vt.c

这是一个同样来自贝尔实验室的和UNIX有着渊源的操作系统, 其简洁的设计和实现易于我们学习和理解

/*
 * Known bugs:
 *
 * 1. We don't handle cursor movement characters inside escape sequences.
 * 	That is, ESC[2C moves two to the right, so ESC[2\bC is supposed to back
 *	up one and then move two to the right.
 *
 * 2. We don't handle tabstops past nelem(tabcol) columns.
 *
 * 3. We don't respect requests to do reverse video for the whole screen.
 *
 * 4. We ignore the ESC#n codes, so that we don't do double-width nor 
 * 	double-height lines, nor the ``fill the screen with E's'' confidence check.
 *
 * 5. Cursor key sequences aren't selected by keypad application mode.
 *
 * 6. "VT220" mode (-2) currently just switches the default cursor key
 *	functions (same as -a); it's still just a VT100 emulation.
 *
 * 7. VT52 mode and a few other rarely used features are not implemented.
 */

#include <u.h>
#include <libc.h>
#include <draw.h>
#include <bio.h>
#include <ctype.h>
#include "cons.h"

int	wraparound = 1;
int	originrelative = 0;

int	tabcol[200];

struct funckey vt100fk[NKEYS] = {
	{ "up key",		"\033OA", },
	{ "down key",		"\033OB", },
	{ "left key",		"\033OD", },
	{ "right key",		"\033OC", },
};

struct funckey ansifk[NKEYS] = {
	{ "up key",		"\033[A", },
	{ "down key",		"\033[B", },
	{ "left key",		"\033[D", },
	{ "right key",		"\033[C", },
	{ "F1",			"\033OP", },
	{ "F2",			"\033OQ", },
	{ "F3",			"\033OR", },
	{ "F4",			"\033OS", },
	{ "F5",			"\033OT", },
	{ "F6",			"\033OU", },
	{ "F7",			"\033OV", },
	{ "F8",			"\033OW", },
	{ "F9",			"\033OX", },
	{ "F10",		"\033OY", },
	{ "F11",		"\033OZ", },
	{ "F12",		"\033O1", },
};

struct funckey vt220fk[NKEYS] = {
	{ "up key",		"\033[A", },
	{ "down key",		"\033[B", },
	{ "left key",		"\033[D", },
	{ "right key",		"\033[C", },
};

struct funckey xtermfk[NKEYS] = {
	{ "page up",	"\033[5~", },
	{ "page down",	"\033[6~", },
	{ "up key",		"\033[A", },
	{ "down key",		"\033[B", },
	{ "left key",		"\033[D", },
	{ "right key",		"\033[C", },
	{ "F1",			"\033[11~", },
	{ "F2",			"\033[12~", },
	{ "F3",			"\033[13~", },
	{ "F4",			"\033[14~", },
	{ "F5",			"\033[15~", },
	{ "F6",			"\033[17~", },
	{ "F7",			"\033[18~", },
	{ "F8",			"\033[19~", },
	{ "F9",			"\033[20~", },
	{ "F10",		"\033[21~", },
	{ "F11",		"\033[22~", },
	{ "F12",		"\033[23~", },
};

char gmap[256] = {
	['_']	' ',	/* blank */
	['\\']	'*',	/* diamond */
	['a']	'X',	/* checkerboard */
	['b']	'\t',	/* HT */
	['c']	'\x0C',	/* FF */
	['d']	'\r',	/* CR */
	['e']	'\n',	/* LF */
	['f']	'o',	/* degree */
	['g']	'+',	/* plus/minus */
	['h']	'\n',	/* NL, but close enough */
	['i']	'\v',	/* VT */
	['j']	'+',	/* lower right corner */
	['k']	'+',	/* upper right corner */
	['l']	'+',	/* upper left corner */
	['m']	'+',	/* lower left corner */
	['n']	'+',	/* crossing lines */
	['o']	'-',	/* horiz line - scan 1 */
	['p']	'-',	/* horiz line - scan 3 */
	['q']	'-',	/* horiz line - scan 5 */
	['r']	'-',	/* horiz line - scan 7 */
	['s']	'-',	/* horiz line - scan 9 */
	['t']	'+',	/* |-   */
	['u']	'+',	/* -| */
	['v']	'+',	/* upside down T */
	['w']	'+',	/* rightside up T */
	['x']	'|',	/* vertical bar */
	['y']	'<',	/* less/equal */
	['z']	'>',	/* gtr/equal */
	['{']	'p',	/* pi */
	['|']	'!',	/* not equal */
	['}']	'L',	/* pound symbol */
	['~']	'.',	/* centered dot: · */
};

static void setattr(int argc, int *argv);

void
fixops(int *operand)
{
	if(operand[0] < 1)
		operand[0] = 1;
}

void
emulate(void)
{
	char buf[BUFS+1];
	int i;
	int n;
	int c;
	int operand[10];
	int noperand;
	int savex, savey, saveattr, saveisgraphics;
	int isgraphics;
	int g0set, g1set;
	int dch;

	isgraphics = 0;
	g0set = 'B';	/* US ASCII */
	g1set = 'B';	/* US ASCII */
	savex = savey = 0;
	yscrmin = 0;
	yscrmax = ymax;
	saveattr = 0;
	saveisgraphics = 0;
	/* set initial tab stops to DEC-standard 8-column spacing */
	for(c=0; (c+=8)<nelem(tabcol);)
		tabcol[c] = 1;

	for (;;) {
		if (y > ymax) {
			x = 0;
			newline();
		}
		buf[0] = get_next_char();
		buf[1] = '\0';
		switch(buf[0]) {

		case '\000':
		case '\001':
		case '\002':
		case '\003':
		case '\004':
		case '\005':
		case '\006':
			goto Default;

		case '\007':		/* bell */
			ringbell();
			break;

		case '\010':		/* backspace */
			if (x > 0)
				--x;
			break;

		case '\011':		/* tab to next tab stop; if none, to right margin */
			for(c=x+1; c<nelem(tabcol) && !tabcol[c]; c++)
				;
			if(c < nelem(tabcol))
				x = c;
			else
				x = xmax;
			break;

		case '\012':		/* linefeed */
		case '\013':
		case '\014':
			newline();
			if (ttystate[cs->raw].nlcr)
				x = 0;
			break;

		case '\015':		/* carriage return */
			x = 0;
			if (ttystate[cs->raw].crnl)
				newline();
			break;

		case '\016':	/* SO: invoke G1 char set */
			isgraphics = (isdigit(g1set));
			break;
		case '\017':	/* SI: invoke G0 char set */
			isgraphics = (isdigit(g0set));
			break;

		case '\020':	/* DLE */
		case '\021':	/* DC1 */
		case '\022':	/* XON */
		case '\023':	/* DC3 */
		case '\024':	/* XOFF */
		case '\025':	/* NAK */
		case '\026':	/* SYN */
		case '\027':	/* ETB */
		case '\030':	/* CAN: cancel escape sequence, display checkerboard (not implemented) */
		case '\031':	/* EM */
		case '\032':	/* SUB: same as CAN */
			goto Default;
;
		/* ESC, \033, is handled below */
		case '\034':	/* FS */
		case '\035':	/* GS */
		case '\036':	/* RS */
		case '\037':	/* US */
			break;
		case '\177':	/* delete: ignored */
			break;

		case '\033':
			switch(dch = get_next_char()){
			/*
			 * 1 - graphic processor option on (no-op; not installed)
			 */
			case '1':
				break;

			/*
			 * 2 - graphic processor option off (no-op; not installed)
			 */
			case '2':
				break;

			/*
			 * 7 - save cursor position.
			 */
			case '7':
//print("save\n");
				savex = x;
				savey = y;
				saveattr = attr;
				saveisgraphics = isgraphics;
				break;

			/*
			 * 8 - restore cursor position.
			 */
			case '8':
//print("restore\n");
				x = savex;
				y = savey;
				attr = saveattr;
				isgraphics = saveisgraphics;
				break;

			/*
			 * c - Reset terminal.
			 */
			case 'c':
print("resetterminal\n");
				cursoron = 1;
				ttystate[cs->raw].nlcr = 0;
				break;

			/*
			 * D - active position down a line, scroll if at bottom margin.
			 * (Original VT100 had a bug: tracked new-line/line-feed mode.)
			 */
			case 'D':
				if(++y > yscrmax) {
					y = yscrmax;
					scroll(yscrmin+1, yscrmax+1, yscrmin, yscrmax);
				}
				break;

			/*
			 * E - active position to start of next line, scroll if at bottom margin.
			 */
			case 'E':
				x = 0;
				if(++y > yscrmax) {
					y = yscrmax;
					scroll(yscrmin+1, yscrmax+1, yscrmin, yscrmax);
				}
				break;

			/*
			 * H - set tab stop at current column.
			 * (This is cursor home in VT52 mode (not implemented).)
			 */
			case 'H':
				if(x < nelem(tabcol))
					tabcol[x] = 1;
				break;

			/*
			 * M - active position up a line, scroll if at top margin..
			 */
			case 'M':
				if(--y < yscrmin) {
					y = yscrmin;
					scroll(yscrmin, yscrmax, yscrmin+1, yscrmin);
				}
				break;

			/*
			 * Z - identification.  the terminal
			 * emulator will return the response
			 * code for a generic VT100.
			 */
			case 'Z':
			Ident:
				sendnchars2(7, "\033[?1;2c");	/* VT100 with AVO option */
//				sendnchars2(5, "\033[?6c");	/* VT102 (insert/delete-char, etc.) */
				break;

			/*
			 * < - enter ANSI mode
			 */
			case '<':
				break;

			/*
			 * > - set numeric keypad mode on (not implemented)
			 */
			case '>':
				break;

			/*
			 * = - set numeric keypad mode off (not implemented)
			 */
			case '=':
				break;

			/*
			 * # - Takes a one-digit argument
			 */
			case '#':
				switch(get_next_char()){
				case '3':		/* Top half of double-height line */
				case '4':		/* Bottom half of double-height line */
				case '5':		/* Single-width single-height line */
				case '6':		/* Double-width line */
				case '7':		/* Screen print */
				case '8':		/* Fill screen with E's */
					break;
				}
				break;

			/*
			 * ( - switch G0 character set
			 */
			case '(':
				g0set = get_next_char();
				break;

			/*
			 * - switch G1 character set
			 */
			case ')':
				g1set = get_next_char();
				break;

			/*
			 * Received left bracket.
			 */
			case '[':
				/*
				 * A semi-colon or ? delimits arguments.
				 */
				memset(operand, 0, sizeof(operand));
				operand[0] = number(buf, &i);
				noperand = 1;
				while(buf[0] == ';' || buf[0] == '?'){
					if(noperand < nelem(operand)){
						noperand++;
						operand[noperand-1] = number(buf, nil);
					} else
						number(buf, nil);
				}

				/*
				 * do escape2 stuff
				 */
				switch(dch = buf[0]){
					/*
					 * c - same as ESC Z: what are you?
					 */
					case 'c':
						goto Ident;

					/*
					 * g - various tabstop manipulation
					 */
					case 'g':
						switch(operand[0]){
						case 0:	/* clear tab at current column */
							if(x < nelem(tabcol))
								tabcol[x] = 0;
							break;
						case 3:	/* clear all tabs */
							memset(tabcol, 0, sizeof tabcol);
							break;
						}
						break;

					/*
					 * l - clear various options.
					 */
					case 'l':
						if(noperand == 1){
							switch(operand[0]){	
							case 20:	/* set line feed mode */
								ttystate[cs->raw].nlcr = 1;
								break;
							case 30:	/* screen invisible (? not supported through VT220) */
								break;
							}
						}else while(--noperand > 0){
							switch(operand[noperand]){
							case 1:	/* set cursor keys to send ANSI functions: ESC [ A..D */
								break;
							case 2:	/* set VT52 mode (not implemented) */
								break;
							case 3:	/* set 80 columns */
								setdim(-1, 80);
								break;
							case 4:	/* set jump scrolling */
								break;
							case 5:	/* set normal video on screen */
								break;
							case 6:	/* set origin to absolute */
								originrelative = 0;
								x = y = 0;
								break;
							case 7:	/* reset auto-wrap mode */
								wraparound = 0;
								break;
							case 8:	/* reset auto-repeat mode */
								break;
							case 9:	/* reset interlacing mode */
								break;
							case 25:	/* text cursor off (VT220) */
								cursoron = 0;
								break;
							}
						}
						break;

					/*
					* s - some dec private stuff. actually [ ? num s, but we can't detect it.
					*/
					case 's':
						break;