From d8c3672bce7edfb82534c3c33e7cbe86afb7cf11 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=D0=91=D1=80=D0=B0=D0=BD=D0=B8=D0=BC=D0=B8=D1=80=20=D0=9A?=
 =?UTF-8?q?=D0=B0=D1=80=D0=B0=D1=9F=D0=B8=D1=9B?=
 <branimirkaradzic@gmail.com>
Date: Sat, 11 Nov 2023 07:42:44 -0800
Subject: [PATCH] Allow 0 as alignment value.

---
 include/bx/inline/uint32_t.inl | 8 ++++----
 tests/uint32_test.cpp          | 7 +++++++
 2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/include/bx/inline/uint32_t.inl b/include/bx/inline/uint32_t.inl
index 7db3788..d5c9e49 100644
--- a/include/bx/inline/uint32_t.inl
+++ b/include/bx/inline/uint32_t.inl
@@ -708,7 +708,7 @@ namespace bx
 	template<typename Ty>
 	inline BX_CONSTEXPR_FUNC bool isAligned(Ty _a, int32_t _align)
 	{
-		const Ty mask = Ty(_align - 1);
+		const Ty mask = Ty(max(1, _align) - 1);
 		return 0 == (_a & mask);
 	}
 
@@ -727,9 +727,9 @@ namespace bx
 	}
 
 	template<typename Ty>
-	inline BX_CONSTEXPR_FUNC  Ty alignDown(Ty _a, int32_t _align)
+	inline BX_CONSTEXPR_FUNC Ty alignDown(Ty _a, int32_t _align)
 	{
-		const Ty mask = Ty(_align - 1);
+		const Ty mask = Ty(max(1, _align) - 1);
 		return Ty(_a & ~mask);
 	}
 
@@ -752,7 +752,7 @@ namespace bx
 	template<typename Ty>
 	inline BX_CONSTEXPR_FUNC Ty alignUp(Ty _a, int32_t _align)
 	{
-		const Ty mask = Ty(_align - 1);
+		const Ty mask = Ty(max(1, _align) - 1);
 		return Ty( (_a + mask) & ~mask);
 	}
 
diff --git a/tests/uint32_test.cpp b/tests/uint32_test.cpp
index 0618c01..5d5fb6b 100644
--- a/tests/uint32_test.cpp
+++ b/tests/uint32_test.cpp
@@ -141,6 +141,13 @@ TEST_CASE("align", "[uint32_t]")
 	REQUIRE( bx::isAligned(64, 8) );
 	REQUIRE(!bx::isAligned(63, 8) );
 
+	for (int32_t ii = 0; ii < 1024; ++ii)
+	{
+		REQUIRE(bx::isAligned(ii, 0) );
+		REQUIRE(ii == bx::alignUp(ii, 0) );
+		REQUIRE(ii == bx::alignDown(ii, 0) );
+	}
+
 	REQUIRE(  0 == bx::alignUp(  0, 16) );
 	REQUIRE( 16 == bx::alignUp(  1, 16) );
 	REQUIRE( 16 == bx::alignUp( 15, 16) );