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27 #include "DecimalNumber.h"
29 #include <wtf/MathExtras.h>
30 #include <wtf/text/WTFString.h>
34 unsigned DecimalNumber::bufferLengthForStringDecimal() const
37 // if the exponent is negative the number decimal representation is of the form:
38 // [<sign>]0.[<zeros>]<significand>
42 length += 2; // for "0."
43 length += -m_exponent - 1;
44 length += m_precision;
48 unsigned digitsBeforeDecimalPoint = m_exponent + 1;
50 // If the precision is <= than the number of digits to get up to the decimal
51 // point, then there is no fractional part, number is of the form:
52 // [<sign>]<significand>[<zeros>]
53 if (m_precision <= digitsBeforeDecimalPoint) {
56 length += m_precision;
57 length += digitsBeforeDecimalPoint - m_precision;
61 // If we get here, number starts before the decimal point, and ends after it,
62 // as such is of the form:
63 // [<sign>]<significand-begin>.<significand-end>
66 length += digitsBeforeDecimalPoint;
67 ++length; // for decimal point
68 length += m_precision - digitsBeforeDecimalPoint;
73 unsigned DecimalNumber::bufferLengthForStringExponential() const
79 // Add the significand
82 if (m_precision > 1) {
83 ++length; // for decimal point
84 length += m_precision - 1;
90 int exponent = (m_exponent >= 0) ? m_exponent : -m_exponent;
102 unsigned DecimalNumber::toStringDecimal(UChar* buffer, unsigned bufferLength) const
104 ASSERT_UNUSED(bufferLength, bufferLength >= bufferLengthForStringDecimal());
106 // Should always be at least one digit to add to the string!
108 UChar* next = buffer;
110 // if the exponent is negative the number decimal representation is of the form:
111 // [<sign>]0.[<zeros>]<significand>
112 if (m_exponent < 0) {
113 unsigned zeros = -m_exponent - 1;
119 for (unsigned i = 0; i < zeros; ++i)
121 for (unsigned i = 0; i < m_precision; ++i)
122 *next++ = m_significand[i];
124 return next - buffer;
127 unsigned digitsBeforeDecimalPoint = m_exponent + 1;
129 // If the precision is <= than the number of digits to get up to the decimal
130 // point, then there is no fractional part, number is of the form:
131 // [<sign>]<significand>[<zeros>]
132 if (m_precision <= digitsBeforeDecimalPoint) {
135 for (unsigned i = 0; i < m_precision; ++i)
136 *next++ = m_significand[i];
137 for (unsigned i = 0; i < (digitsBeforeDecimalPoint - m_precision); ++i)
140 return next - buffer;
143 // If we get here, number starts before the decimal point, and ends after it,
144 // as such is of the form:
145 // [<sign>]<significand-begin>.<significand-end>
149 for (unsigned i = 0; i < digitsBeforeDecimalPoint; ++i)
150 *next++ = m_significand[i];
152 for (unsigned i = digitsBeforeDecimalPoint; i < m_precision; ++i)
153 *next++ = m_significand[i];
155 return next - buffer;
158 unsigned DecimalNumber::toStringExponential(UChar* buffer, unsigned bufferLength) const
160 ASSERT_UNUSED(bufferLength, bufferLength >= bufferLengthForStringExponential());
162 // Should always be at least one digit to add to the string!
164 UChar* next = buffer;
170 // Add the significand
171 *next++ = m_significand[0];
172 if (m_precision > 1) {
174 for (unsigned i = 1; i < m_precision; ++i)
175 *next++ = m_significand[i];
181 if (m_exponent >= 0) {
183 exponent = m_exponent;
186 exponent = -m_exponent;
191 *next++ = '0' + exponent / 100;
193 *next++ = '0' + (exponent % 100) / 10;
194 *next++ = '0' + exponent % 10;
196 return next - buffer;