Handle some IllegalArgument cases in readBytes

The 2nd error covered here potentially could explain cases like

java-native#122

or related. Example: Passed-in 'byteCount' is either far too large or
even a negative value which could trigger undesired behavior when used
to allocate an array.

src/main/cpp/_nix_based/jssc.cpp

@@ -657,10 +657,31 @@ JNIEXPORT jbyteArray JNICALL Java_jssc_SerialNativeInterface_readBytes
   (JNIEnv *env, jobject, jlong portHandle, jint byteCount){
 
     int err;
-    jbyte *lpBuffer = new jbyte[byteCount];
+    jbyte *lpBuffer = NULL;
     jbyteArray returnArray = NULL;
     int byteRemains = byteCount;
 
+    if( byteCount < 0 ){
+        char emsg[32]; emsg[0] = '\0';
+        snprintf(emsg, sizeof emsg, "new byte[%d]", byteCount);
+        jclass exClz = env->FindClass("java/lang/IllegalArgumentException");
+        if( exClz != NULL ) env->ThrowNew(exClz, emsg);
+        returnArray = NULL; goto Finally;
+    }
+
+    try{
+        lpBuffer = new jbyte[byteCount];
+    }catch( const std::bad_alloc& ex ){
+        lpBuffer = NULL;
+    }
+    if( lpBuffer == NULL ){
+        char emsg[32]; emsg[0] = '\0';
+        snprintf(emsg, sizeof emsg, "new byte[%d]", byteCount);
+        jclass exClz = env->FindClass("java/lang/OutOfMemoryError");
+        if( exClz != NULL ) env->ThrowNew(exClz, emsg);
+        returnArray = NULL; goto Finally;
+    }
+
     while(byteRemains > 0) {
         int result = 0;
 
@@ -707,7 +728,7 @@ JNIEXPORT jbyteArray JNICALL Java_jssc_SerialNativeInterface_readBytes
     assert(env->ExceptionCheck() == JNI_FALSE);
 
 Finally:
-    delete[] lpBuffer;
+    if( lpBuffer != NULL ) delete[] lpBuffer;
     return returnArray;
 }