From 98bd4f3ec60ab1bb09b6becd7a5e1d91d35c81cd Mon Sep 17 00:00:00 2001
From: WolverinDEV <git@mcgalaxy.de>
Date: Wed, 25 Apr 2018 19:08:05 +0200
Subject: [PATCH] Added some nice helper methods

---
 CMakeLists.txt |  3 +++
 include/ge.h   | 11 +++++++++--
 include/sc.h   |  8 ++++++++
 src/ge.c       |  7 ++++++-
 4 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index ca51d0f..413f62e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,6 +1,9 @@
 project(ed25519)
 cmake_minimum_required(VERSION 3.9)
 
+set(CMAKE_CXX_STANDARD 11)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+
 option(USE_OPENSSL "Use openssl for sha 512 (Faster than the default installation" ON)
 
 set(SOURCE
diff --git a/include/ge.h b/include/ge.h
index 88509d8..0875f87 100644
--- a/include/ge.h
+++ b/include/ge.h
@@ -51,10 +51,13 @@ typedef struct {
   fe T2d;
 } ge_cached;
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 void ge_p3_tobytes(unsigned char *s, const ge_p3 *h);
 void ge_tobytes(unsigned char *s, const ge_p2 *h);
 int ge_frombytes_negate_vartime(ge_p3 *h, const unsigned char *s);
-
 void ge_add(ge_p1p1 *r, const ge_p3 *p, const ge_cached *q);
 void ge_sub(ge_p1p1 *r, const ge_p3 *p, const ge_cached *q);
 void ge_double_scalarmult_vartime(ge_p2 *r, const unsigned char *a, const ge_p3 *A, const unsigned char *b);
@@ -62,7 +65,6 @@ void ge_scalarmult_vartime(ge_p2 *r, const unsigned char *a, const ge_p3 *A);
 void ge_madd(ge_p1p1 *r, const ge_p3 *p, const ge_precomp *q);
 void ge_msub(ge_p1p1 *r, const ge_p3 *p, const ge_precomp *q);
 void ge_scalarmult_base(ge_p3 *h, const unsigned char *a);
-
 void ge_p1p1_to_p2(ge_p2 *r, const ge_p1p1 *p);
 void ge_p1p1_to_p3(ge_p3 *r, const ge_p1p1 *p);
 void ge_p2_0(ge_p2 *h);
@@ -71,5 +73,10 @@ void ge_p3_0(ge_p3 *h);
 void ge_p3_dbl(ge_p1p1 *r, const ge_p3 *p);
 void ge_p3_to_cached(ge_cached *r, const ge_p3 *p);
 void ge_p3_to_p2(ge_p2 *r, const ge_p3 *p);
+void ge_p2_to_p3(ge_p3 *r, const ge_p2 *p);
+
+#ifdef __cplusplus
+}
+#endif
 
 #endif
diff --git a/include/sc.h b/include/sc.h
index e29e7fa..18b1d73 100644
--- a/include/sc.h
+++ b/include/sc.h
@@ -6,7 +6,15 @@ The set of scalars is \Z/l
 where l = 2^252 + 27742317777372353535851937790883648493.
 */
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 void sc_reduce(unsigned char *s);
 void sc_muladd(unsigned char *s, const unsigned char *a, const unsigned char *b, const unsigned char *c);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif
diff --git a/src/ge.c b/src/ge.c
index 3bb0e14..be6c27a 100644
--- a/src/ge.c
+++ b/src/ge.c
@@ -63,7 +63,7 @@ static void slide(signed char *r, const unsigned char *a) {
  */
 void ge_scalarmult_vartime(ge_p2 *r, const unsigned char *a, const ge_p3 *A) {
     unsigned char zero[32];
-    memset(zero, 0, sizeof(zero));
+    memset(zero, 0, 32);
     ge_double_scalarmult_vartime(r, a, A, zero);
 }
 
@@ -327,6 +327,11 @@ void ge_p3_to_p2(ge_p2 *r, const ge_p3 *p) {
     fe_copy(r->Z, p->Z);
 }
 
+void ge_p2_to_p3(ge_p3 *r, const ge_p2 *p) {
+	uint8_t buffer[32];
+	ge_tobytes(buffer, p);
+	ge_frombytes_negate_vartime(r, buffer);
+}
 
 void ge_p3_tobytes(unsigned char *s, const ge_p3 *h) {
     fe recip;