From 6d40cfd77f1d2f1e1403e4b41c0b53ae6499ea11 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= <bjorn@erlang.org>
Date: Mon, 27 Jun 2016 12:54:04 +0200
Subject: Add math:floor/1 and math:ceil/1

Add math:floor/1 and math:ceil/1 to avoid unnecessary conversions
in floating point expressions. That is, instead of having to write
float(floor(X)) as part of a floating point expressions, we can
write simply math:floor(X).
---
 lib/stdlib/doc/src/math.xml    |  2 +
 lib/stdlib/src/math.erl        | 13 +++++-
 lib/stdlib/test/Makefile       |  1 +
 lib/stdlib/test/math_SUITE.erl | 92 ++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 107 insertions(+), 1 deletion(-)
 create mode 100644 lib/stdlib/test/math_SUITE.erl

(limited to 'lib/stdlib')

diff --git a/lib/stdlib/doc/src/math.xml b/lib/stdlib/doc/src/math.xml
index 1358ce5cbf..70ca6ae78e 100644
--- a/lib/stdlib/doc/src/math.xml
+++ b/lib/stdlib/doc/src/math.xml
@@ -57,9 +57,11 @@
       <name name="atan" arity="1"/>
       <name name="atan2" arity="2"/>
       <name name="atanh" arity="1"/>
+      <name name="ceil" arity="1"/>
       <name name="cos" arity="1"/>
       <name name="cosh" arity="1"/>
       <name name="exp" arity="1"/>
+      <name name="floor" arity="1"/>
       <name name="log" arity="1"/>
       <name name="log10" arity="1"/>
       <name name="log2" arity="1"/>
diff --git a/lib/stdlib/src/math.erl b/lib/stdlib/src/math.erl
index 97c965e27a..1db48cd0a2 100644
--- a/lib/stdlib/src/math.erl
+++ b/lib/stdlib/src/math.erl
@@ -25,7 +25,8 @@
 
 -export([sin/1, cos/1, tan/1, asin/1, acos/1, atan/1, atan2/2, sinh/1,
          cosh/1, tanh/1, asinh/1, acosh/1, atanh/1, exp/1, log/1,
-         log2/1, log10/1, pow/2, sqrt/1, erf/1, erfc/1]).
+         log2/1, log10/1, pow/2, sqrt/1, erf/1, erfc/1,
+	 ceil/1, floor/1]).
 
 -spec acos(X) -> float() when
       X :: number().
@@ -63,6 +64,11 @@ atan2(_, _) ->
 atanh(_) ->
     erlang:nif_error(undef).
 
+-spec ceil(X) -> float() when
+      X :: number().
+ceil(_) ->
+    erlang:nif_error(undef).
+
 -spec cos(X) -> float() when
       X :: number().
 cos(_) ->
@@ -88,6 +94,11 @@ erfc(_) ->
 exp(_) ->
     erlang:nif_error(undef).
 
+-spec floor(X) -> float() when
+      X :: number().
+floor(_) ->
+    erlang:nif_error(undef).
+
 -spec log(X) -> float() when
       X :: number().
 log(_) ->
diff --git a/lib/stdlib/test/Makefile b/lib/stdlib/test/Makefile
index 28c35aed55..deac04aa66 100644
--- a/lib/stdlib/test/Makefile
+++ b/lib/stdlib/test/Makefile
@@ -52,6 +52,7 @@ MODULES= \
 	io_proto_SUITE \
 	lists_SUITE \
 	log_mf_h_SUITE \
+	math_SUITE \
 	ms_transform_SUITE \
 	proc_lib_SUITE \
 	qlc_SUITE \
diff --git a/lib/stdlib/test/math_SUITE.erl b/lib/stdlib/test/math_SUITE.erl
new file mode 100644
index 0000000000..2b29e44228
--- /dev/null
+++ b/lib/stdlib/test/math_SUITE.erl
@@ -0,0 +1,92 @@
+%%
+%% %CopyrightBegin%
+%%
+%% Copyright Ericsson AB 2007-2016. All Rights Reserved.
+%%
+%% Licensed under the Apache License, Version 2.0 (the "License");
+%% you may not use this file except in compliance with the License.
+%% You may obtain a copy of the License at
+%%
+%%     http://www.apache.org/licenses/LICENSE-2.0
+%%
+%% Unless required by applicable law or agreed to in writing, software
+%% distributed under the License is distributed on an "AS IS" BASIS,
+%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+%% See the License for the specific language governing permissions and
+%% limitations under the License.
+%%
+%% %CopyrightEnd%
+%%
+
+-module(math_SUITE).
+
+-include_lib("common_test/include/ct.hrl").
+
+%% Test server specific exports
+-export([all/0, suite/0,groups/0,init_per_suite/1, end_per_suite/1,
+	 init_per_group/2,end_per_group/2,
+	 init_per_testcase/2, end_per_testcase/2]).
+
+%% Test cases
+-export([floor_ceil/1]).
+
+
+suite() ->
+    [{ct_hooks,[ts_install_cth]},
+     {timetrap,{minutes,1}}].
+
+all() ->
+    [floor_ceil].
+
+groups() ->
+    [].
+
+init_per_suite(Config) ->
+    Config.
+
+end_per_suite(_Config) ->
+    ok.
+
+init_per_group(_GroupName, Config) ->
+    Config.
+
+end_per_group(_GroupName, Config) ->
+    Config.
+
+
+init_per_testcase(_Case, Config) ->
+    Config.
+
+end_per_testcase(_Case, _Config) ->
+    ok.
+
+floor_ceil(_Config) ->
+    MinusZero = 0.0/(-1.0),
+    -43.0 = do_floor_ceil(-42.1),
+    -43.0 = do_floor_ceil(-42.7),
+    0.0 = do_floor_ceil(MinusZero),
+    10.0 = do_floor_ceil(10.1),
+    10.0 = do_floor_ceil(10.9),
+
+    -533.0 = do_floor_ceil(-533.0),
+    453555.0 = do_floor_ceil(453555.0),
+
+    -58.0 = do_floor_ceil(-58),
+    777.0 = do_floor_ceil(777),
+
+    ok.
+
+do_floor_ceil(Val) ->
+    Floor = math:floor(Val),
+    Ceil = math:ceil(Val),
+
+    true = is_float(Floor),
+    true = is_float(Ceil),
+
+    if
+	Floor =:= Ceil ->
+	    Floor;
+	true ->
+	    1.0 = Ceil - Floor,
+	    Floor
+    end.
-- 
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