Add base58 support (#150)

io/src/main/java/org/apache/tuweni/io/Base58.java

@@ -0,0 +1,68 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements. See the NOTICE
+ * file distributed with this work for additional information regarding copyright ownership. The ASF licenses this file
+ * to You under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the
+ * License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
+ * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations under the License.
+ */
+package org.apache.tuweni.io;
+
+import static java.nio.charset.StandardCharsets.UTF_8;
+import static java.util.Objects.requireNonNull;
+
+import org.apache.tuweni.bytes.Bytes;
+
+/**
+ * Utility methods for encoding and decoding base58 strings.
+ */
+public final class Base58 {
+  private Base58() {}
+
+  /**
+   * Encode a byte array to a base58 encoded string.
+   *
+   * @param bytes The bytes to encode.
+   * @return A base58 encoded string.
+   */
+  public static String encodeBytes(byte[] bytes) {
+    requireNonNull(bytes);
+    return new String(Base58Codec.encode(bytes), UTF_8);
+  }
+
+  /**
+   * Encode bytes to a base58 encoded string.
+   *
+   * @param bytes The bytes to encode.
+   * @return A base58 encoded string.
+   */
+  public static String encode(Bytes bytes) {
+    requireNonNull(bytes);
+    return encodeBytes(bytes.toArrayUnsafe());
+  }
+
+  /**
+   * Decode a base58 encoded string to a byte array.
+   *
+   * @param b58 The base58 encoded string.
+   * @return A byte array.
+   */
+  public static byte[] decodeBytes(String b58) {
+    requireNonNull(b58);
+    return Base58Codec.decode(b58);
+  }
+
+  /**
+   * Decode a base58 encoded string to bytes.
+   *
+   * @param b58 The base58 encoded string.
+   * @return The decoded bytes.
+   */
+  public static Bytes decode(String b58) {
+    return Bytes.wrap(decodeBytes(b58));
+  }
+}

io/src/main/java/org/apache/tuweni/io/Base58Codec.java

@@ -0,0 +1,104 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements. See the NOTICE
+ * file distributed with this work for additional information regarding copyright ownership. The ASF licenses this file
+ * to You under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the
+ * License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
+ * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations under the License.
+ */
+package org.apache.tuweni.io;
+
+import java.util.Arrays;
+
+class Base58Codec {
+
+  // @formatter:off
+    private static final byte[] ENCODE_TABLE = {
+            '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D',
+            'E', 'F', 'G', 'H', 'J', 'K', 'L', 'M', 'N', 'P', 'Q', 'R', 'S',
+            'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
+            'g', 'h', 'i', 'j', 'k', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't',
+            'u', 'v', 'w', 'x', 'y', 'z'
+    };
+
+    private static final byte[] DECODE_TABLE = {
+        //   0   1   2   3   4   5   6   7   8   9   A   B   C   D   E   F
+            -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 00-0f
+            -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 10-1f
+            -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 20-2f + - /
+            -1,  0,  1,  2,  3,  4,  5,  6,  7,  8, -1, -1, -1, -1, -1, -1, // 30-3f 0-9
+            -1,  9, 10, 11, 12, 13, 14, 15, 16, -1, 17, 18, 19, 20, 21, -1, // 40-4f A-O
+            22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, -1, -1, -1, -1, -1, // 50-5f P-Z _
+            -1, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, -1, 44, 45, 46, // 60-6f a-o
+            47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57                      // 70-7a p-z
+    };
+    // @formatter:on
+
+  static byte[] encode(byte[] decoded) {
+    byte[] input = Arrays.copyOf(decoded, decoded.length);
+    byte[] encoded = new byte[input.length * 2];
+    int inputStart = 0;
+    int outputStart = encoded.length;
+    int zeros = 0;
+
+    while (inputStart < input.length) {
+      if (input[inputStart] == 0 && outputStart == encoded.length) {
+        zeros++;
+        inputStart++;
+        continue;
+      }
+      int remainder = 0;
+      for (int i = 0; i < input.length; i++) {
+        int digit = (int) input[i] & 0xFF;
+        int temp = remainder * 256 + digit;
+        input[i] = (byte) (temp / 58);
+        remainder = temp % 58;
+      }
+      encoded[--outputStart] = ENCODE_TABLE[remainder];
+      if (input[inputStart] == 0) {
+        inputStart++;
+      }
+    }
+    Arrays.fill(encoded, outputStart - zeros, outputStart, ENCODE_TABLE[0]);
+    return Arrays.copyOfRange(encoded, outputStart - zeros, encoded.length);
+  }
+
+  static byte[] decode(String encoded) {
+    byte[] input = new byte[encoded.length()];
+    byte[] decoded = new byte[input.length];
+    for (int i = 0; i < input.length; i++) {
+      input[i] = DECODE_TABLE[encoded.charAt(i)];
+      if (input[i] == -1) {
+        throw new IllegalArgumentException("Invalid character " + encoded.charAt(i));
+      }
+    }
+    int inputStart = 0;
+    int outputStart = input.length;
+    int zeros = 0;
+
+    while (inputStart < input.length) {
+      if (input[inputStart] == 0 && outputStart == input.length) {
+        zeros++;
+        inputStart++;
+        continue;
+      }
+      int remainder = 0;
+      for (int i = 0; i < input.length; i++) {
+        int digit = (int) input[i] & 0xFF;
+        int temp = remainder * 58 + digit;
+        input[i] = (byte) (temp / 256);
+        remainder = temp % 256;
+      }
+      decoded[--outputStart] = (byte) remainder;
+      if (input[inputStart] == 0) {
+        inputStart++;
+      }
+    }
+    Arrays.fill(decoded, outputStart - zeros, outputStart, (byte) 0);
+    return Arrays.copyOfRange(decoded, outputStart - zeros, decoded.length);
+  }
+}

io/src/test/java/org/apache/tuweni/io/Base58Test.java

@@ -0,0 +1,81 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements. See the NOTICE
+ * file distributed with this work for additional information regarding copyright ownership. The ASF licenses this file
+ * to You under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the
+ * License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
+ * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations under the License.
+ */
+package org.apache.tuweni.io;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.apache.tuweni.bytes.Bytes;
+
+import java.nio.charset.StandardCharsets;
+
+import org.junit.jupiter.api.Test;
+
+class Base58Test {
+
+  @Test
+  void testHelloWorld() {
+    String result = Base58.encode(Bytes.wrap("Hello World!".getBytes(StandardCharsets.US_ASCII)));
+    assertEquals("2NEpo7TZRRrLZSi2U", result);
+  }
+
+  @Test
+  void testQuickBrownFox() {
+    String result =
+        Base58.encode(Bytes.wrap("The quick brown fox jumps over the lazy dog.".getBytes(StandardCharsets.US_ASCII)));
+    assertEquals("USm3fpXnKG5EUBx2ndxBDMPVciP5hGey2Jh4NDv6gmeo1LkMeiKrLJUUBk6Z", result);
+  }
+
+  @Test
+  void testHex() {
+    Bytes value = Bytes.fromHexString("1220BA8632EF1A07986B171B3C8FAF0F79B3EE01B6C30BBE15A13261AD6CB0D02E3A");
+    assertEquals("QmatmE9msSfkKxoffpHwNLNKgwZG8eT9Bud6YoPab52vpy", Base58.encode(value));
+  }
+
+  @Test
+  void testHexDecode() {
+    Bytes value = Bytes.fromHexString("00000000");
+    assertEquals(value, Bytes.wrap(Base58.decode(Base58.encode(value))));
+  }
+
+  @Test
+  void testHexDecodeOne() {
+    Bytes value = Bytes.fromHexString("01");
+    assertEquals(value, Bytes.wrap(Base58.decode(Base58.encode(value))));
+  }
+
+  @Test
+  void testHexDecode256() {
+    Bytes value = Bytes.fromHexString("0100");
+    assertEquals(value, Bytes.wrap(Base58.decode(Base58.encode(value))));
+  }
+
+  @Test
+  void testZeros() {
+    Bytes value = Bytes.fromHexString("000000");
+    assertEquals("111", Base58.encode(value));
+  }
+
+  @Test
+  void testZerosThenOne() {
+    Bytes value = Bytes.fromHexString("00000001");
+    assertEquals("1112", Base58.encode(value));
+  }
+
+  @Test
+  void testBadCharacter() {
+    assertThrows(IllegalArgumentException.class, () -> {
+      Base58.decode("%^");
+    });
+  }
+}