Never try to copy more than block len

This fixed a regression which one was introduced at
b7bd1f5 as bugfix for another issue.

When it happened, it throw `ArrayIndexOutOfBoundsException` and doesn't
produce incorrect hash.

Author: catap

CHANGELOG.md

@@ -3,6 +3,7 @@
 All notable changes to this project will be documented in this file.
 
 ## [unreleased]
+- Fixed regression on chunked data that was introduced in 2.6.0.
 
 ## [2.6.0] - 2021-05-17
 - Fixed an issue when chunked data by block len produced incorrect block.

shared/src/main/scala/ky/korins/blake3/ChunkState.scala

@@ -74,14 +74,17 @@ private[blake3] class ChunkState(
 
     val available = BLOCK_LEN - blockLen
     var consume = Math.min(available, to - i)
-    if (consume < available) {
+    if (consume > 0) {
       System.arraycopy(bytes, i, block, blockLen, consume)
       blockLen += consume
       i += consume
-      compressIfRequired()
     }
 
     consume = to - i
+    if (consume > 0) {
+      compressIfRequired()
+    }
+
     while (consume > BLOCK_LEN) {
       blockLen = BLOCK_LEN
       compressedWords(bytes, i)

shared/src/test/scala/ky/korins/blake3/Blake3Test.scala

@@ -254,4 +254,15 @@ class Blake3Test extends AnyWordSpec with should.Matchers {
       expected shouldBe actual
     }
   }
+
+  "Regression in 2.6.0" in {
+    val bytes = new Array[Byte](146)
+    Random.nextBytes(bytes)
+    val expected = Blake3.base16(bytes, 32)
+    val hasher = Blake3.newHasher()
+    hasher.update(bytes, 0, 125)
+    hasher.update(bytes, 125, 21)
+    val actual = hasher.doneBase16(32)
+    expected shouldBe actual
+  }
 }