mirror of
https://github.com/GeyserMC/MCProtocolLib.git
synced 2024-11-14 03:15:11 -05:00
Simplify readVarInt/Long, Fix and simplify writeVarInt/Long, add some simple tests to ensure functionality, VarInt/Long wider than 5/10 bytes will now take precedence over index out of bounds
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valaphee
parent
c2795892fd
commit
cb596f1105
2 changed files with 78 additions and 107 deletions
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@ -9,137 +9,58 @@ public class BasePacketCodecHelper implements PacketCodecHelper {
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@Override
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public void writeVarInt(ByteBuf buf, int value) {
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this.writeVarLong(buf, value & 0xFFFFFFFFL);
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while ((value & ~0x7F) != 0) {
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buf.writeByte(value & 0x7F | 0x80);
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value >>>= 7;
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}
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buf.writeByte(value);
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}
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@Override
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public int readVarInt(ByteBuf buf) {
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int value = 0;
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int size = 0;
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int b;
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while (((b = buf.readByte()) & 0x80) == 0x80) {
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byte b;
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do {
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if (size >= 35) {
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throw new RuntimeException("VarInt wider than 5 bytes");
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}
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b = buf.readByte();
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value |= (b & 0x7F) << size;
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size += 7;
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if (size > 35) {
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throw new IllegalArgumentException("VarInt wider than 35-bit");
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}
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}
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} while ((b & 0x80) == 0x80);
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return value | ((b & 0x7F) << size);
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return value;
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}
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// Based off of Andrew Steinborn's blog post:
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// https://steinborn.me/posts/performance/how-fast-can-you-write-a-varint/
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@Override
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public void writeVarLong(ByteBuf buf, long value) {
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// Peel the one and two byte count cases explicitly as they are the most common VarInt sizes
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// that the server will write, to improve inlining.
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if ((value & ~0x7FL) == 0) {
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buf.writeByte((byte) value);
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} else if ((value & ~0x3FFFL) == 0) {
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int w = (int) ((value & 0x7FL | 0x80L) << 8 |
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(value >>> 7));
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buf.writeShort(w);
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} else {
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writeVarLongFull(buf, value);
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while ((value & ~0x7FL) != 0) {
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buf.writeByte((int) (value & 0x7F | 0x80));
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value >>>= 7;
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}
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}
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private static void writeVarLongFull(ByteBuf buf, long value) {
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if ((value & ~0x7FL) == 0) {
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buf.writeByte((byte) value);
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} else if ((value & ~0x3FFFL) == 0) {
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int w = (int) ((value & 0x7FL | 0x80L) << 8 |
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(value >>> 7));
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buf.writeShort(w);
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} else if ((value & ~0x1FFFFFL) == 0) {
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int w = (int) ((value & 0x7FL | 0x80L) << 16 |
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((value >>> 7) & 0x7FL | 0x80L) << 8 |
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(value >>> 14));
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buf.writeMedium(w);
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} else if ((value & ~0xFFFFFFFL) == 0) {
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int w = (int) ((value & 0x7F | 0x80) << 24 |
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(((value >>> 7) & 0x7F | 0x80) << 16) |
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((value >>> 14) & 0x7F | 0x80) << 8 |
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(value >>> 21));
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buf.writeInt(w);
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} else if ((value & ~0x7FFFFFFFFL) == 0) {
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int w = (int) ((value & 0x7F | 0x80) << 24 |
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((value >>> 7) & 0x7F | 0x80) << 16 |
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((value >>> 14) & 0x7F | 0x80) << 8 |
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((value >>> 21) & 0x7F | 0x80));
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buf.writeInt(w);
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buf.writeByte((int) (value >>> 28));
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} else if ((value & ~0x3FFFFFFFFFFL) == 0) {
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int w = (int) ((value & 0x7F | 0x80) << 24 |
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((value >>> 7) & 0x7F | 0x80) << 16 |
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((value >>> 14) & 0x7F | 0x80) << 8 |
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((value >>> 21) & 0x7F | 0x80));
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int w2 = (int) (((value >>> 28) & 0x7FL | 0x80L) << 8 |
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(value >>> 35));
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buf.writeInt(w);
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buf.writeShort(w2);
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} else if ((value & ~0x1FFFFFFFFFFFFL) == 0) {
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int w = (int) ((value & 0x7F | 0x80) << 24 |
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((value >>> 7) & 0x7F | 0x80) << 16 |
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((value >>> 14) & 0x7F | 0x80) << 8 |
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((value >>> 21) & 0x7F | 0x80));
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int w2 = (int) ((((value >>> 28) & 0x7FL | 0x80L) << 16 |
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((value >>> 35) & 0x7FL | 0x80L) << 8) |
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(value >>> 42));
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buf.writeInt(w);
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buf.writeMedium(w2);
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} else if ((value & ~0xFFFFFFFFFFFFFFL) == 0) {
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long w = (value & 0x7F | 0x80) << 56 |
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((value >>> 7) & 0x7F | 0x80) << 48 |
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((value >>> 14) & 0x7F | 0x80) << 40 |
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((value >>> 21) & 0x7F | 0x80) << 32 |
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((value >>> 28) & 0x7FL | 0x80L) << 24 |
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((value >>> 35) & 0x7FL | 0x80L) << 16 |
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((value >>> 42) & 0x7FL | 0x80L) << 8 |
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(value >>> 49);
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buf.writeLong(w);
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} else if ((value & ~0x7FFFFFFFFFFFFFFFL) == 0) {
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long w = (value & 0x7F | 0x80) << 56 |
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((value >>> 7) & 0x7F | 0x80) << 48 |
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((value >>> 14) & 0x7F | 0x80) << 40 |
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((value >>> 21) & 0x7F | 0x80) << 32 |
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((value >>> 28) & 0x7FL | 0x80L) << 24 |
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((value >>> 35) & 0x7FL | 0x80L) << 16 |
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((value >>> 42) & 0x7FL | 0x80L) << 8 |
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(value >>> 49);
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buf.writeLong(w);
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buf.writeByte((byte) (value >>> 56));
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} else {
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long w = (value & 0x7F | 0x80) << 56 |
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((value >>> 7) & 0x7F | 0x80) << 48 |
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((value >>> 14) & 0x7F | 0x80) << 40 |
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((value >>> 21) & 0x7F | 0x80) << 32 |
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((value >>> 28) & 0x7FL | 0x80L) << 24 |
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((value >>> 35) & 0x7FL | 0x80L) << 16 |
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((value >>> 42) & 0x7FL | 0x80L) << 8 |
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(value >>> 49);
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int w2 = (int) (((value >>> 56) & 0x7FL | 0x80L) << 8 |
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(value >>> 63));
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buf.writeLong(w);
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buf.writeShort(w2);
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}
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buf.writeByte((int) value);
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}
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@Override
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public long readVarLong(ByteBuf buf) {
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long value = 0;
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int size = 0;
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int b;
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while (((b = buf.readByte()) & 0x80) == 0x80) {
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byte b;
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do {
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if (size >= 70) {
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throw new RuntimeException("VarLong wider than 10 bytes");
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}
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b = buf.readByte();
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value |= (b & 0x7FL) << size;
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size += 7;
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if (size > 70) {
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throw new IllegalArgumentException("VarLong wider than 70-bit");
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}
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}
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} while ((b & 0x80) == 0x80);
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return value | ((b & 0x7FL) << size);
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return value;
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}
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@Override
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@ -0,0 +1,50 @@
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package org.geysermc.mcprotocollib.protocol.codec;
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import io.netty.buffer.Unpooled;
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import org.geysermc.mcprotocollib.network.codec.BasePacketCodecHelper;
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import org.junit.jupiter.api.Test;
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import static org.junit.jupiter.api.Assertions.assertEquals;
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public class BasePacketCodecHelperTest {
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private static final BasePacketCodecHelper codecHelper = new BasePacketCodecHelper();
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@Test
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public void readVarInt() {
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assertEquals(0x80808080, codecHelper.readVarInt(Unpooled.wrappedBuffer(new byte[]{
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(byte) 0x80, (byte) 0x81, (byte) 0x82, (byte) 0x84, (byte) 0x08
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})));
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}
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@Test
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public void readVarIntTooLong() {
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try {
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// VarInt too long error should take precedence over IndexOutOfBoundsException
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codecHelper.readVarInt(Unpooled.wrappedBuffer(new byte[]{
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(byte) 0x80, (byte) 0x80, (byte) 0x80, (byte) 0x80, (byte) 0x80
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}));
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} catch (RuntimeException ex) {
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// (assertThrow doesn't work as IndexOutOfBoundsException is also a RuntimeException)
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assertEquals("VarInt wider than 5 bytes", ex.getMessage());
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}
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}
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@Test
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public void readVarLong() {
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assertEquals(0x8080808080808080L, codecHelper.readVarLong(Unpooled.wrappedBuffer(new byte[]{
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(byte) 0x80, (byte) 0x81, (byte) 0x82, (byte) 0x84, (byte) 0x88, (byte) 0x90, (byte) 0xa0, (byte) 0xc0, (byte) 0x80, (byte) 0x01
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})));
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}
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@Test
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public void readVarLongTooLong() {
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try {
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// VarLong too long error should take precedence over IndexOutOfBoundsException
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codecHelper.readVarLong(Unpooled.wrappedBuffer(new byte[]{
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(byte) 0x80, (byte) 0x80, (byte) 0x80, (byte) 0x80, (byte) 0x80, (byte) 0x80, (byte) 0x80, (byte) 0x80, (byte) 0x80, (byte) 0x80
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}));
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} catch (RuntimeException ex) {
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assertEquals("VarLong wider than 10 bytes", ex.getMessage());
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}
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}
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}
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