From 65a3fc67f26c8dc4a86041d0864a4bef3f1b9df6 Mon Sep 17 00:00:00 2001
From: Andrey Rys <rys@lynxlynx.ru>
Date: Tue, 9 Apr 2019 18:14:17 +0700
Subject: [PATCH] tfprng: expose range formula in form of macros to build
 custom range generators.

---
 tfprng.c | 2 +-
 tfprng.h | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/tfprng.c b/tfprng.c
index 5022857..f83963c 100644
--- a/tfprng.c
+++ b/tfprng.c
@@ -85,7 +85,7 @@ TFNG_UNIT_TYPE tfng_prng_range_r(void *sdata, TFNG_UNIT_TYPE s, TFNG_UNIT_TYPE d
 {
 	TFNG_UNIT_TYPE c = tfng_prng_random_r(sdata);
 	if (d <= s) return s;
-	return s + c / ((TFNG_UNIT_TYPE)~0 / (d - s + 1) + 1);
+	return TFNG_PRNG_RANGE(c, TFNG_UNIT_TYPE, s, d);
 }
 
 TFNG_UNIT_TYPE tfng_prng_range(TFNG_UNIT_TYPE s, TFNG_UNIT_TYPE d)
diff --git a/tfprng.h b/tfprng.h
index f7d3b3f..15880b7 100644
--- a/tfprng.h
+++ b/tfprng.h
@@ -6,6 +6,7 @@
 
 #define TFNG_PRNG_KEY_SIZE TFNG_KEY_SIZE
 #define TFNG_PRNG_SIZE_UNIT TFNG_SIZE_UNIT
+#define TFNG_PRNG_RANGE(C, T, S, D) (S + C / ((T)~0 / (D - S + 1) + 1))
 
 size_t tfng_prng_datasize(void);
 void tfng_prng_seedkey_r(void *sdata, const void *skey);