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-rw-r--r--trunk/src/lib/cothread/ucontext.c67
1 files changed, 67 insertions, 0 deletions
diff --git a/trunk/src/lib/cothread/ucontext.c b/trunk/src/lib/cothread/ucontext.c
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index 00000000000..17472f6bccf
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+++ b/trunk/src/lib/cothread/ucontext.c
@@ -0,0 +1,67 @@
+/*
+ libco.ucontext (2008-01-28)
+ author: Nach
+ license: public domain
+*/
+
+/*
+ * WARNING: the overhead of POSIX ucontext is very high,
+ * assembly versions of libco or libco_sjlj should be much faster
+ *
+ * This library only exists for two reasons:
+ * 1 - as an initial test for the viability of a ucontext implementation
+ * 2 - to demonstrate the power and speed of libco over existing implementations,
+ * such as pth (which defaults to wrapping ucontext on unix targets)
+ *
+ * Use this library only as a *last resort*
+ */
+
+#define LIBCO_C
+#include "libco.h"
+#include <stdlib.h>
+#include <ucontext.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+static thread_local ucontext_t co_primary;
+static thread_local ucontext_t *co_running = 0;
+
+cothread_t co_active() {
+ if(!co_running) co_running = &co_primary;
+ return (cothread_t)co_running;
+}
+
+cothread_t co_create(unsigned int heapsize, void (*coentry)(void)) {
+ if(!co_running) co_running = &co_primary;
+ ucontext_t *thread = (ucontext_t*)malloc(sizeof(ucontext_t));
+ if(thread) {
+ if((!getcontext(thread) && !(thread->uc_stack.ss_sp = 0)) && (thread->uc_stack.ss_sp = malloc(heapsize))) {
+ thread->uc_link = co_running;
+ thread->uc_stack.ss_size = heapsize;
+ makecontext(thread, coentry, 0);
+ } else {
+ co_delete((cothread_t)thread);
+ thread = 0;
+ }
+ }
+ return (cothread_t)thread;
+}
+
+void co_delete(cothread_t cothread) {
+ if(cothread) {
+ if(((ucontext_t*)cothread)->uc_stack.ss_sp) { free(((ucontext_t*)cothread)->uc_stack.ss_sp); }
+ free(cothread);
+ }
+}
+
+void co_switch(cothread_t cothread) {
+ ucontext_t *old_thread = co_running;
+ co_running = (ucontext_t*)cothread;
+ swapcontext(old_thread, co_running);
+}
+
+#ifdef __cplusplus
+}
+#endif