#include "u.h"#include "lib.h"#include "mem.h"#include "dat.h"#include "fns.h"#include "io.h" struct Queue {	Block*	first;	Block*	last;	void	(*kick)(void*);	void*	arg;	long	len;}; Block *iallocb(int n){	Block *b; 	b = (Block*)malloc(sizeof(Block)+n);	b->data = (uchar*)b + sizeof(Block);	b->rp = b->wp = b->data;	b->lim = b->data + n;	b->next = 0;	b->magic = 0xcafebee0;	return b;} voidfreeb(Block *b){	if(b){		if(b->magic != 0xcafebee0)			panic("freeb");		b->magic = 0;		b->next = (Block*)0xdeadbabe;		free(b);	}} Queue *qopen(int limit, int msg, void (*kick)(void*), void *arg){	Queue *q; 	USED(limit, msg);	q = (Queue*)malloc(sizeof(Queue));	q->first = q->last = 0;	q->kick = kick;	q->arg = arg;	q->len = 0;	return q;} Block *qget(Queue *q){	int s;	Block *b; 	s = splhi();	if((b = q->first) != 0){		q->first = b->next;		b->next = 0;		q->len -= BLEN(b);		if(q->len < 0)			panic("qget");	}	splx(s);	return b;} voidqbwrite(Queue *q, Block *b){	int s; 	s = splhi();	b->next = 0;	if(q->first == 0)		q->first = b;	else		q->last->next = b;	q->last = b;	q->len += BLEN(b);	splx(s);	if(q->kick)		q->kick(q->arg);} longqlen(Queue *q){	return q->len;} intqbgetc(Queue *q){	Block *b;	int s, c; 	c = -1;	s = splhi();	while(c < 0 && (b = q->first) != nil){		if(b->rp < b->wp){			c = *b->rp++;			q->len--;		}		if(b->rp >= b->wp){			q->first = b->next;			b->next = nil;		}	}	splx(s);	return c;} voidqbputc(Queue *q, int c){	Block *b; 	b = iallocb(1);	*b->wp++ = c;	qbwrite(q, b);}