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#include "asn1.h"
#include <string.h>
/*
** ASN.1 Encoding
*/
int _enc_null (__u8 *dest, int tag)
{
dest[0] = tag;
dest[1] = 0;
return 2;
}
int _enc_bool (__u8 *dest, __u32 i, int tag)
{
dest[0] = tag;
dest[1] = 1;
dest[2] = i ? 1:0;
return 3;
}
int _enc_int (__u8 *dest, __u32 i, int tag)
{
__u8 *p;
dest[0] = tag;
p = &dest[2];
do {
*p++ = i;
i >>= 8;
} while (i);
dest[1] = p - &dest[2];
return p - dest;
}
int _enc_enum (__u8 *dest, __u32 i, int tag)
{
__u8 *p;
dest[0] = tag;
p = &dest[2];
do {
*p++ = i;
i >>= 8;
} while (i);
dest[1] = p - &dest[2];
return p - dest;
}
int _enc_num_string (__u8 *dest, char *nd, __u8 len, int tag)
{
__u8 *p;
int i;
dest[0] = tag;
p = &dest[2];
for (i = 0; i < len; i++)
*p++ = *nd++;
dest[1] = p - &dest[2];
return p - dest;
}
int _enc_sequence_start (__u8 *dest, __u8 **id, int tag)
{
dest[0] = tag;
*id = &dest[1];
return 2;
}
int _enc_sequence_end (__u8 *dest, __u8 *id, int tag_dummy)
{
*id = dest - id - 1;
return 0;
}
/*
** ASN.1 Decoding
*/
#define CHECK_P \
do { \
if (p >= end) \
return -1; \
} while (0)
#define CallASN1(ret, p, end, todo) \
do { \
ret = todo; \
if (ret < 0) { \
return -1; \
} \
p += ret; \
} while (0)
#define INIT \
int len, ret; \
__u8 *begin = p; \
if (tag) \
*tag = *p; \
p++; \
CallASN1(ret, p, end, dec_len(p, &len)); \
if (len >= 0) { \
if (p + len > end) \
return -1; \
end = p + len; \
}
int _dec_null (__u8 *p, __u8 *end, int *tag)
{
INIT;
return p - begin;
}
int _dec_bool (__u8 *p, __u8 *end, int *i, int *tag)
{
INIT;
*i = 0;
while (len--) {
CHECK_P;
*i = (*i >> 8) + *p;
p++;
}
return p - begin;
}
int _dec_int (__u8 *p, __u8 *end, int *i, int *tag)
{
INIT;
*i = 0;
while (len--) {
CHECK_P;
*i = (*i << 8) + *p;
p++;
}
return p - begin;
}
int _dec_enum (__u8 *p, __u8 *end, int *i, int *tag)
{
INIT;
*i = 0;
while (len--) {
CHECK_P;
*i = (*i << 8) + *p;
p++;
}
return p - begin;
}
int _dec_num_string (__u8 *p, __u8 *end, char *str, int *tag)
{
INIT;
while (len--) {
CHECK_P;
*str++ = *p;
p++;
}
*str = 0;
return p - begin;
}
int _dec_octet_string (__u8 *p, __u8 *end, char *str, int *tag)
{
return _dec_num_string(p, end, str, tag);
}
int _dec_sequence (__u8 *p, __u8 *end, int *tag)
{
INIT;
return p - begin;
}
int dec_len (__u8 *p, int *len)
{
*len = *p;
return 1;
}
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