Adding pwhash native and tests

multiplatform-crypto-libsodium-bindings/src/nativeMain/kotlin/com/ionspin/kotlin/crypto/pwhash/PasswordHash.kt

@@ -4,9 +4,11 @@ import com.ionspin.kotlin.crypto.util.toPtr
 import kotlinx.cinterop.addressOf
 import kotlinx.cinterop.convert
 import kotlinx.cinterop.pin
+import kotlinx.cinterop.toCValues
 import libsodium.crypto_pwhash
 import libsodium.crypto_pwhash_str
 import libsodium.crypto_pwhash_str_needs_rehash
+import libsodium.crypto_pwhash_str_verify
 
 actual object PasswordHash {
     /**
@@ -30,7 +32,7 @@ actual object PasswordHash {
         val hashedPasswordPinned = hashedPassword.pin()
         val saltPinned = salt.pin()
 
-        crypto_pwhash(
+        val hashingResult = crypto_pwhash(
             hashedPasswordPinned.toPtr(),
             outputLength.convert(),
             password,
@@ -42,6 +44,9 @@ actual object PasswordHash {
         )
         saltPinned.unpin()
         hashedPasswordPinned.unpin()
+        if (hashingResult != 0) {
+            throw PasswordHashingFailed()
+        }
 
         return hashedPassword
     }
@@ -56,8 +61,8 @@ actual object PasswordHash {
      * and other data stores. No extra information has to be stored in order to verify the password.
      * The function returns 0 on success and -1 if it didn't complete successfully.
      */
-    actual fun str(password: String, opslimit: ULong, memlimit: Int): String {
-        val output = ByteArray(crypto_pwhash_STRBYTES.toInt())
+    actual fun str(password: String, opslimit: ULong, memlimit: Int): UByteArray {
+        val output = ByteArray(crypto_pwhash_STRBYTES)
         val outputPinned = output.pin()
         crypto_pwhash_str(
             outputPinned.addressOf(0),
@@ -68,7 +73,7 @@ actual object PasswordHash {
         )
         outputPinned.unpin()
 
-        return output.decodeToString()
+        return output.asUByteArray()
     }
 
     /**
@@ -78,20 +83,32 @@ actual object PasswordHash {
      * It returns -1 on error. If it happens, applications may want to compute a correct hash the next time the user logs in.
      */
     actual fun strNeedsRehash(
-        password: String,
+        passwordHash: UByteArray,
         opslimit: ULong,
         memlimit: Int
-    ): Boolean {
-        val password = password.encodeToByteArray()
-        crypto_pwhash_str_needs_rehash(
-            ,
+    ): Int {
+        val result = crypto_pwhash_str_needs_rehash(
+            passwordHash.asByteArray().toCValues(),
             opslimit,
             memlimit.convert()
         )
+        return result
+
+
     }
 
-    actual fun strVerify(passwordHash: String, password: UByteArray): Boolean {
-        TODO("Not yet implemented")
+    /**
+     * his function verifies that str is a valid password verification string (as generated by crypto_pwhash_str()) for passwd whose length is passwdlen.
+     * str has to be zero-terminated.
+     * It returns 0 if the verification succeeds, and -1 on error.
+     */
+    actual fun strVerify(passwordHash: UByteArray, password: String): Boolean {
+        val result = crypto_pwhash_str_verify(
+            passwordHash.asByteArray().toCValues(),
+            password,
+            password.length.convert()
+        )
+        return result == 0
     }
 
-}
+}