Add order_gen_input, for reading pregenerated curve order

2 files changed, 25 insertions, 0 deletions

diff --git a/src/math/order.c b/src/math/order.c
index 347015c..2c963f6 100644
--- a/src/math/order.c
+++ b/src/math/order.c
@@ -3,6 +3,7 @@
  * Copyright (C) 2017 J08nY
  */
 #include "order.h"
+#include "io/input.h"
 
 GEN order_factors(curve_t *curve, const config_t *cfg) {
 	if (cfg->prime) {
@@ -37,6 +38,19 @@ GEN order_groups(curve_t *curve, const config_t *cfg, GEN factors) {
 	}
 }
 
+GENERATOR(order_gen_input) {
+	pari_sp ltop = avma;
+	GEN ord = input_int("order", cfg->bits);
+	if (gequalm1(ord)) {
+		avma = ltop;
+		return -4;
+	} else {
+		curve->order = ord;
+		obj_insert_shallow(curve->curve, 1, ord);
+		return 1;
+	}
+}
+
 GENERATOR(order_gen_any) {
 	GEN ord = ellff_get_card(curve->curve);
 	if (isclone(ord)) {
diff --git a/src/math/order.h b/src/math/order.h
index ce3cd0b..6d1ed1f 100644
--- a/src/math/order.h
+++ b/src/math/order.h
@@ -29,6 +29,17 @@ GEN order_groups(curve_t *curve, const config_t *cfg, GEN factors);
 
 /**
  * GENERATOR(gen_t)
+ * Reads the curve order from input, does not verify it.
+ *
+ * @param curve
+ * @param cfg
+ * @param args
+ * @return state diff
+ */
+GENERATOR(order_gen_input);
+
+/**
+ * GENERATOR(gen_t)
  * Calculates the curve order, using a general algorithm.
  * Always succeeds.
  *