509 lines
13 KiB
C
509 lines
13 KiB
C
/*
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* Copyright (c) 1988 Mark Nudleman
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* Copyright (c) 1988 Regents of the University of California.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef lint
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static char sccsid[] = "@(#)line.c 5.5 (Berkeley) 7/24/91";
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#endif /* not lint */
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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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* We keep track of the PRINTABLE length of the line as it is being built.
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*/
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#include <sys/types.h>
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#include <ctype.h>
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#include <less.h>
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static char linebuf[1024]; /* Buffer which holds the current output line */
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static char *curr; /* Pointer into linebuf */
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static int column; /* Printable length, accounting for
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backspaces, etc. */
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/*
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* A ridiculously complex state machine takes care of backspaces. The
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* complexity arises from the attempt to deal with all cases, especially
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* involving long lines with underlining, boldfacing or whatever. There
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* are still some cases which will break it.
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*
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* There are four states:
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* LN_NORMAL is the normal state (not in underline mode).
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* LN_UNDERLINE means we are in underline mode. We expect to get
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* either a sequence like "_\bX" or "X\b_" to continue
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* underline mode, or anything else to end underline mode.
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* LN_BOLDFACE means we are in boldface mode. We expect to get sequences
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* like "X\bX\b...X\bX" to continue boldface mode, or anything
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* else to end boldface mode.
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* LN_UL_X means we are one character after LN_UNDERLINE
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* (we have gotten the '_' in "_\bX" or the 'X' in "X\b_").
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* LN_UL_XB means we are one character after LN_UL_X
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* (we have gotten the backspace in "_\bX" or "X\b_";
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* we expect one more ordinary character,
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* which will put us back in state LN_UNDERLINE).
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* LN_BO_X means we are one character after LN_BOLDFACE
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* (we have gotten the 'X' in "X\bX").
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* LN_BO_XB means we are one character after LN_BO_X
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* (we have gotten the backspace in "X\bX";
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* we expect one more 'X' which will put us back
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* in LN_BOLDFACE).
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*/
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static int ln_state; /* Currently in normal/underline/bold/etc mode? */
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#define LN_NORMAL 0 /* Not in underline, boldface or whatever mode */
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#define LN_UNDERLINE 1 /* In underline, need next char */
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#define LN_UL_X 2 /* In underline, got char, need \b */
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#define LN_UL_XB 3 /* In underline, got char & \b, need one more */
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#define LN_BOLDFACE 4 /* In boldface, need next char */
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#define LN_BO_X 5 /* In boldface, got char, need \b */
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#define LN_BO_XB 6 /* In boldface, got char & \b, need same char */
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char *line; /* Pointer to the current line.
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Usually points to linebuf. */
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extern int bs_mode;
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extern int tabstop;
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extern int bo_width, be_width;
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extern int ul_width, ue_width;
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extern int sc_width, sc_height;
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/*
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* Rewind the line buffer.
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*/
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prewind()
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{
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line = curr = linebuf;
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ln_state = LN_NORMAL;
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column = 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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#define NEW_COLUMN(addon) \
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if (column + addon + (ln_state ? ue_width : 0) > sc_width) \
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return(1); \
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else \
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column += addon
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pappend(c)
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int c;
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{
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if (c == '\0') {
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/*
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* Terminate any special modes, if necessary.
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* Append a '\0' to the end of the line.
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*/
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switch (ln_state) {
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case LN_UL_X:
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curr[0] = curr[-1];
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curr[-1] = UE_CHAR;
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curr++;
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break;
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case LN_BO_X:
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curr[0] = curr[-1];
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curr[-1] = BE_CHAR;
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curr++;
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break;
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case LN_UL_XB:
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case LN_UNDERLINE:
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*curr++ = UE_CHAR;
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break;
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case LN_BO_XB:
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case LN_BOLDFACE:
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*curr++ = BE_CHAR;
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break;
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}
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ln_state = LN_NORMAL;
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*curr = '\0';
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return(0);
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}
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if (curr > linebuf + sizeof(linebuf) - 12)
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/*
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* Almost out of room in the line buffer.
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* Don't take any chances.
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* {{ Linebuf is supposed to be big enough that this
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* will never happen, but may need to be made
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* bigger for wide screens or lots of backspaces. }}
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*/
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return(1);
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if (!bs_mode) {
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/*
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* Advance the state machine.
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*/
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switch (ln_state) {
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case LN_NORMAL:
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if (curr <= linebuf + 1
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|| curr[-1] != (char)('H' | 0200))
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break;
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column -= 2;
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if (c == curr[-2])
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goto enter_boldface;
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if (c == '_' || curr[-2] == '_')
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goto enter_underline;
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curr -= 2;
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break;
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enter_boldface:
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/*
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* We have "X\bX" (including the current char).
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* Switch into boldface mode.
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*/
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column--;
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if (column + bo_width + be_width + 1 >= sc_width)
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/*
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* Not enough room left on the screen to
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* enter and exit boldface mode.
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*/
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return (1);
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if (bo_width > 0 && curr > linebuf + 2
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&& curr[-3] == ' ') {
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/*
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* Special case for magic cookie terminals:
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* if the previous char was a space, replace
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* it with the "enter boldface" sequence.
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*/
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curr[-3] = BO_CHAR;
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column += bo_width-1;
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} else {
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curr[-1] = curr[-2];
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curr[-2] = BO_CHAR;
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column += bo_width;
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curr++;
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}
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goto ln_bo_xb_case;
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enter_underline:
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/*
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* We have either "_\bX" or "X\b_" (including
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* the current char). Switch into underline mode.
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*/
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column--;
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if (column + ul_width + ue_width + 1 >= sc_width)
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/*
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* Not enough room left on the screen to
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* enter and exit underline mode.
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*/
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return (1);
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if (ul_width > 0 &&
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curr > linebuf + 2 && curr[-3] == ' ')
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{
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/*
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* Special case for magic cookie terminals:
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* if the previous char was a space, replace
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* it with the "enter underline" sequence.
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*/
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curr[-3] = UL_CHAR;
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column += ul_width-1;
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} else
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{
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curr[-1] = curr[-2];
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curr[-2] = UL_CHAR;
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column += ul_width;
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curr++;
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}
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goto ln_ul_xb_case;
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/*NOTREACHED*/
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case LN_UL_XB:
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/*
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* Termination of a sequence "_\bX" or "X\b_".
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*/
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if (c != '_' && curr[-2] != '_' && c == curr[-2])
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{
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/*
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* We seem to have run on from underlining
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* into boldfacing - this is a nasty fix, but
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* until this whole routine is rewritten as a
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* real DFA, ... well ...
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*/
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curr[0] = curr[-2];
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curr[-2] = UE_CHAR;
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curr[-1] = BO_CHAR;
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curr += 2; /* char & non-existent backspace */
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ln_state = LN_BO_XB;
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goto ln_bo_xb_case;
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}
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ln_ul_xb_case:
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if (c == '_')
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c = curr[-2];
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curr -= 2;
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ln_state = LN_UNDERLINE;
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break;
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case LN_BO_XB:
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/*
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* Termination of a sequnce "X\bX".
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*/
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if (c != curr[-2] && (c == '_' || curr[-2] == '_'))
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{
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/*
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* We seem to have run on from
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* boldfacing into underlining.
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*/
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curr[0] = curr[-2];
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curr[-2] = BE_CHAR;
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curr[-1] = UL_CHAR;
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curr += 2; /* char & non-existent backspace */
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ln_state = LN_UL_XB;
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goto ln_ul_xb_case;
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}
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ln_bo_xb_case:
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curr -= 2;
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ln_state = LN_BOLDFACE;
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break;
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case LN_UNDERLINE:
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if (column + ue_width + bo_width + 1 + be_width >= sc_width)
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/*
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* We have just barely enough room to
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* exit underline mode and handle a possible
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* underline/boldface run on mixup.
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*/
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return (1);
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ln_state = LN_UL_X;
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break;
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case LN_BOLDFACE:
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if (c == '\b')
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{
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ln_state = LN_BO_XB;
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break;
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}
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if (column + be_width + ul_width + 1 + ue_width >= sc_width)
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/*
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* We have just barely enough room to
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* exit underline mode and handle a possible
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* underline/boldface run on mixup.
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*/
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return (1);
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ln_state = LN_BO_X;
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break;
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case LN_UL_X:
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if (c == '\b')
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ln_state = LN_UL_XB;
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else
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{
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/*
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* Exit underline mode.
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* We have to shuffle the chars a bit
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* to make this work.
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*/
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curr[0] = curr[-1];
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curr[-1] = UE_CHAR;
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column += ue_width;
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if (ue_width > 0 && curr[0] == ' ')
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/*
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* Another special case for magic
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* cookie terminals: if the next
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* char is a space, replace it
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* with the "exit underline" sequence.
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*/
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column--;
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else
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curr++;
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ln_state = LN_NORMAL;
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}
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break;
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case LN_BO_X:
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if (c == '\b')
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ln_state = LN_BO_XB;
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else
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{
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/*
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* Exit boldface mode.
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* We have to shuffle the chars a bit
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* to make this work.
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*/
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curr[0] = curr[-1];
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curr[-1] = BE_CHAR;
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column += be_width;
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if (be_width > 0 && curr[0] == ' ')
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/*
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* Another special case for magic
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* cookie terminals: if the next
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* char is a space, replace it
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* with the "exit boldface" sequence.
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*/
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column--;
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else
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curr++;
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ln_state = LN_NORMAL;
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}
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break;
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}
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}
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if (c == '\t') {
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/*
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* Expand a tab into spaces.
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*/
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do {
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NEW_COLUMN(1);
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} while ((column % tabstop) != 0);
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*curr++ = '\t';
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return (0);
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}
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if (c == '\b') {
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if (ln_state == LN_NORMAL)
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NEW_COLUMN(2);
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else
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column--;
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*curr++ = ('H' | 0200);
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return(0);
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}
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if (CONTROL_CHAR(c)) {
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/*
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* Put a "^X" into the buffer. The 0200 bit is used to tell
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* put_line() to prefix the char with a ^. We don't actually
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* put the ^ in the buffer because we sometimes need to move
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* chars around, and such movement might separate the ^ from
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* its following character.
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*/
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NEW_COLUMN(2);
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*curr++ = (CARAT_CHAR(c) | 0200);
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return(0);
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}
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/*
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* Ordinary character. Just put it in the buffer.
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*/
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NEW_COLUMN(1);
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*curr++ = c;
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return (0);
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}
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/*
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* Analogous to forw_line(), but deals with "raw lines":
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* lines which are not split for screen width.
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* {{ This is supposed to be more efficient than forw_line(). }}
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*/
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off_t
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forw_raw_line(curr_pos)
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off_t curr_pos;
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{
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register char *p;
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register int c;
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off_t new_pos, ch_tell();
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if (curr_pos == NULL_POSITION || ch_seek(curr_pos) ||
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(c = ch_forw_get()) == EOI)
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return (NULL_POSITION);
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p = linebuf;
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for (;;)
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{
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if (c == '\n' || c == EOI)
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{
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new_pos = ch_tell();
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break;
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}
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if (p >= &linebuf[sizeof(linebuf)-1])
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{
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/*
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* Overflowed the input buffer.
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* Pretend the line ended here.
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* {{ The line buffer is supposed to be big
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* enough that this never happens. }}
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*/
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new_pos = ch_tell() - 1;
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break;
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}
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*p++ = c;
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c = ch_forw_get();
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}
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*p = '\0';
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line = linebuf;
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return (new_pos);
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}
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/*
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* Analogous to back_line(), but deals with "raw lines".
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* {{ This is supposed to be more efficient than back_line(). }}
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*/
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off_t
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back_raw_line(curr_pos)
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off_t curr_pos;
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{
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register char *p;
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register int c;
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off_t new_pos, ch_tell();
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if (curr_pos == NULL_POSITION || curr_pos <= (off_t)0 ||
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ch_seek(curr_pos-1))
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return (NULL_POSITION);
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p = &linebuf[sizeof(linebuf)];
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*--p = '\0';
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for (;;)
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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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new_pos = ch_tell() + 1;
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break;
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}
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if (c == EOI)
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{
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/*
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* We have hit the beginning of the file.
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* This must be the first line in the file.
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* This must, of course, be the beginning of the line.
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*/
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new_pos = (off_t)0;
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break;
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}
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if (p <= linebuf)
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{
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/*
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* Overflowed the input buffer.
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* Pretend the line ended here.
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*/
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new_pos = ch_tell() + 1;
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break;
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}
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*--p = c;
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}
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line = p;
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return (new_pos);
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}
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