Keep vanetza-idf in obu-firmware, so a plain clone builds the firmware

obu-firmware builds against the vanetza-idf C-ITS library, which until now
came from the colleague's microbu-esp32c5 tree beside the repository and was
not tracked here, so a clone of this repository could not build the firmware
it ships. The library alone is now part of obu-firmware, as
obu-firmware/external/vanetza-idf: their external/vanetza-idf at commit
cf4b99f, unchanged (9775 files; see its PROVENANCE.md). CMake takes it from
there by default; -DVANETZA_IDF_DIR still points the build elsewhere.

The rest of the colleague's tree (their own VAM firmware, PKI tooling,
station-link Python tools, the V2X2MAP bridge) stays out of this repository
and gitignored; nothing is pushed to their repository. NOTES.md, docs/06,
TODO.md and the pcap verifier's usage line point at the new location.

obu-firmware/external/vanetza-idf/vanetza/asn1/support/BMPString_xer.c

@@ -0,0 +1,93 @@
+/*
+ * 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 "BMPString.h"
+#include "UTF8String.h"
+
+asn_dec_rval_t
+BMPString_decode_xer(const asn_codec_ctx_t *opt_codec_ctx,
+                     const asn_TYPE_descriptor_t *td, void **sptr,
+                     const char *opt_mname, const void *buf_ptr, size_t size) {
+    asn_dec_rval_t rc;
+
+    rc = OCTET_STRING_decode_xer_utf8(opt_codec_ctx, td, sptr, opt_mname,
+        buf_ptr, size);
+    if(rc.code == RC_OK) {
+        /*
+         * Now we have a whole string in UTF-8 format.
+         * Convert it into UCS-2.
+         */
+        uint32_t *wcs;
+        size_t wcs_len;
+        UTF8String_t *st;
+
+        assert(*sptr);
+        st = (UTF8String_t *)*sptr;
+        assert(st->buf);
+        wcs_len = UTF8String_to_wcs(st, 0, 0);
+
+        wcs = (uint32_t *)MALLOC(4 * (wcs_len + 1));
+        if(wcs == 0 || UTF8String_to_wcs(st, wcs, wcs_len) != wcs_len) {
+            rc.code = RC_FAIL;
+            rc.consumed = 0;
+            return rc;
+        } else {
+            wcs[wcs_len] = 0;  /* nul-terminate */
+        }
+
+        if(1) {
+            /* Swap byte order and trim encoding to 2 bytes */
+            uint32_t *wc = wcs;
+            uint32_t *wc_end = wcs + wcs_len;
+            uint16_t *dstwc = (uint16_t *)wcs;
+            for(; wc < wc_end; wc++, dstwc++) {
+                uint32_t wch = *wc;
+                if(wch > 0xffff) {
+                    FREEMEM(wcs);
+                    rc.code = RC_FAIL;
+                    rc.consumed = 0;
+                    return rc;
+                }
+                *((uint8_t *)dstwc + 0) = wch >> 8;
+                *((uint8_t *)dstwc + 1) = wch;
+            }
+            dstwc = (uint16_t *)REALLOC(wcs, 2 * (wcs_len + 1));
+            if(!dstwc) {
+                FREEMEM(wcs);
+                rc.code = RC_FAIL;
+                rc.consumed = 0;
+                return rc;
+            } else {
+                dstwc[wcs_len] = 0;  /* nul-terminate */
+                wcs = (uint32_t *)(void *)dstwc;  /* Alignment OK */
+            }
+        }
+
+        FREEMEM(st->buf);
+        st->buf = (uint8_t *)wcs;
+        st->size = 2 * wcs_len;
+    }
+    return rc;
+}
+
+asn_enc_rval_t
+BMPString_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 BMPString_t *st = (const BMPString_t *)sptr;
+    asn_enc_rval_t er = {0,0,0};
+
+    (void)ilevel;
+    (void)flags;
+
+    if(!st || !st->buf)
+        ASN__ENCODE_FAILED;
+
+    er.encoded = BMPString__dump(st, cb, app_key);
+    if(er.encoded < 0) ASN__ENCODE_FAILED;
+
+    ASN__ENCODED_OK(er);
+}