Offroaders123
commented
1 year ago Thanks to BJTMastermind Games for finding this article! I was wondering how Bedrock's Varint support differed to the ProtoBuf-like format itself, and it covers that very well. Extra helpful for setting this up, it even has an example of how to implement it!
Pseudocode to read and write VarInts and VarLongs:
private static final int SEGMENT_BITS = 0x7F; private static final int CONTINUE_BIT = 0x80;public int readVarInt() { int value = 0; int position = 0; byte currentByte; while (true) { currentByte = readByte(); value |= (currentByte & SEGMENT_BITS) << position; if ((currentByte & CONTINUE_BIT) == 0) break; position += 7; if (position >= 32) throw new RuntimeException("VarInt is too big"); } return value; }public long readVarLong() { long value = 0; int position = 0; byte currentByte; while (true) { currentByte = readByte(); value |= (long) (currentByte & SEGMENT_BITS) << position; if ((currentByte & CONTINUE_BIT) == 0) break; position += 7; if (position >= 64) throw new RuntimeException("VarLong is too big"); } return value; }public void writeVarInt(int value) { while (true) { if ((value & ~SEGMENT_BITS) == 0) { writeByte(value); return; } writeByte((value & SEGMENT_BITS) | CONTINUE_BIT); // Note: >>> means that the sign bit is shifted with the rest of the number rather than being left alone value >>>= 7; } }public void writeVarLong(long value) { while (true) { if ((value & ~((long) SEGMENT_BITS)) == 0) { writeByte(value); return; } writeByte((value & SEGMENT_BITS) | CONTINUE_BIT); // Note: >>> means that the sign bit is shifted with the rest of the number rather than being left alone value >>>= 7; } }
Going to add support for little endian varint encoding and decoding! This is inspired by the use-cases provided by Prismarine-NBT.
Bedrock Edition level format - wiki.vg janispritzkau / mcproto chrisdickinson / varint keithamus / varint CloudburstMC / NBT