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authorPeter Kasting <pkasting@google.com>2014-09-26 18:09:20 -0700
committerPeter Kasting <pkasting@google.com>2014-09-26 18:09:20 -0700
commit1b24b697659b9b933f336238665c835497464a0b (patch)
treef6b15dc4340fa5b77e0ab6330707350e4d1d8c73 /third_party
parent7a649fe262d77f93ad3213f53e973a7665d95a23 (diff)
downloadpdfium-1b24b697659b9b933f336238665c835497464a0b.tar.xz
Use static_assert unconditionally.chromium/2190chromium/2189
BUG=none TEST=none R=jam@chromium.org Review URL: https://codereview.chromium.org/605273004
Diffstat (limited to 'third_party')
-rw-r--r--third_party/macros.h129
1 files changed, 31 insertions, 98 deletions
diff --git a/third_party/macros.h b/third_party/macros.h
index 84c4366b16..92d4f34bda 100644
--- a/third_party/macros.h
+++ b/third_party/macros.h
@@ -1,98 +1,31 @@
-// Copyright 2014 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-// This file contains macros and macro-like constructs (e.g., templates) that
-// are commonly used throughout Chromium source. (It may also contain things
-// that are closely related to things that are commonly used that belong in this
-// file.)
-
-#ifndef BASE_MACROS_H_
-#define BASE_MACROS_H_
-
-// The COMPILE_ASSERT macro can be used to verify that a compile time
-// expression is true. For example, you could use it to verify the
-// size of a static array:
-//
-// COMPILE_ASSERT(ARRAYSIZE_UNSAFE(content_type_names) == CONTENT_NUM_TYPES,
-// content_type_names_incorrect_size);
-//
-// or to make sure a struct is smaller than a certain size:
-//
-// COMPILE_ASSERT(sizeof(foo) < 128, foo_too_large);
-//
-// The second argument to the macro is the name of the variable. If
-// the expression is false, most compilers will issue a warning/error
-// containing the name of the variable.
-
-#undef COMPILE_ASSERT
-
-#if __cplusplus >= 201103L
-
-// Under C++11, just use static_assert.
-#define COMPILE_ASSERT(expr, msg) static_assert(expr, #msg)
-
-#else
-
-template <bool>
-struct CompileAssert {
-};
-
-// Annotate a variable indicating it's ok if the variable is not used.
-// (Typically used to silence a compiler warning when the assignment
-// is important for some other reason.)
-// Use like:
-// int x ALLOW_UNUSED = ...;
-#if defined(COMPILER_GCC)
-#define ALLOW_UNUSED __attribute__((unused))
-#else
-#define ALLOW_UNUSED
-#endif
-
-#define COMPILE_ASSERT(expr, msg) \
- typedef CompileAssert<(bool(expr))> msg[bool(expr) ? 1 : -1] ALLOW_UNUSED
-
-// Implementation details of COMPILE_ASSERT:
-//
-// - COMPILE_ASSERT works by defining an array type that has -1
-// elements (and thus is invalid) when the expression is false.
-//
-// - The simpler definition
-//
-// #define COMPILE_ASSERT(expr, msg) typedef char msg[(expr) ? 1 : -1]
-//
-// does not work, as gcc supports variable-length arrays whose sizes
-// are determined at run-time (this is gcc's extension and not part
-// of the C++ standard). As a result, gcc fails to reject the
-// following code with the simple definition:
-//
-// int foo;
-// COMPILE_ASSERT(foo, msg); // not supposed to compile as foo is
-// // not a compile-time constant.
-//
-// - By using the type CompileAssert<(bool(expr))>, we ensures that
-// expr is a compile-time constant. (Template arguments must be
-// determined at compile-time.)
-//
-// - The outer parentheses in CompileAssert<(bool(expr))> are necessary
-// to work around a bug in gcc 3.4.4 and 4.0.1. If we had written
-//
-// CompileAssert<bool(expr)>
-//
-// instead, these compilers will refuse to compile
-//
-// COMPILE_ASSERT(5 > 0, some_message);
-//
-// (They seem to think the ">" in "5 > 0" marks the end of the
-// template argument list.)
-//
-// - The array size is (bool(expr) ? 1 : -1), instead of simply
-//
-// ((expr) ? 1 : -1).
-//
-// This is to avoid running into a bug in MS VC 7.1, which
-// causes ((0.0) ? 1 : -1) to incorrectly evaluate to 1.
-
-#endif
-
-#endif // BASE_MACROS_H_
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// This file contains macros and macro-like constructs (e.g., templates) that
+// are commonly used throughout Chromium source. (It may also contain things
+// that are closely related to things that are commonly used that belong in this
+// file.)
+
+#ifndef BASE_MACROS_H_
+#define BASE_MACROS_H_
+
+// The COMPILE_ASSERT macro can be used to verify that a compile time
+// expression is true. For example, you could use it to verify the
+// size of a static array:
+//
+// COMPILE_ASSERT(ARRAYSIZE_UNSAFE(content_type_names) == CONTENT_NUM_TYPES,
+// content_type_names_incorrect_size);
+//
+// or to make sure a struct is smaller than a certain size:
+//
+// COMPILE_ASSERT(sizeof(foo) < 128, foo_too_large);
+//
+// The second argument to the macro is the name of the variable. If
+// the expression is false, most compilers will issue a warning/error
+// containing the name of the variable.
+
+#undef COMPILE_ASSERT
+#define COMPILE_ASSERT(expr, msg) static_assert(expr, #msg)
+
+#endif // BASE_MACROS_H_