coroutine.c

#include "coroutine.h"
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <stddef.h>
#include <string.h>
#include <stdint.h>
#include  "coctx.h"

#define STACK_SIZE (1024*1024)
#define DEFAULT_COROUTINE 16

struct coroutine;

struct schedule {
	char stack[STACK_SIZE];
	struct coctx_t main;
	int nco;
	int cap;
	int running;
	struct coroutine **co;
};

struct coroutine {
	coroutine_func func;
	void *ud;
	struct coctx_t tc_ctx;
	struct schedule * sch;
	ptrdiff_t cap;
	ptrdiff_t size;
	int status;
	char *stack;
};

struct coroutine * 
_co_new(struct schedule *S , coroutine_func func, void *ud) {
	struct coroutine * co = malloc(sizeof(*co));
	co->func = func;
	co->ud = ud;
	co->sch = S;
	co->cap = 0;
	co->size = 0;
	co->status = COROUTINE_READY;
	co->stack = NULL;
	return co;
}

void
_co_delete(struct coroutine *co) {
	free(co->stack);
	free(co);
}

struct schedule * 
coroutine_open(void) {
	struct schedule *S = malloc(sizeof(*S));
	S->nco = 0;
	S->cap = DEFAULT_COROUTINE;
	S->running = -1;
	S->co = malloc(sizeof(struct coroutine *) * S->cap);
	memset(S->co, 0, sizeof(struct coroutine *) * S->cap);
	return S;
}

void 
coroutine_close(struct schedule *S) {
	int i;
	for (i=0;i<S->cap;i++) {
		struct coroutine * co = S->co[i];
		if (co) {
			_co_delete(co);
		}
	}
	free(S->co);
	S->co = NULL;
	free(S);
}

int 
coroutine_new(struct schedule *S, coroutine_func func, void *ud) {
	struct coroutine *co = _co_new(S, func , ud);
	if (S->nco >= S->cap) {
		int id = S->cap;
		S->co = realloc(S->co, S->cap * 2 * sizeof(struct coroutine *));
		memset(S->co + S->cap , 0 , sizeof(struct coroutine *) * S->cap);
		S->co[S->cap] = co;
		S->cap *= 2;
		++S->nco;
		return id;
	} else {
		int i;
		for (i=0;i<S->cap;i++) {
			int id = (i+S->nco) % S->cap;
			if (S->co[id] == NULL) {
				S->co[id] = co;
				++S->nco;
				return id;
			}
		}
	}
	assert(0);
	return -1;
}

static void
mainfunc(struct schedule *S,void* a) {
	struct coctx_t tmp;
	int id = S->running;
	struct coroutine *C = S->co[id];
	C->func(S,C->ud);//从这里进入目标协程函数的调用
	_co_delete(C);
	S->co[id] = NULL;
	--S->nco;
	S->running = -1;
	coctx_init(&tmp);
	coctx_swap(&tmp,&S->main);
}

void 
coroutine_resume(struct schedule * S, int id) {
	assert(S->running == -1);
	assert(id >=0 && id < S->cap);
	struct coroutine *C = S->co[id];
	if (C == NULL)
		return;
	int status = C->status;
	switch(status) {
	case COROUTINE_READY:
		coctx_init(&(C->tc_ctx));
		C->tc_ctx.ss_sp=S->stack;
		C->tc_ctx.ss_size=STACK_SIZE;
		S->running = id;
		C->status = COROUTINE_RUNNING;
		coctx_make(&(C->tc_ctx), (coctx_pfn_t)mainfunc,S, NULL);
//		C->tc_ctx.param->f_link= (coctx_pfn_t)&S->main;
		coctx_swap(&S->main, &C->tc_ctx);
		break;
	case COROUTINE_SUSPEND:
		memcpy(S->stack + STACK_SIZE - C->size, C->stack, C->size);
		S->running = id;
		C->status = COROUTINE_RUNNING;
		coctx_swap(&S->main, &C->tc_ctx);
		break;
	default:
		assert(0);
	}
}

static void
_save_stack(struct coroutine *C, char *top) {
	char dummy = 0;
	assert(top - &dummy <= STACK_SIZE);
	if (C->cap < top - &dummy) {
		free(C->stack);
		C->cap = top-&dummy;
		C->stack = malloc(C->cap);
	}
	C->size = top - &dummy;
	memcpy(C->stack, &dummy, C->size);
}

void
coroutine_yield(struct schedule * S) {
	int id = S->running;
	assert(id >= 0);
	struct coroutine * C = S->co[id];
	assert((char *)&C > S->stack);
	_save_stack(C,S->stack + STACK_SIZE);
	C->status = COROUTINE_SUSPEND;
	S->running = -1;
	coctx_swap(&C->tc_ctx , &S->main);
}

int 
coroutine_status(struct schedule * S, int id) {
	assert(id>=0 && id < S->cap);
	if (S->co[id] == NULL) {
		return COROUTINE_DEAD;
	}
	return S->co[id]->status;
}

int 
coroutine_running(struct schedule * S) {
	return S->running;
}