From 9a7e9150f93696fd8c865a458f24a3ae500e5773 Mon Sep 17 00:00:00 2001
From: DBotThePony <dbotthepony@yandex.ru>
Date: Sun, 25 Sep 2022 23:16:33 +0700
Subject: [PATCH] Use variable length ints and longs

---
 .../ru/dbotthepony/mc/otm/core/DataStreams.kt | 34 +++++++++++++++++--
 .../mc/otm/network/FieldSynchronizer.kt       | 10 +-----
 2 files changed, 33 insertions(+), 11 deletions(-)

diff --git a/src/main/kotlin/ru/dbotthepony/mc/otm/core/DataStreams.kt b/src/main/kotlin/ru/dbotthepony/mc/otm/core/DataStreams.kt
index 001b869b5..547c33d93 100644
--- a/src/main/kotlin/ru/dbotthepony/mc/otm/core/DataStreams.kt
+++ b/src/main/kotlin/ru/dbotthepony/mc/otm/core/DataStreams.kt
@@ -51,6 +51,7 @@ val ImpreciseFractionValueCodec = StreamCodec(DataInputStream::readImpreciseFrac
 val BigDecimalValueCodec = StreamCodec(DataInputStream::readBigDecimal, DataOutputStream::writeBigDecimal)
 val UUIDValueCodec = StreamCodec({ s -> UUID(s.readLong(), s.readLong()) }, { s, v -> s.writeLong(v.mostSignificantBits); s.writeLong(v.leastSignificantBits) })
 val VarIntValueCodec = StreamCodec(DataInputStream::readVarIntLE, DataOutputStream::writeVarIntLE)
+val VarLongValueCodec = StreamCodec(DataInputStream::readVarLongLE, DataOutputStream::writeVarLongLE)
 
 class EnumValueCodec<V : Enum<V>>(private val clazz: Class<out V>) : IStreamCodec<V> {
 	private val values = clazz.enumConstants
@@ -131,6 +132,7 @@ fun OutputStream.writeFloat(value: Float) = writeInt(value.toBits())
 fun InputStream.readFloat() = Float.fromBits(readInt())
 fun OutputStream.writeDouble(value: Double) = writeLong(value.toBits())
 fun InputStream.readDouble() = Double.fromBits(readLong())
+
 fun InputStream.readVarIntLE(): Int {
 	var result = 0
 	var read = read()
@@ -159,6 +161,34 @@ fun OutputStream.writeVarIntLE(value: Int) {
 	write(written)
 }
 
+fun InputStream.readVarLongLE(): Long {
+	var result = 0L
+	var read = read()
+	var i = 0
+
+	while (read and 128 != 0) {
+		result = result or ((read and 127) shl i).toLong()
+		read = read()
+		i += 7
+	}
+
+	result = result or ((read and 127) shl i).toLong()
+
+	return result
+}
+
+fun OutputStream.writeVarLongLE(value: Long) {
+	require(value >= 0L) { "Negative number provided: $value" }
+	var written = value
+
+	while (written >= 128) {
+		write(((written and 127) or 128).toInt())
+		written = written ushr 7
+	}
+
+	write(written.toInt())
+}
+
 private data class IndexedStreamCodec<T>(
 	val condition: Predicate<Any?>,
 	val id: Int,
@@ -185,8 +215,8 @@ private val codecs: List<IndexedStreamCodec<*>> = com.google.common.collect.Immu
 	it.add(IndexedStreamCodec(codecID++, BooleanValueCodec))
 	it.add(IndexedStreamCodec(codecID++, ByteValueCodec))
 	it.add(IndexedStreamCodec(codecID++, ShortValueCodec))
-	it.add(IndexedStreamCodec(codecID++, IntValueCodec))
-	it.add(IndexedStreamCodec(codecID++, LongValueCodec))
+	it.add(IndexedStreamCodec(codecID++, VarIntValueCodec))
+	it.add(IndexedStreamCodec(codecID++, VarLongValueCodec))
 	it.add(IndexedStreamCodec(codecID++, FloatValueCodec))
 	it.add(IndexedStreamCodec(codecID++, DoubleValueCodec))
 	it.add(IndexedStreamCodec(codecID++, ItemStackValueCodec))
diff --git a/src/main/kotlin/ru/dbotthepony/mc/otm/network/FieldSynchronizer.kt b/src/main/kotlin/ru/dbotthepony/mc/otm/network/FieldSynchronizer.kt
index ab899224f..94f444ec8 100644
--- a/src/main/kotlin/ru/dbotthepony/mc/otm/network/FieldSynchronizer.kt
+++ b/src/main/kotlin/ru/dbotthepony/mc/otm/network/FieldSynchronizer.kt
@@ -98,7 +98,7 @@ class FieldSynchronizer {
 		getter: FieldGetter<Long>? = null,
 		setter: FieldSetter<Long>? = null,
 	): Field<Long> {
-		return Field(value, LongValueCodec, getter, setter)
+		return Field(value, VarLongValueCodec, getter, setter)
 	}
 
 	fun float(
@@ -129,14 +129,6 @@ class FieldSynchronizer {
 		value: Int = 0,
 		getter: FieldGetter<Int>? = null,
 		setter: FieldSetter<Int>? = null,
-	): Field<Int> {
-		return Field(value, IntValueCodec, getter, setter)
-	}
-
-	fun varInt(
-		value: Int = 0,
-		getter: FieldGetter<Int>? = null,
-		setter: FieldSetter<Int>? = null,
 	): Field<Int> {
 		return Field(value, VarIntValueCodec, getter, setter)
 	}