From 076e845912c2ac09cfb86d59bd1fdff350a40c39 Mon Sep 17 00:00:00 2001
From: Tsuda Kageyu <tsuda.kageyu@gmail.com>
Date: Mon, 3 Aug 2015 13:08:58 +0900
Subject: [PATCH] Run-time check for integer byte order rather than CMake
 check. It will easily be optimized out.

---
 ConfigureChecks.cmake          | 11 -----------
 config.h.cmake                 |  4 ----
 taglib/toolkit/tbytevector.cpp |  4 ++--
 taglib/toolkit/tstring.cpp     |  2 +-
 taglib/toolkit/tutils.h        | 21 +++------------------
 5 files changed, 6 insertions(+), 36 deletions(-)

diff --git a/ConfigureChecks.cmake b/ConfigureChecks.cmake
index fad3ad34..08ef6a4d 100644
--- a/ConfigureChecks.cmake
+++ b/ConfigureChecks.cmake
@@ -1,7 +1,6 @@
 include(CheckLibraryExists)
 include(CheckTypeSize)
 include(CheckCXXSourceCompiles)
-include(TestBigEndian)
 
 # Check if the size of numeric types are suitable.
 
@@ -35,16 +34,6 @@ if(NOT ${SIZEOF_DOUBLE} EQUAL 8)
   message(FATAL_ERROR "TagLib requires that double is 64-bit wide.")
 endif()
 
-# Determine the CPU byte order.
-
-test_big_endian(IS_BIG_ENDIAN)
-
-if(NOT IS_BIG_ENDIAN)
-  set(SYSTEM_BYTEORDER 1)
-else()
-  set(SYSTEM_BYTEORDER 2)
-endif()
-
 # Determine which kind of atomic operations your compiler supports.
 
 check_cxx_source_compiles("
diff --git a/config.h.cmake b/config.h.cmake
index 2feded0f..a001c5c8 100644
--- a/config.h.cmake
+++ b/config.h.cmake
@@ -1,9 +1,5 @@
 /* config.h. Generated by cmake from config.h.cmake */
 
-/* Integer byte order of your target system */
-/* 1 if little-endian, 2 if big-endian. */
-#cmakedefine   SYSTEM_BYTEORDER ${SYSTEM_BYTEORDER}
-
 /* Defined if your compiler supports some byte swap functions */
 #cmakedefine   HAVE_GCC_BYTESWAP_16 1
 #cmakedefine   HAVE_GCC_BYTESWAP_32 1
diff --git a/taglib/toolkit/tbytevector.cpp b/taglib/toolkit/tbytevector.cpp
index ca1c30bc..6262bec6 100644
--- a/taglib/toolkit/tbytevector.cpp
+++ b/taglib/toolkit/tbytevector.cpp
@@ -209,7 +209,7 @@ T toNumber(const ByteVector &v, size_t offset, size_t length, bool mostSignifica
 template <class T>
 T toNumber(const ByteVector &v, size_t offset, bool mostSignificantByteFirst)
 {
-  static const bool isBigEndian = (Utils::SystemByteOrder == Utils::BigEndian);
+  const bool isBigEndian = (Utils::systemByteOrder() == Utils::BigEndian);
   const bool swap = (mostSignificantByteFirst != isBigEndian);
 
   if(offset + sizeof(T) > v.size())
@@ -228,7 +228,7 @@ T toNumber(const ByteVector &v, size_t offset, bool mostSignificantByteFirst)
 template <class T>
 ByteVector fromNumber(T value, bool mostSignificantByteFirst)
 {
-  static const bool isBigEndian = (Utils::SystemByteOrder == Utils::BigEndian);
+  const bool isBigEndian = (Utils::systemByteOrder() == Utils::BigEndian);
   const bool swap = (mostSignificantByteFirst != isBigEndian);
 
   if(swap)
diff --git a/taglib/toolkit/tstring.cpp b/taglib/toolkit/tstring.cpp
index 15db518d..258e1fcf 100644
--- a/taglib/toolkit/tstring.cpp
+++ b/taglib/toolkit/tstring.cpp
@@ -828,7 +828,7 @@ void String::copyFromUTF16(const char *s, size_t length, Type t)
 }
 
 const String::Type String::WCharByteOrder
-  = (Utils::SystemByteOrder == Utils::BigEndian) ? String::UTF16BE : String::UTF16LE;
+  = (Utils::systemByteOrder() == Utils::BigEndian) ? String::UTF16BE : String::UTF16LE;
 
 }
 
diff --git a/taglib/toolkit/tutils.h b/taglib/toolkit/tutils.h
index a1ca76fb..9116c2c3 100644
--- a/taglib/toolkit/tutils.h
+++ b/taglib/toolkit/tutils.h
@@ -216,20 +216,9 @@ namespace TagLib
       BigEndian
     };
 
-#ifdef SYSTEM_BYTEORDER
-
-# if SYSTEM_BYTEORDER == 1
-
-    const ByteOrder SystemByteOrder = LittleEndian;
-
-# else
-
-    const ByteOrder SystemByteOrder = BigEndian;
-
-# endif
-
-#else
-
+    /*!
+     * Returns the integer byte order of the system.
+     */
     inline ByteOrder systemByteOrder()
     {
       union {
@@ -244,10 +233,6 @@ namespace TagLib
         return BigEndian;
     }
 
-    const ByteOrder SystemByteOrder = systemByteOrder();
-
-#endif
-
     /*!
      * Returns the IEEE754 byte order of the system.
      */
-- 
2.40.0