Move Source/WTF/wtf to Source/wtf

Source/WTF/wtf/dtoa/utils.h

-// Copyright 2010 the V8 project authors. 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.
-//     * Neither the name of Google Inc. nor the names of its
-//       contributors may be used to endorse or promote products derived
-//       from this software without specific prior written permission.
-//
-// 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 DOUBLE_CONVERSION_UTILS_H_
-#define DOUBLE_CONVERSION_UTILS_H_
-
-#include <wtf/Assertions.h>
-#include <stdlib.h>
-#include <string.h>
-
-#define UNIMPLEMENTED ASSERT_NOT_REACHED
-#define UNREACHABLE ASSERT_NOT_REACHED
-
-// Double operations detection based on target architecture.
-// Linux uses a 80bit wide floating point stack on x86. This induces double
-// rounding, which in turn leads to wrong results.
-// An easy way to test if the floating-point operations are correct is to
-// evaluate: 89255.0/1e22. If the floating-point stack is 64 bits wide then
-// the result is equal to 89255e-22.
-// The best way to test this, is to create a division-function and to compare
-// the output of the division with the expected result. (Inlining must be
-// disabled.)
-// On Linux,x86 89255e-22 != Div_double(89255.0/1e22)
-#if defined(_M_X64) || defined(__x86_64__) || \
-defined(__ARMEL__) || \
-defined(_MIPS_ARCH_MIPS32R2)
-#define DOUBLE_CONVERSION_CORRECT_DOUBLE_OPERATIONS 1
-#elif CPU(MIPS) || CPU(PPC) || CPU(PPC64) || OS(WINCE) || CPU(SH4) || CPU(S390) || CPU(S390X) || CPU(IA64) || CPU(SPARC) || CPU(ALPHA)
-#define DOUBLE_CONVERSION_CORRECT_DOUBLE_OPERATIONS 1
-#elif defined(_M_IX86) || defined(__i386__)
-#if defined(_WIN32)
-// Windows uses a 64bit wide floating point stack.
-#define DOUBLE_CONVERSION_CORRECT_DOUBLE_OPERATIONS 1
-#else
-#undef DOUBLE_CONVERSION_CORRECT_DOUBLE_OPERATIONS
-#endif  // _WIN32
-#else
-#error Target architecture was not detected as supported by Double-Conversion.
-#endif
-
-
-#if defined(_WIN32) && !defined(__MINGW32__)
-
-typedef signed char int8_t;
-typedef unsigned char uint8_t;
-typedef short int16_t;  // NOLINT
-typedef unsigned short uint16_t;  // NOLINT
-typedef int int32_t;
-typedef unsigned int uint32_t;
-typedef __int64 int64_t;
-typedef unsigned __int64 uint64_t;
-// intptr_t and friends are defined in crtdefs.h through stdio.h.
-
-#else
-
-#include <stdint.h>
-
-#endif
-
-// The following macro works on both 32 and 64-bit platforms.
-// Usage: instead of writing 0x1234567890123456
-//      write UINT64_2PART_C(0x12345678,90123456);
-#define UINT64_2PART_C(a, b) (((static_cast<uint64_t>(a) << 32) + 0x##b##u))
-
-
-// The expression ARRAY_SIZE(a) is a compile-time constant of type
-// size_t which represents the number of elements of the given
-// array. You should only use ARRAY_SIZE on statically allocated
-// arrays.
-#define ARRAY_SIZE(a)                                   \
-((sizeof(a) / sizeof(*(a))) /                         \
-static_cast<size_t>(!(sizeof(a) % sizeof(*(a)))))
-
-// A macro to disallow the evil 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&)
-
-// 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)
-
-namespace WTF {
-
-namespace double_conversion {
-    
-    static const int kCharSize = sizeof(char);
-    
-    // Returns the maximum of the two parameters.
-    template <typename T>
-    static T Max(T a, T b) {
-        return a < b ? b : a;
-    }
-    
-    
-    // Returns the minimum of the two parameters.
-    template <typename T>
-    static T Min(T a, T b) {
-        return a < b ? a : b;
-    }
-    
-    
-    inline int StrLength(const char* string) {
-        size_t length = strlen(string);
-        ASSERT(length == static_cast<size_t>(static_cast<int>(length)));
-        return static_cast<int>(length);
-    }
-    
-    // This is a simplified version of V8's Vector class.
-    template <typename T>
-    class Vector {
-    public:
-        Vector() : start_(NULL), length_(0) {}
-        Vector(T* data, int length) : start_(data), length_(length) {
-            ASSERT(length == 0 || (length > 0 && data != NULL));
-        }
-        
-        // Returns a vector using the same backing storage as this one,
-        // spanning from and including 'from', to but not including 'to'.
-        Vector<T> SubVector(int from, int to) {
-            ASSERT(to <= length_);
-            ASSERT(from < to);
-            ASSERT(0 <= from);
-            return Vector<T>(start() + from, to - from);
-        }
-        
-        // Returns the length of the vector.
-        int length() const { return length_; }
-        
-        // Returns whether or not the vector is empty.
-        bool is_empty() const { return length_ == 0; }
-        
-        // Returns the pointer to the start of the data in the vector.
-        T* start() const { return start_; }
-        
-        // Access individual vector elements - checks bounds in debug mode.
-        T& operator[](int index) const {
-            ASSERT(0 <= index && index < length_);
-            return start_[index];
-        }
-        
-        T& first() { return start_[0]; }
-        
-        T& last() { return start_[length_ - 1]; }
-        
-    private:
-        T* start_;
-        int length_;
-    };
-    
-    
-    // Helper class for building result strings in a character buffer. The
-    // purpose of the class is to use safe operations that checks the
-    // buffer bounds on all operations in debug mode.
-    class StringBuilder {
-    public:
-        StringBuilder(char* buffer, int size)
-        : buffer_(buffer, size), position_(0) { }
-        
-        ~StringBuilder() { if (!is_finalized()) Finalize(); }
-        
-        int size() const { return buffer_.length(); }
-        
-        // Get the current position in the builder.
-        int position() const {
-            ASSERT(!is_finalized());
-            return position_;
-        }
-         
-        // Set the current position in the builder.
-        void SetPosition(int position)
-        {
-            ASSERT(!is_finalized());
-            ASSERT_WITH_SECURITY_IMPLICATION(position < size());
-            position_ = position;
-        }
-        
-        // Reset the position.
-        void Reset() { position_ = 0; }
-        
-        // Add a single character to the builder. It is not allowed to add
-        // 0-characters; use the Finalize() method to terminate the string
-        // instead.
-        void AddCharacter(char c) {
-            ASSERT(c != '\0');
-            ASSERT(!is_finalized() && position_ < buffer_.length());
-            buffer_[position_++] = c;
-        }
-        
-        // Add an entire string to the builder. Uses strlen() internally to
-        // compute the length of the input string.
-        void AddString(const char* s) {
-            AddSubstring(s, StrLength(s));
-        }
-        
-        // Add the first 'n' characters of the given string 's' to the
-        // builder. The input string must have enough characters.
-        void AddSubstring(const char* s, int n) {
-            ASSERT(!is_finalized() && position_ + n < buffer_.length());
-            ASSERT_WITH_SECURITY_IMPLICATION(static_cast<size_t>(n) <= strlen(s));
-            memcpy(&buffer_[position_], s, n * kCharSize);
-            position_ += n;
-        }
-        
-        
-        // Add character padding to the builder. If count is non-positive,
-        // nothing is added to the builder.
-        void AddPadding(char c, int count) {
-            for (int i = 0; i < count; i++) {
-                AddCharacter(c);
-            }
-        }
-        
-        // Finalize the string by 0-terminating it and returning the buffer.
-        char* Finalize() {
-            ASSERT(!is_finalized() && position_ < buffer_.length());
-            buffer_[position_] = '\0';
-            // Make sure nobody managed to add a 0-character to the
-            // buffer while building the string.
-            ASSERT(strlen(buffer_.start()) == static_cast<size_t>(position_));
-            position_ = -1;
-            ASSERT(is_finalized());
-            return buffer_.start();
-        }
-        
-    private:
-        Vector<char> buffer_;
-        int position_;
-        
-        bool is_finalized() const { return position_ < 0; }
-        
-        DISALLOW_IMPLICIT_CONSTRUCTORS(StringBuilder);
-    };
-    
-    // The type-based aliasing rule allows the compiler to assume that pointers of
-    // different types (for some definition of different) never alias each other.
-    // Thus the following code does not work:
-    //
-    // float f = foo();
-    // int fbits = *(int*)(&f);
-    //
-    // The compiler 'knows' that the int pointer can't refer to f since the types
-    // don't match, so the compiler may cache f in a register, leaving random data
-    // in fbits.  Using C++ style casts makes no difference, however a pointer to
-    // char data is assumed to alias any other pointer.  This is the 'memcpy
-    // exception'.
-    //
-    // Bit_cast uses the memcpy exception to move the bits from a variable of one
-    // type of a variable of another type.  Of course the end result is likely to
-    // be implementation dependent.  Most compilers (gcc-4.2 and MSVC 2005)
-    // will completely optimize BitCast away.
-    //
-    // There is an additional use for BitCast.
-    // Recent gccs will warn when they see casts that may result in breakage due to
-    // the type-based aliasing rule.  If you have checked that there is no breakage
-    // you can use BitCast to cast one pointer type to another.  This confuses gcc
-    // enough that it can no longer see that you have cast one pointer type to
-    // another thus avoiding the warning.
-    template <class Dest, class Source>
-    inline Dest BitCast(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;
-    }
-    
-    template <class Dest, class Source>
-    inline Dest BitCast(Source* source) {
-        return BitCast<Dest>(reinterpret_cast<uintptr_t>(source));
-    }
-    
-}  // namespace double_conversion
-
-} // namespace WTF
-
-#endif  // DOUBLE_CONVERSION_UTILS_H_