openssl/doc/man3/OPENSSL_hexchar2int.pod
Richard Levitte 82bd7c2cbd Add OPENSSL_hexstr2buf_ex() and OPENSSL_buf2hexstr_ex()
They do the same thing as OPENSSL_hexstr2buf() and OPENSSL_buf2hexstr(),
except they take a result buffer from the caller.

We take the opportunity to break out the documentation of the hex to /
from buffer conversion routines from the OPENSSL_malloc() file to its
own file.  These routines aren't memory allocation routines per se.

Reviewed-by: Paul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/9303)
2019-08-12 12:50:41 +02:00

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=pod
=head1 NAME
OPENSSL_hexchar2int,
OPENSSL_hexstr2buf_ex, OPENSSL_hexstr2buf,
OPENSSL_buf2hexstr_ex, OPENSSL_buf2hexstr
- Hex encoding and decoding functions
=head1 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);
unsigned char *OPENSSL_hexstr2buf(const char *str, long *len);
int OPENSSL_buf2hexstr_ex(char *str, size_t str_n, size_t *strlen,
const unsigned char *buf, long buflen);
char *OPENSSL_buf2hexstr(const unsigned char *buf, long buflen);
=head1 DESCRIPTION
OPENSSL_hexchar2int() converts a hexadecimal character to its numeric
equivalent.
OPENSSL_hexstr2buf_ex() decodes the hex string B<str> and places the
resulting string of bytes in the given I<buf>.
I<buf_n> gives the size of the buffer.
If I<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 I<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.
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 I<buf> with
length I<buflen> and places the resulting hexadecimal character string
in the given I<str>.
I<str_n> gives the size of the of the string buffer.
If I<strlen> 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 I<str>.
OPENSSL_buf2hexstr() does the same thing as OPENSSL_buf2hexstr_ex(),
but allocates the space for the result, and returns the result.
The memory is allocated by calling OPENSSL_malloc() and should be
released by calling OPENSSL_free().
=head1 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.
=head1 COPYRIGHT
Copyright 2016-2019 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
L<https://www.openssl.org/source/license.html>.
=cut