/**
 * Copyright (C) 2021 Mikael Magnusson <mikma@user.sourceforge.net>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License v2 as published by
 * the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 */

#include "prng.h"

#include <stddef.h>
#include <stdlib.h>
#include <string.h>

#include <libubox/md5.h>


/* PRNG using MD5 from libubox. */
struct prng_context_s
{
	md5_ctx_t md5;
};


prng_context_t *prng_alloc()
{
	prng_context_t *ctx = calloc(1, sizeof(prng_context_t));
	return ctx;
}

void prng_setup(prng_context_t *ctx)
{
	memset(ctx, 0, sizeof(*ctx));
}

void prng_starts(prng_context_t *ctx)
{
	md5_begin(&ctx->md5);
}

void prng_update(prng_context_t *ctx, const uint8_t *input, size_t ilen)
{
	md5_hash(input, ilen, &ctx->md5);
}

void prng_finish(prng_context_t *ctx, uint8_t *output, uint8_t *output2)
{
	uint8_t tmp[16];
	md5_end(tmp, &ctx->md5);
	memcpy(output, tmp, 8);
	if (output2)
		memcpy(output2, tmp + 8, 8);
}

#if 0
void prng_free()
{
}
#endif