Migrated util.go back and formalized pkguiAlloc().

1 files changed, 45 insertions, 0 deletions

diff --git a/util.go b/util.go
new file mode 100644
index 0000000..bcd4d33
--- /dev/null
+++ b/util.go
@@ -0,0 +1,45 @@
+// 12 december 2015
+
+package ui
+
+import (
+	"unsafe"
+)
+
+// #include <stdlib.h>
+// #include "util.h"
+import "C"
+
+// We want Go itself to complain when we're out of memory.
+// The allocators in cgo *should* do this, but there isn't a
+// C.CMalloc(). There *is* a C.CBytes(), however, for transferring
+// binary blobs from Go to C. If we pass this an arbitrary slice
+// of the desired length, we get our C.CMalloc(). Using a slice
+// that's always initialized to zero gives us the memset(0)
+// (or ZeroMemory()) for free.
+var allocBytes = make([]byte, 1024)		// 1024 bytes first
+
+//export pkguiAlloc
+func pkguiAlloc(n C.size_t) unsafe.Pointer {
+	if n > C.size_t(len(allocBytes)) {
+		// TODO round n up to a multiple of a power of 2?
+		// for instance 0x1234 bytes -> 0x1800 bytes
+		allocBytes = make([]byte, n)
+	}
+	return C.CBytes(allocBytes[:n])
+}
+
+func freestr(str *C.char) {
+	C.free(unsafe.Pointer(str))
+}
+
+func tobool(b C.int) bool {
+	return b != 0
+}
+
+func frombool(b bool) C.int {
+	if b {
+		return 1
+	}
+	return 0
+}