feat(Hashing): digest interface

Hashing/src/commonMain/kotlin/io/iohk/prism/hashing/internal/Digest.kt

@@ -0,0 +1,86 @@
+package io.iohk.prism.hashing.internal
+
+/**
+ * Digests are secure one-way hash functions that take arbitrary-sized
+ * data and output a fixed-length hash value.
+ *
+ * An interface that all implemented hashing algorithm will implement.
+ */
+public interface Digest {
+    /**
+     * the internal block length (in bytes), or `-n`
+     */
+    public val blockLength: Int
+
+    /**
+     * the digest output length (in bytes)
+     */
+    public val digestLength: Int
+
+    /**
+     * Updates the digest using the specified byte.
+     *
+     * @param input the byte with which to update the digest.
+     */
+    public fun update(input: Byte)
+
+    /**
+     * Updates the digest using the specified array of bytes.
+     *
+     * @param input the array of bytes.
+     */
+    public fun update(input: ByteArray)
+
+    /**
+     * Updates the digest using the specified array of bytes, starting
+     * at the specified offset.
+     *
+     * @param input the array of bytes.
+     * @param offset the offset to start from in the array of bytes.
+     * @param length the number of bytes to use, starting at [offset]
+     */
+    public fun update(input: ByteArray, offset: Int, length: Int)
+
+    /**
+     * Completes the hash computation by performing final operations
+     * such as padding. The digest is reset after this call is made.
+     *
+     * @return the array of bytes for the resulting hash value.
+     */
+    public fun digest(): ByteArray
+
+    /**
+     * Performs a final update on the digest using the specified array
+     * of bytes, then completes the digest computation. That is, this
+     * method first calls [update], passing the [input] array to the
+     * [update] method, then calls [digest].
+     *
+     * @param input the input to be updated before the digest is
+     * completed.
+     * @return the array of bytes for the resulting hash value.
+     */
+    public fun digest(input: ByteArray): ByteArray
+
+    /**
+     * Completes the hash computation by performing final operations
+     * such as padding. The digest is reset after this call is made.
+     *
+     * @param output output buffer for the computed digest
+     * @param offset offset into the output buffer to begin storing the digest
+     * @param length number of bytes within buf allotted for the digest
+     * @return the number of bytes placed into [output]
+     * @throws [IllegalArgumentException]
+     */
+    @Throws(IllegalArgumentException::class)
+    public fun digest(output: ByteArray, offset: Int, length: Int): Int
+
+    /**
+     * Resets the digest for further use.
+     */
+    public fun reset()
+
+    /**
+     * Get the display name for this function (e.g. `"SHA-1"` for SHA-1).
+     */
+    public override fun toString(): String
+}