ref: 41e27b2d10c6a60c49931332e8677438736a1e36
dir: /os/boot/puma/qio.c/
#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; } void freeb(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; } void qbwrite(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); } long qlen(Queue *q) { return q->len; } int qbgetc(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; } void qbputc(Queue *q, int c) { Block *b; b = iallocb(1); *b->wp++ = c; qbwrite(q, b); }