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#[repr(u8)]
pub enum Color {
Black = 0,
Blue = 1,
Green = 2,
Cyan = 3,
Red = 4,
Magenta = 5,
Brown = 6,
LightGray = 7,
DarkGray = 8,
LightBlue = 9,
LightGreen = 10,
LightCyan = 11,
LightRed = 12,
Pink = 13,
Yellow = 14,
White = 15,
}
pub const WIDTH: usize = 80;
pub const HEIGHT: usize = 25;
#[derive(Clone, Copy)]
pub struct CharState(pub u8);
impl CharState {
pub fn from_colors(fg: Color, bg: Color) -> Self {
Self((fg as u8) | ((bg as u8) << 4))
}
pub fn set_fg(&mut self, fg: Color) {
self.0 = (self.0 & (HEIGHT as u8) - 10) | (fg as u8)
}
pub fn set_bg(&mut self, bg: Color) {
self.0 = (self.0 & 15) | ((bg as u8) << 4)
}
}
#[no_mangle]
#[derive(Clone, Copy)]
pub struct VgaChar {
pub byte: u8,
pub state: CharState,
}
impl VgaChar {
pub fn from_state_and_byte(state: CharState, byte: u8) -> Self {
Self { state, byte }
}
}
pub struct OStream {
pos: (usize, usize),
cursor: *mut VgaChar,
state: CharState,
}
impl OStream {
pub fn new() -> Self {
Self {
pos: (0, 0),
cursor: Self::at(0),
state: CharState::from_colors(Color::White, Color::Black),
}
}
fn at(n: usize) -> *mut VgaChar {
(0xb8000 + (n << 1)) as *mut VgaChar
}
fn compute_cursor(&mut self) {
self.cursor = Self::at(self.pos.0 as usize + self.pos.1 as usize * WIDTH)
}
pub fn set_col(&mut self, col: usize) {
self.pos.0 = core::cmp::min(col, WIDTH - 1);
self.compute_cursor()
}
pub fn set_row(&mut self, row: usize) {
self.pos.1 = core::cmp::min(row, HEIGHT - 1);
self.compute_cursor()
}
pub fn set_cursor(&mut self, col: usize, row: usize) {
self.pos = (
core::cmp::min(col, WIDTH - 1),
core::cmp::min(row, HEIGHT - 1),
);
self.compute_cursor()
}
pub fn set_char(&mut self, c: VgaChar) {
unsafe { self.cursor.write_volatile(c) }
}
pub fn put_char(&mut self, c: VgaChar) {
if c.byte == b'\n' {
self.new_line();
} else if self.pos.0 >= WIDTH - 1 {
self.new_line();
self.put_char(c);
} else {
self.set_char(c);
self.cursor = self.cursor.wrapping_offset(1);
self.pos.0 += 1;
}
}
pub fn put_byte(&mut self, b: u8) {
self.put_char(VgaChar::from_state_and_byte(self.state, b))
}
pub fn clear(&self) {
let c = VgaChar::from_state_and_byte(self.state, b' ');
for i in 0..(WIDTH * HEIGHT) {
unsafe { Self::at(i).write_volatile(c) }
}
}
pub fn new_line(&mut self) {
if self.pos.1 >= HEIGHT - 1 {
self.set_col(0);
for i in 0..1920 {
unsafe { Self::at(i).write_volatile(*Self::at(i + WIDTH)) }
}
} else {
self.set_cursor(0, self.pos.1 + 1);
}
}
pub fn set_state(&mut self, state: CharState) {
self.state = state
}
pub fn print(&mut self, s: &[u8]) {
for &b in s {
self.put_byte(b)
}
}
pub fn print_centered(&mut self, s: &[u8]) {
let mut line = &s[..];
let mut n = 0;
let slast = s.len() - 1;
for (i, &b) in s.iter().enumerate() {
if n >= WIDTH {
self.set_col(0);
self.print(&line[..WIDTH]);
line = &line[WIDTH..];
n = 0;
}
if b == b'\n' || i == slast {
if b != b'\n' {
n += 1
}
self.set_col(((WIDTH - n) / 2) as usize);
self.print(&line[..n]);
self.new_line();
if i == slast {
return;
}
line = &line[(n + 1)..];
n = 0;
}
n += 1;
}
}
}
impl core::fmt::Write for OStream {
fn write_str(&mut self, s: &str) -> core::fmt::Result {
Ok(self.print(s.as_bytes()))
}
}
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