SIM-115: update simulator to use latest E2SM KPM version 3

[sim/e2-interface.git] / e2sim / asn1c / INTEGER_ber.c

diff --git a/e2sim/asn1c/INTEGER_ber.c b/e2sim/asn1c/INTEGER_ber.c
new file mode 100644 (file)
index 0000000..57bfe1e
--- /dev/null
+++ b/e2sim/asn1c/INTEGER_ber.c
@@ -0,0 +1,72 @@
+/*
+ * 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 <INTEGER.h>
+
+/*
+ * Encode INTEGER type using DER.
+ */
+asn_enc_rval_t
+INTEGER_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 INTEGER_t *st = (const INTEGER_t *)sptr;
+    asn_enc_rval_t rval;
+    INTEGER_t effective_integer;
+
+    ASN_DEBUG("%s %s as INTEGER (tm=%d)",
+              cb?"Encoding":"Estimating", td->name, tag_mode);
+
+    /*
+     * Canonicalize integer in the buffer.
+     * (Remove too long sign extension, remove some first 0x00 bytes)
+     */
+    if(st->buf) {
+        uint8_t *buf = st->buf;
+        uint8_t *end1 = buf + st->size - 1;
+        int shift;
+
+        /* Compute the number of superfluous leading bytes */
+        for(; buf < end1; buf++) {
+            /*
+             * If the contents octets of an integer value encoding
+             * consist of more than one octet, then the bits of the
+             * first octet and bit 8 of the second octet:
+             * a) shall not all be ones; and
+             * b) shall not all be zero.
+             */
+            switch(*buf) {
+            case 0x00: 
+               if((buf[1] & 0x80) == 0) continue;
+                break;
+            case 0xff: 
+               if((buf[1] & 0x80)) continue;
+                break;
+            }
+            break;
+        }
+
+        /* Remove leading superfluous bytes from the integer */
+        shift = buf - st->buf;
+        if(shift) {
+            union {
+                const uint8_t *c_buf;
+                uint8_t *nc_buf;
+            } unconst;
+            unconst.c_buf = st->buf;
+            effective_integer.buf = unconst.nc_buf + shift;
+            effective_integer.size = st->size - shift;
+
+            st = &effective_integer;
+        }
+    }
+
+    rval = der_encode_primitive(td, st, tag_mode, tag, cb, app_key);
+    if(rval.structure_ptr == &effective_integer) {
+        rval.structure_ptr = sptr;
+    }
+    return rval;
+}