v86 nodejs text screen example

nodejs_text_screen.js

#!/usr/bin/env node
"use strict";

var fs = require("fs");
var V86Starter = require("../build/libv86.js").V86Starter;

function readfile(path)
{
	return new Uint8Array(fs.readFileSync(path)).buffer;
}

function resize_terminal(rows, cols)
{
	// set size
	process.stdout.write("\x1b[8;" + cols + ";" + rows + "t");
	// move cursor back
	process.stdout.write("\x1b[2J" + cursor_pos(cursor_row, cursor_col + 1));
}

function number_as_rgb(n)
{
	return [
		n >> 16 & 0xFF,
		n >> 8 & 0xFF,
		n & 0xFF
	];
}

function rgb_to_bin(rgb)
{
	// example: [200, 30, 255] -> [255, 0, 255] -> 0b101
	return rgb[0] >> 7 << 2 |
		rgb[1] >> 7 << 1 |
		rgb[2] >> 7;
}

function cursor_pos(y, x)
{
	return cursor_pos_chr + (y + 1) + ";" + x + "H";
}

function should_be_bright(rgb)
{
	return rgb[0] > 198 ||
		rgb[1] > 198 ||
		rgb[2] > 198;
}

function text_update_row(row)
{
	var offset = 3 * row * width,
		text = cursor_pos(row, 0);

	var bg_color,
		fg_color,
		fg_rgb;

	for(var i = 0; i < width; )
	{
		bg_color = text_mode_data[offset + 1];
		fg_color = text_mode_data[offset + 2];
		fg_rgb = number_as_rgb(fg_color);

		text += should_be_bright(fg_rgb) ? fg_bright : reset_all;
		text += bg_chars[rgb_to_bin(number_as_rgb(bg_color))];
		text += fg_chars[rgb_to_bin(fg_rgb)];

		// put characters of the same color in one element
		while(i < width &&
			text_mode_data[offset + 1] === bg_color &&
			text_mode_data[offset + 2] === fg_color)
		{
			var ascii = text_mode_data[offset];

			text += charmap[ascii];

			i++;
			offset += 3;
		}
	}
	return text;
}

var bios = readfile(__dirname + "/../bios/seabios.bin");
var vgabios = readfile(__dirname + "/../bios/vgabios.bin");
var msdos = readfile(__dirname + "/../images/msdos.img");

process.stdin.setRawMode(true);
process.stdin.resume();
process.stdin.setEncoding("utf8");

var emulator = new V86Starter({
    bios: { buffer: bios },
    vga_bios: { buffer: vgabios },
    hda: { buffer: msdos },
	memory_size: 16 * 1024 * 1024,
    autostart: true,
});
var width,
	height,
	cursor_row,
	cursor_col,
	changed_rows,
	text_mode_data,
	running;
// escape codes
var cursor_pos_chr = String.fromCharCode(27, 91),
	reset_all = "\x1b[0m",
	fg_bright = "\x1b[1m",
	fg_chars = {
		0b000: "\x1b[30m",
		0b100: "\x1b[31m",
		0b010: "\x1b[32m",
		0b110: "\x1b[33m",
		0b001: "\x1b[34m",
		0b101: "\x1b[35m",
		0b011: "\x1b[36m",
		0b111: "\x1b[37m"
	},
	bg_chars = {
		0b000: "\x1b[40m",
		0b100: "\x1b[41m",
		0b010: "\x1b[42m",
		0b110: "\x1b[43m",
		0b001: "\x1b[44m",
		0b101: "\x1b[45m",
		0b011: "\x1b[46m",
		0b111: "\x1b[47m"
	},
	// f1 - f12
	f_keys = [
		"\x1B[[A",
		"\x1B[[B",
		"\x1B[[C",
		"\x1B[[D",
		"\x1B[[E",
		"\x1B[17~",
		"\x1B[18~",
		"\x1B[19~",
		"\x1B[10~",
		"\x1B[21~",
		"\x1B[23~",
		"\x1B[24~"
	];
// from screen.js
var charmap = String.fromCharCode(
	0x20, 0x263A, 0x263B, 0x2665, 0x2666, 0x2663, 0x2660, 0x2022,
	0x25D8, 0x25CB, 0x25D9, 0x2642, 0x2640, 0x266A, 0x266B, 0x263C,
	0x25BA, 0x25C4, 0x2195, 0x203C, 0xB6, 0xA7, 0x25AC, 0x21A8,
	0x2191, 0x2193, 0x2192, 0x2190, 0x221F, 0x2194, 0x25B2, 0x25BC,
	0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27,
	0x28, 0x29, 0x2A, 0x2B, 0x2C, 0x2D, 0x2E, 0x2F,
	0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,
	0x38, 0x39, 0x3A, 0x3B, 0x3C, 0x3D, 0x3E, 0x3F,
	0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47,
	0x48, 0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F,
	0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57,
	0x58, 0x59, 0x5A, 0x5B, 0x5C, 0x5D, 0x5E, 0x5F,
	0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67,
	0x68, 0x69, 0x6A, 0x6B, 0x6C, 0x6D, 0x6E, 0x6F,
	0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77,
	0x78, 0x79, 0x7A, 0x7B, 0x7C, 0x7D, 0x7E, 0x7F,
	0xC7, 0xFC, 0xE9, 0xE2, 0xE4, 0xE0, 0xE5, 0xE7,
	0xEA, 0xEB, 0xE8, 0xEF, 0xEE, 0xEC, 0xC4, 0xC5,
	0xC9, 0xE6, 0xC6, 0xF4, 0xF6, 0xF2, 0xFB, 0xF9,
	0xFF, 0xD6, 0xDC, 0xA2, 0xA3, 0xA5, 0x20A7, 0x192,
	0xE1, 0xED, 0xF3, 0xFA, 0xF1, 0xD1, 0xAA, 0xBA,
	0xBF, 0x2310, 0xAC, 0xBD, 0xBC, 0xA1, 0xAB, 0xBB,
	0x2591, 0x2592, 0x2593, 0x2502, 0x2524, 0x2561, 0x2562, 0x2556,
	0x2555, 0x2563, 0x2551, 0x2557, 0x255D, 0x255C, 0x255B, 0x2510,
	0x2514, 0x2534, 0x252C, 0x251C, 0x2500, 0x253C, 0x255E, 0x255F,
	0x255A, 0x2554, 0x2569, 0x2566, 0x2560, 0x2550, 0x256C, 0x2567,
	0x2568, 0x2564, 0x2565, 0x2559, 0x2558, 0x2552, 0x2553, 0x256B,
	0x256A, 0x2518, 0x250C, 0x2588, 0x2584, 0x258C, 0x2590, 0x2580,
	0x3B1, 0xDF, 0x393, 0x3C0, 0x3A3, 0x3C3, 0xB5, 0x3C4,
	0x3A6, 0x398, 0x3A9, 0x3B4, 0x221E, 0x3C6, 0x3B5, 0x2229,
	0x2261, 0xB1, 0x2265, 0x2264, 0x2320, 0x2321, 0xF7, 0x2248,
	0xB0, 0x2219, 0xB7, 0x221A, 0x207F, 0xB2, 0x25A0, 0xA0
);

process.stdin.on("data", function(c)
{
	switch(c)
	{
		case "\u0003":
			// ctrl c
			emulator.stop();
			process.stdin.pause();
			running = false;
			process.stdout.write(reset_all);
			break;
		case "\r":
			// enter
			emulator.keyboard_adapter.simulate_press(0xD);
			break;
		case "\x1B[A":
			// up arrow
			emulator.keyboard_adapter.simulate_press(0x26);
			break;
		case "\x1B[B":
			// down arrow
			emulator.keyboard_adapter.simulate_press(0x28);
			break;
		case "\x1B[C":
			// right arrow
			emulator.keyboard_adapter.simulate_press(0x27);
			break;
		case "\x1B[D":
			// left arrow
			emulator.keyboard_adapter.simulate_press(0x25);
			break;
		case "\x1B":
			// escape
			emulator.keyboard_adapter.simulate_press(0x1B);
			break;
		default:
			if (f_keys.includes(c))
			{
				// f1 - f12
				emulator.keyboard_adapter.simulate_press(0x70 + f_keys.indexOf(c));
				break;
			}
			// any other
			emulator.keyboard_adapter.simulate_char(c);
			break;
	}
});

emulator.bus.register("screen-set-size-text", function(data)
{
	if (data[0] === width && data[1] === height)
		return;
	width = data[0];
	height = data[1];
	changed_rows = new Int8Array(data[1]);
	changed_rows.fill(1); // update all
	text_mode_data = new Int32Array(data[0] * data[1] * 3);
	resize_terminal(width, height);
	if (!running) {
		running = true;
		setImmediate(update_text);
	}
});
emulator.bus.register("screen-update-cursor", function(data)
{
	if (data[0] === cursor_row && data[1] === cursor_col)
		return;
	changed_rows[data[0]] = 1;
	changed_rows[cursor_row] = 1;
	cursor_row = data[0];
	cursor_col = data[1];
});
emulator.bus.register("screen-put-char", function(data)
{
	if(data[0] < height && data[1] < width)
	{
		var p = 3 * (data[0] * width + data[1]);

		text_mode_data[p] = data[2];
		text_mode_data[p + 1] = data[3];
		text_mode_data[p + 2] = data[4];

		changed_rows[data[0]] = 1;
	}
});

function update_text()
{
	if (!running)
		return;
	var text = "";
	for(var i = 0; i < height; i++)
	{
		if(changed_rows[i])
		{
			text += text_update_row(i);
			changed_rows[i] = 0;
		}
	}
	text += cursor_pos(cursor_row, cursor_col + 1);
	// call process.stdout.write one time per update
	process.stdout.write(text);
	setImmediate(update_text);
}