add SetRandFunc function

1 files changed, 34 insertions, 0 deletions

diff --git a/ffi/go/bls/bls.go b/ffi/go/bls/bls.go
index a5c657c..2374d2e 100644
--- a/ffi/go/bls/bls.go
+++ b/ffi/go/bls/bls.go
@@ -10,11 +10,14 @@ package bls
 #cgo LDFLAGS:-lbls384
 #cgo LDFLAGS:-lcrypto -lgmp -lgmpxx -lstdc++
 #include "config.h"
+typedef unsigned int (*ReadRandFunc)(void *, void *, unsigned int);
+int wrapReadRandCgo(void *self, void *buf, unsigned int n);
 #include <bls/bls.h>
 */
 import "C"
 import "fmt"
 import "unsafe"
+import "io"
 
 // Init --
 // call this function before calling all the other operations
@@ -384,3 +387,34 @@ func (sign *Sign) VerifyAggregateHashes(pubVec []PublicKey, hash [][]byte) bool
 	}
 	return C.blsVerifyAggregatedHashes(sign.getPointer(), pubVec[0].getPointer(), unsafe.Pointer(&h[0]), C.size_t(hashByte), C.size_t(n)) == 1
 }
+
+///
+
+var s_randReader *io.Reader
+
+func createSlice(buf *C.char, n C.uint) []byte {
+	size := int(n)
+	return (*[1 << 30]byte)(unsafe.Pointer(buf))[:size:size]
+}
+
+// this function can't be put in callback.go
+//export wrapReadRandGo
+func wrapReadRandGo(buf *C.char, n C.uint) C.uint {
+	slice := createSlice(buf, n)
+	ret, err := (*s_randReader).Read(slice)
+	if ret == int(n) && err == nil {
+		return n
+	}
+	return 0
+}
+
+// SetRandFunc --
+func SetRandFunc(randReader *io.Reader) {
+	s_randReader = randReader
+	if randReader != nil {
+		C.blsSetRandFunc(nil, C.ReadRandFunc(unsafe.Pointer(C.wrapReadRandCgo)))
+	} else {
+		// use default random generator
+		C.blsSetRandFunc(nil, C.ReadRandFunc(unsafe.Pointer(nil)))
+	}
+}