From eaeedfd6c133fa1c7008a344c96451d3117339d0 Mon Sep 17 00:00:00 2001
From: Stephan Renatus <srenatus@chef.io>
Date: Tue, 20 Jun 2017 12:40:06 +0200
Subject: [PATCH] Catch and re-throw big exponent exceptions

```
$ rebar3 shell
===> Verifying dependencies...
===> Compiling jiffy
Erlang/OTP 18 [erts-7.3] [source] [64-bit] [smp:8:8] [async-threads:0] [hipe] [kernel-poll:false]

Eshell V7.3  (abort with ^G)
1> jiffy:decode(<<"[1e310]">>).
** exception error: an error occurred when evaluating an arithmetic expression
     in function  math:pow/2
        called as math:pow(10,310)
     in call from jiffy:finish_decode/1 (jiffy/_build/default/lib/jiffy/src/jiffy.erl, line 118)
     in call from jiffy:finish_decode_arr/2 (jiffy/_build/default/lib/jiffy/src/jiffy.erl, line 149)
2> jiffy:decode(<<"[0.2e310]">>).
** exception error: bad argument
     in function  list_to_float/1
        called as list_to_float("0.2e310")
     in call from jiffy:finish_decode/1 (jiffy/_build/default/lib/jiffy/src/jiffy.erl, line 120)
     in call from jiffy:finish_decode_arr/2 (jiffy/_build/default/lib/jiffy/src/jiffy.erl, line 149)
3>
```

That `310` could depend on my machine, since `math:pow/2` says it's a limitation coming from libc.

With this change, this still throws an exception, but it doesn't come
from math or erlang, but jiffy:

```
1> jiffy:decode(<<"[1e310]">>).
** exception throw: {error,{range,310}}
     in function  jiffy:finish_decode/1 (jiffy/_build/default/lib/jiffy/src/jiffy.erl, line 121)
     in call from jiffy:finish_decode_arr/2 (jiffy/_build/default/lib/jiffy/src/jiffy.erl, line 157)
2>
```

Signed-off-by: Stephan Renatus <srenatus@chef.io>
---
 src/jiffy.erl                  | 12 ++++++++++--
 test/jiffy_03_number_tests.erl |  2 ++
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/src/jiffy.erl b/src/jiffy.erl
index 08fa3c0..8b9432f 100644
--- a/src/jiffy.erl
+++ b/src/jiffy.erl
@@ -115,9 +115,17 @@ finish_decode({bignum_e, Value}) ->
             {E, []} = string:to_integer(ExpStr),
             {I, E}
     end,
-    IVal * math:pow(10, EVal);
+    try
+        IVal * math:pow(10, EVal)
+    catch
+        error:badarith -> throw({error, {range, EVal}})
+    end;
 finish_decode({bigdbl, Value}) ->
-    list_to_float(binary_to_list(Value));
+    try
+        list_to_float(binary_to_list(Value))
+    catch
+        error:badarg -> throw({error, {range, Value}})
+    end;
 finish_decode({Pairs}) when is_list(Pairs) ->
     finish_decode_obj(Pairs, []);
 finish_decode(Vals) when is_list(Vals) ->
diff --git a/test/jiffy_03_number_tests.erl b/test/jiffy_03_number_tests.erl
index ac7b95f..f30b52e 100644
--- a/test/jiffy_03_number_tests.erl
+++ b/test/jiffy_03_number_tests.erl
@@ -97,6 +97,8 @@ cases(error) ->
         <<"1E">>,
         <<"1-E2">>,
         <<"2E +3">>,
+        <<"1E3000">>,
+        <<"0.1E30000">>,
         <<"1EA">>
     ];