ICU-57166.0.1.tar.gz

[apple/icu.git] / icuSources / layout / LESwaps.h

diff --git a/icuSources/layout/LESwaps.h b/icuSources/layout/LESwaps.h
index 87a07d8dc0eea3a978d626f3f3afac43b596a6ef..8cdbd99f890ce3ae1a4259feb6469ef18f2467ff 100644 (file)
--- a/icuSources/layout/LESwaps.h
+++ b/icuSources/layout/LESwaps.h
@@ -1,8 +1,6 @@
-
 /*
- * @(#)LESwaps.h       1.3 00/03/15
  *
- * (C) Copyright IBM Corp. 1998-2003 - All Rights Reserved
+ * (C) Copyright IBM Corp. 1998-2014 - All Rights Reserved
  *
  */
 
@@ -11,85 +9,87 @@
 
 #include "LETypes.h"
 
+/**
+ * \file 
+ * \brief C++ API: Endian independent access to data for LayoutEngine
+ */
+
 U_NAMESPACE_BEGIN
 
 /**
  * A convenience macro which invokes the swapWord member function
  * from a concise call.
  *
- * @draft ICU 2.2
+ * @deprecated ICU 54. See {@link icu::LayoutEngine}
  */
-#define SWAPW(value) (LESwaps::isBigEndian() ? (value) : LESwaps::swapWord(value))
-
+#define SWAPW(value) LESwaps::swapWord((le_uint16)(value))
 
 /**
  * A convenience macro which invokes the swapLong member function
  * from a concise call.
  *
- * @draft ICU 2.2
+ * @deprecated ICU 54. See {@link icu::LayoutEngine}
  */
-#define SWAPL(value) (LESwaps::isBigEndian() ? (value) : LESwaps::swapLong(value))
+#define SWAPL(value) LESwaps::swapLong((le_uint32)(value))
 
 /**
  * This class is used to access data which stored in big endian order
- * regardless of the conventions of the platform. It has been designed
- * to automatically detect the endian-ness of the platform, so that a
- * compilation flag is not needed.
+ * regardless of the conventions of the platform.
  *
  * All methods are static and inline in an attempt to induce the compiler
  * to do most of the calculations at compile time.
  *
- * @draft ICU 2.2
+ * @deprecated ICU 54. See {@link icu::LayoutEngine}
  */
 class U_LAYOUT_API LESwaps /* not : public UObject because all methods are static */ {
 public:
 
     /**
-     * This method detects the endian-ness of the platform by
-     * casting a pointer to a word to a pointer to a byte. On
-     * big endian platforms the FF will be in the byte with the
-     * lowest address. On little endian platforms, the FF will
-     * be in the byte with the highest address.
-     *
-     * @return true if the platform is big endian
-     *
-     * @draft ICU 2.2
-     */
-    static le_bool isBigEndian()
-    {
-        const le_uint16 word = 0xFF00;
-
-        return *((le_uint8 *) &word);
-    };
-
-    /**
-     * This method does the byte swap required on little endian platforms
-     * to correctly access a (16-bit) word.
+     * Reads a big-endian 16-bit word and returns a native-endian value.
+     * No-op on a big-endian platform, byte-swaps on a little-endian platform.
      *
      * @param value - the word to be byte swapped
      *
      * @return the byte swapped word
      *
-     * @draft ICU 2.2
+     * @deprecated ICU 54. See {@link icu::LayoutEngine}
      */
     static le_uint16 swapWord(le_uint16 value)
     {
-        return (((le_uint8) (value >> 8)) | (value << 8));
+#if (defined(U_IS_BIG_ENDIAN) && U_IS_BIG_ENDIAN) || \
+    (defined(BYTE_ORDER) && defined(BIG_ENDIAN) && (BYTE_ORDER == BIG_ENDIAN)) || \
+    defined(__BIG_ENDIAN__)
+        // Fastpath when we know that the platform is big-endian.
+        return value;
+#else
+        // Reads a big-endian value on any platform.
+        const le_uint8 *p = reinterpret_cast<const le_uint8 *>(&value);
+        return (le_uint16)((p[0] << 8) | p[1]);
+#endif
     };
 
     /**
-     * This method does the byte swapping required on little endian platforms
-     * to correctly access a (32-bit) long.
+     * Reads a big-endian 32-bit word and returns a native-endian value.
+     * No-op on a big-endian platform, byte-swaps on a little-endian platform.
      *
      * @param value - the long to be byte swapped
      *
      * @return the byte swapped long
      *
-     * @draft ICU 2.2
+     * @deprecated ICU 54. See {@link icu::LayoutEngine}
      */
     static le_uint32 swapLong(le_uint32 value)
     {
-        return swapWord((le_uint16) (value >> 16)) | (swapWord((le_uint16) value) << 16);
+#if (defined(U_IS_BIG_ENDIAN) && U_IS_BIG_ENDIAN) || \
+    (defined(BYTE_ORDER) && defined(BIG_ENDIAN) && (BYTE_ORDER == BIG_ENDIAN)) || \
+    defined(__BIG_ENDIAN__)
+        // Fastpath when we know that the platform is big-endian.
+        return value;
+#else
+        // Reads a big-endian value on any platform.
+        const le_uint8 *p = reinterpret_cast<const le_uint8 *>(&value);
+        return (le_uint32)((p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3]);
+#endif
     };
 
 private: