refactor: improve VarLong and Utf8String handling for better readability and consistency

- Adjusted `VarLong` logic to use clear variable naming (`numBytes` instead of `shift`).
- Replaced bit-shifting expressions with more readable parenthesized forms.
- Refactored `Utf8String` to utilize `VarInt` methods for encoding and decoding operations.

Author: twisti-dev

surf-cloud-api/surf-cloud-api-common/src/main/kotlin/dev/slne/surf/cloud/api/common/netty/protocol/buffer/types/Utf8String.kt

@@ -3,8 +3,6 @@ package dev.slne.surf.cloud.api.common.netty.protocol.buffer.types
 import dev.slne.surf.cloud.api.common.netty.network.codec.streamCodec
 import dev.slne.surf.cloud.api.common.netty.protocol.buffer.checkDecoded
 import dev.slne.surf.cloud.api.common.netty.protocol.buffer.checkEncoded
-import dev.slne.surf.cloud.api.common.netty.protocol.buffer.readVarInt
-import dev.slne.surf.cloud.api.common.netty.protocol.buffer.writeVarInt
 import io.netty.buffer.ByteBuf
 import io.netty.buffer.ByteBufUtil
 import java.nio.charset.StandardCharsets
@@ -38,7 +36,7 @@ object Utf8String {
      */
     fun read(buf: ByteBuf, maxLength: Int): String {
         val utf8MaxLength = ByteBufUtil.utf8MaxBytes(maxLength)
-        val utf8Length = buf.readVarInt()
+        val utf8Length = VarInt.readVarInt(buf)
 
         checkDecoded(utf8Length <= utf8MaxLength) { "String too long (max $maxLength): $utf8Length" }
         checkDecoded(utf8Length >= 0) { "String length is negative: $utf8Length" }
@@ -78,7 +76,7 @@ object Utf8String {
 
             checkEncoded(bytesWritten <= utf8MaxLength) { "String too long (max $maxLength): $bytesWritten" }
 
-            buf.writeVarInt(bytesWritten)
+            VarInt.writeVarInt(buf, bytesWritten)
             buf.writeBytes(utf8Buffer)
         } finally {
             utf8Buffer.release()

surf-cloud-api/surf-cloud-api-common/src/main/kotlin/dev/slne/surf/cloud/api/common/netty/protocol/buffer/types/VarLong.kt

@@ -23,7 +23,7 @@ object VarLong {
      */
     fun getEncodedSize(value: Long): Int {
         for (i in 1 until MAX_VARLONG_SIZE) {
-            if ((value and -1L shl i * DATA_BITS_PER_BYTE) == 0L) {
+            if (value and (-1L shl (i * DATA_BITS_PER_BYTE)) == 0L) {
                 return i
             }
         }
@@ -49,16 +49,16 @@ object VarLong {
      */
     fun readVarLong(buf: ByteBuf): Long {
         var result = 0L
-        var shift = 0
+        var numBytes = 0
 
         var currentByte: Byte
         do {
             currentByte = buf.readByte()
-            result =
-                result or ((currentByte.toLong() and DATA_BITS_MASK.toLong()) shl (shift++ * DATA_BITS_PER_BYTE))
-            shift += DATA_BITS_PER_BYTE
+            result = result or
+                    ((currentByte.toLong() and DATA_BITS_MASK.toLong()) shl (numBytes * DATA_BITS_PER_BYTE))
+            numBytes++
 
-            checkDecoded(shift <= MAX_VARLONG_SIZE) { "VarLong too big" }
+            checkDecoded(numBytes <= MAX_VARLONG_SIZE) { "VarLong too big" }
         } while (currentByte.toInt() and CONTINUATION_BIT_MASK == CONTINUATION_BIT_MASK)
 
         return result