BinaryIO.cs

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using System;
using System.IO;
 
namespace Terraria.ModLoader.IO
{
    public static class BinaryIO
    {
        public static void WriteItem(this BinaryWriter writer, Item item, bool readStack = false, bool readFavorite = false) =>
            ItemIO.Send(item, writer, readStack, readFavorite);
 
        public static Item ReadItem(this BinaryReader reader, bool readStack = false, bool readFavorite = false) =>
            ItemIO.Receive(reader, readStack, readFavorite);
 
        //copied from BinaryWriter.Read7BitEncodedInt
        public static void WriteVarInt(this BinaryWriter writer, int value) {
            // Write out an int 7 bits at a time.  The high bit of the byte,
            // when on, tells reader to continue reading more bytes.
            uint v = (uint)value;   // support negative numbers
            while (v >= 0x80) {
                writer.Write((byte)(v | 0x80));
                v >>= 7;
            }
            writer.Write((byte)v);
        }
 
        //copied from BinaryReader.Read7BitEncodedInt
        public static int ReadVarInt(this BinaryReader reader) {
            // Read out an Int32 7 bits at a time.  The high bit
            // of the byte when on means to continue reading more bytes.
            int count = 0;
            int shift = 0;
            byte b;
            do {
                // Check for a corrupted stream.  Read a max of 5 bytes.
                if (shift == 5 * 7)  // 5 bytes max per Int32, shift += 7
                    throw new FormatException("variable length int with more than 32 bits");
 
                // ReadByte handles end of stream cases for us.
                b = reader.ReadByte();
                count |= (b & 0x7F) << shift;
                shift += 7;
            } while ((b & 0x80) != 0);
            return count;
        }
 
        public static void SafeWrite(this BinaryWriter writer, Action<BinaryWriter> write) {
            var ms = new MemoryStream();//memory thrash should be fine here
            write(new BinaryWriter(ms));
            writer.WriteVarInt((int)ms.Length);
            ms.Position = 0;
            ms.CopyTo(writer.BaseStream);
        }
 
        public static void SafeRead(this BinaryReader reader, Action<BinaryReader> read) {
            int length = reader.ReadVarInt();
            var ms = new MemoryStream(reader.ReadBytes(length));
            read(new BinaryReader(ms));
            if (ms.Position != length)
                throw new IOException("Read underflow " + ms.Position + " of " + length + " bytes");
        }
 
        public static void ReadBytes(this Stream stream, byte[] buf) {
            int r, pos = 0;
            while ((r = stream.Read(buf, pos, buf.Length - pos)) > 0)
                pos += r;
 
            if (pos != buf.Length)
                throw new IOException($"Stream did not contain enough bytes ({pos}) < ({buf.Length})");
        }
 
        public static byte[] ReadBytes(this Stream stream, int len) => ReadBytes(stream, (long)len);
 
        public static byte[] ReadBytes(this Stream stream, long len) {
            var buf = new byte[len];
            stream.ReadBytes(buf);
            return buf;
        }
    }
}