Chunk

src/chunk.zig

@@ -0,0 +1,44 @@
+const std = @import("std");
+
+const OpCode = enum {
+    OP_RETURN,
+};
+
+pub const Chunk = struct {
+    code: []u8,
+    count: usize,
+    capacity: usize,
+    allocator: std.mem.Allocator,
+
+    pub fn init(allocator: std.mem.Allocator) !Chunk {
+        return .{
+            .count = 0,
+            .capacity = 0,
+            .allocator = allocator,
+            .code = try allocator.alloc(u8, 0),
+        };
+    }
+
+    pub fn write_chunck(self: *Chunk, byte: u8) !void {
+        // If the code slice is full
+        if (self.count == self.capacity) {
+            const old_capacity = self.capacity;
+            self.capacity = if (old_capacity < 8) 8 else old_capacity * 2;
+            self.code = try self.allocator.realloc(self.code, self.capacity);
+        }
+
+        self.code[self.count] = byte;
+        self.count += 1;
+    }
+
+    /// Reinitializes the state of the chunk.
+    pub fn free_chunck(self: *Chunk) !void {
+        self.count = 0;
+        self.capacity = 0;
+        self.code = try self.allocator.realloc(self.code, 0);
+    }
+
+    pub fn deinit(self: Chunk) void {
+        self.allocator.free(self.code);
+    }
+};

src/main.zig

@@ -1,24 +1,27 @@
 const std = @import("std");
+const chunk = @import("./chunk.zig");
 
 pub fn main() !void {
     // Prints to stderr (it's a shortcut based on `std.io.getStdErr()`)
     std.debug.print("All your {s} are belong to us.\n", .{"codebase"});
 
-    // stdout is for the actual output of your application, for example if you
-    // are implementing gzip, then only the compressed bytes should be sent to
-    // stdout, not any debugging messages.
-    const stdout_file = std.io.getStdOut().writer();
-    var bw = std.io.bufferedWriter(stdout_file);
-    const stdout = bw.writer();
+    var mem = std.heap.GeneralPurposeAllocator(.{}){};
+    const alloc = mem.allocator();
 
-    try stdout.print("Run `zig build test` to run the tests.\n", .{});
+    var c = try chunk.Chunk.init(alloc);
+    defer c.deinit();
 
-    try bw.flush(); // don't forget to flush!
+    try c.write_chunck('a');
+    try c.free_chunck();
 }
 
-test "simple test" {
-    var list = std.ArrayList(i32).init(std.testing.allocator);
-    defer list.deinit(); // try commenting this out and see if zig detects the memory leak!
-    try list.append(42);
-    try std.testing.expectEqual(@as(i32, 42), list.pop());
+test "chunk test" {
+    var c = try chunk.Chunk.init(std.testing.allocator);
+    defer c.deinit();
+
+    try c.write_chunck('a');
+    try c.write_chunck('b');
+    try c.free_chunck();
+    try c.write_chunck('J');
+    try c.write_chunck('H');
 }