+/*
+ * 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 <asn_codecs_prim.h>
+
+/*
+ * The OER decoder of any type.
+ */
+asn_dec_rval_t
+oer_decode(const asn_codec_ctx_t *opt_codec_ctx,
+ const asn_TYPE_descriptor_t *type_descriptor, void **struct_ptr,
+ const void *ptr, size_t size) {
+ asn_codec_ctx_t s_codec_ctx;
+
+ /*
+ * Stack checker requires that the codec context
+ * must be allocated on the stack.
+ */
+ if(opt_codec_ctx) {
+ if(opt_codec_ctx->max_stack_size) {
+ s_codec_ctx = *opt_codec_ctx;
+ opt_codec_ctx = &s_codec_ctx;
+ }
+ } else {
+ /* If context is not given, be security-conscious anyway */
+ memset(&s_codec_ctx, 0, sizeof(s_codec_ctx));
+ s_codec_ctx.max_stack_size = ASN__DEFAULT_STACK_MAX;
+ opt_codec_ctx = &s_codec_ctx;
+ }
+
+ /*
+ * Invoke type-specific decoder.
+ */
+ return type_descriptor->op->oer_decoder(opt_codec_ctx, type_descriptor, 0,
+ struct_ptr, /* Pointer to the destination structure */
+ ptr, size /* Buffer and its size */
+ );
+}
+
+/*
+ * Open Type is encoded as a length (#8.6) followed by that number of bytes.
+ * Since we're just skipping, reading the length would be enough.
+ */
+ssize_t
+oer_open_type_skip(const void *bufptr, size_t size) {
+ size_t len = 0;
+ return oer_fetch_length(bufptr, size, &len);
+}
+
+/*
+ * Read the Open Type (X.696 (08/2015), #30).
+ * RETURN VALUES:
+ * 0: More data expected than bufptr contains.
+ * -1: Fatal error deciphering length.
+ * >0: Number of bytes used from bufptr.
+ */
+ssize_t
+oer_open_type_get(const asn_codec_ctx_t *opt_codec_ctx,
+ const struct asn_TYPE_descriptor_s *td,
+ const asn_oer_constraints_t *constraints, void **struct_ptr,
+ const void *bufptr, size_t size) {
+ asn_dec_rval_t dr;
+ size_t container_len = 0;
+ ssize_t len_len;
+ enum asn_struct_free_method dispose_method =
+ (*struct_ptr) ? ASFM_FREE_UNDERLYING_AND_RESET : ASFM_FREE_EVERYTHING;
+
+ /* Get the size of a length determinant */
+ len_len = oer_fetch_length(bufptr, size, &container_len);
+ if(len_len <= 0) {
+ return len_len; /* Error or more data expected */
+ }
+
+ /*
+ * len_len can't be bigger than size, but size without len_len
+ * should be bigger or equal to container length
+ */
+ if(size - len_len < container_len) {
+ /* More data is expected */
+ return 0;
+ }
+
+ dr = td->op->oer_decoder(opt_codec_ctx, td, constraints, struct_ptr,
+ (const uint8_t *)bufptr + len_len, container_len);
+ if(dr.code == RC_OK) {
+ return len_len + container_len;
+ } else {
+ /* Even if RC_WMORE, we can't get more data into a closed container. */
+ td->op->free_struct(td, *struct_ptr, dispose_method);
+ *struct_ptr = NULL;
+ return -1;
+ }
+}
+
+
+asn_dec_rval_t
+oer_decode_primitive(const asn_codec_ctx_t *opt_codec_ctx,
+ const asn_TYPE_descriptor_t *td,
+ const asn_oer_constraints_t *constraints, void **sptr,
+ const void *ptr, size_t size) {
+ ASN__PRIMITIVE_TYPE_t *st = (ASN__PRIMITIVE_TYPE_t *)*sptr;
+ asn_dec_rval_t rval = {RC_OK, 0};
+ size_t expected_length = 0;
+ ssize_t len_len;
+
+ (void)td;
+ (void)opt_codec_ctx;
+ (void)constraints;
+
+ if(!st) {
+ st = (ASN__PRIMITIVE_TYPE_t *)(*sptr = CALLOC(
+ 1, sizeof(ASN__PRIMITIVE_TYPE_t)));
+ if(!st) ASN__DECODE_FAILED;
+ }
+
+
+ /*
+ * X.696 (08/2015) #27.2
+ * Encode length determinant as _number of octets_, but only
+ * if upper bound is not equal to lower bound.
+ */
+ len_len = oer_fetch_length(ptr, size, &expected_length);
+ if(len_len > 0) {
+ rval.consumed = len_len;
+ ptr = (const char *)ptr + len_len;
+ size -= len_len;
+ } else if(len_len == 0) {
+ ASN__DECODE_STARVED;
+ } else if(len_len < 0) {
+ ASN__DECODE_FAILED;
+ }
+
+ if(size < expected_length) {
+ ASN__DECODE_STARVED;
+ } else {
+ uint8_t *buf = MALLOC(expected_length + 1);
+ if(buf == NULL) {
+ ASN__DECODE_FAILED;
+ } else {
+ memcpy(buf, ptr, expected_length);
+ buf[expected_length] = '\0';
+ }
+ FREEMEM(st->buf);
+ st->buf = buf;
+ st->size = expected_length;
+
+ rval.consumed += expected_length;
+ return rval;
+ }
+}