#include <u.h>#include <libc.h>#include <venti.h>#include <libsec.h> #define MAGIC 0x54798314#define NOTFREE(p)	assert((p)->magic == MAGIC) struct Packet{	char *data;	int len;	void (*free)(void*);	void *arg;	int magic;}; Packet*packetalloc(void){	Packet *p;		p = vtmallocz(sizeof *p);	p->free = vtfree;	p->arg = nil;	p->magic = MAGIC;	return p;} voidpacketappend(Packet *p, uchar *buf, int n){	NOTFREE(p);	if(n < 0)		abort();	if(p->free != vtfree)		sysfatal("packetappend");	p->data = vtrealloc(p->data, p->len+n);	p->arg = p->data;	memmove(p->data+p->len, buf, n);	p->len += n;} uintpacketasize(Packet *p){	NOTFREE(p);	return p->len;} intpacketcmp(Packet *p, Packet *q){	int i, len;		NOTFREE(p);	NOTFREE(q);	len = p->len;	if(len > q->len)		len = q->len;	if(len && (i=memcmp(p->data, q->data, len)) != 0)		return i;	if(p->len > len)		return 1;	if(q->len > len)		return -1;	return 0;} voidpacketconcat(Packet *p, Packet *q){	NOTFREE(p);	NOTFREE(q);	packetappend(p, q->data, q->len);	if(q->free == vtfree)		memset(q->data, 0xFE, q->len);	q->free(q->arg);	q->data = nil;	q->len = 0;} intpacketconsume(Packet *p, uchar *buf, int n){	NOTFREE(p);	if(n < 0)		abort();	if(p->len < n)		abort();	memmove(buf, p->data, n);	p->len -= n;	memmove(p->data, p->data+n, p->len);	return 0;} intpacketcopy(Packet *p, uchar *buf, int offset, int n){	NOTFREE(p);	if(offset < 0 || n < 0)		abort();	if(offset > p->len)		abort();	if(offset+n > p->len)		n = p->len - offset;	memmove(buf, p->data+offset, n);	return 0;} Packet*packetdup(Packet *p, int offset, int n){	Packet *q; 	NOTFREE(p);	if(offset < 0 || n < 0)		abort();	if(offset > p->len)		abort();	if(offset+n > p->len)		n = p->len - offset;	q = packetalloc();	packetappend(q, p->data+offset, n);	return q;} Packet*packetforeign(uchar *buf, int n, void (*free)(void*), void *a){	Packet *p;		if(n < 0)		abort();	p = packetalloc();	p->data = (char*)buf;	p->len = n;	p->free = free;	p->arg = a;	return p;} intpacketfragments(Packet *p, IOchunk *io, int nio, int offset){	NOTFREE(p);	if(offset < 0)		abort();	if(nio == 0)		return 0;	memset(io, 0, sizeof(io[0])*nio);	if(offset >= p->len)		return 0;	io[0].addr = p->data + offset;	io[0].len = p->len - offset;	return p->len;} voidpacketfree(Packet *p){	NOTFREE(p);	if(p->free == free)		memset(p->data, 0xFE, p->len);	p->free(p->arg);	p->data = nil;	p->len = 0;	memset(p, 0xFB, sizeof *p);	free(p);} uchar*packetheader(Packet *p, int n){	NOTFREE(p);	if(n < 0)		abort();	if(n > p->len)		abort();	return p->data;} uchar*packetpeek(Packet *p, uchar *buf, int offset, int n){	NOTFREE(p);	if(offset < 0 || n < 0)		abort();	if(offset+n > p->len)		abort();	return p->data+offset;} voidpacketprefix(Packet *p, uchar *buf, int n){	NOTFREE(p);	if(n < 0)		abort();	if(p->free != free)		sysfatal("packetappend");	p->data = vtrealloc(p->data, p->len+n);	p->arg = p->data;	memmove(p->data+n, p->data, p->len);	memmove(p->data, buf, n);	p->len += n;} voidpacketsha1(Packet *p, uchar d[20]){	NOTFREE(p);	sha1((uchar*)p->data, p->len, d, nil);} uintpacketsize(Packet *p){	NOTFREE(p);	return p->len;} Packet*packetsplit(Packet *p, int n){	Packet *q;		NOTFREE(p);	q = packetalloc();	q->data = vtmalloc(n);	q->arg = q->data;	q->free = vtfree;	packetconsume(p, q->data, n);	return q;} voidpacketstats(void){} uchar*packettrailer(Packet *p, int n){	NOTFREE(p);	if(n < 0)		abort();	if(n > p->len)		abort();	return p->data + p->len - n;} intpackettrim(Packet *p, int offset, int n){	NOTFREE(p);	if(offset < 0 || n < 0)		abort();	if(offset+n > p->len)		abort();	memmove(p->data+offset, p->data+offset+n, p->len-offset-n);	p->len -= n;	return 0;}