.TH LIBRECRYPT_DECODE 3 LIBRECRYPT
.SH NAME
librecrypt_decode - Decode ASCII encoding of a salt or hash result into binary

.SH SYNOPSIS
.nf
#include <librecrypt.h>

ssize_t \fBlibrecrypt_decode\fP(void *\fIout_buffer\fP, size_t \fIsize\fP,
                          const char *\fIascii\fP, size_t \fIlen\fP,
                          const unsigned char \fIlut\fP[restrict static 256],
                          char \fIpad\fP, int \fIstrict_pad\fP);
.fi
.PP
Link with
.IR -lrecrypt .

.SH DESCRIPTION
The
.BR librecrypt_decode ()
function decodes
.I len
bytes of ASCII text from
.IR ascii
into raw binary data written to
.IR out_buffer .
This is used for decoding hash results and salts.
.PP
The
.I lut
argument is a reverse lookup table that maps any
valid character (except the padding character) to
its value in the encoding alphabet and maps any
invalid character to
.BR 0xFFu .
.PP
The
.I pad
argument specifies the padding character to use
at the end, or the null byte if none.
.PP
If
.I strict_pad
is non-zero, the padding at the end is mandatory.
.PP
On successful completion, up to
.I size
bytes are written to
.IR out_buffer .
The return value is the number of bytes that would
have been written if
.I size
was sufficiently large.

.SH RETURN VALUES
The
.BR librecrypt_decode ()
function returns the number of bytes that would
have been written to
.IR out_buffer
if
.I size
was sufficiently large.
On failure, -1 is returned and
.IR errno
is set to describe the error.

.SH ERRORS
The
.BR librecrypt_decode ()
function will fail if:
.TP
.B EINVAL
.I ascii
uses an invalid encoding.

.SH ATTRIBUTES
For an explanation of the terms used in this section, see
.BR attributes (7).
.PP
.TS
allbox;
lb lb lb
l l l.
Interface	Attribute	Value
T{
.BR librecrypt_decode ()
T}	Thread safety	MT-Safe
T{
.BR librecrypt_decode ()
T}	Async-signal safety	AS-Safe
.TE
.sp

.SH HISTORY
The
.BR librecrypt_decode ()
function was introduced in version 1.0 of
.BR librecrypt .

.SH SEE ALSO
.BR librecrypt (7),
.BR librecrypt_encode (3),
.BR librecrypt_get_encoding (3)