|
|
*/
|
|
public int
|
|
gline(i, ap)
|
|
register int i;
|
|
register int *ap;
|
|
{
|
|
char *s;
|
|
|
|
if (is_null_line)
|
|
{
|
|
/*
|
|
* If there is no current line, we pretend the line is
|
|
* either "~" or "", depending on the "twiddle" flag.
|
|
*/
|
|
*ap = AT_BOLD;
|
|
s = (twiddle) ? "~\n" : "\n";
|
|
return (s[i]);
|
|
}
|
|
|
|
*ap = attr[i];
|
|
return (linebuf[i] & 0377);
|
|
}
|
|
|
|
/*
|
|
* Indicate that there is no current line.
|
|
*/
|
|
public void
|
|
null_line()
|
|
{
|
|
is_null_line = 1;
|
|
cshift = 0;
|
|
}
|
|
|
|
/*
|
|
* Analogous to forw_line(), but deals with "raw lines":
|
|
* lines which are not split for screen width.
|
|
* {{ This is supposed to be more efficient than forw_line(). }}
|
|
*/
|
|
public POSITION
|
|
forw_raw_line(curr_pos, linep)
|
|
POSITION curr_pos;
|
|
char **linep;
|
|
{
|
|
register char *p;
|
|
register int c;
|
|
POSITION new_pos;
|
|
|
|
if (curr_pos == NULL_POSITION || ch_seek(curr_pos) ||
|
|
(c = ch_forw_get()) == EOI)
|
|
return (NULL_POSITION);
|
|
|
|
p = linebuf;
|
|
|
|
for (;;)
|
|
{
|
|
if (c == '\n' || c == EOI)
|
|
{
|
|
new_pos = ch_tell();
|
|
break;
|
|
}
|
|
if (p >= &linebuf[sizeof(linebuf)-1])
|
|
{
|
|
/*
|
|
* Overflowed the input buffer.
|
|
* Pretend the line ended here.
|
|
* {{ The line buffer is supposed to be big
|
|
* enough that this never happens. }}
|
|
*/
|
|
new_pos = ch_tell() - 1;
|
|
break;
|
|
}
|
|
*p++ = c;
|
|
c = ch_forw_get();
|
|
}
|
|
*p = '\0';
|
|
if (linep != NULL)
|
|
*linep = linebuf;
|
|
return (new_pos);
|
|
}
|
|
|
|
/*
|
|
* Analogous to back_line(), but deals with "raw lines".
|
|
* {{ This is supposed to be more efficient than back_line(). }}
|
|
*/
|
|
public POSITION
|
|
back_raw_line(curr_pos, linep)
|
|
POSITION curr_pos;
|
|
char **linep;
|
|
{
|
|
register char *p;
|
|
register int c;
|
|
POSITION new_pos;
|
|
|
|
if (curr_pos == NULL_POSITION || curr_pos <= ch_zero() ||
|
|
ch_seek(curr_pos-1))
|
|
return (NULL_POSITION);
|
|
|
|
p = &linebuf[sizeof(linebuf)];
|
|
*--p = '\0';
|
|
|
|
for (;;)
|
|
{
|
|
c = ch_back_get();
|
|
if (c == '\n')
|
|
{
|
|
/*
|
|
* This is the newline ending the previous line.
|
|
* We have hit the beginning of the line.
|
|
*/
|
|
new_pos = ch_tell() + 1;
|
|
break;
|
|
}
|
|
if (c == EOI)
|
|
{
|
|
/*
|
|
* We have hit the beginning of the file.
|
|
* This must be the first line in the file.
|
|
* This must, of course, be the beginning of the line.
|
|
*/
|
|
new_pos = ch_zero();
|
|
break;
|
|
}
|
|
if (p <= linebuf)
|
|
{
|
|
/*
|
|
* Overflowed the input buffer.
|
|
* Pretend the line ended here.
|
|
*/
|
|
new_pos = ch_tell() + 1;
|
|
break;
|
|
}
|
|
*--p = c;
|
|
}
|
|
if (linep != NULL)
|
|
*linep = p;
|
|
return (new_pos);
|
|
}
|