/********************************************************************/
/*Title:	asn1.c													*/
/*Descr:	ASN.1 Encoding/Decoding Module							*/
/*Author:	Liang Hanxi												*/
/*Create:	2002-1-15												*/
/*Version:															*/
/*Modify: 	2002-10-22												*/
/********************************************************************/


#include	"./include/asn1.h"
#include 	<string.h>
#include 	<ctype.h>
#include 	<stdio.h>

/*@ignore@*/
void AsnEncode(u_char *msg_buf,u_int maxlen,ASN_BUF *asnbuf)
{
	asnbuf->msgbuf=msg_buf;
	memset(msg_buf,0,2);
	asnbuf->msglen=0;
	asnbuf->maxlen=maxlen;
}

void asn_encode(u_char *msg_buf,ASN_BUF *asnbuf)
{
	AsnEncode(msg_buf,256,asnbuf);
}

void asn_encode_v3(u_char *msg_buf,u_int maxlen,ASN_BUF *asnbuf)
{
	AsnEncode(msg_buf,maxlen,asnbuf);
}

int add_tlv(const char *tag_seq,u_int length,u_char *pvalue,u_char tlv_type,ASN_BUF *asnbuf)
{
	return AddTLV(tag_seq,length,pvalue,tlv_type,asnbuf);
}

int AddTLV(const char *tag_seq,u_int length,u_char *pvalue,u_char tlv_type,ASN_BUF *asnbuf)
{
	u_short 	tags[50][2];
	int			level;
	int			rest,swaplen=0,oldlen=0;
	int			ntag,nlen;
	int			addval,temp,i,rtn;				//temp variable
	u_char		flag;							//temp variable
	u_char		*ptlv,*pt,*ptr[50],asn_swap[1024];
	
	if(asnbuf->msglen+length+5>asnbuf->maxlen)
	{
		printf("No room for new tlv.maxlen=%d,msglen=%d,addlen=%d\n",asnbuf->maxlen,asnbuf->msglen,length);
		return -1;
	}
	/*search position for new data--->*/
	level = parse_tags(tag_seq,tags);
	pt = asnbuf->msgbuf;						//start pointer
	rest = asnbuf->msglen % 1024;					//remain length
	for(i = 1; i < level; i++)
	{
		if(tags[i][1] == 0)	//according to tagcode
			rtn = findtlv(pt, tags[i][0], &ptlv, rest);
		else				//according to order
			rtn = findtlv2(pt, tags[i][1], &ptlv, rest);
			
		if(rtn == -1)				//length check error
			return -1;
		else if(rtn == 1)			//not found,create it
		{
			swaplen = asnbuf->msglen - (ptlv - asnbuf->msgbuf);
			if(swaplen > 0)
				memcpy(asn_swap, ptlv, swaplen);
			pt = ptlv;
			while(i < level)
			{
				//printf("create level=%d\n",i);
				ntag = addtagcode(pt, tags[i][0], 0xA0);
				nlen = addlength(pt + ntag, 0);
				ptr[i] = pt + ntag;
				addval = modifylength(ptr, i - 1, ntag + nlen);
				pt += addval;
				asnbuf->msglen += addval;
				i ++;
			}
			rest = 0;
		}
		else					//found,continue
		{
			if((rtn & 0x20) == 0)
				return -1;
			
			ntag=gettagcode(ptlv,&temp,&flag);
			nlen=getlength(ptlv+ntag,&rest);
			ptr[i]=ptlv+ntag;
			pt=ptlv+ntag+nlen;
		}	
	}
	//insert new data
	if(tags[level][1]==0)
	{
		rtn=findtlv(pt,tags[level][0],&ptlv,rest);
		
		if(rtn<0)
			return -1;
		else if(rtn!=1)
		{
			oldlen=0;
			oldlen=gettagcode(ptlv,&temp,&flag);
			oldlen+=getlength(ptlv+oldlen,&temp);
			oldlen+=temp;
		}
		if(swaplen==0)
		{
			swaplen=asnbuf->msglen-(ptlv+oldlen-asnbuf->msgbuf);
			if(swaplen>0)
				memcpy(asn_swap,ptlv+oldlen,swaplen);
		}
		
		ntag=addtagcode(ptlv,tags[level][0],tlv_type);
		nlen=addlength(ptlv+ntag,length);

		memcpy(ptlv+ntag+nlen,pvalue,length);	
		//modify parent's length
		addval=modifylength(ptr,level-1,ntag+nlen+length);
		asnbuf->msglen+=addval;
		ptlv+=addval;
		
	}
	else
	{
		rtn=findtlv2(pt,tags[level][1],&ptlv,rest);
		if(rtn<0)
			return -1;
		if(swaplen==0)
		{
			swaplen=asnbuf->msglen-(ptlv-asnbuf->msgbuf);
			if(swaplen>0)
				memcpy(asn_swap,ptlv,swaplen);
			
		}
		ntag=addtagcode(ptlv,tags[level][0],tlv_type);
		nlen=addlength(ptlv+ntag,length);
		memcpy(ptlv+ntag+nlen,pvalue,length);
		//modify parent's length
		addval=modifylength(ptr,level-1,ntag+nlen+length);
		asnbuf->msglen+=addval;
		ptlv+=addval;
	}
	if(swaplen>0)
		memcpy(ptlv,asn_swap,swaplen);
	return asnbuf->msglen;
}


int asn_decode(u_char *msg_buf,int ntlv,ASN_BUF *asnbuf)
{
	return AsnDecode(msg_buf,256,ntlv,NULL,asnbuf);
}

int asn_decode_v2(u_char *msg_buf,int ntlv,int *errpos,ASN_BUF *asnbuf)
{
	return AsnDecode(msg_buf,256,ntlv,errpos,asnbuf);
}

int asn_decode_v3(u_char *msg_buf,int msglen,int *errpos,ASN_BUF *asnbuf)
{
	return AsnDecode(msg_buf,msglen,100,errpos,asnbuf);
}

int AsnDecode(u_char *msg_buf,int msglen,int maxtlv,int *errpos,ASN_BUF *asnbuf)
{
	ASN_TLV		*p1=NULL,*p2;
	int			ntlv=0,retval,sublen=0;

	asnbuf->msgbuf = msg_buf;
	asnbuf->tlvcount=0;
	asnbuf->pos = 0;
	asnbuf->msglen = msglen;
	asnbuf->errmsg[0]='\0';

	while(asnbuf->pos < msglen && ntlv<maxtlv)
	{
		if(errpos!=NULL)
			*errpos = asnbuf->pos;

		retval=parse_tlv(&p2,asnbuf);

		if(retval<0)
		{
			return -1;
		}
		else if(retval==0)
		{
			return sublen;
		}
		else
		{
			if(p1!=NULL)
				p1->pnext = p2;
			p1 = p2;
			sublen+=retval;
		}
		ntlv++;
	}
	if(errpos!=NULL)
		*errpos = asnbuf->pos;
	
	return sublen;
}

int get_tlv(const char *tag_seq,u_char *pvalue,ASN_BUF *asnbuf)
{
	return get_tlv_v2(tag_seq,pvalue,NULL,asnbuf);
}

int get_tlv_v2(const char *tag_seq,u_char *pvalue,u_char *flag,ASN_BUF *asnbuf)
{
	u_short		tags[30][2];
	int			depth=1,order=1;
	ASN_TLV		*p1=&asnbuf->heap[0]; 
	parse_tags(tag_seq,tags);

	if(asnbuf->tlvcount < 1)
		return -1;

	while(depth<tags[0][0]+1 && (order<=tags[depth][1] || tags[depth][1]==0))
	{
		//printf("depth=%d/%d,order=%d,tagcode=%d/%d\n",depth,tags[0][0],order,p1->tagcode,tags[depth][0]);
		if((p1->tagcode == tags[depth][0] || tags[depth][0]==0xFFFF) && (tags[depth][1]==0 || order==tags[depth][1]))
		{
			if(depth==tags[0][0])
			{
				if(flag!=NULL)
					*flag=p1->tagtype;

				if(p1->length < 0)
					return -1;
				else if(p1->length <= 256)
				{
					memcpy(pvalue,p1->pvalue,p1->length);
					return p1->length;
				}
				else
				{
					memcpy(pvalue,p1->pvalue,256);
					return 256;
				}
			}
			else
			{
				if(p1->psub==NULL)
					return -1;
				p1=p1->psub;
				depth++;
				order=1;
			}
		}
		else
		{
			if(p1->pnext == NULL)
				return -1;
			p1=p1->pnext;
			order++;
		}
	}
	return -1;
}

int GetTLV(const char *tag_seq,int maxlen,u_char *pvalue,u_char flag,ASN_BUF *asnbuf)
{
	u_short		tags[30][2];
	int			depth=1,order=1;
	ASN_TLV		*p1=&asnbuf->heap[0];
	parse_tags(tag_seq,tags);
	
	if(asnbuf->tlvcount < 1)
		return -1;

	while(depth<tags[0][0]+1 && (order<=tags[depth][1] || tags[depth][1]==0))
	{
		//printf("depth=%d/%d,order=%d,tagcode=%d/%d\n",depth,tags[0][0],order,p1->tagcode,tags[depth][0]);
		//printf("flag:%02X/%02X\n",p1->tagtype,flag);
		if((p1->tagcode == tags[depth][0] || tags[depth][0]==0xFFFF) && (depth<tags[0][0] || p1->tagtype == flag) && (tags[depth][1]==0 || order==tags[depth][1]))
		{
			if(depth==tags[0][0])
			{
				if(p1->length < 0)
					return -1;
				else if(p1->length <= maxlen)
				{
					memcpy(pvalue,p1->pvalue,p1->length);
					return p1->length;
				}
				else
				{
					memcpy(pvalue,p1->pvalue,maxlen);
					return maxlen;
				}
			}
			else
			{
				if(p1->psub==NULL)
					return -1;
				p1=p1->psub;
				depth++;
				order=1;
			}
		}
		else
		{
			if(p1->pnext == NULL)
				return -1;
			p1=p1->pnext;
			order++;
		}
	}
	return -1;
}

int GetAnyTLV(const char *tag_seq,int maxlen,u_char *pvalue,u_char *pflag,u_short *ptagcode,ASN_BUF *asnbuf)
{
	u_short		tags[30][2];
	int			depth=1,order=1;
	ASN_TLV		*p1=&asnbuf->heap[0];
	parse_tags(tag_seq,tags);

	if(asnbuf->tlvcount < 1)
		return -1;
	
	while(depth<tags[0][0]+1 && (order<=tags[depth][1] || tags[depth][1]==0))
	{
		//printf("depth=%d/%d,order=%d,tagcode=%d/%d\n",depth,tags[0][0],order,p1->tagcode,tags[depth][0]);
		//printf("flag:%02X/%02X\n",p1->tagtype,flag);
		if((p1->tagcode == tags[depth][0] || tags[depth][0]==0xFFFF) && (tags[depth][1]==0 || order==tags[depth][1]))
		{
			if(depth==tags[0][0])
			{
				if(pflag!=NULL)
					*pflag = p1->tagtype;
				if(ptagcode != NULL)
					*ptagcode = p1->tagcode;

				if(p1->length < 0)
					return -1;
				else if(p1->length <= maxlen)
				{
					memcpy(pvalue,p1->pvalue,p1->length);
					return p1->length;
				}
				else
				{
					memcpy(pvalue,p1->pvalue,maxlen);
					return maxlen;
				}
			}
			else
			{
				if(p1->psub==NULL)
					return -1;
				p1=p1->psub;
				depth++;
				order=1;
			}
		}
		else
		{
			if(p1->pnext == NULL)
				return -1;
			p1=p1->pnext;
			order++;
		}
	}
	return -1;
}

int parse_tlv(ASN_TLV **pnode,ASN_BUF *asnbuf)
//idefinite length
{
	int			ntag,nlen,length,sublen=0,retval;
	u_int		tagcode;
	u_char		tagtype;
	u_char		*msgbuf=asnbuf->msgbuf;
	ASN_TLV		*ptlv,*p1=NULL,*p2;

	if(asnbuf->pos == asnbuf->msglen)
	{
		*pnode=NULL;
		return 0;
	}

	if(asnbuf->pos+2 > asnbuf->msglen || asnbuf->tlvcount >=256)
	{
		sprintf(asnbuf->errmsg,"Length check error(rest=%d)/exceed limit(tlvcount=%d)\n",asnbuf->msglen-asnbuf->pos,asnbuf->tlvcount);
		return -1;
	}
	//printf("tlvcount=%d\n",asnbuf->tlvcount);
	*pnode = ptlv = &asnbuf->heap[asnbuf->tlvcount++];
	ptlv->psub = ptlv->pnext = NULL;
	ptlv->length = -1;
	
	if((ntag=gettagcode(msgbuf+asnbuf->pos,&tagcode,&tagtype))<1)
	{
		sprintf(asnbuf->errmsg,"Wrong encoding of tag(pos=%d:%02X %02X %02X)\n",asnbuf->pos,msgbuf[asnbuf->pos],msgbuf[asnbuf->pos+1],msgbuf[asnbuf->pos+2]);
		return -1;
	}
	else
		asnbuf->pos+=ntag;

	if((nlen=getlength(msgbuf+asnbuf->pos,&length))<1)
	{
		sprintf(asnbuf->errmsg,"Wrong encoding of Length(pos=%d:%02X %02X %02X)\n",asnbuf->pos,msgbuf[asnbuf->pos],msgbuf[asnbuf->pos+1],msgbuf[asnbuf->pos+2]);
		return -1;
	}
	else
		asnbuf->pos+=nlen;

	if(asnbuf->pos + length >asnbuf->msglen)
	{
		sprintf(asnbuf->errmsg,"Length Check error.length=%d,rest=%d(pos=%d:%02X %02X %02X)\n",length,asnbuf->msglen-asnbuf->pos,asnbuf->pos,msgbuf[asnbuf->pos],msgbuf[asnbuf->pos+1],msgbuf[asnbuf->pos+2]);
		return -1;
	}
	
	ptlv->tagtype=tagtype;
	ptlv->tagcode=tagcode;
	ptlv->pvalue=msgbuf+asnbuf->pos;
	
	if((tagtype & 0x20)==0)					//primitive
	{
		if(length==-1)
		{
			sprintf(asnbuf->errmsg,"Wrong Encoding of Length:primitive form with indefinite length\n(pos=%d)",asnbuf->pos);
			return -1;
		}
		else
		{
			ptlv->length = length;
			asnbuf->pos += length;
			return length+ntag+nlen;
		}
	}
	else									//constructor
	{
		if(length >=0)	//short/long definite length
		{
			ptlv->length = length;
			while(sublen<length)
			{
				retval=parse_tlv(&p2,asnbuf);
				if(retval<0)
					return -1;
				else if(retval==0)
				{
					sprintf(asnbuf->errmsg,"Length Check error.length=%d,sublen=%d(pos=%d:%02X %02X %02X)\n",length,sublen,asnbuf->pos,msgbuf[asnbuf->pos],msgbuf[asnbuf->pos+1],msgbuf[asnbuf->pos+2]);
					return -1;
				}
				else
				{
					if(p1==NULL)
						p1=ptlv->psub = p2;
					else
					{
						p1->pnext = p2;
						p1 = p2;
					}
					sublen+=retval;
				}
			}
			if(sublen>length)
			{
				sprintf(asnbuf->errmsg,"Length Check error.length=%d,sublen=%d(pos=%d:%02X %02X %02X)\n",length,sublen,asnbuf->pos,msgbuf[asnbuf->pos],msgbuf[asnbuf->pos+1],msgbuf[asnbuf->pos+2]);
					return -1;
			}
			ptlv->length = sublen;
			return sublen+ntag+nlen;
		}
		else			//indefinite length
		{
			while(msgbuf[asnbuf->pos]!=0 || msgbuf[asnbuf->pos+1]!=0)
			{		
				retval=parse_tlv(&p2,asnbuf);
				if(retval<0)
				{
					return -1;
				}
				else if(retval==0)
				{
					ptlv->length = sublen;
					return sublen+ntag+nlen;
				}
				else
				{
					if(p1==NULL)
						p1=ptlv->psub = p2;
					else
					{
						p1->pnext = p2;
						p1 = p2;
					}
					sublen+=retval;
				}
			}
			asnbuf->pos += 2;
			ptlv->length = sublen;
			return sublen+ntag+nlen+2;
		}
	}

		
}


int findtlv(u_char *pasn,u_int tagcode,u_char **pnext,int rest)
//according to tagcode
{
	int 	ntag,nlen,nvalue,pos=0;
	u_int	curtag;
	u_char	type;
	//printf("findtlv rest=%d\n",rest);
	if(rest==0)
	{
		*pnext=pasn;
		return 1;
	}
	else if(rest<0)
		return -1;
	ntag=gettagcode(pasn,&curtag,&type);
	if((nlen=getlength(pasn+ntag,&nvalue)) < 0 || nvalue < 0)
		return -1;
	//printf("ntag=%d,nlen=%d,nvalue=%d\n",ntag,nlen,nvalue);
	if(curtag<tagcode)
	{
		if((pos = ntag + nlen + nvalue) <= 0)
			return -1;
		return findtlv(pasn+pos,tagcode,pnext,rest-pos);
	}
	else if(curtag==tagcode)
	{
		*pnext=pasn;
		return type;
	}
	else
	{
		*pnext=pasn;
		return 1;
	}
}
int findtlv2(u_char *pasn,int index,u_char **pnext,int rest)
//according to position
{
	u_int 	curtag,ntag,nlen,nvalue;
	u_char	type;
	(*pnext)=pasn;

	while(--index>0 && rest>0)
	{
		ntag=gettagcode((*pnext),&curtag,&type);
		nlen=getlength((*pnext)+ntag,&nvalue);
		(*pnext)+=(ntag+nlen+nvalue);
		rest-=(ntag+nlen+nvalue);
	}
	
	if(index==0 && rest>0)		//found
	{
		ntag=gettagcode((*pnext),&curtag,&type);
		return type;
	}
	else if(rest==0)			//seek to end(not found)
		return 1;
	else
		return -1;
}

int gettagcode(u_char *asnbuf,u_int *tagcode,u_char *type)
{
	u_int		pos=0;
	*type=asnbuf[pos] & 0xE0;
	*tagcode=asnbuf[pos] & 0x1F;
	pos++;
	if(*tagcode==0x1F)
	{
		*tagcode=0;
		while((asnbuf[pos] & 0x80)==0x80 && pos<3)
		{
			*tagcode=(*tagcode) * 0x80 + (asnbuf[pos++] & 0x7F);
		}
		*tagcode=(*tagcode) * 0x80 + (asnbuf[pos++] & 0x7F);
	}
	return pos;
}

int getlength(u_char *asnbuf,int *len)
{
	u_int		pos=0,lenbyte;
	
	if((asnbuf[pos] & 0x80)==0)
		*len=asnbuf[pos++] & 0x7F;
	else
	{
		*len=0;
		lenbyte=asnbuf[pos++] & 0x7F;
		if(lenbyte>3 || lenbyte<0)
			return -1;

		if(lenbyte==0)
		{
			*len=-1;
			return 1;
		}
		else
		{
			while(lenbyte-->0)
				*len=(*len)*0x100 + asnbuf[pos++];
		}
		
	}

	return pos;
} 

int addtagcode(u_char *msg_buf,u_int tagcode,u_char type)
{
	u_int 	tagbyte=0,pos=0;
	int		i=3;
	u_char buf[4];
	msg_buf[pos]=type & 0xE0;
	if(tagcode<31)
		msg_buf[pos++]+=tagcode;
	else
	{
		msg_buf[pos++]+=0x1F;
		while(i>=0 && tagcode>0)
		{
			buf[i]=tagcode & 0x7F;
			buf[i]|=0x80;
			tagcode=tagcode >> 7;
			i--;
		}
		buf[3]&=0x7F;
		tagbyte=3-i;
		memcpy(msg_buf+pos,buf+i+1,tagbyte);
		pos+=tagbyte;
	}
	return pos;
}
int addlength(u_char *msg_buf,u_int len)
{
	u_int 	lenbyte=0,pos=0;
	int		i=3;
	u_char buf[4];
	
	if(len>=0 && len<=127)
		msg_buf[pos++]=len;
	else if(len>0)
	{
		while(i>=0 && len>0)
		{
			buf[i]=len & 0xFF;
			len=len>>8;
			i--;
		}
		lenbyte=3-i;
		msg_buf[pos++]=lenbyte | 0x80; 
		memcpy(msg_buf+pos,buf+i+1,lenbyte);
		pos+=lenbyte;
	}
	return pos;
}

int parse_tags(const char *tag_seq,u_short (*tags)[2])
{
	u_short i,j=0,level=1,len;
	len=strlen(tag_seq);
	
	tags[1][0]=0xFFFF;
	tags[1][1]=0;
	for(i=0;i<len;i++)
	{
		if(isdigit(tag_seq[i]))
		{
			if(tags[level][j]==0xFFFF)
				tags[level][j]=0;
			tags[level][j]=tags[level][j]*10+tag_seq[i]-'0';
		}
		else if(tag_seq[i]=='-')
			j=1;
		else if(tag_seq[i]=='.')
		{
			j=0;
			level++;
			tags[level][0]=0xFFFF;
			tags[level][1]=0;
		}
		else if(isspace(tag_seq[i])==0)
			return -1;
	}
	tags[0][0]=level;
	return level;
}

int modifylength(u_char *ptr[],int level,int addval)
{
	int lenbyte1,lenbyte2,len;
	u_char swapbuf[1024];

	if(level<1)
		return addval;
	lenbyte1=getlength(ptr[level],&len);
	memcpy(swapbuf,ptr[level]+lenbyte1,2);
	lenbyte2=addlength(ptr[level],len+addval);
	if(lenbyte2>lenbyte1)
	{
		memcpy(swapbuf+2,ptr[level]+lenbyte1+2,len+addval-2);
		memcpy(ptr[level]+lenbyte2,swapbuf,len+addval);
	}
	return modifylength(ptr,level-1,addval+lenbyte2-lenbyte1);
}

void showbuf(u_char *buf,int len)
{
	int i;
	for(i=0;i<len;i++)
		printf("%02X ",buf[i]);
	printf("\n");	
}

/////////////////////////////////////////////////
/*Functions for add/get special data types --->*/
/////////////////////////////////////////////////
int add_bool(const char *tag_seq,u_char value,u_char tlv_type,ASN_BUF *asnbuf)
{
	return add_tlv(tag_seq,1,&value,tlv_type,asnbuf);
}

u_char get_bool(const char *tag_seq,ASN_BUF *asnbuf)
{
	u_char 	pvalue[10];
	get_tlv(tag_seq,pvalue,asnbuf);
	return pvalue[0];
}

int add_int(const char *tag_seq,int value,u_char tlv_type,ASN_BUF *asnbuf)
{
	return AddInteger(tag_seq,value,tlv_type,asnbuf);
}

int AddInteger(const char *tag_seq,int value,u_char tlv_type,ASN_BUF *asnbuf)
{
	u_char 	buf[4];
	u_int	*p_uint=(u_int *)buf;
	int		i;

	*p_uint=htonl(value);

	if(value<0)
	{
		for(i=0;i<4;i++)
		{
			if(buf[i]!=0xFF)
			{
				if((buf[i] & 0x80)==0)
					i--;
				break;
			}
		}
	}
	else
	{
		for(i=0;i<4;i++)
		{
			if(buf[i]!=0)
			{
				if((buf[i] & 0x80)==0x80)
					i--;
				break;
			}
		}
	}

	if(i>=4)
		i=3;

	return add_tlv(tag_seq,4-i,buf+i,tlv_type,asnbuf);
}

int GetInteger(const char *tag_seq,int *rtn,u_char flag,ASN_BUF *asnbuf)
{
	u_char 	pvalue[10];
	int		length,i;
	length=GetTLV(tag_seq,5,pvalue,flag,asnbuf);
	if(length==-1)
		return -1;

	if((pvalue[0] & 0x80)==0x80)
		*rtn=-1;
	else
		*rtn=0;

	for(i=0;i<length;i++)
		*rtn=((*rtn)<<8)|(pvalue[i]);
	return length;
}

int get_int(const char *tag_seq,ASN_BUF *asnbuf)
{
	u_char 	pvalue[10];
	int		length,i,value;
	length=get_tlv(tag_seq,pvalue,asnbuf);
	if(length==-1)
		return -1;

	if((pvalue[0] & 0x80)==0x80)
		value=-1;
	else
		value=0;

	for(i=0;i<length;i++)
		value=(value<<8)|(pvalue[i]);
	return value;
}

int get_int_v2(const char *tag_seq,int *rtn,ASN_BUF *asnbuf)
{
	u_char 	pvalue[10];
	int		length,i;
	length=get_tlv(tag_seq,pvalue,asnbuf);
	if(length==-1)
		return -1;

	if((pvalue[0] & 0x80)==0x80)
		*rtn=-1;
	else
		*rtn=0;

	for(i=0;i<length;i++)
		*rtn=((*rtn)<<8)|(pvalue[i]);
	return length;
}

int add_null(const char *tag_seq,u_char tlv_type,ASN_BUF *asnbuf)
{
	u_char pvalue[2];
	return add_tlv(tag_seq,0,pvalue,tlv_type,asnbuf);
	
}
int get_null(const char *tag_seq,ASN_BUF *asnbuf)
{
	u_char pvalue[50];
	if(get_tlv(tag_seq,pvalue,asnbuf)>=0)
		return 1;
	else
		return -1;
}
int add_oid(const char *tag_seq,const char *oidstr,u_char tlv_type,ASN_BUF *asnbuf)
{
	u_char	pvalue[50],buf[4];
	int oid[20],len,i,j,level=0,pos=0;
	len=strlen(oidstr);
	memset(oid,0,sizeof(oid));
	for(i=0;i<len;i++)
	{
		if(isdigit(oidstr[i]))
			oid[level]=oid[level]*10+oidstr[i]-'0';
		else if(oidstr[i]=='.')
			level++;
	}
	oid[1]=oid[0]*40 + oid[1];
	for(i=1;i<=level;i++)
	{
		j=3;
		do
		{
			
			buf[j]=oid[i] & 0x7F;
			buf[j]|=0x80;
			oid[i]=oid[i]>>7;
			j--;
		}while(oid[i]>0 && j>=0);
		buf[3]&=0x7F;
		len=3-j;
		memcpy(pvalue+pos,buf+j+1,len);
		pos+=len;
	}
	return add_tlv(tag_seq,pos,pvalue,tlv_type,asnbuf);
}

int get_oid(const char *tag_seq,char *oid,ASN_BUF *asnbuf)
{
	u_char 	pvalue[50];
	char	tempstr[50],firstoctet=1;
	int		length,i,temp=0;
	length=get_tlv(tag_seq,pvalue,asnbuf);
	
	if(length<=0)
		return -1;
	
	for(i=0;i<length;i++)
	{
		temp=temp * 0x80 +(pvalue[i] & 0x7F);

		if((pvalue[i] & 0x80)==0x00)
		{
			if(firstoctet==1)
			{
				if(temp<40)
					sprintf(tempstr,"0.%d",temp);
				else if(temp<80)
					sprintf(tempstr,"1.%d",temp-40);
				else
					sprintf(tempstr,"2.%d",temp-80);
				firstoctet=0;
			}
			else
				sprintf(tempstr+strlen(tempstr),".%d",temp);
			temp=0;
		}
	}
	strcpy(oid,tempstr);
	return 1;
}

int DecodeInteger(u_char *buf, u_char len)
{
	int		ret;
	u_char	i, pad = 0, *ptr = (u_char *)&ret;

	if(buf[0] & 0x80)
		pad = 0xFF;

	for(i = 0; i < 4; i++)
	{
		if(len > 0)
		{
			len--;
			ptr[i] = buf[len];
		}
		else
			ptr[i] = pad;
	}
	return ret;
}
/*@end@*/