NoSoliciting/NoSoliciting.Trainer/XivString.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;

namespace NoSoliciting.Trainer {
    public static class XivString {
        private const byte Start = 2;
        private const byte End = 3;

        public static string GetText(IEnumerable<byte> bytes) {
            var stringBytes = new List<byte>();

            var reader = new BinaryReader(new MemoryStream(bytes.ToArray()));
            while (reader.BaseStream.Position < reader.BaseStream.Length) {
                var b = reader.ReadByte();
                if (b == Start) {
                    reader.ReadByte(); // kind
                    var len = GetInteger(reader); // data length
                    reader.ReadBytes((int) len); // data
                    var end = reader.ReadByte(); // end
                    if (end != End) {
                        throw new ArgumentException("Input was not a valid XivString");
                    }

                    continue;
                }

                stringBytes.Add(b);
            }

            return Encoding.UTF8.GetString(stringBytes.ToArray());
        }

        // Thanks, Dalamud

        public static uint GetInteger(BinaryReader input) {
            uint marker = input.ReadByte();
            if (marker < 0xD0) {
                return marker - 1;
            }

            // the game adds 0xF0 marker for values >= 0xCF
            // uasge of 0xD0-0xEF is unknown, should we throw here?
            // if (marker < 0xF0) throw new NotSupportedException();

            marker = (marker + 1) & 0b1111;

            var ret = new byte[4];
            for (var i = 3; i >= 0; i--) {
                ret[i] = (marker & (1 << i)) == 0 ? (byte) 0 : input.ReadByte();
            }

            return BitConverter.ToUInt32(ret, 0);
        }
    }
}