How do I convert jstring to wchar_t *

Question

Let\'s say that on the C++ side my function takes a variable of type jstring named myString. I can convert it to an ANSI string as follows:

Answer 1

I try to jstring->char->wchar_t

char* js2c(JNIEnv* env, jstring jstr)
{
    char* rtn = NULL;
    jclass clsstring = env->FindClass("java/lang/String");
    jstring strencode = env->NewStringUTF("utf-8");
    jmethodID mid = env->GetMethodID(clsstring, "getBytes", "(Ljava/lang/String;)[B");
    jbyteArray barr = (jbyteArray)env->CallObjectMethod(jstr, mid, strencode);
    jsize alen = env->GetArrayLength(barr);
    jbyte* ba = env->GetByteArrayElements(barr, JNI_FALSE);
    if (alen > 0)
    {
        rtn = (char*)malloc(alen + 1);
        memcpy(rtn, ba, alen);
        rtn[alen] = 0;
    }
    env->ReleaseByteArrayElements(barr, ba, 0);
    return rtn;
}

jstring c2js(JNIEnv* env, const char* str) {
    jstring rtn = 0;
    int slen = strlen(str);
    unsigned short * buffer = 0;
    if (slen == 0)
        rtn = (env)->NewStringUTF(str);
    else {
        int length = MultiByteToWideChar(CP_ACP, 0, (LPCSTR)str, slen, NULL, 0);
        buffer = (unsigned short *)malloc(length * 2 + 1);
        if (MultiByteToWideChar(CP_ACP, 0, (LPCSTR)str, slen, (LPWSTR)buffer, length) > 0)
            rtn = (env)->NewString((jchar*)buffer, length);
        free(buffer);
    }
    return rtn;
}



jstring w2js(JNIEnv *env, wchar_t *src)
{
    size_t len = wcslen(src) + 1;
    size_t converted = 0;
    char *dest;
    dest = (char*)malloc(len * sizeof(char));
    wcstombs_s(&converted, dest, len, src, _TRUNCATE);

    jstring dst = c2js(env, dest);
    return dst;
}

wchar_t *js2w(JNIEnv *env, jstring src) {

    char *dest = js2c(env, src);
    size_t len = strlen(dest) + 1;
    size_t converted = 0;
    wchar_t *dst;
    dst = (wchar_t*)malloc(len * sizeof(wchar_t));
    mbstowcs_s(&converted, dst, len, dest, _TRUNCATE);
    return dst;
}