.\"	$NetBSD: prop_data.3,v 1.9 2020/06/06 21:25:59 thorpej Exp $
.\"
.\" Copyright (c) 2006, 2020 The NetBSD Foundation, Inc.
.\" All rights reserved.
.\"
.\" This code is derived from software contributed to The NetBSD Foundation
.\" by Jason R. Thorpe.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
.\" PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
.\" POSSIBILITY OF SUCH DAMAGE.
.\"
.Dd June 2, 2020
.Dt PROP_DATA 3
.Os
.Sh NAME
.Nm prop_data ,
.Nm prop_data_create_copy ,
.Nm prop_data_create_nocopy ,
.Nm prop_data_copy ,
.Nm prop_data_size ,
.Nm prop_data_value ,
.Nm prop_data_copy_value ,
.Nm prop_data_equals ,
.Nm prop_data_equals_data
.Nd opaque data value property object
.Sh LIBRARY
.Lb libprop
.Sh SYNOPSIS
.In prop/proplib.h
.\"
.Ft prop_data_t
.Fn prop_data_create_copy "const void *blob" "size_t len"
.Ft prop_data_t
.Fn prop_data_create_nocopy "const void *blob" "size_t len"
.\"
.Ft prop_data_t
.Fn prop_data_copy "prop_data_t data"
.\"
.Ft const void *
.Fn prop_data_value "prop_data_t data"
.Ft bool
.Fn prop_data_copy_value "prop_data_t data" "void *buf" "size_t buflen"
.\"
.Ft size_t
.Fn prop_data_size "prop_data_t data"
.\"
.Ft bool
.Fn prop_data_equals "prop_data_t dat1" "prop_data_t dat2"
.Ft bool
.Fn prop_data_equals_data "prop_data_t data" "const void *blob" "size_t len"
.Sh DESCRIPTION
The
.Nm
family of functions operate on an opaque data value property object type.
.Bl -tag -width "xxxxx"
.It Fn prop_data_create_copy "const void *blob" "size_t len"
Create a data object that contains a copy of
.Fa blob
with size
.Fa len .
Returns
.Dv NULL
on failure.
.It Fn prop_data_create_nocopy "const void *blob" "size_t len"
Similar to
.Fn prop_data_create_copy ,
but is allowed to not create aan internal copy of the opaque data, instead
referencing the buffer passed by the caller.
Caution must be exercised because data objects can have an indefinite
lifespan.
The caller must therefore ensure that the provided buffer reference will
also be valid indefinitely.
This is provided as a memory optimization; it is not guaranteed that
the returned data object will reference the provided buffer, and thus
callers should not rely on this behavior.
Returns
.Dv NULL
on failure.
.It Fn prop_data_copy "prop_data_t data"
Copy a data object.
If the data object being copied is an external data reference,
then the copy also references the same external data.
Returns
.Dv NULL
on failure.
.It Fn prop_data_size "prop_data_t data"
Returns the size of the data object.
If the supplied object isn't a data object, zero is returned.
.It Fn prop_data_value "prop_data_t data"
Returns a reference to the data object's buffer.
If the supplied object isn't a data object or
if the data container is empty,
.Dv NULL
is returned.
.It Fn prop_data_copy_value "prop_data_t data" "void *buf" "size_t buflen"
Copies the contents of the data object into the supplied buffer of the
specified size.
Returns
.Dv true
if the copy succeeds and
.Dv false
iff the supplied buffer is not large enough or if the object is not a
data object.
.It Fn prop_data_equals "prop_data_t dat1" "prop_data_t dat2"
Returns
.Dv true
if the two data objects are equivalent.
If at least one of the supplied objects isn't a data object,
.Dv false
is returned.
.It Fn prop_data_equals_data "prop_data_t data" "const void *blob" "size_t len"
Returns
.Dv true
if the data object's value is equivalent to
.Fa blob
with size
.Fa len .
If the supplied object isn't a data object,
.Dv false
is returned.
.El
.Sh SEE ALSO
.Xr prop_array 3 ,
.Xr prop_bool 3 ,
.Xr prop_dictionary 3 ,
.Xr prop_number 3 ,
.Xr prop_object 3 ,
.Xr prop_string 3 ,
.Xr proplib 3
.Sh HISTORY
The
.Xr proplib 3
property container object library first appeared in
.Nx 4.0 .
Support for mutable data objects was deprecated in
.Nx 10.0 .