1 files changed, 98 insertions, 0 deletions
diff --git a/ebics/src/main/kotlin/EbicsOrderUtil.kt b/ebics/src/main/kotlin/EbicsOrderUtil.kt
new file mode 100644
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--- /dev/null
+++ b/ebics/src/main/kotlin/EbicsOrderUtil.kt
@@ -0,0 +1,98 @@
+/*
+ * This file is part of LibEuFin.
+ * Copyright (C) 2024 Taler Systems S.A.
+
+ * LibEuFin is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation; either version 3, or
+ * (at your option) any later version.
+
+ * LibEuFin is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Affero General
+ * Public License for more details.
+
+ * You should have received a copy of the GNU Affero General Public
+ * License along with LibEuFin; see the file COPYING.  If not, see
+ * <http://www.gnu.org/licenses/>
+ */
+
+package tech.libeufin.ebics
+
+import java.lang.IllegalArgumentException
+import java.security.SecureRandom
+import java.util.zip.DeflaterInputStream
+import java.util.zip.InflaterInputStream
+
+/**
+ * Helpers for dealing with order compression, encryption, decryption, chunking and re-assembly.
+ */
+object EbicsOrderUtil {
+
+    // Decompression only, no XML involved.
+    fun decodeOrderData(encodedOrderData: ByteArray): ByteArray {
+        return InflaterInputStream(encodedOrderData.inputStream()).use {
+            it.readAllBytes()
+        }
+    }
+
+    inline fun <reified T> decodeOrderDataXml(encodedOrderData: ByteArray): T {
+        return InflaterInputStream(encodedOrderData.inputStream()).use {
+            val bytes = it.readAllBytes()
+            XMLUtil.convertStringToJaxb<T>(bytes.toString(Charsets.UTF_8)).value
+        }
+    }
+
+    inline fun <reified T> encodeOrderDataXml(obj: T): ByteArray {
+        val bytes = XMLUtil.convertJaxbToString(obj).toByteArray()
+        return DeflaterInputStream(bytes.inputStream()).use {
+            it.readAllBytes()
+        }
+    }
+
+    @kotlin.ExperimentalStdlibApi
+    fun generateTransactionId(): String {
+        val rng = SecureRandom()
+        val res = ByteArray(16)
+        rng.nextBytes(res)
+        return res.toHexString().uppercase()
+    }
+
+    /**
+     * Calculate the resulting size of base64-encoding data of the given length,
+     * including padding.
+     */
+    fun calculateBase64EncodedLength(dataLength: Int): Int {
+        val blocks = (dataLength + 3 - 1) / 3
+        return blocks * 4
+    }
+
+    fun checkOrderIDOverflow(n: Int): Boolean {
+        if (n <= 0)
+            throw IllegalArgumentException()
+        val base = 10 + 26
+        return n >= base * base
+    }
+
+    private fun getDigitChar(x: Int): Char {
+        if (x < 10) {
+            return '0' + x
+        }
+        return 'A' + (x - 10)
+    }
+
+    fun computeOrderIDFromNumber(n: Int): String {
+        if (n <= 0)
+            throw IllegalArgumentException()
+        if (checkOrderIDOverflow(n))
+            throw IllegalArgumentException()
+        var ni = n
+        val base = 10 + 26
+        val x1 = ni % base
+        ni = ni / base
+        val x2 = ni % base
+        val c1 = getDigitChar(x1)
+        val c2 = getDigitChar(x2)
+        return String(charArrayOf('O', 'R', c2, c1))
+    }
+}