Enable creating and releasing contexts

README.md

@@ -14,7 +14,7 @@ It is mainly developed and tested on Linux and with Intel and Nvidia GPUs. It sh
   - [x] querying info
 - [ ] subdevices (not planned for now)
 - [ ] context
-  - [ ] creating and releasing contexts
+  - [x] creating and releasing contexts
   - [ ] querying info
 - [ ] command queues
   - [ ] creating and releasing command queues

context.go

+package opencl
+
+/*
+#ifdef __APPLE__
+#include <OpenCL/opencl.h>
+#else
+#include <CL/cl.h>
+#endif
+
+extern void contextCallback(char *, void *, size_t, void *);
+*/
+import "C"
+import (
+	"fmt"
+	"unsafe"
+)
+
+type Context struct {
+	context  C.cl_context
+	callback func(string, unsafe.Pointer, uintptr, interface{})
+	userdata interface{}
+}
+
+type ContextProperties struct {
+}
+
+//export contextCallback
+func contextCallback(errinfo *C.char, private_info unsafe.Pointer, cb C.size_t, user_data unsafe.Pointer) {
+	context := *(*Context)(user_data)
+	context.callback(C.GoString(errinfo), private_info, uintptr(cb), context.userdata)
+}
+
+func CreateContext(properties *ContextProperties, devices []*Device, notify func(string, unsafe.Pointer, uintptr, interface{}), userdata interface{}) (*Context, error) {
+	context := Context{nil, notify, userdata}
+
+	ids := make([]C.cl_device_id, len(devices))
+	for i, d := range devices {
+		ids[i] = d.id
+	}
+
+	var callback *[0]byte
+	var user unsafe.Pointer
+	if notify != nil {
+		callback = (*[0]byte)(unsafe.Pointer(C.contextCallback))
+		user = unsafe.Pointer(&context)
+	}
+
+	var err C.cl_int
+	context.context = C.clCreateContext(nil, C.cl_uint(len(ids)), &ids[0], callback, user, &err)
+	if err != C.CL_SUCCESS {
+		return nil, fmt.Errorf("Error creating context: %d", err)
+	}
+	return &context, nil
+}
+
+func (c Context) Release() error {
+	err := C.clReleaseContext(c.context)
+	if err != C.CL_SUCCESS {
+		return fmt.Errorf("Error releasing context: %d", err)
+	}
+	return nil
+}