/*
 * Copyright 2003-2017 The OpenSSL Project Authors. All Rights Reserved.
 *
 * Licensed under the Apache License 2.0 (the "License").  You may not use
 * this file except in compliance with the License.  You can obtain a copy
 * in the file LICENSE in the source distribution or at
 * https://www.openssl.org/source/license.html
 */

#include "e_os.h"
#include <limits.h>
#include <openssl/crypto.h>
#include "internal/cryptlib.h"

size_t OPENSSL_strnlen(const char *str, size_t maxlen)
{
    const char *p;

    for (p = str; maxlen-- != 0 && *p != '\0'; ++p) ;

    return p - str;
}

size_t OPENSSL_strlcpy(char *dst, const char *src, size_t size)
{
    size_t l = 0;
    for (; size > 1 && *src; size--) {
        *dst++ = *src++;
        l++;
    }
    if (size)
        *dst = '\0';
    return l + strlen(src);
}

size_t OPENSSL_strlcat(char *dst, const char *src, size_t size)
{
    size_t l = 0;
    for (; size > 0 && *dst; size--, dst++)
        l++;
    return l + OPENSSL_strlcpy(dst, src, size);
}

int OPENSSL_hexchar2int(unsigned char c)
{
#ifdef CHARSET_EBCDIC
    c = os_toebcdic[c];
#endif

    switch (c) {
    case '0':
        return 0;
    case '1':
        return 1;
    case '2':
        return 2;
    case '3':
        return 3;
    case '4':
          return 4;
    case '5':
          return 5;
    case '6':
          return 6;
    case '7':
          return 7;
    case '8':
          return 8;
    case '9':
          return 9;
    case 'a': case 'A':
          return 0x0A;
    case 'b': case 'B':
          return 0x0B;
    case 'c': case 'C':
          return 0x0C;
    case 'd': case 'D':
          return 0x0D;
    case 'e': case 'E':
          return 0x0E;
    case 'f': case 'F':
          return 0x0F;
    }
    return -1;
}

int openssl_strerror_r(int errnum, char *buf, size_t buflen)
{
#if defined(_MSC_VER) && _MSC_VER>=1400
    return !strerror_s(buf, buflen, errnum);
#elif defined(_GNU_SOURCE)
    char *err;

    /*
     * GNU strerror_r may not actually set buf.
     * It can return a pointer to some (immutable) static string in which case
     * buf is left unused.
     */
    err = strerror_r(errnum, buf, buflen);
    if (err == NULL || buflen == 0)
        return 0;
    /*
     * If err is statically allocated, err != buf and we need to copy the data.
     * If err points somewhere inside buf, OPENSSL_strlcpy can handle this,
     * since src and dest are not annotated with __restrict and the function
     * reads src byte for byte and writes to dest.
     * If err == buf we do not have to copy anything.
     */
    if (err != buf)
        OPENSSL_strlcpy(buf, err, buflen);
    return 1;
#elif (defined(_POSIX_C_SOURCE) && _POSIX_C_SOURCE >= 200112L) || \
      (defined(_XOPEN_SOURCE) && _XOPEN_SOURCE >= 600)
    /*
     * We can use "real" strerror_r. The OpenSSL version differs in that it
     * gives 1 on success and 0 on failure for consistency with other OpenSSL
     * functions. Real strerror_r does it the other way around
     */
    return !strerror_r(errnum, buf, buflen);
#else
    char *err;

    /* Fall back to non-thread safe strerror()...its all we can do */
    if (buflen < 2)
        return 0;
    err = strerror(errnum);
    /* Can this ever happen? */
    if (err == NULL)
        return 0;
    OPENSSL_strlcpy(buf, err, buflen);
    return 1;
#endif
}