Function ip_addr2a

ip_addr.h:430–550

 */
extern __thread char _ip_addr_A_buffs[IP_ADDR2STR_BUF_NO][IP_ADDR_MAX_STR_SIZE];
static inline char* ip_addr2a(struct ip_addr* ip)
{
	static __thread unsigned int it = 0;
	int offset;
	register unsigned char a,b,c;
	register unsigned char d;
	register unsigned short hex4;
	int r;
	char *_ip_addr_A_buff;
	#define HEXDIG(x) (((x)>=10)?(x)-10+'A':(x)+'0')

	if ((++it)==IP_ADDR2STR_BUF_NO) it = 0;
	_ip_addr_A_buff = _ip_addr_A_buffs[it];

	offset=0;
	switch(ip->af){
		case AF_INET6:
			for(r=0;r<7;r++){
				hex4=ntohs(ip->u.addr16[r]);
				a=hex4>>12;
				b=(hex4>>8)&0xf;
				c=(hex4>>4)&0xf;
				d=hex4&0xf;
				if (a){
					_ip_addr_A_buff[offset]=HEXDIG(a);
					_ip_addr_A_buff[offset+1]=HEXDIG(b);
					_ip_addr_A_buff[offset+2]=HEXDIG(c);
					_ip_addr_A_buff[offset+3]=HEXDIG(d);
					_ip_addr_A_buff[offset+4]=':';
					offset+=5;
				}else if(b){
					_ip_addr_A_buff[offset]=HEXDIG(b);
					_ip_addr_A_buff[offset+1]=HEXDIG(c);
					_ip_addr_A_buff[offset+2]=HEXDIG(d);
					_ip_addr_A_buff[offset+3]=':';
					offset+=4;
				}else if(c){
					_ip_addr_A_buff[offset]=HEXDIG(c);
					_ip_addr_A_buff[offset+1]=HEXDIG(d);
					_ip_addr_A_buff[offset+2]=':';
					offset+=3;
				}else{
					_ip_addr_A_buff[offset]=HEXDIG(d);
					_ip_addr_A_buff[offset+1]=':';
					offset+=2;
				}
			}
			/* last int16*/
			hex4=ntohs(ip->u.addr16[r]);
			a=hex4>>12;
			b=(hex4>>8)&0xf;
			c=(hex4>>4)&0xf;
			d=hex4&0xf;
			if (a){
				_ip_addr_A_buff[offset]=HEXDIG(a);
				_ip_addr_A_buff[offset+1]=HEXDIG(b);
				_ip_addr_A_buff[offset+2]=HEXDIG(c);
				_ip_addr_A_buff[offset+3]=HEXDIG(d);