/*
 * Copyright 2010-2018 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License").
 * You may not use this file except in compliance with the License.
 * A copy of the License is located at
 *
 *  http://aws.amazon.com/apache2.0
 *
 * or in the "license" file accompanying this file. This file is distributed
 * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
 * express or implied. See the License for the specific language governing
 * permissions and limitations under the License.
 */

#include <stddef.h>

/** Abstract memcmp to check that pointers are valid, and then return nondet */

int memcmp(const void *s1, const void *s2, size_t n) {
    //  __CPROVER_HIDE:;
    int res = 0;
    __CPROVER_precondition(__CPROVER_r_ok(s1, n), "memcmp region 1 readable");
    __CPROVER_precondition(__CPROVER_r_ok(s2, n), "memcpy region 2 readable");

#if 1
    const unsigned char *sc1 = s1, *sc2 = s2;
    for (; n != 0; n--) {
        res = (*sc1++) - (*sc2++);
        if (res != 0)
            return res;
    }
    return res;
#else
    return nondet_int();
#endif
}
