Issue-ID: SIM-18
[sim/e2-interface.git] / e2sim / e2apv1sim / ricsim / ASN1c / constr_CHOICE.c
diff --git a/e2sim/e2apv1sim/ricsim/ASN1c/constr_CHOICE.c b/e2sim/e2apv1sim/ricsim/ASN1c/constr_CHOICE.c
new file mode 100644 (file)
index 0000000..86dcbb0
--- /dev/null
@@ -0,0 +1,1533 @@
+/*
+ * Copyright (c) 2003-2017 Lev Walkin <vlm@lionet.info>. All rights reserved.
+ * Redistribution and modifications are permitted subject to BSD license.
+ */
+#include <asn_internal.h>
+#include <constr_CHOICE.h>
+#include <per_opentype.h>
+
+/*
+ * Number of bytes left for this structure.
+ * (ctx->left) indicates the number of bytes _transferred_ for the structure.
+ * (size) contains the number of bytes in the buffer passed.
+ */
+#define        LEFT    ((size<(size_t)ctx->left)?size:(size_t)ctx->left)
+
+/*
+ * If the subprocessor function returns with an indication that it wants
+ * more data, it may well be a fatal decoding problem, because the
+ * size is constrained by the <TLV>'s L, even if the buffer size allows
+ * reading more data.
+ * For example, consider the buffer containing the following TLVs:
+ * <T:5><L:1><V> <T:6>...
+ * The TLV length clearly indicates that one byte is expected in V, but
+ * if the V processor returns with "want more data" even if the buffer
+ * contains way more data than the V processor have seen.
+ */
+#define        SIZE_VIOLATION  (ctx->left >= 0 && (size_t)ctx->left <= size)
+
+/*
+ * This macro "eats" the part of the buffer which is definitely "consumed",
+ * i.e. was correctly converted into local representation or rightfully skipped.
+ */
+#undef ADVANCE
+#define        ADVANCE(num_bytes)      do {            \
+               size_t num = num_bytes;         \
+               ptr = ((const char *)ptr) + num;\
+               size -= num;                    \
+               if(ctx->left >= 0)              \
+                       ctx->left -= num;       \
+               consumed_myself += num;         \
+       } while(0)
+
+/*
+ * Switch to the next phase of parsing.
+ */
+#undef NEXT_PHASE
+#define        NEXT_PHASE(ctx) do {                    \
+               ctx->phase++;                   \
+               ctx->step = 0;                  \
+       } while(0)
+
+/*
+ * Return a standardized complex structure.
+ */
+#undef RETURN
+#define        RETURN(_code)   do {                    \
+               rval.code = _code;              \
+               rval.consumed = consumed_myself;\
+               return rval;                    \
+       } while(0)
+
+/*
+ * See the definitions.
+ */
+static unsigned _fetch_present_idx(const void *struct_ptr, unsigned off,
+                                   unsigned size);
+static void _set_present_idx(void *sptr, unsigned offset, unsigned size,
+                             unsigned pres);
+static const void *_get_member_ptr(const asn_TYPE_descriptor_t *,
+                                   const void *sptr, asn_TYPE_member_t **elm,
+                                   unsigned *present);
+
+/*
+ * Tags are canonically sorted in the tag to member table.
+ */
+static int
+_search4tag(const void *ap, const void *bp) {
+       const asn_TYPE_tag2member_t *a = (const asn_TYPE_tag2member_t *)ap;
+       const asn_TYPE_tag2member_t *b = (const asn_TYPE_tag2member_t *)bp;
+
+       int a_class = BER_TAG_CLASS(a->el_tag);
+       int b_class = BER_TAG_CLASS(b->el_tag);
+
+       if(a_class == b_class) {
+               ber_tlv_tag_t a_value = BER_TAG_VALUE(a->el_tag);
+               ber_tlv_tag_t b_value = BER_TAG_VALUE(b->el_tag);
+
+               if(a_value == b_value)
+                       return 0;
+               else if(a_value < b_value)
+                       return -1;
+               else
+                       return 1;
+       } else if(a_class < b_class) {
+               return -1;
+       } else {
+               return 1;
+       }
+}
+
+/*
+ * The decoder of the CHOICE type.
+ */
+asn_dec_rval_t
+CHOICE_decode_ber(const asn_codec_ctx_t *opt_codec_ctx,
+                  const asn_TYPE_descriptor_t *td, void **struct_ptr,
+                  const void *ptr, size_t size, int tag_mode) {
+    /*
+        * Bring closer parts of structure description.
+        */
+       const asn_CHOICE_specifics_t *specs =
+               (const asn_CHOICE_specifics_t *)td->specifics;
+       asn_TYPE_member_t *elements = td->elements;
+
+       /*
+        * Parts of the structure being constructed.
+        */
+       void *st = *struct_ptr; /* Target structure. */
+       asn_struct_ctx_t *ctx;  /* Decoder context */
+
+       ber_tlv_tag_t tlv_tag;  /* T from TLV */
+       ssize_t tag_len;        /* Length of TLV's T */
+       asn_dec_rval_t rval;    /* Return code from subparsers */
+
+       ssize_t consumed_myself = 0;    /* Consumed bytes from ptr */
+
+       ASN_DEBUG("Decoding %s as CHOICE", td->name);
+
+       /*
+        * Create the target structure if it is not present already.
+        */
+       if(st == 0) {
+               st = *struct_ptr = CALLOC(1, specs->struct_size);
+               if(st == 0) {
+                       RETURN(RC_FAIL);
+               }
+       }
+
+       /*
+        * Restore parsing context.
+        */
+       ctx = (asn_struct_ctx_t *)((char *)st + specs->ctx_offset);
+       
+       /*
+        * Start to parse where left previously
+        */
+       switch(ctx->phase) {
+       case 0:
+               /*
+                * PHASE 0.
+                * Check that the set of tags associated with given structure
+                * perfectly fits our expectations.
+                */
+
+               if(tag_mode || td->tags_count) {
+                       rval = ber_check_tags(opt_codec_ctx, td, ctx, ptr, size,
+                               tag_mode, -1, &ctx->left, 0);
+                       if(rval.code != RC_OK) {
+                               ASN_DEBUG("%s tagging check failed: %d",
+                                       td->name, rval.code);
+                               return rval;
+                       }
+
+                       if(ctx->left >= 0) {
+                               /* ?Substracted below! */
+                               ctx->left += rval.consumed;
+                       }
+                       ADVANCE(rval.consumed);
+               } else {
+                       ctx->left = -1;
+               }
+
+               NEXT_PHASE(ctx);
+
+               ASN_DEBUG("Structure consumes %ld bytes, buffer %ld",
+                       (long)ctx->left, (long)size);
+
+               /* Fall through */
+       case 1:
+               /*
+                * Fetch the T from TLV.
+                */
+               tag_len = ber_fetch_tag(ptr, LEFT, &tlv_tag);
+               ASN_DEBUG("In %s CHOICE tag length %d", td->name, (int)tag_len);
+               switch(tag_len) {
+               case 0: if(!SIZE_VIOLATION) RETURN(RC_WMORE);
+                       /* Fall through */
+               case -1: RETURN(RC_FAIL);
+               }
+
+               do {
+                       const asn_TYPE_tag2member_t *t2m;
+                       asn_TYPE_tag2member_t key;
+
+                       key.el_tag = tlv_tag;
+                       t2m = (const asn_TYPE_tag2member_t *)bsearch(&key,
+                                       specs->tag2el, specs->tag2el_count,
+                                       sizeof(specs->tag2el[0]), _search4tag);
+                       if(t2m) {
+                               /*
+                                * Found the element corresponding to the tag.
+                                */
+                               NEXT_PHASE(ctx);
+                               ctx->step = t2m->el_no;
+                               break;
+                       } else if(specs->ext_start == -1) {
+                               ASN_DEBUG("Unexpected tag %s "
+                                       "in non-extensible CHOICE %s",
+                                       ber_tlv_tag_string(tlv_tag), td->name);
+                               RETURN(RC_FAIL);
+                       } else {
+                               /* Skip this tag */
+                               ssize_t skip;
+
+                               ASN_DEBUG("Skipping unknown tag %s",
+                                       ber_tlv_tag_string(tlv_tag));
+
+                               skip = ber_skip_length(opt_codec_ctx,
+                                       BER_TLV_CONSTRUCTED(ptr),
+                                       (const char *)ptr + tag_len,
+                                       LEFT - tag_len);
+
+                               switch(skip) {
+                               case 0: if(!SIZE_VIOLATION) RETURN(RC_WMORE);
+                                       /* Fall through */
+                               case -1: RETURN(RC_FAIL);
+                               }
+
+                               ADVANCE(skip + tag_len);
+                               RETURN(RC_OK);
+                       }
+               } while(0);
+
+       case 2:
+               /*
+                * PHASE 2.
+                * Read in the element.
+                */
+           do {
+               asn_TYPE_member_t *elm;/* CHOICE's element */
+               void *memb_ptr;         /* Pointer to the member */
+               void **memb_ptr2;       /* Pointer to that pointer */
+
+               elm = &elements[ctx->step];
+
+               /*
+                * Compute the position of the member inside a structure,
+                * and also a type of containment (it may be contained
+                * as pointer or using inline inclusion).
+                */
+               if(elm->flags & ATF_POINTER) {
+                       /* Member is a pointer to another structure */
+                       memb_ptr2 = (void **)((char *)st + elm->memb_offset);
+               } else {
+                       /*
+                        * A pointer to a pointer
+                        * holding the start of the structure
+                        */
+                       memb_ptr = (char *)st + elm->memb_offset;
+                       memb_ptr2 = &memb_ptr;
+               }
+               /* Set presence to be able to free it properly at any time */
+               _set_present_idx(st, specs->pres_offset,
+                               specs->pres_size, ctx->step + 1);
+               /*
+                * Invoke the member fetch routine according to member's type
+                */
+               rval = elm->type->op->ber_decoder(opt_codec_ctx, elm->type,
+                               memb_ptr2, ptr, LEFT, elm->tag_mode);
+               switch(rval.code) {
+               case RC_OK:
+                       break;
+               case RC_WMORE: /* More data expected */
+                       if(!SIZE_VIOLATION) {
+                               ADVANCE(rval.consumed);
+                               RETURN(RC_WMORE);
+                       }
+                       RETURN(RC_FAIL);
+               case RC_FAIL: /* Fatal error */
+                       RETURN(rval.code);
+               } /* switch(rval) */
+               
+               ADVANCE(rval.consumed);
+         } while(0);
+
+               NEXT_PHASE(ctx);
+
+               /* Fall through */
+       case 3:
+               ASN_DEBUG("CHOICE %s Leftover: %ld, size = %ld, tm=%d, tc=%d",
+                       td->name, (long)ctx->left, (long)size,
+                       tag_mode, td->tags_count);
+
+               if(ctx->left > 0) {
+                       /*
+                        * The type must be fully decoded
+                        * by the CHOICE member-specific decoder.
+                        */
+                       RETURN(RC_FAIL);
+               }
+
+               if(ctx->left == -1
+               && !(tag_mode || td->tags_count)) {
+                       /*
+                        * This is an untagged CHOICE.
+                        * It doesn't contain nothing
+                        * except for the member itself, including all its tags.
+                        * The decoding is completed.
+                        */
+                       NEXT_PHASE(ctx);
+                       break;
+               }
+
+               /*
+                * Read in the "end of data chunks"'s.
+                */
+               while(ctx->left < 0) {
+                       ssize_t tl;
+
+                       tl = ber_fetch_tag(ptr, LEFT, &tlv_tag);
+                       switch(tl) {
+                       case 0: if(!SIZE_VIOLATION) RETURN(RC_WMORE);
+                               /* Fall through */
+                       case -1: RETURN(RC_FAIL);
+                       }
+
+                       /*
+                        * Expected <0><0>...
+                        */
+                       if(((const uint8_t *)ptr)[0] == 0) {
+                               if(LEFT < 2) {
+                                       if(SIZE_VIOLATION)
+                                               RETURN(RC_FAIL);
+                                       else
+                                               RETURN(RC_WMORE);
+                               } else if(((const uint8_t *)ptr)[1] == 0) {
+                                       /*
+                                        * Correctly finished with <0><0>.
+                                        */
+                                       ADVANCE(2);
+                                       ctx->left++;
+                                       continue;
+                               }
+                       } else {
+                               ASN_DEBUG("Unexpected continuation in %s",
+                                       td->name);
+                               RETURN(RC_FAIL);
+                       }
+
+                       /* UNREACHABLE */
+               }
+
+               NEXT_PHASE(ctx);
+       case 4:
+               /* No meaningful work here */
+               break;
+       }
+       
+       RETURN(RC_OK);
+}
+
+asn_enc_rval_t
+CHOICE_encode_der(const asn_TYPE_descriptor_t *td, const void *sptr,
+                  int tag_mode, ber_tlv_tag_t tag, asn_app_consume_bytes_f *cb,
+                  void *app_key) {
+    const asn_CHOICE_specifics_t *specs = (const asn_CHOICE_specifics_t *)td->specifics;
+       asn_TYPE_member_t *elm; /* CHOICE element */
+       asn_enc_rval_t erval = {0,0,0};
+       const void *memb_ptr;
+       size_t computed_size = 0;
+       unsigned present;
+
+       if(!sptr) ASN__ENCODE_FAILED;
+
+       ASN_DEBUG("%s %s as CHOICE",
+               cb?"Encoding":"Estimating", td->name);
+
+       present = _fetch_present_idx(sptr,
+               specs->pres_offset, specs->pres_size);
+
+       /*
+        * If the structure was not initialized, it cannot be encoded:
+        * can't deduce what to encode in the choice type.
+        */
+       if(present == 0 || present > td->elements_count) {
+               if(present == 0 && td->elements_count == 0) {
+                       /* The CHOICE is empty?! */
+                       erval.encoded = 0;
+                       ASN__ENCODED_OK(erval);
+               }
+               ASN__ENCODE_FAILED;
+       }
+
+       /*
+        * Seek over the present member of the structure.
+        */
+       elm = &td->elements[present-1];
+       if(elm->flags & ATF_POINTER) {
+        memb_ptr =
+            *(const void *const *)((const char *)sptr + elm->memb_offset);
+        if(memb_ptr == 0) {
+                       if(elm->optional) {
+                               erval.encoded = 0;
+                               ASN__ENCODED_OK(erval);
+                       }
+                       /* Mandatory element absent */
+                       ASN__ENCODE_FAILED;
+               }
+       } else {
+        memb_ptr = (const void *)((const char *)sptr + elm->memb_offset);
+    }
+
+       /*
+        * If the CHOICE itself is tagged EXPLICIT:
+        * T ::= [2] EXPLICIT CHOICE { ... }
+        * Then emit the appropriate tags.
+        */
+       if(tag_mode == 1 || td->tags_count) {
+               /*
+                * For this, we need to pre-compute the member.
+                */
+               ssize_t ret;
+
+               /* Encode member with its tag */
+               erval = elm->type->op->der_encoder(elm->type, memb_ptr,
+                       elm->tag_mode, elm->tag, 0, 0);
+               if(erval.encoded == -1)
+                       return erval;
+
+               /* Encode CHOICE with parent or my own tag */
+               ret = der_write_tags(td, erval.encoded, tag_mode, 1, tag,
+                       cb, app_key);
+               if(ret == -1)
+                       ASN__ENCODE_FAILED;
+               computed_size += ret;
+       }
+
+       /*
+        * Encode the single underlying member.
+        */
+       erval = elm->type->op->der_encoder(elm->type, memb_ptr,
+               elm->tag_mode, elm->tag, cb, app_key);
+       if(erval.encoded == -1)
+               return erval;
+
+       ASN_DEBUG("Encoded CHOICE member in %ld bytes (+%ld)",
+               (long)erval.encoded, (long)computed_size);
+
+       erval.encoded += computed_size;
+
+       return erval;
+}
+
+ber_tlv_tag_t
+CHOICE_outmost_tag(const asn_TYPE_descriptor_t *td, const void *ptr, int tag_mode, ber_tlv_tag_t tag) {
+       const asn_CHOICE_specifics_t *specs = (const asn_CHOICE_specifics_t *)td->specifics;
+       unsigned present;
+
+       assert(tag_mode == 0); (void)tag_mode;
+       assert(tag == 0); (void)tag;
+
+       /*
+        * Figure out which CHOICE element is encoded.
+        */
+       present = _fetch_present_idx(ptr, specs->pres_offset, specs->pres_size);
+
+       if(present > 0 && present <= td->elements_count) {
+               const asn_TYPE_member_t *elm = &td->elements[present-1];
+               const void *memb_ptr;
+
+               if(elm->flags & ATF_POINTER) {
+                       memb_ptr = *(const void * const *)
+                                       ((const char *)ptr + elm->memb_offset);
+               } else {
+                       memb_ptr = (const void *)
+                                       ((const char *)ptr + elm->memb_offset);
+               }
+
+               return asn_TYPE_outmost_tag(elm->type, memb_ptr,
+                       elm->tag_mode, elm->tag);
+       } else {
+               return (ber_tlv_tag_t)-1;
+       }
+}
+
+int
+CHOICE_constraint(const asn_TYPE_descriptor_t *td, const void *sptr,
+                  asn_app_constraint_failed_f *ctfailcb, void *app_key) {
+    const asn_CHOICE_specifics_t *specs =
+        (const asn_CHOICE_specifics_t *)td->specifics;
+    unsigned present;
+
+       if(!sptr) {
+               ASN__CTFAIL(app_key, td, sptr,
+                       "%s: value not given (%s:%d)",
+                       td->name, __FILE__, __LINE__);
+               return -1;
+       }
+
+       /*
+        * Figure out which CHOICE element is encoded.
+        */
+       present = _fetch_present_idx(sptr, specs->pres_offset,specs->pres_size);
+       if(present > 0 && present <= td->elements_count) {
+               asn_TYPE_member_t *elm = &td->elements[present-1];
+               const void *memb_ptr;
+
+               if(elm->flags & ATF_POINTER) {
+                       memb_ptr = *(const void * const *)((const char *)sptr + elm->memb_offset);
+                       if(!memb_ptr) {
+                               if(elm->optional)
+                                       return 0;
+                               ASN__CTFAIL(app_key, td, sptr,
+                                       "%s: mandatory CHOICE element %s absent (%s:%d)",
+                                       td->name, elm->name, __FILE__, __LINE__);
+                               return -1;
+                       }
+               } else {
+                       memb_ptr = (const void *)((const char *)sptr + elm->memb_offset);
+               }
+
+               if(elm->encoding_constraints.general_constraints) {
+                       return elm->encoding_constraints.general_constraints(elm->type, memb_ptr,
+                               ctfailcb, app_key);
+               } else {
+                       return elm->type->encoding_constraints.general_constraints(elm->type,
+                                       memb_ptr, ctfailcb, app_key);
+               }
+       } else {
+               ASN__CTFAIL(app_key, td, sptr,
+                       "%s: no CHOICE element given (%s:%d)",
+                       td->name, __FILE__, __LINE__);
+               return -1;
+       }
+}
+
+#undef XER_ADVANCE
+#define        XER_ADVANCE(num_bytes)  do {                    \
+               size_t num = num_bytes;                 \
+               buf_ptr = (const void *)(((const char *)buf_ptr) + num); \
+               size -= num;                            \
+               consumed_myself += num;                 \
+       } while(0)
+
+/*
+ * Decode the XER (XML) data.
+ */
+asn_dec_rval_t
+CHOICE_decode_xer(const asn_codec_ctx_t *opt_codec_ctx,
+                  const asn_TYPE_descriptor_t *td, void **struct_ptr,
+                  const char *opt_mname, const void *buf_ptr, size_t size) {
+    /*
+        * Bring closer parts of structure description.
+        */
+       const asn_CHOICE_specifics_t *specs = (const asn_CHOICE_specifics_t *)td->specifics;
+       const char *xml_tag = opt_mname ? opt_mname : td->xml_tag;
+
+       /*
+        * Parts of the structure being constructed.
+        */
+       void *st = *struct_ptr; /* Target structure. */
+       asn_struct_ctx_t *ctx;  /* Decoder context */
+
+       asn_dec_rval_t rval;            /* Return value of a decoder */
+       ssize_t consumed_myself = 0;    /* Consumed bytes from ptr */
+       size_t edx;                     /* Element index */
+
+       /*
+        * Create the target structure if it is not present already.
+        */
+       if(st == 0) {
+               st = *struct_ptr = CALLOC(1, specs->struct_size);
+               if(st == 0) RETURN(RC_FAIL);
+       }
+
+       /*
+        * Restore parsing context.
+        */
+       ctx = (asn_struct_ctx_t *)((char *)st + specs->ctx_offset);
+       if(ctx->phase == 0 && !*xml_tag)
+               ctx->phase = 1; /* Skip the outer tag checking phase */
+
+       /*
+        * Phases of XER/XML processing:
+        * Phase 0: Check that the opening tag matches our expectations.
+        * Phase 1: Processing body and reacting on closing tag.
+        * Phase 2: Processing inner type.
+        * Phase 3: Only waiting for closing tag.
+        * Phase 4: Skipping unknown extensions.
+        * Phase 5: PHASED OUT
+        */
+       for(edx = ctx->step; ctx->phase <= 4;) {
+               pxer_chunk_type_e ch_type;      /* XER chunk type */
+               ssize_t ch_size;                /* Chunk size */
+               xer_check_tag_e tcv;            /* Tag check value */
+               asn_TYPE_member_t *elm;
+
+               /*
+                * Go inside the member.
+                */
+               if(ctx->phase == 2) {
+                       asn_dec_rval_t tmprval;
+                       void *memb_ptr;         /* Pointer to the member */
+                       void **memb_ptr2;       /* Pointer to that pointer */
+                       unsigned old_present;
+
+                       elm = &td->elements[edx];
+
+                       if(elm->flags & ATF_POINTER) {
+                               /* Member is a pointer to another structure */
+                               memb_ptr2 = (void **)((char *)st
+                                       + elm->memb_offset);
+                       } else {
+                               memb_ptr = (char *)st + elm->memb_offset;
+                               memb_ptr2 = &memb_ptr;
+                       }
+
+                       /* Start/Continue decoding the inner member */
+                       tmprval = elm->type->op->xer_decoder(opt_codec_ctx,
+                                       elm->type, memb_ptr2, elm->name,
+                                       buf_ptr, size);
+                       XER_ADVANCE(tmprval.consumed);
+                       ASN_DEBUG("XER/CHOICE: itdf: [%s] code=%d",
+                               elm->type->name, tmprval.code);
+                       old_present = _fetch_present_idx(st,
+                               specs->pres_offset, specs->pres_size);
+                       assert(old_present == 0 || old_present == edx + 1);
+                       /* Record what we've got */
+                       _set_present_idx(st,
+                               specs->pres_offset, specs->pres_size, edx + 1);
+                       if(tmprval.code != RC_OK)
+                               RETURN(tmprval.code);
+                       ctx->phase = 3;
+                       /* Fall through */
+               }
+
+               /* No need to wait for closing tag; special mode. */
+               if(ctx->phase == 3 && !*xml_tag) {
+                       ctx->phase = 5; /* Phase out */
+                       RETURN(RC_OK);
+               }
+
+               /*
+                * Get the next part of the XML stream.
+                */
+               ch_size = xer_next_token(&ctx->context, buf_ptr, size, &ch_type);
+               if(ch_size == -1) {
+            RETURN(RC_FAIL);
+        } else {
+                       switch(ch_type) {
+                       case PXER_WMORE:
+                RETURN(RC_WMORE);
+                       case PXER_COMMENT:      /* Got XML comment */
+                       case PXER_TEXT:         /* Ignore free-standing text */
+                               XER_ADVANCE(ch_size);   /* Skip silently */
+                               continue;
+                       case PXER_TAG:
+                               break;  /* Check the rest down there */
+                       }
+               }
+
+               tcv = xer_check_tag(buf_ptr, ch_size, xml_tag);
+               ASN_DEBUG("XER/CHOICE checked [%c%c%c%c] vs [%s], tcv=%d",
+                       ch_size>0?((const uint8_t *)buf_ptr)[0]:'?',
+                       ch_size>1?((const uint8_t *)buf_ptr)[1]:'?',
+                       ch_size>2?((const uint8_t *)buf_ptr)[2]:'?',
+                       ch_size>3?((const uint8_t *)buf_ptr)[3]:'?',
+               xml_tag, tcv);
+
+               /* Skip the extensions section */
+               if(ctx->phase == 4) {
+                       ASN_DEBUG("skip_unknown(%d, %ld)",
+                               tcv, (long)ctx->left);
+                       switch(xer_skip_unknown(tcv, &ctx->left)) {
+                       case -1:
+                               ctx->phase = 5;
+                               RETURN(RC_FAIL);
+                       case 1:
+                               ctx->phase = 3;
+                               /* Fall through */
+                       case 0:
+                               XER_ADVANCE(ch_size);
+                               continue;
+                       case 2:
+                               ctx->phase = 3;
+                               break;
+                       }
+               }
+
+               switch(tcv) {
+               case XCT_BOTH:
+                       break;  /* No CHOICE? */
+               case XCT_CLOSING:
+                       if(ctx->phase != 3)
+                               break;
+                       XER_ADVANCE(ch_size);
+                       ctx->phase = 5; /* Phase out */
+                       RETURN(RC_OK);
+               case XCT_OPENING:
+                       if(ctx->phase == 0) {
+                               XER_ADVANCE(ch_size);
+                               ctx->phase = 1; /* Processing body phase */
+                               continue;
+                       }
+                       /* Fall through */
+               case XCT_UNKNOWN_OP:
+               case XCT_UNKNOWN_BO:
+
+                       if(ctx->phase != 1)
+                               break;  /* Really unexpected */
+
+                       /*
+                        * Search which inner member corresponds to this tag.
+                        */
+                       for(edx = 0; edx < td->elements_count; edx++) {
+                               elm = &td->elements[edx];
+                               tcv = xer_check_tag(buf_ptr,ch_size,elm->name);
+                               switch(tcv) {
+                               case XCT_BOTH:
+                               case XCT_OPENING:
+                                       /*
+                                        * Process this member.
+                                        */
+                                       ctx->step = edx;
+                                       ctx->phase = 2;
+                                       break;
+                               case XCT_UNKNOWN_OP:
+                               case XCT_UNKNOWN_BO:
+                                       continue;
+                               default:
+                                       edx = td->elements_count;
+                                       break;  /* Phase out */
+                               }
+                               break;
+                       }
+                       if(edx != td->elements_count)
+                               continue;
+
+                       /* It is expected extension */
+                       if(specs->ext_start != -1) {
+                               ASN_DEBUG("Got anticipated extension");
+                               /*
+                                * Check for (XCT_BOTH or XCT_UNKNOWN_BO)
+                                * By using a mask. Only record a pure
+                                * <opening> tags.
+                                */
+                               if(tcv & XCT_CLOSING) {
+                                       /* Found </extension> without body */
+                                       ctx->phase = 3; /* Terminating */
+                               } else {
+                                       ctx->left = 1;
+                                       ctx->phase = 4; /* Skip ...'s */
+                               }
+                               XER_ADVANCE(ch_size);
+                               continue;
+                       }
+
+                       /* Fall through */
+               default:
+                       break;
+               }
+
+               ASN_DEBUG("Unexpected XML tag [%c%c%c%c] in CHOICE [%s]"
+                       " (ph=%d, tag=%s)",
+                       ch_size>0?((const uint8_t *)buf_ptr)[0]:'?',
+                       ch_size>1?((const uint8_t *)buf_ptr)[1]:'?',
+                       ch_size>2?((const uint8_t *)buf_ptr)[2]:'?',
+                       ch_size>3?((const uint8_t *)buf_ptr)[3]:'?',
+                       td->name, ctx->phase, xml_tag);
+               break;
+       }
+
+       ctx->phase = 5; /* Phase out, just in case */
+       RETURN(RC_FAIL);
+}
+
+
+asn_enc_rval_t
+CHOICE_encode_xer(const asn_TYPE_descriptor_t *td, const void *sptr, int ilevel,
+                  enum xer_encoder_flags_e flags, asn_app_consume_bytes_f *cb,
+                  void *app_key) {
+       const asn_CHOICE_specifics_t *specs =
+               (const asn_CHOICE_specifics_t *)td->specifics;
+       asn_enc_rval_t er = {0,0,0};
+       unsigned present = 0;
+
+       if(!sptr)
+               ASN__ENCODE_FAILED;
+
+       /*
+        * Figure out which CHOICE element is encoded.
+        */
+       present = _fetch_present_idx(sptr, specs->pres_offset,specs->pres_size);
+
+       if(present == 0 || present > td->elements_count) {
+               ASN__ENCODE_FAILED;
+       }  else {
+               asn_enc_rval_t tmper = {0,0,0};
+               asn_TYPE_member_t *elm = &td->elements[present-1];
+               const void *memb_ptr = NULL;
+               const char *mname = elm->name;
+               unsigned int mlen = strlen(mname);
+
+               if(elm->flags & ATF_POINTER) {
+            memb_ptr =
+                *(const void *const *)((const char *)sptr + elm->memb_offset);
+            if(!memb_ptr) ASN__ENCODE_FAILED;
+               } else {
+            memb_ptr = (const void *)((const char *)sptr + elm->memb_offset);
+        }
+
+        er.encoded = 0;
+
+               if(!(flags & XER_F_CANONICAL)) ASN__TEXT_INDENT(1, ilevel);
+               ASN__CALLBACK3("<", 1, mname, mlen, ">", 1);
+
+               tmper = elm->type->op->xer_encoder(elm->type, memb_ptr,
+                               ilevel + 1, flags, cb, app_key);
+               if(tmper.encoded == -1) return tmper;
+               er.encoded += tmper.encoded;
+
+               ASN__CALLBACK3("</", 2, mname, mlen, ">", 1);
+       }
+
+       if(!(flags & XER_F_CANONICAL)) ASN__TEXT_INDENT(1, ilevel - 1);
+
+       ASN__ENCODED_OK(er);
+cb_failed:
+       ASN__ENCODE_FAILED;
+}
+
+asn_dec_rval_t
+CHOICE_decode_uper(const asn_codec_ctx_t *opt_codec_ctx,
+                   const asn_TYPE_descriptor_t *td,
+                   const asn_per_constraints_t *constraints, void **sptr,
+                   asn_per_data_t *pd) {
+    const asn_CHOICE_specifics_t *specs =
+        (const asn_CHOICE_specifics_t *)td->specifics;
+    asn_dec_rval_t rv;
+       const asn_per_constraint_t *ct;
+       asn_TYPE_member_t *elm; /* CHOICE's element */
+       void *memb_ptr;
+       void **memb_ptr2;
+       void *st = *sptr;
+       int value;
+
+       if(ASN__STACK_OVERFLOW_CHECK(opt_codec_ctx))
+               ASN__DECODE_FAILED;
+
+       /*
+        * Create the target structure if it is not present already.
+        */
+       if(!st) {
+               st = *sptr = CALLOC(1, specs->struct_size);
+               if(!st) ASN__DECODE_FAILED;
+       }
+
+       if(constraints) ct = &constraints->value;
+       else if(td->encoding_constraints.per_constraints) ct = &td->encoding_constraints.per_constraints->value;
+       else ct = 0;
+
+       if(ct && ct->flags & APC_EXTENSIBLE) {
+               value = per_get_few_bits(pd, 1);
+               if(value < 0) ASN__DECODE_STARVED;
+               if(value) ct = 0;       /* Not restricted */
+       }
+
+       if(ct && ct->range_bits >= 0) {
+               value = per_get_few_bits(pd, ct->range_bits);
+               if(value < 0) ASN__DECODE_STARVED;
+               ASN_DEBUG("CHOICE %s got index %d in range %d",
+                       td->name, value, ct->range_bits);
+               if(value > ct->upper_bound)
+                       ASN__DECODE_FAILED;
+       } else {
+               if(specs->ext_start == -1)
+                       ASN__DECODE_FAILED;
+               value = uper_get_nsnnwn(pd);
+               if(value < 0) ASN__DECODE_STARVED;
+               value += specs->ext_start;
+               if((unsigned)value >= td->elements_count)
+                       ASN__DECODE_FAILED;
+       }
+
+       /* Adjust if canonical order is different from natural order */
+       if(specs->from_canonical_order) {
+        ASN_DEBUG("CHOICE presence from wire %d", value);
+               value = specs->from_canonical_order[value];
+        ASN_DEBUG("CHOICE presence index effective %d", value);
+    }
+
+       /* Set presence to be able to free it later */
+       _set_present_idx(st, specs->pres_offset, specs->pres_size, value + 1);
+
+       elm = &td->elements[value];
+       if(elm->flags & ATF_POINTER) {
+               /* Member is a pointer to another structure */
+               memb_ptr2 = (void **)((char *)st + elm->memb_offset);
+       } else {
+               memb_ptr = (char *)st + elm->memb_offset;
+               memb_ptr2 = &memb_ptr;
+       }
+       ASN_DEBUG("Discovered CHOICE %s encodes %s", td->name, elm->name);
+
+       if(ct && ct->range_bits >= 0) {
+               rv = elm->type->op->uper_decoder(opt_codec_ctx, elm->type,
+                       elm->encoding_constraints.per_constraints, memb_ptr2, pd);
+       } else {
+               rv = uper_open_type_get(opt_codec_ctx, elm->type,
+                       elm->encoding_constraints.per_constraints, memb_ptr2, pd);
+       }
+
+       if(rv.code != RC_OK)
+               ASN_DEBUG("Failed to decode %s in %s (CHOICE) %d",
+                       elm->name, td->name, rv.code);
+       return rv;
+}
+
+asn_enc_rval_t
+CHOICE_encode_uper(const asn_TYPE_descriptor_t *td,
+                   const asn_per_constraints_t *constraints, const void *sptr,
+                   asn_per_outp_t *po) {
+       const asn_CHOICE_specifics_t *specs = (const asn_CHOICE_specifics_t *)td->specifics;
+       asn_TYPE_member_t *elm; /* CHOICE's element */
+       const asn_per_constraint_t *ct;
+       const void *memb_ptr;
+       unsigned present;
+       int present_enc;
+
+       if(!sptr) ASN__ENCODE_FAILED;
+
+       ASN_DEBUG("Encoding %s as CHOICE", td->name);
+
+       if(constraints) ct = &constraints->value;
+       else if(td->encoding_constraints.per_constraints)
+               ct = &td->encoding_constraints.per_constraints->value;
+       else ct = 0;
+
+       present = _fetch_present_idx(sptr, specs->pres_offset, specs->pres_size);
+
+       /*
+        * If the structure was not initialized properly, it cannot be encoded:
+        * can't deduce what to encode in the choice type.
+        */
+       if(present == 0 || present > td->elements_count)
+               ASN__ENCODE_FAILED;
+       else
+               present--;
+
+       ASN_DEBUG("Encoding %s CHOICE element %d", td->name, present);
+
+    /* Adjust if canonical order is different from natural order */
+    if(specs->to_canonical_order)
+        present_enc = specs->to_canonical_order[present];
+    else
+        present_enc = present;
+
+    if(ct && ct->range_bits >= 0) {
+               if(present_enc < ct->lower_bound
+               || present_enc > ct->upper_bound) {
+                       if(ct->flags & APC_EXTENSIBLE) {
+                ASN_DEBUG(
+                    "CHOICE member %d (enc %d) is an extension (%ld..%ld)",
+                    present, present_enc, ct->lower_bound, ct->upper_bound);
+                if(per_put_few_bits(po, 1, 1))
+                                       ASN__ENCODE_FAILED;
+                       } else {
+                               ASN__ENCODE_FAILED;
+                       }
+                       ct = 0;
+               }
+       }
+       if(ct && ct->flags & APC_EXTENSIBLE) {
+        ASN_DEBUG("CHOICE member %d (enc %d) is not an extension (%ld..%ld)",
+                  present, present_enc, ct->lower_bound, ct->upper_bound);
+        if(per_put_few_bits(po, 0, 1))
+                       ASN__ENCODE_FAILED;
+    }
+
+
+       elm = &td->elements[present];
+    ASN_DEBUG("CHOICE member \"%s\" %d (as %d)", elm->name, present,
+              present_enc);
+    if(elm->flags & ATF_POINTER) {
+               /* Member is a pointer to another structure */
+        memb_ptr =
+            *(const void *const *)((const char *)sptr + elm->memb_offset);
+        if(!memb_ptr) ASN__ENCODE_FAILED;
+       } else {
+        memb_ptr = (const char *)sptr + elm->memb_offset;
+    }
+
+    if(ct && ct->range_bits >= 0) {
+        if(per_put_few_bits(po, present_enc, ct->range_bits))
+            ASN__ENCODE_FAILED;
+
+        return elm->type->op->uper_encoder(
+            elm->type, elm->encoding_constraints.per_constraints, memb_ptr, po);
+    } else {
+        asn_enc_rval_t rval = {0,0,0};
+        if(specs->ext_start == -1) ASN__ENCODE_FAILED;
+        if(uper_put_nsnnwn(po, present_enc - specs->ext_start))
+            ASN__ENCODE_FAILED;
+        if(uper_open_type_put(elm->type,
+                              elm->encoding_constraints.per_constraints,
+                              memb_ptr, po))
+            ASN__ENCODE_FAILED;
+        rval.encoded = 0;
+        ASN__ENCODED_OK(rval);
+    }
+}
+
+asn_dec_rval_t
+CHOICE_decode_aper(const asn_codec_ctx_t *opt_codec_ctx,
+                   const asn_TYPE_descriptor_t *td,
+                   const asn_per_constraints_t *constraints, void **sptr, asn_per_data_t *pd) {
+       const asn_CHOICE_specifics_t *specs = (const asn_CHOICE_specifics_t *)td->specifics;
+       asn_dec_rval_t rv;
+       const asn_per_constraint_t *ct;
+       const asn_per_constraint_t *ext_ct = NULL;
+       asn_TYPE_member_t *elm; /* CHOICE's element */
+       void *memb_ptr;
+       void **memb_ptr2;
+       void *st = *sptr;
+       int value;
+
+       if(ASN__STACK_OVERFLOW_CHECK(opt_codec_ctx))
+               ASN__DECODE_FAILED;
+
+       /*
+        * Create the target structure if it is not present already.
+        */
+       if(!st) {
+               st = *sptr = CALLOC(1, specs->struct_size);
+               if(!st) ASN__DECODE_FAILED;
+       }
+
+       if(constraints) ct = &constraints->value;
+       else if(td->encoding_constraints.per_constraints)
+               ct = &td->encoding_constraints.per_constraints->value;
+       else ct = 0;
+
+       if(ct && ct->flags & APC_EXTENSIBLE) {
+               value = per_get_few_bits(pd, 1);
+               if(value < 0) ASN__DECODE_STARVED;
+               if(value) {
+                 ext_ct = ct;
+                 ct = 0;       /* Not restricted */
+               }
+       }
+
+
+       if(ct && ct->range_bits >= 0) {
+               value = per_get_few_bits(pd, ct->range_bits);
+               if(value < 0) ASN__DECODE_STARVED;
+               ASN_DEBUG("CHOICE %s got index %d in range %d",
+                         td->name, value, ct->range_bits);
+               if(value > ct->upper_bound)
+                       ASN__DECODE_FAILED;
+       } else {
+               if(specs->ext_start == -1)
+                       ASN__DECODE_FAILED;
+               value = aper_get_nsnnwn(pd, ext_ct->range_bits);
+               if(value < 0) ASN__DECODE_STARVED;
+               value += specs->ext_start;
+               if((unsigned)value >= td->elements_count)
+                       ASN__DECODE_FAILED;
+       }
+
+       /* Adjust if canonical order is different from natural order */
+       if(specs->from_canonical_order)
+               value = specs->from_canonical_order[value];
+
+       /* Set presence to be able to free it later */
+       _set_present_idx(st, specs->pres_offset, specs->pres_size, value + 1);
+
+       elm = &td->elements[value];
+       if(elm->flags & ATF_POINTER) {
+               /* Member is a pointer to another structure */
+               memb_ptr2 = (void **)((char *)st + elm->memb_offset);
+       } else {
+               memb_ptr = (char *)st + elm->memb_offset;
+               memb_ptr2 = &memb_ptr;
+       }
+       ASN_DEBUG("Discovered CHOICE %s encodes %s", td->name, elm->name);
+
+       if(ct && ct->range_bits >= 0) {
+               rv = elm->type->op->aper_decoder(opt_codec_ctx, elm->type,
+                                                elm->encoding_constraints.per_constraints, memb_ptr2, pd);
+       } else {
+               rv = aper_open_type_get(opt_codec_ctx, elm->type,
+                                       elm->encoding_constraints.per_constraints, memb_ptr2, pd);
+       }
+
+       if(rv.code != RC_OK)
+               ASN_DEBUG("Failed to decode %s in %s (CHOICE) %d",
+                         elm->name, td->name, rv.code);
+       return rv;
+}
+
+asn_enc_rval_t
+CHOICE_encode_aper(const asn_TYPE_descriptor_t *td,
+                   const asn_per_constraints_t *constraints,
+                   const void *sptr, asn_per_outp_t *po) {
+       const asn_CHOICE_specifics_t *specs = (const asn_CHOICE_specifics_t *)td->specifics;
+       const asn_TYPE_member_t *elm; /* CHOICE's element */
+       const asn_per_constraint_t *ct = NULL;
+       const asn_per_constraint_t *ext_ct = NULL;
+       const void *memb_ptr;
+       unsigned present;
+       int present_enc;
+       
+       if(!sptr) ASN__ENCODE_FAILED;
+
+       ASN_DEBUG("Encoding %s as CHOICE using ALIGNED PER", td->name);
+
+       if(constraints) ct = &constraints->value;
+       else if(td->encoding_constraints.per_constraints)
+               ct = &td->encoding_constraints.per_constraints->value;
+       else ct = NULL;
+
+       present = _fetch_present_idx(sptr,
+                                    specs->pres_offset, specs->pres_size);
+
+       /*
+        * If the structure was not initialized properly, it cannot be encoded:
+        * can't deduce what to encode in the choice type.
+        */
+       if(present <= 0 || (unsigned)present > td->elements_count)
+               ASN__ENCODE_FAILED;
+       else
+               present--;
+
+       /* Adjust if canonical order is different from natural order */
+       if(specs->to_canonical_order)
+               present_enc = specs->to_canonical_order[present];
+       else
+               present_enc = present;
+       
+       ASN_DEBUG("Encoding %s CHOICE element %d", td->name, present);
+
+       if(ct && (ct->range_bits >= 0)) {
+         // Value is not within the range of the primary values ?
+         if(present < ct->lower_bound || present > ct->upper_bound) {
+           if(ct->flags & APC_EXTENSIBLE) {
+             ASN_DEBUG("CHOICE member %d (enc %d) is an extension (%ld..%ld)",
+                       present, present_enc, ct->lower_bound, ct->upper_bound);
+             // X691/23.5 Extension marker = 1 
+             if(per_put_few_bits(po, 1, 1)) {
+               ASN__ENCODE_FAILED;
+             }
+           } else {
+             ASN__ENCODE_FAILED;
+           }
+           // no more need of constraint.
+           ext_ct = ct;
+           ct = NULL;
+         }
+       }
+       
+       if(ct && (ct->flags & APC_EXTENSIBLE)) {
+         ASN_DEBUG("CHOICE member %d (enc %d) is not an extension (%ld..%ld)",
+                   present, present, ct->lower_bound, ct->upper_bound);
+         // X691.23.5 Extension marker = 0
+         if(per_put_few_bits(po, 0, 1)) {
+           ASN__ENCODE_FAILED;
+         }
+       }
+
+       elm = &td->elements[present];
+       if(elm->flags & ATF_POINTER) {
+               /* Member is a pointer to another structure */
+               memb_ptr = *(const void *const *)((const char *)sptr + elm->memb_offset);
+               if(!memb_ptr) ASN__ENCODE_FAILED;
+       } else {
+               memb_ptr = (const char *)sptr + elm->memb_offset;
+       }
+
+       if(ct && (ct->range_bits >= 0)) {
+               // By construction (ct != 0), the alternative value is a non extended one.
+               // X691/23.7 X691/23.6 alternative value encoded as a range_bits bits value.
+               if(per_put_few_bits(po, present_enc, ct->range_bits))
+                       ASN__ENCODE_FAILED;
+
+               return elm->type->op->aper_encoder(elm->type, elm->encoding_constraints.per_constraints,
+                                                  memb_ptr, po);
+       } else {
+               asn_enc_rval_t rval = {0,0,0};
+               if(specs->ext_start == -1)
+                       ASN__ENCODE_FAILED;
+               // X691/23.8 normally encoded as a small non negative whole number
+               
+               if(ext_ct && aper_put_nsnnwn(po, ext_ct->range_bits, present_enc - specs->ext_start))
+                       ASN__ENCODE_FAILED;
+               if(aper_open_type_put(elm->type, elm->encoding_constraints.per_constraints,
+                                     memb_ptr, po))
+                       ASN__ENCODE_FAILED;
+               rval.encoded = 0;
+               ASN__ENCODED_OK(rval);
+       }
+}
+
+int
+CHOICE_print(const asn_TYPE_descriptor_t *td, const void *sptr, int ilevel,
+             asn_app_consume_bytes_f *cb, void *app_key) {
+    const asn_CHOICE_specifics_t *specs = (const asn_CHOICE_specifics_t *)td->specifics;
+       unsigned present;
+
+       if(!sptr) return (cb("<absent>", 8, app_key) < 0) ? -1 : 0;
+
+       /*
+        * Figure out which CHOICE element is encoded.
+        */
+       present = _fetch_present_idx(sptr, specs->pres_offset,specs->pres_size);
+
+       /*
+        * Print that element.
+        */
+       if(present > 0 && present <= td->elements_count) {
+               asn_TYPE_member_t *elm = &td->elements[present-1];
+               const void *memb_ptr;
+
+               if(elm->flags & ATF_POINTER) {
+                       memb_ptr = *(const void * const *)((const char *)sptr + elm->memb_offset);
+                       if(!memb_ptr) return (cb("<absent>", 8, app_key) < 0) ? -1 : 0;
+               } else {
+                       memb_ptr = (const void *)((const char *)sptr + elm->memb_offset);
+               }
+
+               /* Print member's name and stuff */
+               if(0) {
+                       if(cb(elm->name, strlen(elm->name), app_key) < 0
+                       || cb(": ", 2, app_key) < 0)
+                               return -1;
+               }
+
+               return elm->type->op->print_struct(elm->type, memb_ptr, ilevel,
+                       cb, app_key);
+       } else {
+               return (cb("<absent>", 8, app_key) < 0) ? -1 : 0;
+       }
+}
+
+void
+CHOICE_free(const asn_TYPE_descriptor_t *td, void *ptr,
+            enum asn_struct_free_method method) {
+    const asn_CHOICE_specifics_t *specs =
+        (const asn_CHOICE_specifics_t *)td->specifics;
+    unsigned present;
+
+       if(!td || !ptr)
+               return;
+
+       ASN_DEBUG("Freeing %s as CHOICE", td->name);
+
+       /*
+        * Figure out which CHOICE element is encoded.
+        */
+       present = _fetch_present_idx(ptr, specs->pres_offset, specs->pres_size);
+
+       /*
+        * Free that element.
+        */
+       if(present > 0 && present <= td->elements_count) {
+               asn_TYPE_member_t *elm = &td->elements[present-1];
+               void *memb_ptr;
+
+               if(elm->flags & ATF_POINTER) {
+                       memb_ptr = *(void **)((char *)ptr + elm->memb_offset);
+                       if(memb_ptr)
+                               ASN_STRUCT_FREE(*elm->type, memb_ptr);
+               } else {
+                       memb_ptr = (void *)((char *)ptr + elm->memb_offset);
+                       ASN_STRUCT_FREE_CONTENTS_ONLY(*elm->type, memb_ptr);
+               }
+       }
+
+    switch(method) {
+    case ASFM_FREE_EVERYTHING:
+        FREEMEM(ptr);
+        break;
+    case ASFM_FREE_UNDERLYING:
+        break;
+    case ASFM_FREE_UNDERLYING_AND_RESET:
+        memset(ptr, 0, specs->struct_size);
+        break;
+    }
+}
+
+
+/*
+ * The following functions functions offer protection against -fshort-enums,
+ * compatible with little- and big-endian machines.
+ * If assertion is triggered, either disable -fshort-enums, or add an entry
+ * here with the ->pres_size of your target stracture.
+ * Unless the target structure is packed, the ".present" member
+ * is guaranteed to be aligned properly. ASN.1 compiler itself does not
+ * produce packed code.
+ */
+static unsigned
+_fetch_present_idx(const void *struct_ptr, unsigned pres_offset,
+                   unsigned pres_size) {
+    const void *present_ptr;
+       unsigned present;
+
+       present_ptr = ((const char *)struct_ptr) + pres_offset;
+
+       switch(pres_size) {
+       case sizeof(int):       present = *(const unsigned int *)present_ptr; break;
+       case sizeof(short):     present = *(const unsigned short *)present_ptr; break;
+       case sizeof(char):      present = *(const unsigned char *)present_ptr; break;
+       default:
+               /* ANSI C mandates enum to be equivalent to integer */
+               assert(pres_size != sizeof(int));
+               return 0;       /* If not aborted, pass back safe value */
+       }
+
+       return present;
+}
+
+static void
+_set_present_idx(void *struct_ptr, unsigned pres_offset, unsigned pres_size,
+                 unsigned present) {
+    void *present_ptr;
+       present_ptr = ((char *)struct_ptr) + pres_offset;
+
+       switch(pres_size) {
+       case sizeof(int):       *(unsigned int *)present_ptr   = present; break;
+       case sizeof(short):     *(unsigned short *)present_ptr = present; break;
+       case sizeof(char):      *(unsigned char *)present_ptr  = present; break;
+       default:
+               /* ANSI C mandates enum to be equivalent to integer */
+               assert(pres_size != sizeof(int));
+       }
+}
+
+static const void *
+_get_member_ptr(const asn_TYPE_descriptor_t *td, const void *sptr,
+                asn_TYPE_member_t **elm_ptr, unsigned *present_out) {
+    const asn_CHOICE_specifics_t *specs =
+        (const asn_CHOICE_specifics_t *)td->specifics;
+    unsigned present;
+
+    if(!sptr) {
+        *elm_ptr = NULL;
+        *present_out = 0;
+        return NULL;
+    }
+
+    /*
+        * Figure out which CHOICE element is encoded.
+        */
+       present = _fetch_present_idx(sptr, specs->pres_offset, specs->pres_size);
+    *present_out = present;
+
+    /*
+     * The presence index is intentionally 1-based to avoid
+     * treating zeroed structure as a valid one.
+     */
+       if(present > 0 && present <= td->elements_count) {
+        asn_TYPE_member_t *const elm = &td->elements[present - 1];
+        const void *memb_ptr;
+
+               if(elm->flags & ATF_POINTER) {
+            memb_ptr =
+                *(const void *const *)((const char *)sptr + elm->memb_offset);
+        } else {
+            memb_ptr = (const void *)((const char *)sptr + elm->memb_offset);
+        }
+        *elm_ptr = elm;
+        return memb_ptr;
+    } else {
+        *elm_ptr = NULL;
+        return NULL;
+    }
+
+}
+
+int
+CHOICE_compare(const asn_TYPE_descriptor_t *td, const void *aptr, const void *bptr) {
+    asn_TYPE_member_t *aelm;
+    asn_TYPE_member_t *belm;
+    unsigned apresent = 0;
+    unsigned bpresent = 0;
+    const void *amember = _get_member_ptr(td, aptr, &aelm, &apresent);
+    const void *bmember = _get_member_ptr(td, bptr, &belm, &bpresent);
+
+    if(amember && bmember) {
+        if(apresent == bpresent) {
+            assert(aelm == belm);
+            return aelm->type->op->compare_struct(aelm->type, amember, bmember);
+        } else if(apresent < bpresent) {
+            return -1;
+        } else {
+            return 1;
+        }
+    } else if(!amember) {
+        return -1;
+    } else {
+        return 1;
+    }
+}
+
+/*
+ * Return the 1-based choice variant presence index.
+ * Returns 0 in case of error.
+ */
+unsigned
+CHOICE_variant_get_presence(const asn_TYPE_descriptor_t *td, const void *sptr) {
+    const asn_CHOICE_specifics_t *specs =
+        (const asn_CHOICE_specifics_t *)td->specifics;
+    return _fetch_present_idx(sptr, specs->pres_offset, specs->pres_size);
+}
+
+/*
+ * Sets or resets the 1-based choice variant presence index.
+ * In case a previous index is not zero, the currently selected structure
+ * member is freed and zeroed-out first.
+ * Returns 0 on success and -1 on error.
+ */
+int
+CHOICE_variant_set_presence(const asn_TYPE_descriptor_t *td, void *sptr,
+                            unsigned present) {
+    const asn_CHOICE_specifics_t *specs =
+        (const asn_CHOICE_specifics_t *)td->specifics;
+    unsigned old_present;
+
+    if(!sptr) {
+        return -1;
+    }
+
+    if(present > td->elements_count)
+        return -1;
+
+    old_present =
+        _fetch_present_idx(sptr, specs->pres_offset, specs->pres_size);
+    if(present == old_present)
+        return 0;
+
+    if(old_present != 0) {
+        assert(old_present <= td->elements_count);
+        ASN_STRUCT_RESET(*td, sptr);
+    }
+
+    _set_present_idx(sptr, specs->pres_offset, specs->pres_size, present);
+
+    return 0;
+}
+
+
+asn_random_fill_result_t
+CHOICE_random_fill(const asn_TYPE_descriptor_t *td, void **sptr,
+                   const asn_encoding_constraints_t *constr,
+                   size_t max_length) {
+    const asn_CHOICE_specifics_t *specs =
+        (const asn_CHOICE_specifics_t *)td->specifics;
+    asn_random_fill_result_t res;
+    asn_random_fill_result_t result_failed = {ARFILL_FAILED, 0};
+    asn_random_fill_result_t result_skipped = {ARFILL_SKIPPED, 0};
+    const asn_TYPE_member_t *elm;
+    unsigned present;
+    void *memb_ptr;   /* Pointer to the member */
+    void **memb_ptr2; /* Pointer to that pointer */
+    void *st = *sptr;
+
+    if(max_length == 0) return result_skipped;
+
+    (void)constr;
+
+    if(st == NULL) {
+        st = CALLOC(1, specs->struct_size);
+        if(st == NULL) {
+            return result_failed;
+        }
+    }
+
+    present = asn_random_between(1, td->elements_count);
+    elm = &td->elements[present - 1];
+
+       if(elm->flags & ATF_POINTER) {
+               /* Member is a pointer to another structure */
+               memb_ptr2 = (void **)((char *)st + elm->memb_offset);
+       } else {
+               memb_ptr = (char *)st + elm->memb_offset;
+               memb_ptr2 = &memb_ptr;
+       }
+
+    res = elm->type->op->random_fill(elm->type, memb_ptr2,
+                                    &elm->encoding_constraints, max_length);
+    _set_present_idx(st, specs->pres_offset, specs->pres_size, present);
+    if(res.code == ARFILL_OK) {
+        *sptr = st;
+    } else {
+        if(st == *sptr) {
+            ASN_STRUCT_RESET(*td, st);
+        } else {
+            ASN_STRUCT_FREE(*td, st);
+        }
+    }
+
+    return res;
+}
+
+
+asn_TYPE_operation_t asn_OP_CHOICE = {
+       CHOICE_free,
+       CHOICE_print,
+       CHOICE_compare,
+       CHOICE_decode_ber,
+       CHOICE_encode_der,
+       CHOICE_decode_xer,
+       CHOICE_encode_xer,
+#ifdef ASN_DISABLE_OER_SUPPORT
+       0,
+       0,
+#else
+       CHOICE_decode_oer,
+       CHOICE_encode_oer,
+#endif  /* ASN_DISABLE_OER_SUPPORT */
+#ifdef ASN_DISABLE_PER_SUPPORT
+       0,
+       0,
+       0,
+       0,
+#else
+       CHOICE_decode_uper,
+       CHOICE_encode_uper,
+       CHOICE_decode_aper,
+       CHOICE_encode_aper,
+#endif /* ASN_DISABLE_PER_SUPPORT */
+       CHOICE_random_fill,
+       CHOICE_outmost_tag
+};