From 700520d4d65244c03ef6d90044064a0b1819656c Mon Sep 17 00:00:00 2001
From: Sam Hocevar <sam@hocevar.net>
Date: Wed, 27 Feb 2013 18:13:22 +0000
Subject: [PATCH] math: move rand() to its own header, ensure it only returns
 positive values, and add a unit test for rand<int>.

---
 src/Makefile.am                  |  13 ++--
 src/core.h                       |  12 ++--
 src/lol/base/{base.h => all.h}   |   6 +-
 src/lol/debug/{debug.h => all.h} |   6 +-
 src/lol/gpu/{gpu.h => all.h}     |   6 +-
 src/lol/image/{image.h => all.h} |   6 +-
 src/lol/math/{math.h => all.h}   |   7 +-
 src/lol/math/rand.h              | 114 +++++++++++++++++++++++++++++++
 src/lol/math/vector.h            |   1 -
 src/lol/sys/{sys.h => all.h}     |   6 +-
 src/lolcore.vcxproj              |  12 ++--
 src/lolcore.vcxproj.filters      |  13 ++--
 src/numeric.h                    |  71 -------------------
 test/Makefile.am                 |   3 +-
 test/testsuite.vcxproj           |   1 +
 test/unit/rand.cpp               |  55 +++++++++++++++
 16 files changed, 219 insertions(+), 113 deletions(-)
 rename src/lol/base/{base.h => all.h} (85%)
 rename src/lol/debug/{debug.h => all.h} (78%)
 rename src/lol/gpu/{gpu.h => all.h} (85%)
 rename src/lol/image/{image.h => all.h} (78%)
 rename src/lol/math/{math.h => all.h} (81%)
 create mode 100644 src/lol/math/rand.h
 rename src/lol/sys/{sys.h => all.h} (84%)
 create mode 100644 test/unit/rand.cpp

diff --git a/src/Makefile.am b/src/Makefile.am
index f6fe843d..b5b45e51 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -31,26 +31,27 @@ EXTRA_DIST = easymesh/easymesh-scanner.l easymesh/easymesh-parser.y \
              gpu/lolfx-scanner.l gpu/lolfx-parser.y
 
 liblolcore_headers = \
-    lol/base/base.h \
+    lol/base/all.h \
     lol/base/log.h lol/base/array.h lol/base/types.h lol/base/array.h \
     lol/base/assert.h lol/base/string.h lol/base/hash.h lol/base/map.h \
     \
-    lol/math/math.h \
+    lol/math/all.h \
     lol/math/functions.h lol/math/vector.h lol/math/half.h lol/math/real.h \
     lol/math/remez.h lol/math/math.h lol/math/geometry.h lol/math/interp.h \
+    lol/math/rand.h \
     \
-    lol/sys/sys.h \
+    lol/sys/all.h \
     lol/sys/init.h lol/sys/file.h lol/sys/thread.h lol/sys/atomic.h \
     lol/sys/timer.h \
     \
-    lol/image/image.h \
+    lol/image/all.h \
     lol/image/color.h \
     \
-    lol/gpu/gpu.h \
+    lol/gpu/all.h \
     lol/gpu/shader.h lol/gpu/indexbuffer.h lol/gpu/vertexbuffer.h \
     lol/gpu/framebuffer.h lol/gpu/texture.h lol/gpu/lolfx.h \
     \
-    lol/debug/debug.h \
+    lol/debug/all.h \
     lol/debug/line.h \
     \
     lol/unit.h
diff --git a/src/core.h b/src/core.h
index 78f1aa9a..15710824 100644
--- a/src/core.h
+++ b/src/core.h
@@ -91,12 +91,12 @@ static inline int isnan(float f)
 #endif
 
 // Base types
-#include <lol/base/base.h>
-#include <lol/math/math.h>
-#include <lol/sys/sys.h>
-#include <lol/image/image.h>
-#include <lol/gpu/gpu.h>
-#include <lol/debug/debug.h>
+#include <lol/base/all.h>
+#include <lol/math/all.h>
+#include <lol/sys/all.h>
+#include <lol/image/all.h>
+#include <lol/gpu/all.h>
+#include <lol/debug/all.h>
 
 #include "numeric.h"
 
diff --git a/src/lol/base/base.h b/src/lol/base/all.h
similarity index 85%
rename from src/lol/base/base.h
rename to src/lol/base/all.h
index 7b3925bf..20f42df2 100644
--- a/src/lol/base/base.h
+++ b/src/lol/base/all.h
@@ -8,8 +8,8 @@
 //   http://www.wtfpl.net/ for more details.
 //
 
-#if !defined __LOL_BASE_BASE_H__
-#define __LOL_BASE_BASE_H__
+#if !defined __LOL_BASE_ALL_H__
+#define __LOL_BASE_ALL_H__
 
 #include <lol/base/types.h>
 #include <lol/base/log.h>
@@ -19,5 +19,5 @@
 #include <lol/base/hash.h>
 #include <lol/base/map.h>
 
-#endif // __LOL_BASE_BASE_H__
+#endif // __LOL_BASE_ALL_H__
 
diff --git a/src/lol/debug/debug.h b/src/lol/debug/all.h
similarity index 78%
rename from src/lol/debug/debug.h
rename to src/lol/debug/all.h
index 5c2532f2..22d772e5 100644
--- a/src/lol/debug/debug.h
+++ b/src/lol/debug/all.h
@@ -8,10 +8,10 @@
 //   http://www.wtfpl.net/ for more details.
 //
 
-#if !defined __LOL_DEBUG_DEBUG_H__
-#define __LOL_DEBUG_DEBUG_H__
+#if !defined __LOL_DEBUG_ALL_H__
+#define __LOL_DEBUG_ALL_H__
 
 #include <lol/debug/lines.h>
 
-#endif // __LOL_DEBUG_DEBUG_H__
+#endif // __LOL_DEBUG_ALL_H__
 
diff --git a/src/lol/gpu/gpu.h b/src/lol/gpu/all.h
similarity index 85%
rename from src/lol/gpu/gpu.h
rename to src/lol/gpu/all.h
index 3010d379..d134f539 100644
--- a/src/lol/gpu/gpu.h
+++ b/src/lol/gpu/all.h
@@ -8,8 +8,8 @@
 //   http://www.wtfpl.net/ for more details.
 //
 
-#if !defined __LOL_GPU_GPU_H__
-#define __LOL_GPU_GPU_H__
+#if !defined __LOL_GPU_ALL_H__
+#define __LOL_GPU_ALL_H__
 
 #include <lol/gpu/shader.h>
 #include <lol/gpu/indexbuffer.h>
@@ -18,5 +18,5 @@
 #include <lol/gpu/framebuffer.h>
 #include <lol/gpu/lolfx.h>
 
-#endif // __LOL_GPU_GPU_H__
+#endif // __LOL_GPU_ALL_H__
 
diff --git a/src/lol/image/image.h b/src/lol/image/all.h
similarity index 78%
rename from src/lol/image/image.h
rename to src/lol/image/all.h
index fb4f1e8f..d770b5fb 100644
--- a/src/lol/image/image.h
+++ b/src/lol/image/all.h
@@ -8,10 +8,10 @@
 //   http://www.wtfpl.net/ for more details.
 //
 
-#if !defined __LOL_IMAGE_IMAGE_H__
-#define __LOL_IMAGE_IMAGE_H__
+#if !defined __LOL_IMAGE_ALL_H__
+#define __LOL_IMAGE_ALL_H__
 
 #include <lol/image/color.h>
 
-#endif // __LOL_IMAGE_IMAGE_H__
+#endif // __LOL_IMAGE_ALL_H__
 
diff --git a/src/lol/math/math.h b/src/lol/math/all.h
similarity index 81%
rename from src/lol/math/math.h
rename to src/lol/math/all.h
index c5dea454..e0c889d2 100644
--- a/src/lol/math/math.h
+++ b/src/lol/math/all.h
@@ -8,8 +8,8 @@
 //   http://www.wtfpl.net/ for more details.
 //
 
-#if !defined __LOL_MATH_MATH_H__
-#define __LOL_MATH_MATH_H__
+#if !defined __LOL_MATH_ALL_H__
+#define __LOL_MATH_ALL_H__
 
 #include <lol/math/functions.h>
 #include <lol/math/half.h>
@@ -17,6 +17,7 @@
 #include <lol/math/vector.h>
 #include <lol/math/geometry.h>
 #include <lol/math/interp.h>
+#include <lol/math/rand.h>
 
-#endif // __LOL_MATH_MATH_H__
+#endif // __LOL_MATH_ALL_H__
 
diff --git a/src/lol/math/rand.h b/src/lol/math/rand.h
new file mode 100644
index 00000000..8abf7b72
--- /dev/null
+++ b/src/lol/math/rand.h
@@ -0,0 +1,114 @@
+//
+// Lol Engine
+//
+// Copyright: (c) 2010-2013 Sam Hocevar <sam@hocevar.net>
+//   This program is free software; you can redistribute it and/or
+//   modify it under the terms of the Do What The Fuck You Want To
+//   Public License, Version 2, as published by Sam Hocevar. See
+//   http://www.wtfpl.net/ for more details.
+//
+
+//
+// The Random number generators
+// ----------------------------
+//
+
+#if !defined __LOL_MATH_RAND_H__
+#define __LOL_MATH_RAND_H__
+
+#include <cstdlib>
+#include <stdint.h>
+
+namespace lol
+{
+
+/* Random number generators */
+template<typename T> static inline T rand();
+template<typename T> static inline T rand(T a);
+template<typename T> static inline T rand(T a, T b);
+
+/* One-value random number generators */
+template<typename T> static inline T rand(T a)
+{
+    return rand<T>() % a;
+}
+
+template<>
+inline half rand<half>(half a) { return a * std::rand() / RAND_MAX; }
+template<>
+inline float rand<float>(float a) { return a * std::rand() / RAND_MAX; }
+template<>
+inline double rand<double>(double a) { return a * std::rand() / RAND_MAX; }
+template<>
+inline ldouble rand<ldouble>(ldouble a) { return a * std::rand() / RAND_MAX; }
+
+/* Two-value random number generator -- no need for specialisation */
+template<typename T> static inline T rand(T a, T b)
+{
+    return a + rand<T>(b - a);
+}
+
+/* Default random number generator */
+template<typename T> static inline T rand()
+{
+    switch (sizeof(T))
+    {
+    case 1:
+        return static_cast<T>(std::rand() & 0x7f);
+    case 2:
+    {
+        uint16_t ret = std::rand();
+        if (RAND_MAX < 0x7fff)
+            ret = (ret << 7) ^ std::rand();
+        return static_cast<T>(ret & 0x7fffu);
+    }
+    case 4:
+    {
+        uint32_t ret = std::rand();
+        if (RAND_MAX >= 0xffff)
+            ret = (ret << 16) ^ std::rand();
+        else
+        {
+            ret = (ret << 8) ^ std::rand();
+            ret = (ret << 8) ^ std::rand();
+            ret = (ret << 8) ^ std::rand();
+        }
+        return static_cast<T>(ret & 0x7fffffffu);
+    }
+    case 8:
+    {
+        uint64_t ret = std::rand();
+        if (RAND_MAX >= 0xffff)
+        {
+            ret = (ret << 16) ^ std::rand();
+            ret = (ret << 16) ^ std::rand();
+            ret = (ret << 16) ^ std::rand();
+        }
+        else
+        {
+            ret = (ret << 8) ^ std::rand();
+            ret = (ret << 8) ^ std::rand();
+            ret = (ret << 8) ^ std::rand();
+            ret = (ret << 8) ^ std::rand();
+            ret = (ret << 8) ^ std::rand();
+            ret = (ret << 8) ^ std::rand();
+            ret = (ret << 8) ^ std::rand();
+        }
+        return static_cast<T>(ret & 0x7fffffffffffffffllu);
+    }
+    default:
+        ASSERT(false, "rand() doesn’t support types of size %d\n",
+               (int)sizeof(T));
+        return 0;
+    }
+}
+
+template<> inline half rand<half>() { return rand<half>(1.f); }
+template<> inline float rand<float>() { return rand<float>(1.f); }
+template<> inline double rand<double>() { return rand<double>(1.0); }
+template<> inline ldouble rand<ldouble>() { return rand<ldouble>(1.0); }
+
+} /* namespace lol */
+
+#endif // __LOL_MATH_RAND_H__
+
diff --git a/src/lol/math/vector.h b/src/lol/math/vector.h
index d164b269..c6451ec0 100644
--- a/src/lol/math/vector.h
+++ b/src/lol/math/vector.h
@@ -19,7 +19,6 @@
 #include <stdint.h>
 #include <ostream>
 
-#include <lol/math/math.h>
 #include <lol/math/half.h>
 #include <lol/math/real.h>
 
diff --git a/src/lol/sys/sys.h b/src/lol/sys/all.h
similarity index 84%
rename from src/lol/sys/sys.h
rename to src/lol/sys/all.h
index a43705ef..64c45df8 100644
--- a/src/lol/sys/sys.h
+++ b/src/lol/sys/all.h
@@ -8,8 +8,8 @@
 //   http://www.wtfpl.net/ for more details.
 //
 
-#if !defined __LOL_SYS_SYS_H__
-#define __LOL_SYS_SYS_H__
+#if !defined __LOL_SYS_ALL_H__
+#define __LOL_SYS_ALL_H__
 
 #include <lol/sys/thread.h>
 #include <lol/sys/atomic.h>
@@ -17,5 +17,5 @@
 #include <lol/sys/file.h>
 #include <lol/sys/timer.h>
 
-#endif // __LOL_SYS_SYS_H__
+#endif // __LOL_SYS_ALL_H__
 
diff --git a/src/lolcore.vcxproj b/src/lolcore.vcxproj
index 1fd0da3a..44a051ed 100644
--- a/src/lolcore.vcxproj
+++ b/src/lolcore.vcxproj
@@ -196,33 +196,35 @@
     <ClInclude Include="light.h" />
     <ClInclude Include="loldebug.h" />
     <ClInclude Include="lolgl.h" />
+    <ClInclude Include="lol\base\all.h" />
     <ClInclude Include="lol\base\array.h" />
     <ClInclude Include="lol\base\assert.h" />
-    <ClInclude Include="lol\base\base.h" />
     <ClInclude Include="lol\base\hash.h" />
     <ClInclude Include="lol\base\log.h" />
     <ClInclude Include="lol\base\map.h" />
     <ClInclude Include="lol\base\string.h" />
     <ClInclude Include="lol\base\types.h" />
-    <ClInclude Include="lol\debug\debug.h" />
+    <ClInclude Include="lol\debug\all.h" />
     <ClInclude Include="lol\debug\lines.h" />
+    <ClInclude Include="lol\gpu\all.h" />
     <ClInclude Include="lol\gpu\framebuffer.h" />
-    <ClInclude Include="lol\gpu\gpu.h" />
     <ClInclude Include="lol\gpu\indexbuffer.h" />
     <ClInclude Include="lol\gpu\lolfx.h" />
     <ClInclude Include="lol\gpu\shader.h" />
     <ClInclude Include="lol\gpu\texture.h" />
     <ClInclude Include="lol\gpu\vertexbuffer.h" />
+    <ClInclude Include="lol\image\all.h" />
     <ClInclude Include="lol\image\color.h" />
-    <ClInclude Include="lol\image\image.h" />
+    <ClInclude Include="lol\math\all.h" />
     <ClInclude Include="lol\math\functions.h" />
     <ClInclude Include="lol\math\geometry.h" />
     <ClInclude Include="lol\math\half.h" />
     <ClInclude Include="lol\math\interp.h" />
-    <ClInclude Include="lol\math\math.h" />
+    <ClInclude Include="lol\math\rand.h" />
     <ClInclude Include="lol\math\real.h" />
     <ClInclude Include="lol\math\remez.h" />
     <ClInclude Include="lol\math\vector.h" />
+    <ClInclude Include="lol\sys\all.h" />
     <ClInclude Include="lol\sys\atomic.h" />
     <ClInclude Include="lol\sys\file.h" />
     <ClInclude Include="lol\sys\init.h" />
diff --git a/src/lolcore.vcxproj.filters b/src/lolcore.vcxproj.filters
index a2b883d6..c74dfd6c 100644
--- a/src/lolcore.vcxproj.filters
+++ b/src/lolcore.vcxproj.filters
@@ -326,7 +326,10 @@
     <ClInclude Include="lol\math\half.h">
       <Filter>lol\math</Filter>
     </ClInclude>
-    <ClInclude Include="lol\math\math.h">
+    <ClInclude Include="lol\math\all.h">
+      <Filter>lol\math</Filter>
+    </ClInclude>
+    <ClInclude Include="lol\math\rand.h">
       <Filter>lol\math</Filter>
     </ClInclude>
     <ClInclude Include="lol\math\real.h">
@@ -521,7 +524,7 @@
     <ClInclude Include="easymesh\csgbsp.h">
       <Filter>easymesh</Filter>
     </ClInclude>
-    <ClInclude Include="lol\base\base.h">
+    <ClInclude Include="lol\base\all.h">
       <Filter>lol\base</Filter>
     </ClInclude>
     <ClInclude Include="lol\sys\atomic.h">
@@ -539,10 +542,10 @@
     <ClInclude Include="lol\gpu\indexbuffer.h">
       <Filter>lol\gpu</Filter>
     </ClInclude>
-    <ClInclude Include="lol\image\image.h">
+    <ClInclude Include="lol\image\all.h">
       <Filter>lol\image</Filter>
     </ClInclude>
-    <ClInclude Include="lol\gpu\gpu.h">
+    <ClInclude Include="lol\gpu\all.h">
       <Filter>lol\gpu</Filter>
     </ClInclude>
     <ClInclude Include="lol\sys\init.h">
@@ -566,7 +569,7 @@
     <ClInclude Include="lol\gpu\vertexbuffer.h">
       <Filter>lol\gpu</Filter>
     </ClInclude>
-    <ClInclude Include="lol\sys\sys.h">
+    <ClInclude Include="lol\sys\all.h">
       <Filter>lol\sys</Filter>
     </ClInclude>
     <ClInclude Include="lol\gpu\lolfx.h">
diff --git a/src/numeric.h b/src/numeric.h
index 79edea7a..04c9259c 100644
--- a/src/numeric.h
+++ b/src/numeric.h
@@ -22,77 +22,6 @@
 namespace lol
 {
 
-/* Random number generators */
-template<typename T> static inline T rand();
-template<typename T> static inline T rand(T a);
-template<typename T> static inline T rand(T a, T b);
-
-/* One-value random number generators */
-template<typename T> static inline T rand(T a)
-{
-    return rand<T>() % a;
-}
-
-template<>
-inline half rand<half>(half a) { return a * std::rand() / RAND_MAX; }
-template<>
-inline float rand<float>(float a) { return a * std::rand() / RAND_MAX; }
-template<>
-inline double rand<double>(double a) { return a * std::rand() / RAND_MAX; }
-template<>
-inline ldouble rand<ldouble>(ldouble a) { return a * std::rand() / RAND_MAX; }
-
-/* Two-value random number generator -- no need for specialisation */
-template<typename T> static inline T rand(T a, T b)
-{
-    return a + rand<T>(b - a);
-}
-
-/* Default random number generator */
-template<typename T> static inline T rand()
-{
-    switch (sizeof(T))
-    {
-    case 1:
-        return static_cast<T>(std::rand() & 0xff);
-    case 2:
-        if (RAND_MAX >= 0xffff)
-            return static_cast<T>(std::rand());
-        else
-            return static_cast<T>((std::rand() << 8) ^ std::rand());
-    case 4:
-        if (RAND_MAX >= 0xffff)
-            return static_cast<T>((std::rand() << 16) ^ std::rand());
-        else
-            return static_cast<T>((std::rand() << 24) ^ (std::rand() << 16)
-                                 ^ (std::rand() << 8) ^ std::rand());
-    case 8:
-        if (RAND_MAX >= 0xffff)
-            return static_cast<T>(((uint64_t)std::rand() << 48)
-                                ^ ((uint64_t)std::rand() << 32)
-                                ^ ((uint64_t)std::rand() << 16)
-                                ^ ((uint64_t)std::rand()));
-        else
-            return static_cast<T>(((uint64_t)std::rand() << 56)
-                                ^ ((uint64_t)std::rand() << 48)
-                                ^ ((uint64_t)std::rand() << 40)
-                                ^ ((uint64_t)std::rand() << 32)
-                                ^ ((uint64_t)std::rand() << 24)
-                                ^ ((uint64_t)std::rand() << 16)
-                                ^ ((uint64_t)std::rand() << 8)
-                                ^ ((uint64_t)std::rand()));
-    default:
-        ASSERT(false, "rand() doesn’t support types of size %d\n",
-               (int)sizeof(T));
-    }
-}
-
-template<> inline half rand<half>() { return rand<half>(1.f); }
-template<> inline float rand<float>() { return rand<float>(1.f); }
-template<> inline double rand<double>() { return rand<double>(1.0); }
-template<> inline ldouble rand<ldouble>() { return rand<ldouble>(1.0); }
-
-
 /* Next power of two. */
 template <typename T> static inline T PotUp(T val)
 {
diff --git a/test/Makefile.am b/test/Makefile.am
index ce9611db..f56d499c 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -21,7 +21,8 @@ testsuite_SOURCES = testsuite.cpp \
     unit/vector.cpp unit/matrix.cpp unit/half.cpp unit/trig.cpp \
     unit/build.cpp unit/real.cpp unit/image.cpp unit/quat.cpp unit/cmplx.cpp \
     unit/array.cpp unit/rotation.cpp unit/string.cpp unit/map.cpp \
-    unit/color.cpp unit/atomic.cpp unit/interp.cpp unit/box.cpp
+    unit/color.cpp unit/atomic.cpp unit/interp.cpp unit/box.cpp \
+    unit/rand.cpp
 testsuite_CPPFLAGS = $(AM_CPPFLAGS)
 testsuite_DEPENDENCIES = @LOL_DEPENDENCIES@
 
diff --git a/test/testsuite.vcxproj b/test/testsuite.vcxproj
index 31d5c116..063fece9 100644
--- a/test/testsuite.vcxproj
+++ b/test/testsuite.vcxproj
@@ -47,6 +47,7 @@
     <ClCompile Include="unit\map.cpp" />
     <ClCompile Include="unit\matrix.cpp" />
     <ClCompile Include="unit\quat.cpp" />
+    <ClCompile Include="unit\rand.cpp" />
     <ClCompile Include="unit\real.cpp" />
     <ClCompile Include="unit\rotation.cpp" />
     <ClCompile Include="unit\string.cpp" />
diff --git a/test/unit/rand.cpp b/test/unit/rand.cpp
new file mode 100644
index 00000000..ccc4b7fc
--- /dev/null
+++ b/test/unit/rand.cpp
@@ -0,0 +1,55 @@
+//
+// Lol Engine
+//
+// Copyright: (c) 2010-2013 Sam Hocevar <sam@hocevar.net>
+//   This program is free software; you can redistribute it and/or
+//   modify it under the terms of the Do What The Fuck You Want To
+//   Public License, Version 2, as published by Sam Hocevar. See
+//   http://www.wtfpl.net/ for more details.
+//
+
+#if defined HAVE_CONFIG_H
+#   include "config.h"
+#endif
+
+#include "core.h"
+#include "lol/unit.h"
+
+namespace lol
+{
+
+LOLUNIT_FIXTURE(RandTest)
+{
+    void SetUp() {}
+
+    void TearDown() {}
+
+    LOLUNIT_TEST(Int32Bits)
+    {
+        int const rolls = 2000;
+
+        int bits[32];
+        memset(bits, 0, sizeof(bits));
+
+        for (int i = 0; i < rolls; ++i)
+        {
+            uint32_t r = rand<int>();
+            for (int k = 0; k < 31; k++)
+            {
+                bits[k] += r & 1;
+                r >>= 1;
+            }
+        }
+
+        for (int k = 0; k < 31; k++)
+        {
+            LOLUNIT_SET_CONTEXT(k);
+            LOLUNIT_ASSERT_GREATER(bits[k], rolls / 3);
+            LOLUNIT_ASSERT_LESS(bits[k], rolls * 2 / 3);
+            LOLUNIT_UNSET_CONTEXT(k);
+        }
+    }
+};
+
+} /* namespace lol */
+