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/****************************************************************
*
* The author of this software is David M. Gay.
*
* Copyright (c) 1991, 2000, 2001 by Lucent Technologies.
* Copyright (C) 2002, 2005, 2006, 2007, 2008, 2010, 2012 Apple Inc.
* All rights reserved.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose without fee is hereby granted, provided that this entire notice
* is included in all copies of any software which is or includes a copy
* or modification of this software and in all copies of the supporting
* documentation for such software.
*
* THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED
* WARRANTY. IN PARTICULAR, NEITHER THE AUTHOR NOR LUCENT MAKES ANY
* REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY
* OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE.
*
***************************************************************/
/* Please send bug reports to David M. Gay (dmg at acm dot org,
* with " at " changed at "@" and " dot " changed to "."). */
/* On a machine with IEEE extended-precision registers, it is
* necessary to specify double-precision (53-bit) rounding precision
* before invoking strtod or dtoa. If the machine uses (the equivalent
* of) Intel 80x87 arithmetic, the call
* _control87(PC_53, MCW_PC);
* does this with many compilers. Whether this or another call is
* appropriate depends on the compiler; for this to work, it may be
* necessary to #include "float.h" or another system-dependent header
* file.
*/
#include "wtf/dtoa.h"
#include "wtf/Vector.h"
#include <string.h>
namespace WTF {
const char* numberToString(double d, NumberToStringBuffer buffer) {
double_conversion::StringBuilder builder(buffer, NumberToStringBufferLength);
const double_conversion::DoubleToStringConverter& converter =
double_conversion::DoubleToStringConverter::EcmaScriptConverter();
converter.ToShortest(d, &builder);
return builder.Finalize();
}
static inline const char* formatStringTruncatingTrailingZerosIfNeeded(
NumberToStringBuffer buffer,
double_conversion::StringBuilder& builder) {
size_t length = builder.position();
// If there is an exponent, stripping trailing zeros would be incorrect.
// FIXME: Zeros should be stripped before the 'e'.
if (memchr(buffer, 'e', length))
return builder.Finalize();
size_t decimalPointPosition = 0;
for (; decimalPointPosition < length; ++decimalPointPosition) {
if (buffer[decimalPointPosition] == '.')
break;
}
// No decimal seperator found, early exit.
if (decimalPointPosition == length)
return builder.Finalize();
size_t truncatedLength = length - 1;
for (; truncatedLength > decimalPointPosition; --truncatedLength) {
if (buffer[truncatedLength] != '0')
break;
}
// No trailing zeros found to strip.
if (truncatedLength == length - 1)
return builder.Finalize();
// If we removed all trailing zeros, remove the decimal point as well.
if (truncatedLength == decimalPointPosition) {
DCHECK_GT(truncatedLength, 0u);
--truncatedLength;
}
// Truncate the StringBuilder, and return the final result.
builder.SetPosition(truncatedLength + 1);
return builder.Finalize();
}
const char* numberToFixedPrecisionString(double d,
unsigned significantFigures,
NumberToStringBuffer buffer) {
// Mimic String::format("%.[precision]g", ...), but use dtoas rounding
// facilities.
// "g": Signed value printed in f or e format, whichever is more compact for
// the given value and precision.
// The e format is used only when the exponent of the value is less than -4 or
// greater than or equal to the precision argument. Trailing zeros are
// truncated, and the decimal point appears only if one or more digits follow
// it.
// "precision": The precision specifies the maximum number of significant
// digits printed.
double_conversion::StringBuilder builder(buffer, NumberToStringBufferLength);
const double_conversion::DoubleToStringConverter& converter =
double_conversion::DoubleToStringConverter::EcmaScriptConverter();
converter.ToPrecision(d, significantFigures, &builder);
// FIXME: Trailing zeros should never be added in the first place. The
// current implementation does not strip when there is an exponent, eg.
// 1.50000e+10.
return formatStringTruncatingTrailingZerosIfNeeded(buffer, builder);
}
const char* numberToFixedWidthString(double d,
unsigned decimalPlaces,
NumberToStringBuffer buffer) {
// Mimic String::format("%.[precision]f", ...), but use dtoas rounding
// facilities.
// "f": Signed value having the form [ - ]dddd.dddd, where dddd is one or more
// decimal digits. The number of digits before the decimal point depends on
// the magnitude of the number, and the number of digits after the decimal
// point depends on the requested precision.
// "precision": The precision value specifies the number of digits after the
// decimal point. If a decimal point appears, at least one digit appears
// before it. The value is rounded to the appropriate number of digits.
double_conversion::StringBuilder builder(buffer, NumberToStringBufferLength);
const double_conversion::DoubleToStringConverter& converter =
double_conversion::DoubleToStringConverter::EcmaScriptConverter();
converter.ToFixed(d, decimalPlaces, &builder);
return builder.Finalize();
}
namespace Internal {
double parseDoubleFromLongString(const UChar* string,
size_t length,
size_t& parsedLength) {
Vector<LChar> conversionBuffer(length);
for (size_t i = 0; i < length; ++i)
conversionBuffer[i] = isASCII(string[i]) ? string[i] : 0;
return parseDouble(conversionBuffer.data(), length, parsedLength);
}
} // namespace Internal
} // namespace WTF
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