using System;
using System.IO;
using System.Text;

namespace Cryville.Common {
	public static class IOExtensions {
		public static DirectoryInfo GetSubdirectory(this DirectoryInfo dir, string name) {
			var l1 = dir.GetDirectories(name);
			if (l1.Length == 0) return dir.CreateSubdirectory(name);
			else return l1[0];
		}
		
		public static string ReadUInt16String(this BinaryReader reader, Encoding encoding = null) {
			if (encoding == null) encoding = Encoding.UTF8;
			var len = reader.ReadUInt16();
			byte[] buffer = reader.ReadBytes(len);
			return encoding.GetString(buffer);
		}
		
		public static void WriteUInt16String(this BinaryWriter writer, string value, Encoding encoding = null) {
			if (encoding == null) encoding = Encoding.UTF8;
			byte[] buffer = encoding.GetBytes(value);
			writer.Write((ushort)buffer.Length);
			writer.Write(buffer);
		}
	}
}