Add group element storage type

sipa · sipa · commit e68d7208ecb5 · 2015-01-25T00:31:56.000-04:00
diff --git a/src/group.h b/src/group.h
@@ -25,6 +25,11 @@ typedef struct {
     int infinity; /* whether this represents the point at infinity */
 } secp256k1_gej_t;
 
+typedef struct {
+    secp256k1_fe_storage_t x;
+    secp256k1_fe_storage_t y;
+} secp256k1_ge_storage_t;
+
 /** Set a group element equal to the point at infinity */
 static void secp256k1_ge_set_infinity(secp256k1_ge_t *r);
 
@@ -99,4 +104,10 @@ static void secp256k1_gej_clear(secp256k1_gej_t *r);
 /** Clear a secp256k1_ge_t to prevent leaking sensitive information. */
 static void secp256k1_ge_clear(secp256k1_ge_t *r);
 
+/** Convert a group element to the storage type. */
+static void secp256k1_ge_to_storage(secp256k1_ge_storage_t *r, const secp256k1_ge_t*);
+
+/** Convert a group element back from the storage type. */
+static void secp256k1_ge_from_storage(secp256k1_ge_t *r, const secp256k1_ge_storage_t*);
+
 #endif
diff --git a/src/group_impl.h b/src/group_impl.h
@@ -392,6 +392,23 @@ static void secp256k1_gej_get_hex(char *r131, const secp256k1_gej_t *a) {
     secp256k1_ge_get_hex(r131, &t);
 }
 
+static void secp256k1_ge_to_storage(secp256k1_ge_storage_t *r, const secp256k1_ge_t *a) {
+    secp256k1_fe_t x, y;
+    VERIFY_CHECK(!a->infinity);
+    x = a->x;
+    secp256k1_fe_normalize(&x);
+    y = a->y;
+    secp256k1_fe_normalize(&y);
+    secp256k1_fe_to_storage(&r->x, &x);
+    secp256k1_fe_to_storage(&r->y, &y);
+}
+
+static void secp256k1_ge_from_storage(secp256k1_ge_t *r, const secp256k1_ge_storage_t *a) {
+    secp256k1_fe_from_storage(&r->x, &a->x);
+    secp256k1_fe_from_storage(&r->y, &a->y);
+    r->infinity = 0;
+}
+
 #ifdef USE_ENDOMORPHISM
 static void secp256k1_gej_mul_lambda(secp256k1_gej_t *r, const secp256k1_gej_t *a) {
     static const secp256k1_fe_t beta = SECP256K1_FE_CONST(
