// This is to avoid running into a bug in MS VC 7.1, which
// causes ((0.0) ? 1 : -1) to incorrectly evaluate to 1.
-
-// 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 betweeen 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 time assertion: sizeof(Dest) == sizeof(Source)
- // A compile error here means your Dest and Source have different sizes.
- typedef char VerifySizesAreEqual [sizeof(Dest) == sizeof(Source) ? 1 : -1];
-
- 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:
// This is to avoid running into a bug in MS VC 7.1, which
// causes ((0.0) ? 1 : -1) to incorrectly evaluate to 1.
-
-// 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 betweeen 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 time assertion: sizeof(Dest) == sizeof(Source)
- // A compile error here means your Dest and Source have different sizes.
- typedef char VerifySizesAreEqual [sizeof(Dest) == sizeof(Source) ? 1 : -1];
-
- 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:
+++ /dev/null
-// Copyright (c) 2010 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.
-
-#ifndef BASE_BASICTYPES_H_
-#define BASE_BASICTYPES_H_
-#pragma once
-
-#include <limits.h> // So we can set the bounds of our types
-#include <stddef.h> // For size_t
-#include <string.h> // for memcpy
-
-#ifndef COMPILER_MSVC
-// stdint.h is part of C99 but MSVC doesn't have it.
-#include <stdint.h> // For intptr_t.
-#endif
-
-#ifdef INT64_MAX
-
-// INT64_MAX is defined if C99 stdint.h is included; use the
-// native types if available.
-typedef int8_t int8;
-typedef int16_t int16;
-typedef int32_t int32;
-typedef int64_t int64;
-typedef uint8_t uint8;
-typedef uint16_t uint16;
-typedef uint32_t uint32;
-typedef uint64_t uint64;
-
-const uint8 kuint8max = UINT8_MAX;
-const uint16 kuint16max = UINT16_MAX;
-const uint32 kuint32max = UINT32_MAX;
-const uint64 kuint64max = UINT64_MAX;
-const int8 kint8min = INT8_MIN;
-const int8 kint8max = INT8_MAX;
-const int16 kint16min = INT16_MIN;
-const int16 kint16max = INT16_MAX;
-const int32 kint32min = INT32_MIN;
-const int32 kint32max = INT32_MAX;
-const int64 kint64min = INT64_MIN;
-const int64 kint64max = INT64_MAX;
-
-#else // !INT64_MAX
-
-typedef signed char int8;
-typedef short int16;
-// TODO: Remove these type guards. These are to avoid conflicts with
-// obsolete/protypes.h in the Gecko SDK.
-#ifndef _INT32
-#define _INT32
-typedef int int32;
-#endif
-
-// The NSPR system headers define 64-bit as |long| when possible. In order to
-// not have typedef mismatches, we do the same on LP64.
-#if __LP64__
-typedef long int64;
-#else
-typedef long long int64;
-#endif
-
-// NOTE: unsigned types are DANGEROUS in loops and other arithmetical
-// places. Use the signed types unless your variable represents a bit
-// pattern (eg a hash value) or you really need the extra bit. Do NOT
-// use 'unsigned' to express "this value should always be positive";
-// use assertions for this.
-
-typedef unsigned char uint8;
-typedef unsigned short uint16;
-// TODO: Remove these type guards. These are to avoid conflicts with
-// obsolete/protypes.h in the Gecko SDK.
-#ifndef _UINT32
-#define _UINT32
-typedef unsigned int uint32;
-#endif
-
-// See the comment above about NSPR and 64-bit.
-#if __LP64__
-typedef unsigned long uint64;
-#else
-typedef unsigned long long uint64;
-#endif
-
-#endif // !INT64_MAX
-
-typedef signed char schar;
-
-// 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;
-
-// 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 baned 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 convertable 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.
-
-template <bool>
-struct CompileAssert {
-};
-
-#undef COMPILE_ASSERT
-#define COMPILE_ASSERT(expr, msg) \
- typedef CompileAssert<(bool(expr))> msg[bool(expr) ? 1 : -1]
-
-// 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 outter 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.
-
-
-// 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 betweeen 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 time assertion: sizeof(Dest) == sizeof(Source)
- // A compile error here means your Dest and Source have different sizes.
- typedef char VerifySizesAreEqual [sizeof(Dest) == sizeof(Source) ? 1 : -1];
-
- 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& ignored) {
-}
-
-// 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 };
-} // base
-
-#endif // BASE_BASICTYPES_H_