I have 2 very similar C functions being called fro

Basically I have 2 implementations of a C function "encrypt" which I call from python using ctypes and java using JNI. I've been told to take the two dynamic libraries that were used for java and python, and combine them into a static library that can be called from both. To clarify, here's the C function implementation for java using JNI:

#include "jniTest.h"
#include <stdio.h>

JNIEXPORT void JNICALL Java_jniTest_passBytes
  (JNIEnv *env, jclass cls, jbyteArray array) {
    unsigned char *buffer = (*env)->GetByteArrayElements(env, array, NULL);
    jsize size = (*env)->GetArrayLength(env,array);

    for(int i=0; i<size; i++){
        buffer[i] += 1;
        printf("%c",buffer[i]);
    }
    (*env)->ReleaseByteArrayElements(env, array, buffer, 0);
}

So the function takes in a byte array and increments each byte by 1 then returns each element of the new byte array. Here's the java side:

class jniTest{
    public static native void passBytes(byte[] bytes);
    static{
        System.loadLibrary("encrypter");
    {
    public static void main(String[] args){
        Tester tester = new Tester();
        byte[] b = "hello";
        tester.passBytes(b);
    }
}

The python implementation of the C function is the exact same, just not using all that JNI syntax:

#include <stdio.h>

void encrypt(int size, unsigned char *buffer);

void encrypt(int size, unsigned char *buffer){
    for(int i=0; i < size; i++){
        buffer[i]+=1; 
        printf("%c", buffer[i]);
    }
}

And the python side:

import ctypes

encryptPy = ctypes.CDLL('/home/aradhak/Documents/libencrypt.so')
hello = "hello"
byteArr = bytearray(hello)
rawBytes = (ctyes_c.ubyte*len(byteArr)(*(byteArr))
encryptPy.encrypt(len(byteArr), rawBytes)

As you can see, the C function for python and java do the exact same thing (few minor differences). They take in a byte array, increment each byte by 1, and print each incremented byte. I just need to combine these two C libraries and combine them into a single static library which can be accessed from both python AND java. Is this possible? Thanks.

You can call the python version from the java one. This avoids the duplicate code. You’ll still have to do the to/from JNI marshalling though:

void encrypt(int size, unsigned char *buffer){
    for(int i=0; i < size; i++){
        buffer[i]+=1; 
        printf("%c", buffer[i]);
    }
}

JNIEXPORT void JNICALL Java_jniTest_passBytes
  (JNIEnv *env, jclass cls, jbyteArray array) {
    unsigned char *buffer = (*env)->GetByteArrayElements(env, array, NULL);
    jsize size = (*env)->GetArrayLength(env,array);

    encrypt(size, buffer);

    (*env)->ReleaseByteArrayElements(env, array, buffer, 0);
}