conversions.h.svn-base

Google浏览器V8内核代码

// Copyright 2006-2008 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
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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#ifndef V8_CONVERSIONS_H_
#define V8_CONVERSIONS_H_

namespace v8 { namespace internal {

// The fast double-to-int conversion routine does not guarantee
// rounding towards zero.
// The result is unspecified if x is infinite or NaN, or if the rounded
// integer value is outside the range of type int.
static inline int FastD2I(double x);


static inline double FastI2D(int x) {
  // There is no rounding involved in converting an integer to a
  // double, so this code should compile to a few instructions without
  // any FPU pipeline stalls.
  return static_cast<double>(x);
}


static inline double FastUI2D(unsigned x) {
  // There is no rounding involved in converting an unsigned integer to a
  // double, so this code should compile to a few instructions without
  // any FPU pipeline stalls.
  return static_cast<double>(x);
}


// This function should match the exact semantics of ECMA-262 9.4.
static inline double DoubleToInteger(double x);


// This function should match the exact semantics of ECMA-262 9.5.
static inline int32_t DoubleToInt32(double x);


// This function should match the exact semantics of ECMA-262 9.6.
static inline uint32_t DoubleToUint32(double x) {
  return static_cast<uint32_t>(DoubleToInt32(x));
}


// Returns the value (0 .. 15) of a hexadecimal character c.
// If c is not a legal hexadecimal character, returns a value < 0.
int HexValue(uc32 c);


// Enumeration for allowing octals and ignoring junk when converting
// strings to numbers.
enum ConversionFlags {
  NO_FLAGS = 0,
  ALLOW_HEX = 1,
  ALLOW_OCTALS = 2,
  ALLOW_TRAILING_JUNK = 4
};


// Convert from Number object to C integer.
static inline int32_t NumberToInt32(Object* number);
static inline uint32_t NumberToUint32(Object* number);


// Converts a string into a double value according to ECMA-262 9.3.1
double StringToDouble(const char* str, int flags, double empty_string_val = 0);
double StringToDouble(String* str, int flags, double empty_string_val = 0);

// Converts a string into an integer.
int StringToInt(String* str, int index, int radix, double* value);
int StringToInt(const char* str, int index, int radix, double* value);

// Converts a double to a string value according to ECMA-262 9.8.1.
// The buffer should be large enough for any floating point number.
// 100 characters is enough.
const char* DoubleToCString(double value, Vector<char> buffer);

// Convert an int to a null-terminated string. The returned string is
// located inside the buffer, but not necessarily at the start.
const char* IntToCString(int n, Vector<char> buffer);

// Additional number to string conversions for the number type.
// The caller is responsible for calling free on the returned pointer.
char* DoubleToFixedCString(double value, int f);
char* DoubleToExponentialCString(double value, int f);
char* DoubleToPrecisionCString(double value, int f);
char* DoubleToRadixCString(double value, int radix);

} }  // namespace v8::internal

#endif  // V8_CONVERSIONS_H_