1 files changed, 51 insertions, 0 deletions
diff --git a/formats/json-tests/commonTest/src/kotlinx/serialization/test/InternalHexConverter.kt b/formats/json-tests/commonTest/src/kotlinx/serialization/test/InternalHexConverter.kt
new file mode 100644
index 00000000..349eb43c
--- /dev/null
+++ b/formats/json-tests/commonTest/src/kotlinx/serialization/test/InternalHexConverter.kt
@@ -0,0 +1,51 @@
+/*
+ * Copyright 2017-2021 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
+ */
+
+package kotlinx.serialization.test
+
+object InternalHexConverter {
+    private const val hexCode = "0123456789ABCDEF"
+
+    fun parseHexBinary(s: String): ByteArray {
+        val len = s.length
+        require(len % 2 == 0) { "HexBinary string must be even length" }
+        val bytes = ByteArray(len / 2)
+        var i = 0
+
+        while (i < len) {
+            val h = hexToInt(s[i])
+            val l = hexToInt(s[i + 1])
+            require(!(h == -1 || l == -1)) { "Invalid hex chars: ${s[i]}${s[i+1]}" }
+
+            bytes[i / 2] = ((h shl 4) + l).toByte()
+            i += 2
+        }
+
+        return bytes
+    }
+
+    private fun hexToInt(ch: Char): Int = when (ch) {
+        in '0'..'9' -> ch - '0'
+        in 'A'..'F' -> ch - 'A' + 10
+        in 'a'..'f' -> ch - 'a' + 10
+        else -> -1
+    }
+
+    fun printHexBinary(data: ByteArray, lowerCase: Boolean = false): String {
+        val r = StringBuilder(data.size * 2)
+        for (b in data) {
+            r.append(hexCode[b.toInt() shr 4 and 0xF])
+            r.append(hexCode[b.toInt() and 0xF])
+        }
+        return if (lowerCase) r.toString().lowercase() else r.toString()
+    }
+
+    fun toHexString(n: Int): String {
+        val arr = ByteArray(4)
+        for (i in 0 until 4) {
+            arr[i] = (n shr (24 - i * 8)).toByte()
+        }
+        return printHexBinary(arr, true).trimStart('0').takeIf { it.isNotEmpty() } ?: "0"
+    }
+}