Initial commit

src/commonMain/kotlin/cn/rtast/mcping/mc_primitives.kt

@@ -0,0 +1,48 @@
+/*
+ * Copyright © 2026 RTAkland
+ * Author: RTAkland
+ * Date: 2026/9/3
+ */
+
+package cn.rtast.mcping
+
+import cn.rtast.mcping.platform.PlatformBuffer
+import cn.rtast.mcping.platform.PlatformReadChannel
+
+
+internal fun PlatformBuffer.writeVarInt(value: Int) {
+    var v = value
+    while (true) {
+        if ((v and 0x7F.inv()) == 0) {
+            this.writeByte(v.toByte())
+            return
+        }
+        this.writeByte(((v and 0x7F) or 0x80).toByte())
+        v = v ushr 7
+    }
+}
+
+internal fun PlatformReadChannel.readVarInt(): Int {
+    var value = 0
+    var position = 0
+    while (true) {
+        val currentByte = this.readByte().toInt() and 0xFF
+        value = value or ((currentByte and 0x7F) shl position)
+        if ((currentByte and 0x80) == 0) break
+        position += 7
+        if (position >= 35) throw IllegalArgumentException("VarInt too long")
+    }
+    return value
+}
+
+internal fun PlatformBuffer.writeMcString(value: String) {
+    val bytes = value.encodeToByteArray()
+    this.writeVarInt(bytes.size)
+    this.writeBytes(bytes)
+}
+
+internal fun PlatformReadChannel.readMcString(): String {
+    val length = this.readVarInt()
+    val bytes = this.readBytes(length)
+    return bytes.decodeToString()
+}