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Diffstat (limited to 'chromium/base/basictypes.h')
| -rw-r--r-- | chromium/base/basictypes.h | 373 |
1 files changed, 27 insertions, 346 deletions
diff --git a/chromium/base/basictypes.h b/chromium/base/basictypes.h index e77d7b10f24..b0019f2a193 100644 --- a/chromium/base/basictypes.h +++ b/chromium/base/basictypes.h @@ -1,377 +1,58 @@ -// Copyright (c) 2011 The Chromium Authors. All rights reserved. +// 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 <string.h> // for memcpy - -#include "base/compiler_specific.h" -#include "base/port.h" // Types that only need exist on certain systems +#include <limits.h> // So we can set the bounds of our types. +#include <stddef.h> // For size_t. +#include <stdint.h> // For intptr_t. -#ifndef COMPILER_MSVC -// stdint.h is part of C99 but MSVC doesn't have it. -#include <stdint.h> // For intptr_t. -#endif +#include "base/macros.h" +#include "base/port.h" // Types that only need exist on certain systems. -typedef signed char schar; -typedef signed char int8; -typedef short int16; -typedef int int32; +// 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; -#else -typedef long long int64; -#endif - -// NOTE: It is DANGEROUS to compare signed with unsigned types in loop -// conditions and other conditional expressions, and it is DANGEROUS to -// compute object/allocation sizes, indices, and offsets with signed types. -// Integer overflow behavior for signed types is UNDEFINED in the C/C++ -// standards, but is defined for unsigned types. -// -// Use the unsigned types if your variable represents a bit pattern (e.g. a -// hash value), object or allocation size, object count, offset, -// array/vector index, etc. -// -// Do NOT use 'unsigned' to express "this value should always be positive"; -// use assertions for this. -// -// See the Chromium style guide for more information. -// https://sites.google.com/a/chromium.org/dev/developers/coding-style - -typedef unsigned char uint8; -typedef unsigned short uint16; -typedef unsigned int uint32; - -// See the comment above about NSPR and 64-bit. -#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 -// A type to represent a Unicode code-point value. As of Unicode 4.0, -// such values require up to 21 bits. -// (For type-checking on pointers, make this explicitly signed, -// and it should always be the signed version of whatever int32 is.) -typedef signed int char32; - +// DEPRECATED: Please use std::numeric_limits (from <limits>) instead. const uint8 kuint8max = (( uint8) 0xFF); const uint16 kuint16max = ((uint16) 0xFFFF); const uint32 kuint32max = ((uint32) 0xFFFFFFFF); -const uint64 kuint64max = ((uint64) GG_LONGLONG(0xFFFFFFFFFFFFFFFF)); +const uint64 kuint64max = ((uint64) 0xFFFFFFFFFFFFFFFFULL); 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 +const int64 kint64min = (( int64) 0x8000000000000000LL); +const int64 kint64max = (( int64) 0x7FFFFFFFFFFFFFFFLL); #endif // BASE_BASICTYPES_H_ |