Add slice functionality to SlicedByteArray with tests and edge case validation

Implemented a `slice` method in `SlicedByteArray` to allow creating sub-arrays with specified offset and length. Added validations to handle invalid inputs and bounds. Introduced `SliceTest` to cover standard, edge cases, and error scenarios. Bumped version to 0.3.2.

build.gradle.kts

@@ -8,7 +8,7 @@ plugins {
 }
 
 group = "nl.astraeus"
-version = "0.3.0"
+version = "0.3.2"
 
 repositories {
     mavenCentral()

src/commonMain/kotlin/nl/astraeus/tba/SlicedByteArray.kt

@@ -185,6 +185,14 @@ class SlicedByteArray(
 
   fun decodeToString(): String = data.decodeToString(offset, offset + length)
 
+  fun slice(offset: Int, length: Int): SlicedByteArray {
+    check(offset >= 0) { "Offset must be non-negative" }
+    check(length >= 0) { "Length must be non-negative" }
+    check(offset + length <= this.length) { "Offset + length exceeds array bounds (offset: $offset, length: $length, array length: ${this.length})" }
+
+    return SlicedByteArray(data, this.offset + offset, length)
+  }
+
   companion object {
     fun wrap(
       data: ByteArray,

src/commonTest/kotlin/nl/astraeus/tba/SliceTest.kt

@@ -0,0 +1,93 @@
+package nl.astraeus.tba
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertFailsWith
+
+/**
+ * Test class for the slice method in SlicedByteArray
+ */
+class SliceTest {
+
+    @Test
+    fun testSlice() {
+        // Create a SlicedByteArray with some test data
+        val array = SlicedByteArray(10)
+        for (i in 0 until 10) {
+            array[i] = i.toByte()
+        }
+
+        // Test basic slicing
+        val slice1 = array.slice(2, 3)
+        assertEquals(3, slice1.size)
+        assertEquals(2.toByte(), slice1[0])
+        assertEquals(3.toByte(), slice1[1])
+        assertEquals(4.toByte(), slice1[2])
+
+        // Test slicing with offset 0
+        val slice2 = array.slice(0, 5)
+        assertEquals(5, slice2.size)
+        for (i in 0 until 5) {
+            assertEquals(i.toByte(), slice2[i])
+        }
+
+        // Test slicing to the end
+        val slice3 = array.slice(5, 5)
+        assertEquals(5, slice3.size)
+        for (i in 0 until 5) {
+            assertEquals((i + 5).toByte(), slice3[i])
+        }
+
+        // Test nested slicing
+        val nestedSlice = slice1.slice(1, 2)
+        assertEquals(2, nestedSlice.size)
+        assertEquals(3.toByte(), nestedSlice[0])
+        assertEquals(4.toByte(), nestedSlice[1])
+    }
+
+    @Test
+    fun testSliceEdgeCases() {
+        val array = SlicedByteArray(10)
+        for (i in 0 until 10) {
+            array[i] = i.toByte()
+        }
+
+        // Test empty slice
+        val emptySlice = array.slice(5, 0)
+        assertEquals(0, emptySlice.size)
+
+        // Test slice at the very end
+        val endSlice = array.slice(9, 1)
+        assertEquals(1, endSlice.size)
+        assertEquals(9.toByte(), endSlice[0])
+    }
+
+    @Test
+    fun testSliceErrorCases() {
+        val array = SlicedByteArray(10)
+
+        // Test negative offset
+        assertFailsWith<IllegalStateException> {
+            array.slice(-1, 5)
+        }
+
+        // Test negative length
+        assertFailsWith<IllegalStateException> {
+            array.slice(0, -1)
+        }
+
+        // Test offset + length > array.length
+        assertFailsWith<IllegalStateException> {
+            array.slice(6, 5)
+        }
+
+        // Test offset = array.length (valid if length = 0)
+        val emptyEndSlice = array.slice(10, 0)
+        assertEquals(0, emptyEndSlice.size)
+
+        // Test offset > array.length
+        assertFailsWith<IllegalStateException> {
+            array.slice(11, 0)
+        }
+    }
+}