StreamUtils: support for arrays of BigIntegers

Author: pvriel

README.md

@@ -3,7 +3,7 @@ A Java library containing math, stream, ... util classes that I used to work wit
 <br>This project mainly exists to make my life easier (so that I don't have to copy-paste code), but feel free to use it if you want.
 
 [![Project Status: Active](https://www.repostatus.org/badges/latest/active.svg)](https://www.repostatus.org/#active)
-[![Coverage](https://badgen.net/badge/coverage/96%25/green)](https://badgen.net/badge/coverage/96%25/green)
+[![Coverage](https://badgen.net/badge/coverage/97%25/green)](https://badgen.net/badge/coverage/97%25/green)
 
 ***
 

build.gradle

@@ -4,7 +4,7 @@ plugins {
 }
 
 group = 'com.github.pvriel'
-version = '1.3.0'
+version = '1.3.1'
 
 repositories {
     mavenLocal()

src/main/java/com/github/pvriel/mpcutils4j/stream/StreamUtils.java

@@ -40,6 +40,42 @@ public static BigInteger readBigIntegerFromInputStream(InputStream inputStream)
         return new BigInteger(receiveInputWithLengthPrefix(inputStream));
     }
 
+    /**
+     * Method to write a {@link BigInteger} array to an {@link OutputStream}.
+     * @param   bigIntegers
+     *          The {@link BigInteger} array to write. No null values are allowed.
+     * @param   outputStream
+     *          The {@link OutputStream} to write the instance to. No null values are allowed.
+     * @throws  IOException
+     *          If the {@link OutputStream} threw an exception while writing the data.
+     */
+    public static void writeArrayOfBigIntegersToOutputStream(BigInteger[] bigIntegers, OutputStream outputStream) throws IOException {
+        outputStream.write(ByteBuffer.allocate(4).putInt(bigIntegers.length).array());
+        for (BigInteger bigInteger : bigIntegers) {
+            writeBigIntegerToOutputStream(bigInteger, outputStream);
+        }
+    }
+
+    /**
+     * Method to read a {@link BigInteger} array from an {@link OutputStream}.
+     * @param   inputStream
+     *          The {@link InputStream} to read the instance from. No null values are allowed.
+     * @return  The resulting {@link BigInteger} array.
+     * @throws  IOException
+     *          If the {@link OutputStream} threw an exception while reading the data.
+     */
+    public static BigInteger[] readArrayOfBigIntegersFromInputStream(InputStream inputStream) throws IOException {
+        ByteBuffer byteBuffer = ByteBuffer.wrap(inputStream.readNBytes(4));
+        int length = byteBuffer.getInt();
+        byteBuffer.clear();
+
+        BigInteger[] bigIntegers = new BigInteger[length];
+        for (int i = 0; i < length; i++) {
+            bigIntegers[i] = readBigIntegerFromInputStream(inputStream);
+        }
+        return bigIntegers;
+    }
+
 /**
      * Method to read a byte array from an {@link OutputStream}.
      * This method first reads a 4-byte long length prefix at the beginning of the resulting array.
@@ -48,6 +84,7 @@ public static BigInteger readBigIntegerFromInputStream(InputStream inputStream)
      *          The {@link InputStream} to read the instance from. No null values are allowed.
      * @throws  IOException
      *          If the {@link OutputStream} threw an exception while reading the data.
+     * @return  The resulting byte array.
      */
     public static byte[] readByteArrayFromInputStream(InputStream inputStream) throws IOException {
         return receiveInputWithLengthPrefix(inputStream);

src/test/java/com/github/pvriel/mpcutils4j/stream/StreamUtilsTest.java

@@ -19,7 +19,7 @@ class StreamUtilsTest {
 
     @BeforeEach
     void setUp() throws IOException {
-        PipedInputStream pipedInputStream = new PipedInputStream(10_000);
+        PipedInputStream pipedInputStream = new PipedInputStream(100_000);
         PipedOutputStream pipedOutputStream = new PipedOutputStream(pipedInputStream);
 
         inputStream = pipedInputStream;
@@ -45,6 +45,22 @@ void writeBigIntegerToOutputStream() throws IOException {
         }
     }
 
+    @Test
+    @DisplayName("Check if an array of BigIntegers can be correctly written to an OutputStream and read from an InputStream.")
+    void writeArrayOfBigIntegersToOutputStream() throws IOException {
+        int amountOfValues = 100;
+        int bitLengthValues = 2048;
+
+        BigInteger[] randomValues = new BigInteger[amountOfValues];
+        for (int j = 0; j < randomValues.length; j++) {
+            randomValues[j] = new BigInteger(bitLengthValues, random);
+        }
+        StreamUtils.writeArrayOfBigIntegersToOutputStream(randomValues, outputStream);
+        BigInteger[] readValues = StreamUtils.readArrayOfBigIntegersFromInputStream(inputStream);
+        assertArrayEquals(randomValues, readValues);
+
+    }
+
     @Test
     @DisplayName("Check if a byte array can be correctly written to an OutputStream and read from an InputStream.")
     void writeByteArrayToOutputStream() throws IOException {