Split macros, etc. from base/basictypes.h into base/macros.h.

base/basictypes.h

 // Copyright 2013 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 definitions of our old basic integral types
+// ((u)int{8,16,32,64}) and further includes. I recommend that you use the C99
+// standard types instead, and include <stdint.h>/<stddef.h>/etc. as needed.
+// Note that the macros and macro-like constructs that were formerly defined in
+// this file are now available separately in base/macros.h.
+
 #ifndef BASE_BASICTYPES_H_
 #define BASE_BASICTYPES_H_
 
 #include <limits.h>  // So we can set the bounds of our types.
 #include <stddef.h>  // For size_t.
 #include <stdint.h>  // For intptr_t.
-#include <string.h>  // For memcpy.
 
-#include "base/compiler_specific.h"
+#include "base/macros.h"
 #include "base/port.h"  // Types that only need exist on certain systems.
 
+// DEPRECATED: Please use (u)int{8,16,32,64}_t instead (and include <stdint.h>).
 typedef int8_t int8;
 typedef uint8_t uint8;
 typedef int16_t int16;
 typedef int32_t int32;
 typedef uint16_t uint16;
 typedef uint32_t uint32;
 
 // TODO(vtl): Figure what's up with the 64-bit types. Can we just define them as
 // |int64_t|/|uint64_t|?
 // The NSPR system headers define 64-bit as |long| when possible, except on
 // Mac OS X.  In order to not have typedef mismatches, we do the same on LP64.
 //
 // On Mac OS X, |long long| is used for 64-bit types for compatibility with
 // <inttypes.h> format macros even in the LP64 model.
 #if defined(__LP64__) && !defined(OS_MACOSX) && !defined(OS_OPENBSD)
 typedef long int64;
 typedef unsigned long uint64;
 #else
 typedef long long int64;
 typedef unsigned long long uint64;
 #endif
 
+// DEPRECATED: Please use std::numeric_limits (from <limits>) instead.

[brettw, 2014/01/08 21:24:03]

BTW the problem with numeric_limits is that it introduces an initializer so
can't be used for static globals.

[Nico, 2014/04/04 01:07:14]

+1, just came by to say "this is bad advice as it causes static initializers".

 const uint8  kuint8max  = (( uint8) 0xFF);
 const uint16 kuint16max = ((uint16) 0xFFFF);
 const uint32 kuint32max = ((uint32) 0xFFFFFFFF);
 const uint64 kuint64max = ((uint64) GG_LONGLONG(0xFFFFFFFFFFFFFFFF));
 const  int8  kint8min   = ((  int8) 0x80);
 const  int8  kint8max   = ((  int8) 0x7F);
 const  int16 kint16min  = (( int16) 0x8000);
 const  int16 kint16max  = (( int16) 0x7FFF);
 const  int32 kint32min  = (( int32) 0x80000000);
 const  int32 kint32max  = (( int32) 0x7FFFFFFF);
 const  int64 kint64min  = (( int64) GG_LONGLONG(0x8000000000000000));
 const  int64 kint64max  = (( int64) GG_LONGLONG(0x7FFFFFFFFFFFFFFF));
 
-// Put this in the private: declarations for a class to be uncopyable.
-#define DISALLOW_COPY(TypeName) \
-  TypeName(const TypeName&)
-
-// Put this in the private: declarations for a class to be unassignable.
-#define DISALLOW_ASSIGN(TypeName) \
-  void operator=(const TypeName&)
-
-// A macro to disallow the copy constructor and operator= functions
-// This should be used in the private: declarations for a class
-#define DISALLOW_COPY_AND_ASSIGN(TypeName) \
-  TypeName(const TypeName&);               \
-  void operator=(const TypeName&)
-
-// An older, deprecated, politically incorrect name for the above.
-// NOTE: The usage of this macro was banned from our code base, but some
-// third_party libraries are yet using it.
-// TODO(tfarina): Figure out how to fix the usage of this macro in the
-// third_party libraries and get rid of it.
-#define DISALLOW_EVIL_CONSTRUCTORS(TypeName) DISALLOW_COPY_AND_ASSIGN(TypeName)
-
-// A macro to disallow all the implicit constructors, namely the
-// default constructor, copy constructor and operator= functions.
-//
-// This should be used in the private: declarations for a class
-// that wants to prevent anyone from instantiating it. This is
-// especially useful for classes containing only static methods.
-#define DISALLOW_IMPLICIT_CONSTRUCTORS(TypeName) \
-  TypeName();                                    \
-  DISALLOW_COPY_AND_ASSIGN(TypeName)
-
-// The arraysize(arr) macro returns the # of elements in an array arr.
-// The expression is a compile-time constant, and therefore can be
-// used in defining new arrays, for example.  If you use arraysize on
-// a pointer by mistake, you will get a compile-time error.
-//
-// One caveat is that arraysize() doesn't accept any array of an
-// anonymous type or a type defined inside a function.  In these rare
-// cases, you have to use the unsafe ARRAYSIZE_UNSAFE() macro below.  This is
-// due to a limitation in C++'s template system.  The limitation might
-// eventually be removed, but it hasn't happened yet.
-
-// This template function declaration is used in defining arraysize.
-// Note that the function doesn't need an implementation, as we only
-// use its type.
-template <typename T, size_t N>
-char (&ArraySizeHelper(T (&array)[N]))[N];
-
-// That gcc wants both of these prototypes seems mysterious. VC, for
-// its part, can't decide which to use (another mystery). Matching of
-// template overloads: the final frontier.
-#ifndef _MSC_VER
-template <typename T, size_t N>
-char (&ArraySizeHelper(const T (&array)[N]))[N];
-#endif
-
-#define arraysize(array) (sizeof(ArraySizeHelper(array)))
-
-// ARRAYSIZE_UNSAFE performs essentially the same calculation as arraysize,
-// but can be used on anonymous types or types defined inside
-// functions.  It's less safe than arraysize as it accepts some
-// (although not all) pointers.  Therefore, you should use arraysize
-// whenever possible.
-//
-// The expression ARRAYSIZE_UNSAFE(a) is a compile-time constant of type
-// size_t.
-//
-// ARRAYSIZE_UNSAFE catches a few type errors.  If you see a compiler error
-//
-//   "warning: division by zero in ..."
-//
-// when using ARRAYSIZE_UNSAFE, you are (wrongfully) giving it a pointer.
-// You should only use ARRAYSIZE_UNSAFE on statically allocated arrays.
-//
-// The following comments are on the implementation details, and can
-// be ignored by the users.
-//
-// ARRAYSIZE_UNSAFE(arr) works by inspecting sizeof(arr) (the # of bytes in
-// the array) and sizeof(*(arr)) (the # of bytes in one array
-// element).  If the former is divisible by the latter, perhaps arr is
-// indeed an array, in which case the division result is the # of
-// elements in the array.  Otherwise, arr cannot possibly be an array,
-// and we generate a compiler error to prevent the code from
-// compiling.
-//
-// Since the size of bool is implementation-defined, we need to cast
-// !(sizeof(a) & sizeof(*(a))) to size_t in order to ensure the final
-// result has type size_t.
-//
-// This macro is not perfect as it wrongfully accepts certain
-// pointers, namely where the pointer size is divisible by the pointee
-// size.  Since all our code has to go through a 32-bit compiler,
-// where a pointer is 4 bytes, this means all pointers to a type whose
-// size is 3 or greater than 4 will be (righteously) rejected.
-
-#define ARRAYSIZE_UNSAFE(a) \
-  ((sizeof(a) / sizeof(*(a))) / \
-   static_cast<size_t>(!(sizeof(a) % sizeof(*(a)))))
-
-
-// Use implicit_cast as a safe version of static_cast or const_cast
-// for upcasting in the type hierarchy (i.e. casting a pointer to Foo
-// to a pointer to SuperclassOfFoo or casting a pointer to Foo to
-// a const pointer to Foo).
-// When you use implicit_cast, the compiler checks that the cast is safe.
-// Such explicit implicit_casts are necessary in surprisingly many
-// situations where C++ demands an exact type match instead of an
-// argument type convertible to a target type.
-//
-// The From type can be inferred, so the preferred syntax for using
-// implicit_cast is the same as for static_cast etc.:
-//
-//   implicit_cast<ToType>(expr)
-//
-// implicit_cast would have been part of the C++ standard library,
-// but the proposal was submitted too late.  It will probably make
-// its way into the language in the future.
-template<typename To, typename From>
-inline To implicit_cast(From const &f) {
-  return f;
-}
-
-// 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 {
-};
-
-#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
-
-// bit_cast<Dest,Source> is a template function that implements the
-// equivalent of "*reinterpret_cast<Dest*>(&source)".  We need this in
-// very low-level functions like the protobuf library and fast math
-// support.
-//
-//   float f = 3.14159265358979;
-//   int i = bit_cast<int32>(f);
-//   // i = 0x40490fdb
-//
-// The classical address-casting method is:
-//
-//   // WRONG
-//   float f = 3.14159265358979;            // WRONG
-//   int i = * reinterpret_cast<int*>(&f);  // WRONG
-//
-// The address-casting method actually produces undefined behavior
-// according to ISO C++ specification section 3.10 -15 -.  Roughly, this
-// section says: if an object in memory has one type, and a program
-// accesses it with a different type, then the result is undefined
-// behavior for most values of "different type".
-//
-// This is true for any cast syntax, either *(int*)&f or
-// *reinterpret_cast<int*>(&f).  And it is particularly true for
-// conversions between integral lvalues and floating-point lvalues.
-//
-// The purpose of 3.10 -15- is to allow optimizing compilers to assume
-// that expressions with different types refer to different memory.  gcc
-// 4.0.1 has an optimizer that takes advantage of this.  So a
-// non-conforming program quietly produces wildly incorrect output.
-//
-// The problem is not the use of reinterpret_cast.  The problem is type
-// punning: holding an object in memory of one type and reading its bits
-// back using a different type.
-//
-// The C++ standard is more subtle and complex than this, but that
-// is the basic idea.
-//
-// Anyways ...
-//
-// bit_cast<> calls memcpy() which is blessed by the standard,
-// especially by the example in section 3.9 .  Also, of course,
-// bit_cast<> wraps up the nasty logic in one place.
-//
-// Fortunately memcpy() is very fast.  In optimized mode, with a
-// constant size, gcc 2.95.3, gcc 4.0.1, and msvc 7.1 produce inline
-// code with the minimal amount of data movement.  On a 32-bit system,
-// memcpy(d,s,4) compiles to one load and one store, and memcpy(d,s,8)
-// compiles to two loads and two stores.
-//
-// I tested this code with gcc 2.95.3, gcc 4.0.1, icc 8.1, and msvc 7.1.
-//
-// WARNING: if Dest or Source is a non-POD type, the result of the memcpy
-// is likely to surprise you.
-
-template <class Dest, class Source>
-inline Dest bit_cast(const Source& source) {
-  COMPILE_ASSERT(sizeof(Dest) == sizeof(Source), VerifySizesAreEqual);
-
-  Dest dest;
-  memcpy(&dest, &source, sizeof(dest));
-  return dest;
-}
-
-// Used to explicitly mark the return value of a function as unused. If you are
-// really sure you don't want to do anything with the return value of a function
-// that has been marked WARN_UNUSED_RESULT, wrap it with this. Example:
-//
-//   scoped_ptr<MyType> my_var = ...;
-//   if (TakeOwnership(my_var.get()) == SUCCESS)
-//     ignore_result(my_var.release());
-//
-template<typename T>
-inline void ignore_result(const T&) {
-}
-
-// The following enum should be used only as a constructor argument to indicate
-// that the variable has static storage class, and that the constructor should
-// do nothing to its state.  It indicates to the reader that it is legal to
-// declare a static instance of the class, provided the constructor is given
-// the base::LINKER_INITIALIZED argument.  Normally, it is unsafe to declare a
-// static variable that has a constructor or a destructor because invocation
-// order is undefined.  However, IF the type can be initialized by filling with
-// zeroes (which the loader does for static variables), AND the destructor also
-// does nothing to the storage, AND there are no virtual methods, then a
-// constructor declared as
-//       explicit MyClass(base::LinkerInitialized x) {}
-// and invoked as
-//       static MyClass my_variable_name(base::LINKER_INITIALIZED);
-namespace base {
-enum LinkerInitialized { LINKER_INITIALIZED };
-
-// Use these to declare and define a static local variable (static T;) so that
-// it is leaked so that its destructors are not called at exit. If you need
-// thread-safe initialization, use base/lazy_instance.h instead.
-#define CR_DEFINE_STATIC_LOCAL(type, name, arguments) \
-  static type& name = *new type arguments
-
-}  // base
-
 #endif  // BASE_BASICTYPES_H_