From 02b8d9b4d669ae215b1c2423fa961db1b69a487f Mon Sep 17 00:00:00 2001
From: Sverker Eriksson <sverker@erlang.org>
Date: Wed, 7 Sep 2011 11:09:43 +0200
Subject: [crypto] Fix rand_uniform for negative values

Also let it throw badarg if 'Hi' is not larger than 'Lo'.
---
 lib/crypto/src/crypto.erl | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

(limited to 'lib/crypto/src')

diff --git a/lib/crypto/src/crypto.erl b/lib/crypto/src/crypto.erl
index c35dfcebab..c3e13d6b91 100644
--- a/lib/crypto/src/crypto.erl
+++ b/lib/crypto/src/crypto.erl
@@ -415,6 +415,13 @@ rand_uniform(From,To) when is_binary(From), is_binary(To) ->
 	    Whatever
     end;
 rand_uniform(From,To) when is_integer(From),is_integer(To) ->
+    if From < 0 -> 
+	    rand_uniform_pos(0, To - From) + From;
+       true ->
+	    rand_uniform_pos(From, To)
+    end.
+
+rand_uniform_pos(From,To) when From < To ->
     BinFrom = mpint(From),
     BinTo = mpint(To),
     case rand_uniform(BinFrom, BinTo) of
@@ -422,7 +429,9 @@ rand_uniform(From,To) when is_integer(From),is_integer(To) ->
             erlint(Result);
         Other ->
             Other
-    end.
+    end;
+rand_uniform_pos(_,_) ->
+    error(badarg).
 
 rand_uniform_nif(_From,_To) -> ?nif_stub.     
 
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