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/* 
 * Copyright 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 <string.h> 
#include <sys/param.h> 
#include "utils/s2n_str.h" 
 
char *s2n_strcpy(char *buf, char *last, const char *str) { 
 
/* CBMC pointer checks need to be disabled to compare buf and last for 
 * the case where they are the same. */ 
#pragma CPROVER check push 
#pragma CPROVER check disable "pointer" 
 
    if (buf >= last) { 
        return buf; 
    } 
 
#pragma CPROVER check pop 
 
    if (NULL == str) { 
        *buf = '\0'; 
        return buf; 
    } 
 
    /* Free bytes needs to be one byte smaller than size of a storage,  
     * as strncpy always writes '\0', but doesn't include it in n  
     */ 
    size_t bytes_to_copy = MIN(last - buf - 1, strlen(str)); 
 
    char *p = buf; 
    if (bytes_to_copy > 0) { 
        p = (char *)memcpy(buf, str, bytes_to_copy) + bytes_to_copy; 
    } 
    *p = '\0'; 
 
    return p; 
}