381 lines
11 KiB
C
381 lines
11 KiB
C
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/*
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* Copyright (c) 2017 Lev Walkin <vlm@lionet.info>.
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* 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 ASN_DISABLE_OER_SUPPORT
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#include <asn_internal.h>
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#include <constr_CHOICE.h>
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#include <errno.h>
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/*
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* Return a standardized complex structure.
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*/
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#undef RETURN
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#define RETURN(_code) \
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do { \
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asn_dec_rval_t rval; \
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rval.code = _code; \
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rval.consumed = consumed_myself; \
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return rval; \
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} while(0)
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#undef ADVANCE
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#define ADVANCE(num_bytes) \
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do { \
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size_t num = num_bytes; \
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ptr = ((const char *)ptr) + num; \
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size -= num; \
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consumed_myself += num; \
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} while(0)
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/*
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* Switch to the next phase of parsing.
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*/
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#undef NEXT_PHASE
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#define NEXT_PHASE(ctx) \
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do { \
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ctx->phase++; \
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ctx->step = 0; \
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} while(0)
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#undef SET_PHASE
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#define SET_PHASE(ctx, value) \
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do { \
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ctx->phase = value; \
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ctx->step = 0; \
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} while(0)
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/*
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* Tags are canonically sorted in the tag to member table.
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*/
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static int
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_search4tag(const void *ap, const void *bp) {
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const asn_TYPE_tag2member_t *a = (const asn_TYPE_tag2member_t *)ap;
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const asn_TYPE_tag2member_t *b = (const asn_TYPE_tag2member_t *)bp;
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int a_class = BER_TAG_CLASS(a->el_tag);
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int b_class = BER_TAG_CLASS(b->el_tag);
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if(a_class == b_class) {
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ber_tlv_tag_t a_value = BER_TAG_VALUE(a->el_tag);
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ber_tlv_tag_t b_value = BER_TAG_VALUE(b->el_tag);
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if(a_value == b_value)
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return 0;
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else if(a_value < b_value)
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return -1;
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else
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return 1;
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} else if(a_class < b_class) {
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return -1;
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} else {
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return 1;
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}
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}
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/*
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* X.696 (08/2015) #8.7 Encoding of tags
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*/
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static ssize_t
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oer_fetch_tag(const void *ptr, size_t size, ber_tlv_tag_t *tag_r) {
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ber_tlv_tag_t val;
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ber_tlv_tag_t tclass;
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size_t skipped;
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if(size == 0)
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return 0;
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val = *(const uint8_t *)ptr;
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tclass = (val >> 6);
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if((val & 0x3F) != 0x3F) {
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/* #8.7.1 */
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*tag_r = ((val & 0x3F) << 2) | tclass;
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return 1;
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}
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/*
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* Each octet contains 7 bits of useful information.
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* The MSB is 0 if it is the last octet of the tag.
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*/
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for(val = 0, ptr = ((const char *)ptr) + 1, skipped = 2; skipped <= size;
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ptr = ((const char *)ptr) + 1, skipped++) {
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unsigned int oct = *(const uint8_t *)ptr;
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if(oct & 0x80) {
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val = (val << 7) | (oct & 0x7F);
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/*
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* Make sure there are at least 9 bits spare
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* at the MS side of a value.
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*/
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if(val >> ((8 * sizeof(val)) - 9)) {
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/*
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* We would not be able to accomodate
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* any more tag bits.
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*/
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return -1;
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}
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} else {
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val = (val << 7) | oct;
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*tag_r = (val << 2) | tclass;
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return skipped;
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}
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}
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return 0; /* Want more */
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}
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asn_dec_rval_t
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CHOICE_decode_oer(const asn_codec_ctx_t *opt_codec_ctx,
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const asn_TYPE_descriptor_t *td,
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const asn_oer_constraints_t *constraints, void **struct_ptr,
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const void *ptr, size_t size) {
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/*
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* Bring closer parts of structure description.
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*/
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const asn_CHOICE_specifics_t *specs =
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(const asn_CHOICE_specifics_t *)td->specifics;
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asn_TYPE_member_t *elements = td->elements;
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/*
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* Parts of the structure being constructed.
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*/
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void *st = *struct_ptr; /* Target structure. */
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asn_struct_ctx_t *ctx; /* Decoder context */
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ssize_t consumed_myself = 0; /* Consumed bytes from ptr */
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(void)constraints;
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ASN_DEBUG("Decoding %s as CHOICE", td->name);
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/*
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* Create the target structure if it is not present already.
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*/
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if(st == 0) {
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st = *struct_ptr = CALLOC(1, specs->struct_size);
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if(st == 0) {
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RETURN(RC_FAIL);
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}
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}
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/*
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* Restore parsing context.
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*/
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ctx = (asn_struct_ctx_t *)((char *)st + specs->ctx_offset);
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switch(ctx->phase) {
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case 0: {
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/*
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* Discover the tag.
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*/
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ber_tlv_tag_t tlv_tag; /* T from TLV */
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ssize_t tag_len; /* Length of TLV's T */
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tag_len = oer_fetch_tag(ptr, size, &tlv_tag);
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switch(tag_len) {
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case 0:
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ASN__DECODE_STARVED;
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case -1:
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ASN__DECODE_FAILED;
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}
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do {
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const asn_TYPE_tag2member_t *t2m;
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asn_TYPE_tag2member_t key = {0, 0, 0, 0};
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key.el_tag = tlv_tag;
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t2m = (const asn_TYPE_tag2member_t *)bsearch(
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&key, specs->tag2el, specs->tag2el_count,
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sizeof(specs->tag2el[0]), _search4tag);
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if(t2m) {
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/*
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* Found the element corresponding to the tag.
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*/
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NEXT_PHASE(ctx);
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ctx->step = t2m->el_no;
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break;
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} else if(specs->ext_start == -1) {
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ASN_DEBUG(
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"Unexpected tag %s "
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"in non-extensible CHOICE %s",
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ber_tlv_tag_string(tlv_tag), td->name);
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RETURN(RC_FAIL);
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} else {
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/* Skip open type extension */
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ASN_DEBUG(
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"Not implemented skipping open type extension for tag %s",
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ber_tlv_tag_string(tlv_tag));
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RETURN(RC_FAIL);
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}
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} while(0);
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ADVANCE(tag_len);
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}
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/* Fall through */
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case 1: {
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asn_TYPE_member_t *elm = &elements[ctx->step]; /* CHOICE's element */
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void *memb_ptr; /* Pointer to the member */
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void **memb_ptr2; /* Pointer to that pointer */
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asn_dec_rval_t rval = {0,0};
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/*
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* Compute the position of the member inside a structure,
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* and also a type of containment (it may be contained
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* as pointer or using inline inclusion).
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*/
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if(elm->flags & ATF_POINTER) {
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/* Member is a pointer to another structure */
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memb_ptr2 = (void **)((char *)st + elm->memb_offset);
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} else {
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/*
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* A pointer to a pointer
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* holding the start of the structure
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*/
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memb_ptr = (char *)st + elm->memb_offset;
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memb_ptr2 = &memb_ptr;
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}
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/* Set presence to be able to free it properly at any time */
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(void)CHOICE_variant_set_presence(td, st, ctx->step + 1);
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if(specs->ext_start >= 0 && specs->ext_start <= ctx->step) {
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ssize_t got =
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oer_open_type_get(opt_codec_ctx, elm->type,
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elm->encoding_constraints.oer_constraints,
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memb_ptr2, ptr, size);
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if(got < 0) ASN__DECODE_FAILED;
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if(got == 0) ASN__DECODE_STARVED;
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rval.code = RC_OK;
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rval.consumed = got;
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} else {
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rval = elm->type->op->oer_decoder(
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opt_codec_ctx, elm->type,
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elm->encoding_constraints.oer_constraints, memb_ptr2, ptr,
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size);
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}
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rval.consumed += consumed_myself;
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switch(rval.code) {
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case RC_OK:
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NEXT_PHASE(ctx);
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case RC_WMORE:
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break;
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case RC_FAIL:
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SET_PHASE(ctx, 3); /* => 3 */
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}
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return rval;
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}
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case 2:
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/* Already decoded everything */
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RETURN(RC_OK);
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case 3:
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/* Failed to decode, after all */
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RETURN(RC_FAIL);
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}
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RETURN(RC_FAIL);
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}
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/*
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* X.696 (08/2015) #8.7 Encoding of tags
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*/
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static ssize_t
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oer_put_tag(ber_tlv_tag_t tag, asn_app_consume_bytes_f *cb, void *app_key) {
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uint8_t tclass = BER_TAG_CLASS(tag);
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ber_tlv_tag_t tval = BER_TAG_VALUE(tag);
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if(tval < 0x3F) {
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uint8_t b = (uint8_t)((tclass << 6) | tval);
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if(cb(&b, 1, app_key) < 0) {
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return -1;
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}
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return 1;
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} else {
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uint8_t buf[1 + 2 * sizeof(tval)];
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uint8_t *b = &buf[sizeof(buf)-1]; /* Last addressable */
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size_t encoded;
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for(; ; tval >>= 7) {
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if(tval >> 7) {
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*b-- = 0x80 | (tval & 0x7f);
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} else {
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*b-- = tval & 0x7f;
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break;
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}
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}
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*b = (uint8_t)((tclass << 6) | 0x3F);
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encoded = sizeof(buf) - (b - buf);
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if(cb(b, encoded, app_key) < 0) {
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return -1;
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}
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return encoded;
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}
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}
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/*
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* Encode as Canonical OER.
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*/
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asn_enc_rval_t
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CHOICE_encode_oer(const asn_TYPE_descriptor_t *td,
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const asn_oer_constraints_t *constraints, const void *sptr,
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asn_app_consume_bytes_f *cb, void *app_key) {
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const asn_CHOICE_specifics_t *specs =
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(const asn_CHOICE_specifics_t *)td->specifics;
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asn_TYPE_member_t *elm; /* CHOICE element */
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unsigned present;
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const void *memb_ptr;
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ber_tlv_tag_t tag;
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ssize_t tag_len;
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asn_enc_rval_t er = {0, 0, 0};
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(void)constraints;
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if(!sptr) ASN__ENCODE_FAILED;
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ASN_DEBUG("OER %s encoding as CHOICE", td->name);
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present = CHOICE_variant_get_presence(td, sptr);
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if(present == 0 || present > td->elements_count) {
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ASN_DEBUG("CHOICE %s member is not selected", td->name);
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ASN__ENCODE_FAILED;
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}
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elm = &td->elements[present-1];
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if(elm->flags & ATF_POINTER) {
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memb_ptr =
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*(const void *const *)((const char *)sptr + elm->memb_offset);
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if(memb_ptr == 0) {
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/* Mandatory element absent */
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ASN__ENCODE_FAILED;
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}
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} else {
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memb_ptr = (const void *)((const char *)sptr + elm->memb_offset);
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}
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tag = asn_TYPE_outmost_tag(elm->type, memb_ptr, elm->tag_mode, elm->tag);
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if(tag == 0) {
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ASN__ENCODE_FAILED;
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}
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tag_len = oer_put_tag(tag, cb, app_key);
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if(tag_len < 0) {
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ASN__ENCODE_FAILED;
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}
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if(specs->ext_start >= 0 && (unsigned)specs->ext_start <= (present-1)) {
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ssize_t encoded = oer_open_type_put(elm->type,
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elm->encoding_constraints.oer_constraints,
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memb_ptr, cb, app_key);
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if(encoded < 0) ASN__ENCODE_FAILED;
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er.encoded = tag_len + encoded;
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} else {
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er = elm->type->op->oer_encoder(
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elm->type, elm->encoding_constraints.oer_constraints, memb_ptr, cb,
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app_key);
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if(er.encoded >= 0) er.encoded += tag_len;
|
||
|
|
}
|
||
|
|
|
||
|
|
return er;
|
||
|
|
}
|
||
|
|
|
||
|
|
#endif /* ASN_DISABLE_OER_SUPPORT */
|