Initial commit

src/Console.zig

@@ -0,0 +1,135 @@
+const std = @import("std");
+
+const Self = @This();
+
+pub fn init() Self {
+    var self = Self{};
+    self.clear();
+    return self;
+}
+
+const vga_width = 80;
+const vga_height = 25;
+const vga_size = vga_width * vga_height;
+
+pub const ConsoleColor = enum(u8) {
+    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,
+    lightMagenta = 13,
+    lightBrown = 14,
+    white = 15,
+};
+
+const default_color = vgaEntryColor(ConsoleColor.lightGray, ConsoleColor.black);
+
+column: usize = 0,
+color: u8 = default_color,
+buffer: [*]volatile u16 = @ptrFromInt(0xb8000),
+
+fn vgaEntryColor(fg: ConsoleColor, bg: ConsoleColor) u8 {
+    return @intFromEnum(fg) | (@intFromEnum(bg) << 4);
+}
+
+fn vgaEntry(uc: u8, new_color: u8) u16 {
+    const c: u16 = new_color;
+    return uc | (c << 8);
+}
+
+fn index(x: usize, y: usize) usize {
+    return y * vga_width + x;
+}
+
+pub fn setColor(self: *Self, fg: ConsoleColor, bg: ConsoleColor) void {
+    self.color = vgaEntryColor(fg, bg);
+}
+
+pub fn resetColor(self: *Self) void {
+    self.color = default_color;
+}
+
+pub fn clear(self: *Self) void {
+    @memset(self.buffer[0..vga_size], vgaEntry(' ', self.color));
+}
+
+fn clearRow(self: *Self, y: usize) void {
+    for (0..vga_width) |x| {
+        const i = index(x, y);
+        self.buffer[i] = vgaEntry(' ', self.color);
+    }
+}
+
+fn newLine(self: *Self) void {
+    for (1..vga_height) |y| {
+        for (0..vga_width) |x| {
+            const entry = self.getEntryAt(x, y);
+            self.putEntryAt(entry, x, y - 1);
+        }
+    }
+    self.clearRow(vga_height - 1);
+    self.column = 0;
+}
+
+pub fn putCharAt(self: *Self, c: u8, new_color: u8, x: usize, y: usize) void {
+    self.putEntryAt(vgaEntry(c, new_color), x, y);
+}
+
+fn putEntryAt(self: *Self, entry: u16, x: usize, y: usize) void {
+    const i = index(x, y);
+    self.buffer[i] = entry;
+}
+
+fn getEntryAt(self: *Self, x: usize, y: usize) u16 {
+    const i = index(x, y);
+    return self.buffer[i];
+}
+
+pub fn putChar(self: *Self, c: u8) void {
+    switch (c) {
+        '\n' => self.newLine(),
+        else => {
+            if (self.column >= vga_width) {
+                self.newLine();
+            }
+            const y = vga_height - 1;
+            const x = self.column;
+            self.putCharAt(c, self.color, x, y);
+            self.column += 1;
+        },
+    }
+}
+
+pub fn puts(self: *Self, data: []const u8) void {
+    for (data) |c| {
+        self.putChar(c);
+    }
+}
+
+const Writer = std.io.Writer(
+    *Self,
+    error{},
+    callback,
+);
+
+pub fn writer(self: *Self) Writer {
+    return .{ .context = self };
+}
+
+fn callback(self: *Self, string: []const u8) error{}!usize {
+    self.puts(string);
+    return string.len;
+}
+
+pub fn printf(self: *Self, comptime format: []const u8, args: anytype) void {
+    std.fmt.format(self.writer(), format, args) catch unreachable;
+}