ndk: Fix WCHAR_MIN / WCHAR_MAX definitions.

This fixes WCHAR_MIN / WCHAR_MAX to be signed / unsigned based on
the target ABI.

This only impacts ARM where wchar_t is really 'unsigned int'.
One can define _WCHAR_IS_ALWAYS_SIGNED to restore the old behaviour.

See http://b.android.com/55749

Change-Id: Idb63b7b11aecd3cfee37f5b6dd2eba78b308876f

ndk/platforms/android-3/include/sys/_wchar_limits.h

@@ -0,0 +1,108 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+#ifndef _SYS__WCHAR_LIMITS_H
+#define _SYS__WCHAR_LIMITS_H
+
+#include <android/api-level.h>
+
+/* WCHAR_MIN / WCHAR_MAX can be defined by <stdint.h> or <wchar.h>.
+ * Due to historical reasons, their definition is a bit complex.
+ *
+ * - In NDK r8e and older, all definitions of WCHAR_MIN and WCHAR_MAX
+ *   where 32-bit signed values (with one exception described below),
+ *   despite the fact that wchar_t is 'unsigned' on ARM.
+ *   See http://b.android.com/57749
+ *
+ *   This is no longer the case, unless you define _WCHAR_IS_ALWAYS_SIGNED
+ *   at compile time to restore the old (broken) behaviour. This doesn't
+ *   affect other CPU ABIs.
+ *
+ * - Before API level 9, on ARM, wchar_t was typedef to 'char' when
+ *   compiling C (not C++). Also, the definitions of WCHAR_MIN and
+ *   WCHAR_MAX differed between <stdint.h> and <wchar.h>:
+ *
+ *     <stdint.h> conditionally defined them to INT32_MIN / INT32_MAX.
+ *     <wchar.h> conditionally defined them to 0 and 255 instead.
+ *
+ *   <stdint.h> would only define WCHAR_MIN and WCHAR_MAX when:
+ *    - Compiling C sources.
+ *    - Compiling C++ sources with __STDC_LIMIT_MACROS being defined.
+ *
+ *   <wchar.h> always ends up including <stdint.h> indirectly. This
+ *   means that:
+ *
+ *     - When compiling C sources, WCHAR_MIN / WCHAR_MAX were always
+ *       defined as INT32_MIN / INT32_MAX.
+ *
+ *     - When compiling C++ sources with __STDC_LIMIT_MACROS defined,
+ *       they were always defined to INT32_MIN / INT32_MAX
+ *
+ *     - When compiling C++ sources without __STDC_LIMIT_MACROS defined,
+ *       they were defined by <wchar.h> as 0 and 255, respectively.
+ *
+ *    Keep in mind that this was ARM-specific, only for API level < 9.
+ *
+ *    If _WCHAR_IS_8BIT is defined, the same broken behaviour will
+ *    be restored. See http://b.android.com/57267
+ */ 
+#if !defined(WCHAR_MIN)
+
+#  if defined(_WCHAR_IS_8BIT) && defined(__arm__) && __ANDROID_API__ < 9
+#    if defined(__cplusplus) && !defined(__STDC_LIMIT_MACROS)
+#      define WCHAR_MIN  0
+#      define WCHAR_MAX  255
+#    else
+#      define WCHAR_MIN   (-2147483647 - 1)
+#      define WCHAR_MAX   (2147483647)
+#    endif
+#  elif defined(_WCHAR_IS_ALWAYS_SIGNED)
+#    define WCHAR_MIN   (-2147483647 - 1)
+#    define WCHAR_MAX   (2147483647)
+#  else
+  /* Otherwise, the value is derived from the toolchain configuration.
+   * to avoid putting explicit CPU checks in this header. */
+#    ifndef __WCHAR_MAX__
+#      error "__WCHAR_MAX__ is not defined. Check your toolchain!"
+#    endif
+  /* Clang does define __WCHAR_MAX__, but not __WCHAR_MIN__ */
+#    ifndef __WCHAR_MIN__
+#      if __WCHAR_MAX__ == 4294967295
+#        define __WCHAR_MIN__  (0U)
+#      elif __WCHAR_MAX__ == 2147483647
+#        define __WCHAR_MIN__  (-2147483647 - 1)
+#      else
+#        error "Invalid __WCHAR_MAX__ value. Check your toolchain!"
+#      endif
+#    endif /* !__WCHAR_MIN__ */
+#    define WCHAR_MIN    __WCHAR_MIN__
+#    define WCHAR_MAX    __WCHAR_MAX__
+#  endif /* !_WCHAR_IS_ALWAYS_SIGNED */
+
+#endif /* !WCHAR_MIN */
+
+#endif  /* _SYS__WCHAR_LIMITS_H */