DIR: Format byte amounts with commas.

1 files changed, 47 insertions, 3 deletions

diff --git a/src/cmd/dir.zig b/src/cmd/dir.zig
index dde0707..d7e8d8e 100644
--- a/src/cmd/dir.zig
+++ b/src/cmd/dir.zig
@@ -53,6 +53,43 @@ fn formatDosDateTime(allocator: Allocator, timestamp_secs: i64) ![]const u8 {
     return try std.fmt.allocPrint(allocator, "{d:0>2}-{d:0>2}-{d:0>2}  {d:>2}:{d:0>2}{s}", .{ @as(u32, @intCast(month)), @as(u32, @intCast(day)), @as(u32, @intCast(year % 100)), @as(u32, @intCast(display_hour)), @as(u32, @intCast(minutes)), am_pm });
 }
 
+fn formatWithCommas(allocator: Allocator, number: u64) ![]const u8 {
+    // Convert number to string first
+    const num_str = try std.fmt.allocPrint(allocator, "{d}", .{number});
+    defer allocator.free(num_str);
+
+    // Calculate how many commas we need
+    const digits = num_str.len;
+    const comma_count = if (digits <= 3) 0 else @divFloor(digits - 1, 3);
+
+    if (comma_count == 0) {
+        return try allocator.dupe(u8, num_str);
+    }
+
+    // Allocate space for number + commas
+    const result = try allocator.alloc(u8, digits + comma_count);
+
+    var result_idx: usize = result.len;
+    var num_idx: usize = num_str.len;
+    var digit_count: usize = 0;
+
+    // Work backwards, adding commas every 3 digits
+    while (num_idx > 0) {
+        num_idx -= 1;
+        result_idx -= 1;
+        result[result_idx] = num_str[num_idx];
+        digit_count += 1;
+
+        // Add comma every 3 digits (but not at the beginning)
+        if (digit_count % 3 == 0 and num_idx > 0) {
+            result_idx -= 1;
+            result[result_idx] = ',';
+        }
+    }
+
+    return result;
+}
+
 fn isLeapYear(year: u32) bool {
     return (year % 4 == 0 and year % 100 != 0) or (year % 400 == 0);
 }
@@ -128,7 +165,9 @@ pub const Dir = struct {
                     dir_count += 1;
                 },
                 .file => {
-                    try output_buffer.writer().print("{s:<8} {s:<3}  {d:>14} {s}\n", .{ short_name.name, short_name.ext, stat.size, date_time });
+                    const formatted_size = try formatWithCommas(ctx.allocator, stat.size);
+                    defer ctx.allocator.free(formatted_size);
+                    try output_buffer.writer().print("{s:<8} {s:<3}  {s:>14} {s}\n", .{ short_name.name, short_name.ext, formatted_size, date_time });
                     file_count += 1;
                     total_file_bytes += stat.size;
                 },
@@ -144,8 +183,13 @@ pub const Dir = struct {
             error.NotImplemented => 0,
         };
 
-        try output_buffer.writer().print("        {d} File(s) {d:>14} bytes\n", .{ file_count, total_file_bytes });
-        try output_buffer.writer().print("        {d} Dir(s)  {d:>14} bytes free\n", .{ dir_count, bytes_free });
+        const formatted_total_bytes = try formatWithCommas(ctx.allocator, total_file_bytes);
+        defer ctx.allocator.free(formatted_total_bytes);
+        const formatted_free_bytes = try formatWithCommas(ctx.allocator, bytes_free);
+        defer ctx.allocator.free(formatted_free_bytes);
+
+        try output_buffer.writer().print("        {d} File(s) {s:>14} bytes\n", .{ file_count, formatted_total_bytes });
+        try output_buffer.writer().print("        {d} Dir(s)  {s:>14} bytes free\n", .{ dir_count, formatted_free_bytes });
 
         if (ctx.output_capture) |capture| {
             try capture.write(output_buffer.items);