--- /dev/null
+/*
+ * Copyright (c) 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>
+
+/*
+ * 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)
+
+/*
+ * 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) {
+ /* ?Subtracted 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;
+}
Code Review / sim / e2-interface.git / blobdiff