add blsInitThreadSafe

4 files changed, 62 insertions, 0 deletions

diff --git a/Makefile b/Makefile
index f798e71..1260ed7 100644
--- a/Makefile
+++ b/Makefile
@@ -3,6 +3,7 @@ LIB_DIR=lib
 OBJ_DIR=obj
 EXE_DIR=bin
 CFLAGS += -std=c++11
+LDFLAGS += -lpthread
 
 SRC_SRC=bls.cpp bls_c.cpp
 TEST_SRC=bls_test.cpp bls_c384_test.cpp
diff --git a/include/bls/bls.h b/include/bls/bls.h
index f063ca6..2a9df84 100644
--- a/include/bls/bls.h
+++ b/include/bls/bls.h
@@ -50,6 +50,10 @@ typedef struct {
 	@note init() is not thread safe
 */
 BLS_DLL_API int blsInit(int curve, int maxUnitSize);
+/*
+	wait for the finish of the first call blsInit() and do nothing
+*/
+BLS_DLL_API int blsInitThreadSafe(int curve, int maxUnitSize);
 
 BLS_DLL_API size_t blsGetOpUnitSize(void);
 // return strlen(buf) if success else 0
diff --git a/src/bls_c.cpp b/src/bls_c.cpp
index ccdc909..563ecc9 100644
--- a/src/bls_c.cpp
+++ b/src/bls_c.cpp
@@ -36,6 +36,23 @@ int blsInit(int curve, int maxUnitSize)
 	return -1;
 }
 
+#if CYBOZU_CPP_VERSION >= CYBOZU_CPP_VERSION_CPP11
+#include <mutex>
+static std::mutex g_mutex;
+static int g_curve = -1;
+
+int blsInitThreadSafe(int curve, int maxUnitSize)
+{
+	int ret = 0;
+	std::lock_guard<std::mutex> lock(g_mutex);
+	if (g_curve != curve) {
+		ret = blsInit(curve, maxUnitSize);
+		g_curve = curve;
+	}
+	return ret;
+}
+#endif
+
 static inline const mclBnG1 *cast(const G1* x) { return (const mclBnG1*)x; }
 static inline const mclBnG2 *cast(const G2* x) { return (const mclBnG2*)x; }
 
diff --git a/test/bls_c384_test.cpp b/test/bls_c384_test.cpp
index 8c3761f..2e61e2c 100644
--- a/test/bls_c384_test.cpp
+++ b/test/bls_c384_test.cpp
@@ -62,6 +62,46 @@ void blsOrderTest(const char *curveOrder, const char *fieldOrder)
 	CYBOZU_TEST_EQUAL(buf, fieldOrder);
 }
 
+#if CYBOZU_CPP_VERSION >= CYBOZU_CPP_VERSION_CPP11
+#include <thread>
+#include <vector>
+struct Thread {
+	std::unique_ptr<std::thread> t;
+	Thread() : t() {}
+	~Thread()
+	{
+		if (t) {
+			t->join();
+		}
+	}
+	template<class F>
+	void run(F func, int p1, int p2)
+	{
+		t.reset(new std::thread(func, p1, p2));
+	}
+};
+CYBOZU_TEST_AUTO(multipleInit)
+{
+	const size_t n = 100;
+	{
+		std::vector<Thread> vt(n);
+		for (size_t i = 0; i < n; i++) {
+			vt[i].run(blsInitThreadSafe, mclBn_CurveFp254BNb, MCLBN_FP_UNIT_SIZE);
+		}
+	}
+	CYBOZU_TEST_EQUAL(blsGetOpUnitSize(), 4u);
+#if MCLBN_FP_UNIT_SIZE == 6
+	{
+		std::vector<Thread> vt(n);
+		for (size_t i = 0; i < n; i++) {
+			vt[i].run(blsInitThreadSafe, mclBn_CurveFp382_1, MCLBN_FP_UNIT_SIZE);
+		}
+	}
+	CYBOZU_TEST_EQUAL(blsGetOpUnitSize(), 6u);
+#endif
+}
+#endif
+
 CYBOZU_TEST_AUTO(all)
 {
 	const int tbl[] = {