Add ANSI helpers and rand/srand.

Author: thejpster

src/console.rs

@@ -0,0 +1,104 @@
+//! Helper functions for sending ANSI sequences
+
+// ============================================================================
+// Imports
+// ============================================================================
+
+use core::fmt::Write;
+
+use crate::File;
+
+// ============================================================================
+// Types
+// ============================================================================
+
+/// Represents a position on a screen.
+///
+/// A position is 0-indexed. That is (0, 0) is the top-left corner.
+///
+/// Translation to 1-based is performed before sending the ANSI sequences.
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+pub struct Position {
+    pub row: u8,
+    pub col: u8,
+}
+
+impl Position {
+    pub const fn origin() -> Position {
+        Position { row: 0, col: 0 }
+    }
+}
+
+/// Represents a Select Graphic Rendition parameter you can send in an SGR ANSI
+/// sequence.
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+#[repr(u8)]
+pub enum SgrParam {
+    Reset = 0,
+    Bold = 1,
+    Reverse = 7,
+    NotBold = 22,
+    NotReverse = 27,
+    FgBlack = 30,
+    FgRed = 31,
+    FgGreen = 32,
+    FgYellow = 33,
+    FgBlue = 34,
+    FgMagenta = 35,
+    FgCyan = 36,
+    FgWhite = 37,
+    BgBlack = 40,
+    BgRed = 41,
+    BgGreen = 42,
+    BgYellow = 43,
+    BgBlue = 44,
+    BgMagenta = 45,
+    BgCyan = 46,
+    BgWhite = 47,
+}
+
+// ============================================================================
+// Functions
+// ============================================================================
+
+/// Erase the screen
+pub fn clear_screen(f: &mut File) {
+    let _ = f.write_str("\u{001b}[2J");
+}
+
+/// Turn the cursor on
+pub fn cursor_on(f: &mut File) {
+    let _ = f.write_str("\u{001b}[?25h");
+}
+
+/// Turn the cursor off
+pub fn cursor_off(f: &mut File) {
+    let _ = f.write_str("\u{001b}[?25l");
+}
+
+/// Move the cursor to the given position
+pub fn move_cursor(f: &mut File, pos: Position) {
+    let _ = write!(f, "\u{001b}[{};{}H", 1 + pos.row, 1 + pos.col);
+}
+
+/// Change the background
+///
+/// Only values 0..8 will work.
+pub fn set_sgr<T>(f: &mut File, values: T)
+where
+    T: IntoIterator<Item = SgrParam>,
+{
+    let _ = write!(f, "\u{001b}[");
+    let mut iter = values.into_iter();
+    if let Some(value) = iter.next() {
+        let _ = write!(f, "{}", value as u8);
+    }
+    while let Some(value) = iter.next() {
+        let _ = write!(f, ";{}", value as u8);
+    }
+    let _ = write!(f, "m");
+}
+
+// ============================================================================
+// End of File
+// ============================================================================

src/lib.rs

@@ -16,6 +16,8 @@ pub use neotron_api::{path, Api, Error};
 
 use neotron_api as api;
 
+pub mod console;
+
 #[cfg(not(target_os = "none"))]
 mod fake_os_api;
 
@@ -315,10 +317,8 @@ pub const fn stderr() -> File {
 }
 
 /// Delay for some milliseconds
+#[cfg(target_os = "none")]
 pub fn delay(period: core::time::Duration) {
-    #[cfg(not(target_os = "none"))]
-    std::thread::sleep(period);
-
     // TODO: sleep on real hardware?
     for _ in 0..period.as_micros() {
         for _ in 0..50 {
@@ -327,6 +327,28 @@ pub fn delay(period: core::time::Duration) {
     }
 }
 
+/// Delay for some milliseconds
+#[cfg(not(target_os = "none"))]
+pub fn delay(period: core::time::Duration) {
+    std::thread::sleep(period);
+}
+
+static RAND_STATE: core::sync::atomic::AtomicU16 = core::sync::atomic::AtomicU16::new(0);
+
+/// Seed the 16-bit psuedorandom number generator
+pub fn srand(seed: u16) {
+    RAND_STATE.store(seed, core::sync::atomic::Ordering::Relaxed);
+}
+
+/// Get a 16-bit psuedorandom number
+pub fn rand() -> u16 {
+    let mut state = RAND_STATE.load(core::sync::atomic::Ordering::Relaxed);
+    let bit = ((state >> 0) ^ (state >> 2) ^ (state >> 3) ^ (state >> 5)) & 0x01;
+    state = (state >> 1) | (bit << 15);
+    RAND_STATE.store(state, core::sync::atomic::Ordering::Relaxed);
+    state
+}
+
 /// Get the API structure so we can call APIs manually.
 ///
 /// If you managed to not have `app_entry` called on start-up, this will panic.