f08648dc4c
Review URL: http://codereview.chromium.org/1128010 git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4223 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
111 lines
4.0 KiB
C++
111 lines
4.0 KiB
C++
// Copyright 2006-2008 the V8 project authors. All rights reserved.
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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//
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following
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// disclaimer in the documentation and/or other materials provided
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// with the distribution.
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// * Neither the name of Google Inc. nor the names of its
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// contributors may be used to endorse or promote products derived
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// from this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#ifndef V8_CONVERSIONS_INL_H_
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#define V8_CONVERSIONS_INL_H_
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#include <math.h>
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#include <float.h> // required for DBL_MAX and on Win32 for finite()
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#include <stdarg.h>
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// ----------------------------------------------------------------------------
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// Extra POSIX/ANSI functions for Win32/MSVC.
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#include "conversions.h"
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#include "platform.h"
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namespace v8 {
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namespace internal {
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// The fast double-to-unsigned-int conversion routine does not guarantee
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// rounding towards zero, or any reasonable value if the argument is larger
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// than what fits in an unsigned 32-bit integer.
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static inline unsigned int FastD2UI(double x) {
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// There is no unsigned version of lrint, so there is no fast path
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// in this function as there is in FastD2I. Using lrint doesn't work
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// for values of 2^31 and above.
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// Convert "small enough" doubles to uint32_t by fixing the 32
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// least significant non-fractional bits in the low 32 bits of the
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// double, and reading them from there.
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const double k2Pow52 = 4503599627370496.0;
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bool negative = x < 0;
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if (negative) {
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x = -x;
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}
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if (x < k2Pow52) {
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x += k2Pow52;
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uint32_t result;
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#ifdef BIG_ENDIAN_FLOATING_POINT
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Address mantissa_ptr = reinterpret_cast<Address>(&x) + kIntSize;
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#else
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Address mantissa_ptr = reinterpret_cast<Address>(&x);
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#endif
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// Copy least significant 32 bits of mantissa.
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memcpy(&result, mantissa_ptr, sizeof(result));
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return negative ? ~result + 1 : result;
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}
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// Large number (outside uint32 range), Infinity or NaN.
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return 0x80000000u; // Return integer indefinite.
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}
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static inline double DoubleToInteger(double x) {
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if (isnan(x)) return 0;
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if (!isfinite(x) || x == 0) return x;
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return (x >= 0) ? floor(x) : ceil(x);
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}
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int32_t NumberToInt32(Object* number) {
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if (number->IsSmi()) return Smi::cast(number)->value();
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return DoubleToInt32(number->Number());
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}
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uint32_t NumberToUint32(Object* number) {
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if (number->IsSmi()) return Smi::cast(number)->value();
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return DoubleToUint32(number->Number());
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}
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int32_t DoubleToInt32(double x) {
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int32_t i = FastD2I(x);
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if (FastI2D(i) == x) return i;
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static const double two32 = 4294967296.0;
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static const double two31 = 2147483648.0;
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if (!isfinite(x) || x == 0) return 0;
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if (x < 0 || x >= two32) x = modulo(x, two32);
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x = (x >= 0) ? floor(x) : ceil(x) + two32;
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return (int32_t) ((x >= two31) ? x - two32 : x);
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}
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} } // namespace v8::internal
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#endif // V8_CONVERSIONS_INL_H_
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