Initial revision
git-svn-id: https://asn1c.svn.sourceforge.net/svnroot/asn1c/trunk@2 59561ff5-6e30-0410-9f3c-9617f08c8826
diff --git a/skeletons/ber_tlv_length.c b/skeletons/ber_tlv_length.c
new file mode 100644
index 0000000..cd08f6a
--- /dev/null
+++ b/skeletons/ber_tlv_length.c
@@ -0,0 +1,159 @@
+/*-
+ * Copyright (c) 2003, 2004 Lev Walkin <vlm@lionet.info>. All rights reserved.
+ * Redistribution and modifications are permitted subject to BSD license.
+ */
+#include <constr_TYPE.h>
+#include <ber_tlv_length.h>
+#include <ber_tlv_tag.h>
+
+ssize_t
+ber_fetch_length(int _is_constructed, void *bufptr, size_t size,
+ ber_tlv_len_t *len_r) {
+ uint8_t *buf = bufptr;
+ unsigned oct;
+
+ if(size == 0)
+ return 0; /* Want more */
+
+ oct = *(uint8_t *)buf;
+ if((oct & 0x80) == 0) {
+ /*
+ * Short definite length.
+ */
+ *len_r = (oct & 0x7F);
+ return 1;
+ } else {
+ ber_tlv_len_t len;
+ ssize_t skipped;
+
+ if(_is_constructed && oct == 0x80) {
+ *len_r = -1; /* Indefinite length */
+ return 1;
+ }
+
+ if(oct == 0xff) {
+ /* Reserved in standard for future use. */
+ return -1;
+ }
+
+ oct &= 0x7F; /* Leave only the 7 LS bits */
+ for(len = 0, buf++, skipped = 1;
+ oct && (++skipped < size); buf++, oct--) {
+
+ len = (len << 8) | *buf;
+ if(len < 0
+ || (len >> ((8 * sizeof(len)) - 8) && oct > 1)) {
+ /*
+ * Too large length value.
+ */
+ return -1;
+ }
+ }
+
+ if(oct == 0) {
+ *len_r = len;
+ return skipped;
+ }
+
+ return 0; /* Want more */
+ }
+
+}
+
+ssize_t
+ber_skip_length(int _is_constructed, void *ptr, size_t size) {
+ ber_tlv_len_t vlen; /* Length of V in TLV */
+ ssize_t tl; /* Length of L in TLV */
+ ssize_t ll; /* Length of L in TLV */
+ ssize_t skip;
+
+ /*
+ * Determine the size of L in TLV.
+ */
+ ll = ber_fetch_length(_is_constructed, ptr, size, &vlen);
+ if(ll <= 0) return ll;
+
+ /*
+ * Definite length.
+ */
+ if(vlen >= 0) {
+ skip = ll + vlen;
+ if(skip > size)
+ return 0; /* Want more */
+ return skip;
+ }
+
+ /*
+ * Indefinite length!
+ */
+ ASN_DEBUG("Skipping indefinite length");
+ for(skip = ll, ptr += ll, size -= ll;;) {
+ ber_tlv_tag_t tag;
+
+ /* Fetch the tag */
+ tl = ber_fetch_tag(ptr, size, &tag);
+ if(tl <= 0) return tl;
+
+ ll = ber_skip_length(BER_TLV_CONSTRUCTED(ptr),
+ ptr + tl, size - tl);
+ if(ll <= 0) return ll;
+
+ skip += tl + ll;
+
+ /*
+ * This may be the end of the indefinite length structure,
+ * two consecutive 0 octets.
+ * Check if it is true.
+ */
+ if(((uint8_t *)ptr)[0] == 0
+ && ((uint8_t *)ptr)[1] == 0)
+ return skip;
+
+ ptr += tl + ll;
+ size -= tl + ll;
+ }
+
+ /* UNREACHABLE */
+}
+
+ssize_t
+der_tlv_length_serialize(ber_tlv_len_t len, void *bufp, size_t size) {
+ ssize_t computed_size; /* Size of len encoding */
+ uint8_t *buf = bufp;
+ uint8_t *end;
+ int i;
+
+ if(len <= 127) {
+ /* Encoded in 1 octet */
+ if(size) *buf = len;
+ return 1;
+ }
+
+ /*
+ * Compute the size of the subsequent bytes.
+ */
+ computed_size = sizeof(len); /* assert(sizeof(len)<128), n.p. */
+ for(i = (8*(sizeof(len)-1)); i > 0; i -= 8) {
+ if((len >> i) & 0xFF) break;
+ computed_size--;
+ }
+
+ if(size) {
+ *buf++ = 0x80 | computed_size; /* Length of the encoding */
+ size--;
+ }
+
+ /*
+ * Produce the len encoding, space permitting.
+ */
+ if(size > computed_size)
+ end = buf + computed_size;
+ else
+ end = buf + size;
+ for((void)i /* Reuse bits count */; buf < end; i -= 8, buf++) {
+ *buf = (len >> i) & 0xFF;
+ }
+
+ return computed_size + 1;
+}
+