restructured some go wrapper files

go/inst.go

@@ -0,0 +1,71 @@
+package hcl
+
+/*
+#cgo CFLAGS: -I/home/hyung-hwan/xxx/include -g -Wall
+#cgo LDFLAGS: -L/home/hyung-hwan/xxx/lib -lhcl -ldl -lquadmath
+
+#include <hcl.h>
+*/
+import "C"
+import (
+	"sync"
+)
+
+type Instance struct {
+	c *C.hcl_t // c object
+	g *HCL     // go object
+}
+
+type InstanceTable struct {
+	mtx        sync.Mutex
+	insts      []Instance
+	free_slots []int
+}
+
+func (itab *InstanceTable) add_instance(c *C.hcl_t, g *HCL) int {
+	itab.mtx.Lock()
+	defer itab.mtx.Unlock()
+
+	var n int = len(itab.free_slots)
+
+	if n <= 0 { // no free slots
+		itab.insts = append(itab.insts, Instance{c: c, g: g})
+		return len(itab.insts) - 1
+	} else {
+		var slot int
+		n--
+		slot = itab.free_slots[n]
+		itab.free_slots = itab.free_slots[:n]
+		itab.insts[slot].c = c
+		return slot
+	}
+}
+
+func (itab *InstanceTable) delete_instance(slot int) Instance {
+	var (
+		h Instance
+		n int
+	)
+
+	itab.mtx.Lock()
+	defer itab.mtx.Unlock()
+
+	h = itab.insts[slot]
+	itab.insts[slot].c = nil
+	itab.insts[slot].g = nil
+
+	n = len(itab.insts)
+	if slot == n-1 {
+		itab.insts = itab.insts[:n-1]
+	} else {
+		itab.free_slots = append(itab.free_slots, slot)
+	}
+
+	return h
+}
+
+func (itab *InstanceTable) slot_to_instance(slot int) Instance {
+	itab.mtx.Lock()
+	defer itab.mtx.Unlock()
+	return itab.insts[slot]
+}