replace IllegalArgumentException with require

README.md

@@ -1,18 +1,21 @@
-# Kotlin OTP
+# prng-kt
 
-This library provides various [Pseudorandom Number Generator](https://en.wikipedia.org/wiki/Pseudorandom_number_generator)
-implementations in Kotlin Multiplatform.
+`prng-kt` is a Kotlin Multiplatform library that provides common pseudorandom number generators.
 
-## Features
+Supported PRNGs:
+- LCG
 
-* Generate random numbers using Kotlin's Random interface.
-* Seed the PRNGs to receive predictable results.
-* Reseed the PRNGs to add entropy to the following results.
-* [HMAC DRBG](https://en.wikipedia.org/wiki/NIST_SP_800-90A#Hash_DRBG_and_HMAC_DRBG)
-* Multiplatform support
-    * JVM
-    * JavaScript
-    * Native (Linux)
+Supported CSPRNGs:
+- HMAC DRBG
+
+## Targets
+
+| Target           | Status        |
+|------------------|---------------|
+| JVM              | Supported     |
+| JavaScript       | Supported     |
+| Native (Linux)   | Supported     |
+| Native (Windows) | Not Supported |
 
 ## Installation
 
@@ -24,19 +27,19 @@ repositories {
 }
 
 dependencies {
-    implementation("com.infendro:random:1.1.0")
+    implementation("com.infendro:prng:1.2.0")
 }
 ```
 
 ## Usage
 
 ```kotlin
-import com.infendro.hash.SHA256
-import com.infendro.random.PRNG
+import com.infendro.hash.sha2.`SHA-256`
+import com.infendro.random.csprng.CSPRNG
 
 fun main() {
     // create a PRNG instance
-    val rng = PRNG.HMAC(SHA256)
+    val rng = CSPRNG.HMAC(`SHA-256`)
 
     // seed the PRNG to receive predictable results
     rng.seed(/* some seed */)

src/commonMain/kotlin/com/infendro/random/csprng/HMAC.kt

@@ -35,7 +35,6 @@ class HMAC internal constructor(
         val bytes = buildList {
             while (size < count) {
                 v = hmac.hash(k, v)
-
                 addAll(v.take(min(count - size, function.bytes)))
             }
         }.toUByteArray()

src/commonMain/kotlin/com/infendro/random/prng/LCG.kt

@@ -26,7 +26,6 @@ class LCG internal constructor() : PRNG() {
         return buildList {
             while (size < count) {
                 x = (a * x + c) % m
-
                 addAll(x.toUByteArray().takeLast(min(count - size, 6)))
             }
         }.toUByteArray()

src/commonMain/kotlin/com/infendro/random/prng/PRNG.kt

@@ -15,12 +15,29 @@ abstract class PRNG : Random() {
     override fun nextBits(
         bitCount: Int,
     ): Int {
-        if (bitCount !in 0..32) throw Exception()
-        if (bitCount == 0) return 0
+        require(bitCount in 0..32)
 
+        if (bitCount == 0) return 0
         return generate(4).toInt() ushr (32 - bitCount)
     }
 
+    override fun nextBytes(
+        array: ByteArray,
+        fromIndex: Int,
+        toIndex: Int,
+    ): ByteArray {
+        require(fromIndex in 0..array.size && toIndex in 0..array.size)
+        require(fromIndex <= toIndex)
+
+        val size = toIndex - fromIndex
+        val bytes = generate(size).asByteArray()
+        for (i in 0..<size) {
+            array[i + fromIndex] = bytes[i]
+        }
+
+        return array
+    }
+
     companion object {
         fun LCG() = com.infendro.random.prng.LCG()
     }