From acda316c12f36991f9044ed94ee70c59d23efa7c Mon Sep 17 00:00:00 2001
From: Recep Aslantas <info@recp.me>
Date: Mon, 2 Apr 2018 16:18:50 +0300
Subject: [PATCH] get sign of float helper as -1, +1 and  0

* add clarification for zero input
---
 docs/source/util.rst | 17 ++++++++++++++++-
 include/cglm/util.h  | 17 ++++++++++++++++-
 2 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/docs/source/util.rst b/docs/source/util.rst
index 43a9d49..a9f4066 100644
--- a/docs/source/util.rst
+++ b/docs/source/util.rst
@@ -13,6 +13,7 @@ Table of contents (click to go):
 Functions:
 
 1. :c:func:`glm_sign`
+#. :c:func:`glm_signf`
 #. :c:func:`glm_rad`
 #. :c:func:`glm_deg`
 #. :c:func:`glm_make_rad`
@@ -27,7 +28,9 @@ Functions documentation
 
 .. c:function:: int  glm_sign(int val)
 
-    | returns sign of 32 bit integer as +1 or -1
+    | returns sign of 32 bit integer as +1, -1, 0
+
+    | **Important**: It returns 0 for zero input
 
     Parameters:
       | *[in]*  **val**   an integer
@@ -35,6 +38,18 @@ Functions documentation
     Returns:
       sign of given number
 
+.. c:function:: float  glm_signf(float val)
+
+    | returns sign of 32 bit integer as +1.0, -1.0, 0.0
+
+    | **Important**: It returns 0.0f for zero input
+
+    Parameters:
+      | *[in]*  **val**   a float
+
+    Returns:
+      sign of given number
+
 .. c:function:: float  glm_rad(float deg)
 
     | convert degree to radians
diff --git a/include/cglm/util.h b/include/cglm/util.h
index 20b4c67..2a9ece7 100644
--- a/include/cglm/util.h
+++ b/include/cglm/util.h
@@ -21,7 +21,9 @@
 #include "common.h"
 
 /*!
- * @brief get sign of 32 bit integer as +1 or -1
+ * @brief get sign of 32 bit integer as +1, -1, 0
+ *
+ * Important: It returns 0 for zero input
  *
  * @param val integer value
  */
@@ -31,6 +33,19 @@ glm_sign(int val) {
   return ((val >> 31) - (-val >> 31));
 }
 
+/*!
+ * @brief get sign of 32 bit float as +1, -1, 0
+ *
+ * Important: It returns 0 for zero/NaN input
+ *
+ * @param val float value
+ */
+CGLM_INLINE
+float
+glm_signf(float val) {
+  return (val > 0.0f) - (val < 0.0f);
+}
+
 /*!
  * @brief convert degree to radians
  *