OSSL_ENCODER_CTX_new(3ossl)

1OSSL_ENCODER_CTX(3ossl)             OpenSSL            OSSL_ENCODER_CTX(3ossl)
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NAME

6       OSSL_ENCODER_CTX, OSSL_ENCODER_CTX_new,
7       OSSL_ENCODER_settable_ctx_params, OSSL_ENCODER_CTX_set_params,
8       OSSL_ENCODER_CTX_free, OSSL_ENCODER_CTX_set_selection,
9       OSSL_ENCODER_CTX_set_output_type,
10       OSSL_ENCODER_CTX_set_output_structure, OSSL_ENCODER_CTX_add_encoder,
11       OSSL_ENCODER_CTX_add_extra, OSSL_ENCODER_CTX_get_num_encoders,
12       OSSL_ENCODER_INSTANCE, OSSL_ENCODER_INSTANCE_get_encoder,
13       OSSL_ENCODER_INSTANCE_get_encoder_ctx,
14       OSSL_ENCODER_INSTANCE_get_output_type,
15       OSSL_ENCODER_INSTANCE_get_output_structure, OSSL_ENCODER_CONSTRUCT,
16       OSSL_ENCODER_CLEANUP, OSSL_ENCODER_CTX_set_construct,
17       OSSL_ENCODER_CTX_set_construct_data, OSSL_ENCODER_CTX_set_cleanup -
18       Encoder context routines
19

SYNOPSIS

21        #include <openssl/encoder.h>
22
23        typedef struct ossl_encoder_ctx_st OSSL_ENCODER_CTX;
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25        OSSL_ENCODER_CTX *OSSL_ENCODER_CTX_new();
26        const OSSL_PARAM *OSSL_ENCODER_settable_ctx_params(OSSL_ENCODER *encoder);
27        int OSSL_ENCODER_CTX_set_params(OSSL_ENCODER_CTX *ctx,
28                                        const OSSL_PARAM params[]);
29        void OSSL_ENCODER_CTX_free(OSSL_ENCODER_CTX *ctx);
30
31        int OSSL_ENCODER_CTX_set_selection(OSSL_ENCODER_CTX *ctx, int selection);
32        int OSSL_ENCODER_CTX_set_output_type(OSSL_ENCODER_CTX *ctx,
33                                             const char *output_type);
34        int OSSL_ENCODER_CTX_set_output_structure(OSSL_ENCODER_CTX *ctx,
35                                                  const char *output_structure);
36
37        int OSSL_ENCODER_CTX_add_encoder(OSSL_ENCODER_CTX *ctx, OSSL_ENCODER *encoder);
38        int OSSL_ENCODER_CTX_add_extra(OSSL_ENCODER_CTX *ctx,
39                                       OSSL_LIB_CTX *libctx, const char *propq);
40        int OSSL_ENCODER_CTX_get_num_encoders(OSSL_ENCODER_CTX *ctx);
41
42        typedef struct ossl_encoder_instance_st OSSL_ENCODER_INSTANCE;
43        OSSL_ENCODER *
44        OSSL_ENCODER_INSTANCE_get_encoder(OSSL_ENCODER_INSTANCE *encoder_inst);
45        void *
46        OSSL_ENCODER_INSTANCE_get_encoder_ctx(OSSL_ENCODER_INSTANCE *encoder_inst);
47        const char *
48        OSSL_ENCODER_INSTANCE_get_output_type(OSSL_ENCODER_INSTANCE *encoder_inst);
49        const char *
50        OSSL_ENCODER_INSTANCE_get_output_structure(OSSL_ENCODER_INSTANCE *encoder_inst);
51
52        typedef const void *OSSL_ENCODER_CONSTRUCT(OSSL_ENCODER_INSTANCE *encoder_inst,
53                                                   void *construct_data);
54        typedef void OSSL_ENCODER_CLEANUP(void *construct_data);
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56        int OSSL_ENCODER_CTX_set_construct(OSSL_ENCODER_CTX *ctx,
57                                           OSSL_ENCODER_CONSTRUCT *construct);
58        int OSSL_ENCODER_CTX_set_construct_data(OSSL_ENCODER_CTX *ctx,
59                                                void *construct_data);
60        int OSSL_ENCODER_CTX_set_cleanup(OSSL_ENCODER_CTX *ctx,
61                                         OSSL_ENCODER_CLEANUP *cleanup);
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DESCRIPTION

64       Encoding an input object to the desired encoding may be done with a
65       chain of encoder implementations, which means that the output from one
66       encoder may be the input for the next in the chain.  The
67       OSSL_ENCODER_CTX holds all the data about these encoders.  This allows
68       having generic format encoders such as DER to PEM, as well as more
69       specialized encoders like RSA to DER.
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71       The final output type must be given, and a chain of encoders must end
72       with an implementation that produces that output type.
73
74       At the beginning of the encoding process, a constructor provided by the
75       caller is called to ensure that there is an appropriate provider-side
76       object to start with.  The constructor is set with
77       OSSL_ENCODER_CTX_set_construct().
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79       OSSL_ENCODER_INSTANCE is an opaque structure that contains data about
80       the encoder that is going to be used, and that may be useful for the
81       constructor.  There are some functions to extract data from this type,
82       described in "Constructor" below.
83
84   Functions
85       OSSL_ENCODER_CTX_new() creates a OSSL_ENCODER_CTX.
86
87       OSSL_ENCODER_settable_ctx_params() returns an OSSL_PARAM(3) array of
88       parameter descriptors.
89
90       OSSL_ENCODER_CTX_set_params() attempts to set parameters specified with
91       an OSSL_PARAM(3) array params.  Parameters that the implementation
92       doesn't recognise should be ignored.
93
94       OSSL_ENCODER_CTX_free() frees the given context ctx.
95
96       OSSL_ENCODER_CTX_add_encoder() populates the OSSL_ENCODER_CTX ctx with
97       a encoder, to be used to encode an input object.
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99       OSSL_ENCODER_CTX_add_extra() finds encoders that further encodes output
100       from already added encoders, and adds them as well.  This is used to
101       build encoder chains.
102
103       OSSL_ENCODER_CTX_set_output_type() sets the ending output type.  This
104       must be specified, and determines if a complete encoder chain is
105       available.
106
107       OSSL_ENCODER_CTX_set_output_structure() sets the desired output
108       structure.  This may be used to determines what encoder implementations
109       may be used.  Depending on the type of object being encoded, the output
110       structure may not be relevant.
111
112       OSSL_ENCODER_CTX_get_num_encoders() gets the number of encoders
113       currently added to the context ctx.
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115       OSSL_ENCODER_CTX_set_construct() sets the constructor construct.
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117       OSSL_ENCODER_CTX_set_construct_data() sets the constructor data that is
118       passed to the constructor every time it's called.
119
120       OSSL_ENCODER_CTX_set_cleanup() sets the constructor data cleanup
121       function.  This is called by OSSL_ENCODER_CTX_free(3).
122
123   Constructor
124       A OSSL_ENCODER_CONSTRUCT gets the following arguments:
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126       encoder_inst
127           The OSSL_ENCODER_INSTANCE for the encoder from which the
128           constructor gets its data.
129
130       construct_data
131           The pointer that was set with OSSL_ENCODE_CTX_set_construct_data().
132
133       The constructor is expected to return a valid (non-NULL) pointer to a
134       provider-native object that can be used as first input of an encoding
135       chain, or NULL to indicate that an error has occurred.
136
137       These utility functions may be used by a constructor:
138
139       OSSL_ENCODER_INSTANCE_get_encoder() can be used to get the encoder
140       implementation of the encoder instance encoder_inst.
141
142       OSSL_ENCODER_INSTANCE_get_encoder_ctx() can be used to get the encoder
143       implementation's provider context of the encoder instance encoder_inst.
144
145       OSSL_ENCODER_INSTANCE_get_output_type() can be used to get the output
146       type for the encoder implementation of the encoder instance
147       encoder_inst.  This will never be NULL.
148
149       OSSL_ENCODER_INSTANCE_get_output_structure() can be used to get the
150       output structure for the encoder implementation of the encoder instance
151       encoder_inst.  This may be NULL.
152

RETURN VALUES

154       OSSL_ENCODER_CTX_new() returns a pointer to a OSSL_ENCODER_CTX, or NULL
155       if the context structure couldn't be allocated.
156
157       OSSL_ENCODER_settable_ctx_params() returns an OSSL_PARAM(3) array, or
158       NULL if none is available.
159
160       OSSL_ENCODER_CTX_set_params() returns 1 if all recognised parameters
161       were valid, or 0 if one of them was invalid or caused some other
162       failure in the implementation.
163
164       OSSL_ENCODER_CTX_add_encoder(), OSSL_ENCODER_CTX_add_extra(),
165       OSSL_ENCODER_CTX_set_construct(), OSSL_ENCODER_CTX_set_construct_data()
166       and OSSL_ENCODER_CTX_set_cleanup() return 1 on success, or 0 on
167       failure.
168
169       OSSL_ENCODER_CTX_get_num_encoders() returns the current number of
170       encoders.  It returns 0 if ctx is NULL.
171
172       OSSL_ENCODER_INSTANCE_get_encoder() returns an OSSL_ENCODER pointer on
173       success, or NULL on failure.
174
175       OSSL_ENCODER_INSTANCE_get_encoder_ctx() returns a provider context
176       pointer on success, or NULL on failure.
177
178       OSSL_ENCODER_INSTANCE_get_output_type() returns a string with the name
179       of the input type, if relevant.  NULL is a valid returned value.
180
181       OSSL_ENCODER_INSTANCE_get_output_type() returns a string with the name
182       of the output type.
183
184       OSSL_ENCODER_INSTANCE_get_output_structure() returns a string with the
185       name of the output structure.
186

HISTORY

191       The functions described here were added in OpenSSL 3.0.
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COPYRIGHT

194       Copyright 2019-2022 The OpenSSL Project Authors. All Rights Reserved.
195
196       Licensed under the Apache License 2.0 (the "License").  You may not use
197       this file except in compliance with the License.  You can obtain a copy
198       in the file LICENSE in the source distribution or at
199       <https://www.openssl.org/source/license.html>.
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2033.1.1                             2023-08-31           OSSL_ENCODER_CTX(3ossl)

NAME

SYNOPSIS

DESCRIPTION

RETURN VALUES

SEE ALSO

HISTORY

COPYRIGHT