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/*
libco.sjlj (2008-01-28)
author: Nach
license: public domain
*/
/*
note this was designed for UNIX systems. Based on ideas expressed in a paper by Ralf Engelschall.
for SJLJ on other systems, one would want to rewrite springboard() and co_create() and hack the jmb_buf stack pointer.
*/
#define LIBCO_C
#include "libco.h"
#include <stdlib.h>
#include <signal.h>
#include <setjmp.h>
#include "settings.h"
#ifdef __cplusplus
extern "C" {
#endif
typedef struct {
sigjmp_buf context;
void (*coentry)(void);
void* stack;
} cothread_struct;
static thread_local cothread_struct co_primary;
static thread_local cothread_struct* creating;
static thread_local cothread_struct* co_running = 0;
static void springboard(int ignored) {
if(sigsetjmp(creating->context, 0)) {
co_running->coentry();
}
}
cothread_t co_active() {
if(!co_running) co_running = &co_primary;
return (cothread_t)co_running;
}
cothread_t co_create(unsigned int size, void (*coentry)(void),
size_t *out_size) {
if(!co_running) co_running = &co_primary;
cothread_struct *thread = (cothread_struct*)malloc(sizeof(cothread_struct));
if(thread) {
struct sigaction handler;
struct sigaction old_handler;
stack_t stack;
stack_t old_stack;
thread->coentry = thread->stack = 0;
stack.ss_flags = 0;
stack.ss_size = size;
thread->stack = stack.ss_sp = malloc(size);
if(stack.ss_sp && !sigaltstack(&stack, &old_stack)) {
handler.sa_handler = springboard;
handler.sa_flags = SA_ONSTACK;
sigemptyset(&handler.sa_mask);
creating = thread;
if(!sigaction(SIGUSR1, &handler, &old_handler)) {
if(!raise(SIGUSR1)) {
thread->coentry = coentry;
}
sigaltstack(&old_stack, 0);
sigaction(SIGUSR1, &old_handler, 0);
}
}
if(thread->coentry != coentry) {
co_delete(thread);
thread = 0;
}
}
*out_size = size;
return (cothread_t)thread;
}
void co_delete(cothread_t cothread) {
if(cothread) {
if(((cothread_struct*)cothread)->stack) {
free(((cothread_struct*)cothread)->stack);
}
free(cothread);
}
}
void co_switch(cothread_t cothread) {
if(!sigsetjmp(co_running->context, 0)) {
co_running = (cothread_struct*)cothread;
siglongjmp(co_running->context, 1);
}
}
#ifdef __cplusplus
}
#endif
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