From 90c022c803ff378df63a5dc583925d2b817ced1a Mon Sep 17 00:00:00 2001
From: Zhi Guan <guanzhi1980@gmail.com>
Date: Sun, 19 Feb 2023 08:24:17 +0800
Subject: [PATCH] Add sm2_point_ functions

---
 include/gmssl/sm2.h | 5 ++++-
 src/sm2_alg.c       | 6 ++++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/include/gmssl/sm2.h b/include/gmssl/sm2.h
index 44888758..1d39fde0 100644
--- a/include/gmssl/sm2.h
+++ b/include/gmssl/sm2.h
@@ -164,13 +164,16 @@ typedef struct {
 	uint8_t y[32];
 } SM2_POINT;
 
+#define sm2_point_init(P) memset((P),0,sizeof(SM2_POINT))
+#define sm2_point_set_infinity(P) sm2_point_init(P)
+int sm2_point_from_octets(SM2_POINT *P, const uint8_t *in, size_t inlen);
 void sm2_point_to_compressed_octets(const SM2_POINT *P, uint8_t out[33]);
 void sm2_point_to_uncompressed_octets(const SM2_POINT *P, uint8_t out[65]);
-int sm2_point_from_octets(SM2_POINT *P, const uint8_t *in, size_t inlen);
 
 int sm2_point_from_x(SM2_POINT *P, const uint8_t x[32], int y);
 int sm2_point_from_xy(SM2_POINT *P, const uint8_t x[32], const uint8_t y[32]);
 int sm2_point_is_on_curve(const SM2_POINT *P);
+int sm2_point_is_at_infinity(const SM2_POINT *P);
 int sm2_point_add(SM2_POINT *R, const SM2_POINT *P, const SM2_POINT *Q);
 int sm2_point_sub(SM2_POINT *R, const SM2_POINT *P, const SM2_POINT *Q);
 int sm2_point_neg(SM2_POINT *R, const SM2_POINT *P);
diff --git a/src/sm2_alg.c b/src/sm2_alg.c
index 8364a8ab..1865eaf4 100644
--- a/src/sm2_alg.c
+++ b/src/sm2_alg.c
@@ -13,6 +13,7 @@
 #include <string.h>
 #include <assert.h>
 #include <gmssl/sm2.h>
+#include <gmssl/mem.h>
 #include <gmssl/asn1.h>
 #include <gmssl/rand.h>
 #include <gmssl/error.h>
@@ -1088,6 +1089,11 @@ int sm2_point_is_on_curve(const SM2_POINT *P)
 	return sm2_jacobian_point_is_on_curve(&T);
 }
 
+int sm2_point_is_at_infinity(const SM2_POINT *P)
+{
+	return mem_is_zero((uint8_t *)P, sizeof(SM2_POINT));
+}
+
 int sm2_point_from_x(SM2_POINT *P, const uint8_t x[32], int y)
 {
 	SM2_BN _x, _y, _g, _z;