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/*
* This file is part of the "Coroutine" project and released under the MIT License.
*
* Created by Samuel Williams on 24/6/2019.
* Copyright, 2019, by Samuel Williams. All rights reserved.
*/
#pragma once
#include <assert.h>
#include <stddef.h>
#include <ucontext.h>
#define COROUTINE __attribute__((noreturn)) void
struct coroutine_context
{
ucontext_t state;
struct coroutine_context * from;
};
typedef COROUTINE(* coroutine_start)(struct coroutine_context *from, struct coroutine_context *self);
COROUTINE coroutine_trampoline(void * _start, void * _context);
static inline void coroutine_initialize_main(struct coroutine_context * context) {
context->from = NULL;
getcontext(&context->state);
}
static inline void coroutine_initialize(
struct coroutine_context *context,
coroutine_start start,
void *stack,
size_t size
) {
assert(start && stack && size >= 1024);
coroutine_initialize_main(context);
context->state.uc_stack.ss_size = size;
// Despite what it's called, this is not actually a stack pointer. It points to the address of the stack allocation (the lowest address).
context->state.uc_stack.ss_sp = (char*)stack;
context->state.uc_stack.ss_flags = 0;
context->state.uc_link = NULL;
makecontext(&context->state, (void(*)(void))coroutine_trampoline, 2, (void*)start, (void*)context);
}
static inline struct coroutine_context * coroutine_transfer(struct coroutine_context * current, struct coroutine_context * target)
{
struct coroutine_context * previous = target->from;
target->from = current;
swapcontext(¤t->state, &target->state);
target->from = previous;
return target;
}
static inline void coroutine_destroy(struct coroutine_context * context)
{
context->state.uc_stack.ss_sp = NULL;
context->state.uc_stack.ss_size = 0;
context->from = NULL;
}
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