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BNER support: Add top-level bner {en,de}coding
The BNER support in the asn1c compiler will only support the BNER variable encoding rules. The bner_{en,de}code() functions will to see if the PDU being {en,de}coded is one that requires BNER fixed encoding rules (these are "BACnet.*PDU". If it is, then it will call bner_fixed_{en,de}coder() These two functions are declared as weak functions that will return an error. The intent here is that an external project will provide replacement functions for these two functions.
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‎skeletons/Makefile.am‎

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@@ -107,6 +107,8 @@ check_PROGRAMS = \
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# BNER Support
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libasn1cskeletons_la_SOURCES += \
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bner_decoder.c bner_decoder.h \
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bner_encoder.c bner_encoder.h \
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bner_support.c bner_support.h \
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constr_CHOICE_bner.c \
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constr_SEQUENCE_bner.c \

‎skeletons/bner_decoder.c‎

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/*
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* Copyright (c) 2017 Jon Ringle <[email protected]>. All rights reserved.
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* Redistribution and modifications are permitted subject to BSD license.
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*/
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#include <asn_internal.h>
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#include <bner_decoder.h>
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#include <errno.h>
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/*
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* The BNER decoder of any type.
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*/
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asn_dec_rval_t
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bner_decode(const asn_codec_ctx_t *opt_codec_ctx,
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const asn_TYPE_descriptor_t *td, void **struct_ptr, const void *ptr,
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size_t size) {
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asn_codec_ctx_t s_codec_ctx;
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if(!td) {
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asn_dec_rval_t tmp_error = {RC_FAIL, 0};
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ASN_DEBUG("%s: Failed to decode. type_descriptor NULL", __func__);
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return tmp_error;
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}
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/*
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* Stack checker requires that the codec context
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* must be allocated on the stack.
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*/
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if(opt_codec_ctx) {
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if(opt_codec_ctx->max_stack_size) {
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s_codec_ctx = *opt_codec_ctx;
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opt_codec_ctx = &s_codec_ctx;
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}
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} else {
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/* If context is not given, be security-conscious anyway */
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memset(&s_codec_ctx, 0, sizeof(s_codec_ctx));
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s_codec_ctx.max_stack_size = ASN__DEFAULT_STACK_MAX;
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opt_codec_ctx = &s_codec_ctx;
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}
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if(is_bner_fixed_pdu(td->name)) {
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return bner_fixed_decoder(opt_codec_ctx, td,
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struct_ptr, /* Pointer to the dest struct */
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ptr, size /* Buffer and its size */
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);
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}
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/*
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* Invoke type-specific decoder.
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*/
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return td->op->bner_decoder(opt_codec_ctx, td,
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struct_ptr, /* Pointer to the dest struct */
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ptr, size, /* Buffer and its size */
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0 /* Default tag mode is 0 */
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);
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}
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__attribute__((weak)) asn_dec_rval_t
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bner_fixed_decoder(const struct asn_codec_ctx_s *opt_codec_ctx,
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const struct asn_TYPE_descriptor_s *td,
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void **struct_ptr, /* Ptr to a target struct's ptr */
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const void *buffer, /* Data to be decoded */
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size_t size /* Size of that buffer */
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) {
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(void)opt_codec_ctx;
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(void)td;
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(void)struct_ptr;
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(void)buffer;
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(void)size;
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asn_dec_rval_t tmp_error = {RC_FAIL, 0};
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ASN_DEBUG("Failed to decode %s. No bner_fixed_decoder function provided",
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td->name);
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return tmp_error;
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}

‎skeletons/bner_decoder.h‎

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/*
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* Copyright (c) 2017 Jon Ringle <[email protected]>. All rights reserved.
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* Redistribution and modifications are permitted subject to BSD license.
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*/
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#ifndef _BNER_DECODER_H_
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#define _BNER_DECODER_H_
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#include <asn_application.h>
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#include <bner_support.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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struct asn_TYPE_descriptor_s; /* Forward declaration */
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struct asn_codec_ctx_s; /* Forward declaration */
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/*
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* Type of generic function which decodes the byte stream into the structure.
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*/
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typedef asn_dec_rval_t(bner_type_decoder_f)(
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const struct asn_codec_ctx_s *opt_codec_ctx,
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const struct asn_TYPE_descriptor_s *td, void **struct_ptr,
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const void *buf_ptr, size_t size, int tag_mode);
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/*
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* The BNER decoder of any type.
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* This function may be invoked directly from the application.
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*/
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asn_dec_rval_t bner_decode(const struct asn_codec_ctx_s *opt_codec_ctx,
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const struct asn_TYPE_descriptor_s *td,
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void **struct_ptr, /* Ptr to target's struct ptr */
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const void *buffer, /* Data to be decoded */
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size_t size /* Size of that buffer */
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);
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asn_dec_rval_t bner_fixed_decoder(const struct asn_codec_ctx_s *opt_codec_ctx,
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const struct asn_TYPE_descriptor_s *td,
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void **struct_ptr, /* Ptr to target ptr */
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const void *buffer, /* Data to be decoded */
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size_t size /* Size of that buffer */
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);
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#ifdef __cplusplus
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}
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#endif
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#endif /* _BNER_DECODER_H_ */

‎skeletons/bner_encoder.c‎

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/*
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* Copyright (c) 2017 Jon Ringle <[email protected]>. All rights reserved.
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* Redistribution and modifications are permitted subject to BSD license.
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*/
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#include <asn_internal.h>
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#include <bner_encoder.h>
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#include <errno.h>
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/*
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* The BNER encoder of any type.
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*/
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asn_enc_rval_t
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bner_encode(const asn_TYPE_descriptor_t *td, const void *sptr,
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asn_app_consume_bytes_f *consume_bytes, void *app_key) {
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if(!td) ASN__ENCODE_FAILED;
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ASN_DEBUG("BNER encoder invoked for %s", td->name);
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if(is_bner_fixed_pdu(td->name)) {
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return bner_fixed_encoder(td, sptr, consume_bytes, app_key);
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}
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/*
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* Invoke type-specific encoder.
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*/
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return td->op->bner_encoder(td, sptr, 0, 0, consume_bytes, app_key);
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}
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/*
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* Argument type and callback necessary for bner_encode_to_buffer().
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*/
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typedef struct enc_to_buf_arg {
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void *buffer;
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size_t left;
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} enc_to_buf_arg;
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static int
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encode_to_buffer_cb(const void *buffer, size_t size, void *key) {
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enc_to_buf_arg *arg = (enc_to_buf_arg *)key;
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if(arg->left < size) return -1; /* Data exceeds the available buffer size */
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memcpy(arg->buffer, buffer, size);
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arg->buffer = ((char *)arg->buffer) + size;
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arg->left -= size;
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return 0;
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}
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/*
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* A variant of the bner_encode() which encodes the data into the provided
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* buffer
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*/
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asn_enc_rval_t
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bner_encode_to_buffer(const asn_TYPE_descriptor_t *td,
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const void *struct_ptr, void *buffer,
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size_t buffer_size) {
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enc_to_buf_arg arg;
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asn_enc_rval_t ec;
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arg.buffer = buffer;
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arg.left = buffer_size;
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if(is_bner_fixed_pdu(td->name)) {
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ec = bner_fixed_encoder(td, struct_ptr,
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encode_to_buffer_cb, &arg);
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} else {
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ec = td->op->bner_encoder(
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td,
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struct_ptr, /* Pointer to the destination structure */
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0, 0, encode_to_buffer_cb, &arg);
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}
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if(ec.encoded != -1) {
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assert(ec.encoded == (ssize_t)(buffer_size - arg.left));
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/* Return the encoded contents size */
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}
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return ec;
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}
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__attribute__((weak)) asn_enc_rval_t
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bner_fixed_encoder(const struct asn_TYPE_descriptor_s *td,
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const void *sptr, /* Structure to be encoded */
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asn_app_consume_bytes_f *consume_bytes_cb,
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void *app_key /* Arbitrary callback argument */
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) {
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(void)td;
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(void)sptr;
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(void)consume_bytes_cb;
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(void)app_key;
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ASN_DEBUG("Failed to decode %s. No bner_fixed_encoder function provided",
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td->name);
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ASN__ENCODE_FAILED;
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}

‎skeletons/bner_encoder.h‎

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/*
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* Copyright (c) 2017 Jon Ringle <[email protected]>. All rights reserved.
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* Redistribution and modifications are permitted subject to BSD license.
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*/
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#ifndef _BNER_ENCODER_H_
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#define _BNER_ENCODER_H_
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#include <asn_application.h>
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#include <bner_support.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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struct asn_TYPE_descriptor_s; /* Forward declaration */
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struct asn_codec_ctx_s; /* Forward declaration */
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/*
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* Type of the generic BNER encoder.
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*/
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typedef asn_enc_rval_t(bner_type_encoder_f)(
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const struct asn_TYPE_descriptor_s *td,
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const void *struct_ptr, /* Structure to be encoded */
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int tag_mode, /* {-1,0,1}: IMPLICIT, no, EXPLICIT */
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ber_tlv_tag_t tag, asn_app_consume_bytes_f *consume_bytes_cb, /* Callback */
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void *app_key /* Arbitrary callback argument */
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);
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/*
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* The BNER encoder of any type.
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* This function may be invoked directly by the application.
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*/
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asn_enc_rval_t bner_encode(const struct asn_TYPE_descriptor_s *td,
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const void *struct_ptr, /* Structure to be encoded */
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asn_app_consume_bytes_f *consume_bytes_cb,
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void *app_key /* Arbitrary callback argument */
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);
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/* A variant of bner_encode() which encodes data into a pre-allocated buffer */
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asn_enc_rval_t bner_encode_to_buffer(const struct asn_TYPE_descriptor_s *td,
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const void *struct_ptr, void *buffer,
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size_t buffer_size);
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asn_enc_rval_t bner_fixed_encoder(const struct asn_TYPE_descriptor_s *td,
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const void *sptr, /* Struct to encode */
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asn_app_consume_bytes_f *consume_bytes_cb,
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void *app_key /* Arbitrary callback arg */
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);
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#ifdef __cplusplus
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}
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#endif
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#endif /* _BNER_ENCODER_H_ */

‎skeletons/constr_TYPE.h‎

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@@ -52,6 +52,9 @@ typedef void asn_oer_constraints_t;
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#include <oer_encoder.h> /* Octet Encoding Rules encoder */
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#endif
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#include <bner_decoder.h> /* BACnet Encoding Rules decoder */
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#include <bner_encoder.h> /* BACnet Encoding Rules encoder */
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/*
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* Free the structure according to its specification.
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* Use one of ASN_STRUCT_{FREE,RESET,CONTENTS_ONLY} macros instead.

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