73 lines
2.1 KiB
C
73 lines
2.1 KiB
C
|
/*
|
||
|
|
* 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;
|
||
|
|
}
|