feat: duplicate_buffer example

Author: guidoschmidt

src/duplicate_buffer.zig

@@ -0,0 +1,52 @@
+const std = @import("std");
+
+fn printMap(map: *const [][]u8) void {
+    std.debug.print("\n", .{});
+    for (0..map.len) |x| {
+        const row = map.*[x];
+        std.debug.print("{d: >3}    ", .{x});
+        for (0..row.len) |y| {
+            std.debug.print("{c}", .{map.*[x][y]});
+        }
+        std.debug.print("\n", .{});
+    }
+}
+
+fn fillMap(map: *const [][]u8) void {
+    for (0..map.len) |x| {
+        const row = map.*[x];
+        for (0..row.len) |y| {
+            map.*[x][y] = '#';
+        }
+    }
+}
+
+pub fn main() !void {
+    var arena = std.heap.ArenaAllocator.init(std.heap.page_allocator);
+    defer arena.deinit();
+    const allocator = arena.allocator();
+
+    var map = try allocator.alloc([]u8, 10);
+    for (0..map.len) |x| {
+        map[x] = try allocator.alloc(u8, 12);
+        for (0..map[x].len) |y| {
+            map[x][y] = '.';
+        }
+    }
+    printMap(&map);
+
+    const map_copy: [][]u8 = try allocator.alloc([]u8, map.len);
+    for (0..map.len) |x| {
+        map_copy[x] = try allocator.alloc(u8, map[x].len);
+        for (0..map[x].len) |y| map_copy[x][y] = map[x][y];
+    }
+
+    std.debug.print("\nMap:", .{});
+    printMap(&map);
+    std.debug.print("\nCopy:", .{});
+    printMap(&map_copy);
+    std.debug.print("\nAfter Fill:", .{});
+    fillMap(&map);
+    printMap(&map);
+    printMap(&map_copy);
+}