[thirdparty/openssl.git] / doc / man3 / OSSL_DECODER.pod

=pod

=head1 NAME

OSSL_DECODER,
OSSL_DECODER_fetch,
OSSL_DECODER_up_ref,
OSSL_DECODER_free,
OSSL_DECODER_provider,
OSSL_DECODER_properties,
OSSL_DECODER_is_a,
OSSL_DECODER_number,
OSSL_DECODER_do_all_provided,
OSSL_DECODER_names_do_all,
OSSL_DECODER_gettable_params,
OSSL_DECODER_get_params
- Decoder method routines

=head1 SYNOPSIS

 #include <openssl/decoder.h>

 typedef struct ossl_decoder_st OSSL_DECODER;

 OSSL_DECODER *OSSL_DECODER_fetch(OSSL_LIB_CTX *ctx, const char *name,
                                  const char *properties);
 int OSSL_DECODER_up_ref(OSSL_DECODER *decoder);
 void OSSL_DECODER_free(OSSL_DECODER *decoder);
 const OSSL_PROVIDER *OSSL_DECODER_provider(const OSSL_DECODER *decoder);
 const char *OSSL_DECODER_properties(const OSSL_DECODER *decoder);
 int OSSL_DECODER_is_a(const OSSL_DECODER *decoder, const char *name);
 int OSSL_DECODER_number(const OSSL_DECODER *decoder);
 void OSSL_DECODER_do_all_provided(OSSL_LIB_CTX *libctx,
                                   void (*fn)(OSSL_DECODER *decoder, void *arg),
                                   void *arg);
 void OSSL_DECODER_names_do_all(const OSSL_DECODER *decoder,
                                void (*fn)(const char *name, void *data),
                                void *data);
 const OSSL_PARAM *OSSL_DECODER_gettable_params(OSSL_DECODER *decoder);
 int OSSL_DECODER_get_params(OSSL_DECODER_CTX *ctx, const OSSL_PARAM params[]);

=head1 DESCRIPTION

B<OSSL_DECODER> is a method for decoders, which know how to
decode encoded data into an object of some type that the rest
of OpenSSL knows how to handle.

OSSL_DECODER_fetch() looks for an algorithm within the provider that
has been loaded into the B<OSSL_LIB_CTX> given by I<ctx>, having the
name given by I<name> and the properties given by I<properties>.
The I<name> determines what type of object the fetched decoder
method is expected to be able to decode, and the properties are
used to determine the expected output type.
For known properties and the values they may have, please have a look
in L<provider-encoder(7)/Names and properties>.

OSSL_DECODER_up_ref() increments the reference count for the given
I<decoder>.

OSSL_DECODER_free() decrements the reference count for the given
I<decoder>, and when the count reaches zero, frees it.

OSSL_DECODER_provider() returns the provider of the given
I<decoder>.

OSSL_DECODER_properties() returns the property definition associated
with the given I<decoder>.

OSSL_DECODER_is_a() checks if I<decoder> is an implementation
of an algorithm that's identifiable with I<name>.

OSSL_DECODER_number() returns the internal dynamic number assigned
to the given I<decoder>.

OSSL_DECODER_names_do_all() traverses all names for the given
I<decoder>, and calls I<fn> with each name and I<data>.

OSSL_DECODER_do_all_provided() traverses all encoder
implementations by all activated providers in the library context
I<libctx>, and for each of the implementations, calls I<fn> with the
implementation method and I<data> as arguments.

OSSL_DECODER_gettable_params() returns an L<OSSL_PARAM(3)>
array of parameter descriptors.

OSSL_DECODER_get_params() attempts to get parameters specified
with an L<OSSL_PARAM(3)> array I<params>.  Parameters that the
implementation doesn't recognise should be ignored.

=head1 RETURN VALUES

OSSL_DECODER_fetch() returns a pointer to an OSSL_DECODER object,
or NULL on error.

OSSL_DECODER_up_ref() returns 1 on success, or 0 on error.

OSSL_DECODER_free() doesn't return any value.

OSSL_DECODER_provider() returns a pointer to a provider object, or
NULL on error.

OSSL_DECODER_properties() returns a pointer to a property
definition string, or NULL on error.

OSSL_DECODER_is_a() returns 1 if I<decoder> was identifiable,
otherwise 0.

OSSL_DECODER_number() returns an integer.

=head1 NOTES

OSSL_DECODER_fetch() may be called implicitly by other fetching
functions, using the same library context and properties.
Any other API that uses keys will typically do this.

=begin comment TODO(3.0) Add examples!

=head1 EXAMPLES

Text, because pod2xxx doesn't like empty sections

=end comment

=head1 SEE ALSO

L<provider(7)>, L<OSSL_DECODER_CTX(3)>, L<OSSL_DECODER_from_bio(3)>,
L<OSSL_DECODER_CTX_new_by_EVP_PKEY(3)>, L<OSSL_LIB_CTX(3)>

=head1 HISTORY

The functions described here were added in OpenSSL 3.0.

=head1 COPYRIGHT

Copyright 2020 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
Commit	Line	Data
ece9304c RL	1	=pod
	2
	3	=head1 NAME
	4
	5	OSSL_DECODER,
	6	OSSL_DECODER_fetch,
	7	OSSL_DECODER_up_ref,
	8	OSSL_DECODER_free,
	9	OSSL_DECODER_provider,
	10	OSSL_DECODER_properties,
	11	OSSL_DECODER_is_a,
	12	OSSL_DECODER_number,
	13	OSSL_DECODER_do_all_provided,
	14	OSSL_DECODER_names_do_all,
	15	OSSL_DECODER_gettable_params,
	16	OSSL_DECODER_get_params
	17	- Decoder method routines
	18
	19	=head1 SYNOPSIS
	20
	21	#include <openssl/decoder.h>
	22
	23	typedef struct ossl_decoder_st OSSL_DECODER;
	24
b4250010	25	OSSL_DECODER OSSL_DECODER_fetch(OSSL_LIB_CTX ctx, const char *name,
ece9304c RL	26	const char *properties);
	27	int OSSL_DECODER_up_ref(OSSL_DECODER *decoder);
	28	void OSSL_DECODER_free(OSSL_DECODER *decoder);
	29	const OSSL_PROVIDER OSSL_DECODER_provider(const OSSL_DECODER decoder);
	30	const char OSSL_DECODER_properties(const OSSL_DECODER decoder);
	31	int OSSL_DECODER_is_a(const OSSL_DECODER decoder, const char name);
	32	int OSSL_DECODER_number(const OSSL_DECODER *decoder);
b4250010	33	void OSSL_DECODER_do_all_provided(OSSL_LIB_CTX *libctx,
ece9304c RL	34	void (fn)(OSSL_DECODER decoder, void *arg),
	35	void *arg);
	36	void OSSL_DECODER_names_do_all(const OSSL_DECODER *decoder,
	37	void (fn)(const char name, void *data),
	38	void *data);
	39	const OSSL_PARAM OSSL_DECODER_gettable_params(OSSL_DECODER decoder);
	40	int OSSL_DECODER_get_params(OSSL_DECODER_CTX *ctx, const OSSL_PARAM params[]);
	41
	42	=head1 DESCRIPTION
	43
	44	B<OSSL_DECODER> is a method for decoders, which know how to
	45	decode encoded data into an object of some type that the rest
	46	of OpenSSL knows how to handle.
	47
	48	OSSL_DECODER_fetch() looks for an algorithm within the provider that
b4250010	49	has been loaded into the B<OSSL_LIB_CTX> given by I<ctx>, having the
ece9304c RL	50	name given by I<name> and the properties given by I<properties>.
	51	The I<name> determines what type of object the fetched decoder
	52	method is expected to be able to decode, and the properties are
	53	used to determine the expected output type.
	54	For known properties and the values they may have, please have a look
	55	in L<provider-encoder(7)/Names and properties>.
	56
	57	OSSL_DECODER_up_ref() increments the reference count for the given
	58	I<decoder>.
	59
	60	OSSL_DECODER_free() decrements the reference count for the given
	61	I<decoder>, and when the count reaches zero, frees it.
	62
	63	OSSL_DECODER_provider() returns the provider of the given
	64	I<decoder>.
	65
	66	OSSL_DECODER_properties() returns the property definition associated
	67	with the given I<decoder>.
	68
	69	OSSL_DECODER_is_a() checks if I<decoder> is an implementation
	70	of an algorithm that's identifiable with I<name>.
	71
	72	OSSL_DECODER_number() returns the internal dynamic number assigned
	73	to the given I<decoder>.
	74
	75	OSSL_DECODER_names_do_all() traverses all names for the given
	76	I<decoder>, and calls I<fn> with each name and I<data>.
	77
	78	OSSL_DECODER_do_all_provided() traverses all encoder
	79	implementations by all activated providers in the library context
	80	I<libctx>, and for each of the implementations, calls I<fn> with the
	81	implementation method and I<data> as arguments.
	82
	83	OSSL_DECODER_gettable_params() returns an L<OSSL_PARAM(3)>
	84	array of parameter descriptors.
	85
	86	OSSL_DECODER_get_params() attempts to get parameters specified
	87	with an L<OSSL_PARAM(3)> array I<params>. Parameters that the
	88	implementation doesn't recognise should be ignored.
	89
	90	=head1 RETURN VALUES
	91
	92	OSSL_DECODER_fetch() returns a pointer to an OSSL_DECODER object,
	93	or NULL on error.
	94
	95	OSSL_DECODER_up_ref() returns 1 on success, or 0 on error.
	96
	97	OSSL_DECODER_free() doesn't return any value.
	98
	99	OSSL_DECODER_provider() returns a pointer to a provider object, or
	100	NULL on error.
	101
	102	OSSL_DECODER_properties() returns a pointer to a property
	103	definition string, or NULL on error.
	104
	105	OSSL_DECODER_is_a() returns 1 if I<decoder> was identifiable,
	106	otherwise 0.
	107
	108	OSSL_DECODER_number() returns an integer.
	109
	110	=head1 NOTES
	111
	112	OSSL_DECODER_fetch() may be called implicitly by other fetching
	113	functions, using the same library context and properties.
114	Any other API that uses keys will typically do this.
115
116	=begin comment TODO(3.0) Add examples!
117
118	=head1 EXAMPLES
119
120	Text, because pod2xxx doesn't like empty sections
121
122	=end comment
123
124	=head1 SEE ALSO
125
126	L<provider(7)>, L<OSSL_DECODER_CTX(3)>, L<OSSL_DECODER_from_bio(3)>,
b4250010	127	L<OSSL_DECODER_CTX_new_by_EVP_PKEY(3)>, L<OSSL_LIB_CTX(3)>
ece9304c RL	128
	129	=head1 HISTORY
	130
	131	The functions described here were added in OpenSSL 3.0.
	132
	133	=head1 COPYRIGHT
	134
	135	Copyright 2020 The OpenSSL Project Authors. All Rights Reserved.
	136
	137	Licensed under the Apache License 2.0 (the "License"). You may not use
	138	this file except in compliance with the License. You can obtain a copy
	139	in the file LICENSE in the source distribution or at
	140	L<https://www.openssl.org/source/license.html>.
	141
	142	=cut