OPENSSL_hexchar2int(3)

OPENSSL_hexchar2int(3) | OpenSSL | OPENSSL_hexchar2int(3)

# NAME

OPENSSL_hexchar2int, OPENSSL_hexstr2buf_ex, OPENSSL_hexstr2buf, OPENSSL_buf2hexstr_ex, OPENSSL_buf2hexstr - Hex encoding and decoding functions

# SYNOPSIS

     #include <openssl/crypto.h>
     int OPENSSL_hexchar2int(unsigned char c);
     int OPENSSL_hexstr2buf_ex(unsigned char *buf, size_t buf_n, long *buflen,
                               const char *str, const char sep);
     unsigned char *OPENSSL_hexstr2buf(const char *str, long *len);
     int OPENSSL_buf2hexstr_ex(char *str, size_t str_n, size_t *strlength,
                               const unsigned char *buf, long buflen,
                               const char sep);
     char *OPENSSL_buf2hexstr(const unsigned char *buf, long buflen);

# DESCRIPTION

OPENSSL_hexchar2int() converts a hexadecimal character to its numeric equivalent.

OPENSSL_hexstr2buf_ex() decodes the hex string str and places the resulting string of bytes in the given buf. The character sep is the separator between the bytes, setting this to '\0' means that there is no separator. buf_n gives the size of the buffer. If buflen is not NULL, it is filled in with the result length. To find out how large the result will be, call this function with NULL for buf. Colons between two-character hex "bytes" are accepted and ignored. An odd number of hex digits is an error.

OPENSSL_hexstr2buf() does the same thing as OPENSSL_hexstr2buf_ex(), but allocates the space for the result, and returns the result. It uses a default separator of ':'. The memory is allocated by calling OPENSSL_malloc() and should be released by calling OPENSSL_free().

OPENSSL_buf2hexstr_ex() encodes the contents of the given buf with length buflen and places the resulting hexadecimal character string in the given str. The character sep is the separator between the bytes, setting this to '\0' means that there is no separator. str_n gives the size of the of the string buffer. If strlength is not NULL, it is filled in with the result length. To find out how large the result will be, call this function with NULL for str.

OPENSSL_buf2hexstr() does the same thing as OPENSSL_buf2hexstr_ex(), but allocates the space for the result, and returns the result. It uses a default separator of ':'. The memory is allocated by calling OPENSSL_malloc() and should be released by calling OPENSSL_free().

# RETURN VALUES

OPENSSL_hexchar2int returns the value of a decoded hex character, or -1 on error.

OPENSSL_buf2hexstr() and OPENSSL_hexstr2buf() return a pointer to allocated memory, or NULL on error.

OPENSSL_buf2hexstr_ex() and OPENSSL_hexstr2buf_ex() return 1 on success, or 0 on error.

# COPYRIGHT

Copyright 2016-2022 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>.

2025-07-01 | 3.5.1