1 /* 2 * Copyright (C) 2010 Apple Inc. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY 14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR 17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY 21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24 */ 25 26 #include "config.h" 27 #include "DecimalNumber.h" 28 #include <math.h> 29 #include <wtf/MathExtras.h> 30 #include <wtf/text/WTFString.h> 31 32 namespace WTF { 33 34 unsigned DecimalNumber::bufferLengthForStringDecimal() const 35 { 36 unsigned length = 0; 37 // if the exponent is negative the number decimal representation is of the form: 38 // [<sign>]0.[<zeros>]<significand> 39 if (m_exponent < 0) { 40 if (m_sign) 41 ++length; 42 length += 2; // for "0." 43 length += -m_exponent - 1; 44 length += m_precision; 45 return length; 46 } 47 48 unsigned digitsBeforeDecimalPoint = m_exponent + 1; 49 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) { 54 if (m_sign) 55 ++length; 56 length += m_precision; 57 length += digitsBeforeDecimalPoint - m_precision; 58 return length; 59 } 60 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> 64 if (m_sign) 65 ++length; 66 length += digitsBeforeDecimalPoint; 67 ++length; // for decimal point 68 length += m_precision - digitsBeforeDecimalPoint; 69 70 return length; 71 } 72 73 unsigned DecimalNumber::bufferLengthForStringExponential() const 74 { 75 unsigned length = 0; 76 if (m_sign) 77 ++length; 78 79 // Add the significand 80 ++length; 81 82 if (m_precision > 1) { 83 ++length; // for decimal point 84 length += m_precision - 1; 85 } 86 87 // Add "e+" or "e-" 88 length += 2; 89 90 int exponent = (m_exponent >= 0) ? m_exponent : -m_exponent; 91 92 // Add the exponent 93 if (exponent >= 100) 94 ++length; 95 if (exponent >= 10) 96 ++length; 97 ++length; 98 99 return length; 100 } 101 102 unsigned DecimalNumber::toStringDecimal(UChar* buffer, unsigned bufferLength) const 103 { 104 ASSERT_UNUSED(bufferLength, bufferLength >= bufferLengthForStringDecimal()); 105 106 // Should always be at least one digit to add to the string! 107 ASSERT(m_precision); 108 UChar* next = buffer; 109 110 // 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; 114 115 if (m_sign) 116 *next++ = '-'; 117 *next++ = '0'; 118 *next++ = '.'; 119 for (unsigned i = 0; i < zeros; ++i) 120 *next++ = '0'; 121 for (unsigned i = 0; i < m_precision; ++i) 122 *next++ = m_significand[i]; 123 124 return next - buffer; 125 } 126 127 unsigned digitsBeforeDecimalPoint = m_exponent + 1; 128 129 // 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) { 133 if (m_sign) 134 *next++ = '-'; 135 for (unsigned i = 0; i < m_precision; ++i) 136 *next++ = m_significand[i]; 137 for (unsigned i = 0; i < (digitsBeforeDecimalPoint - m_precision); ++i) 138 *next++ = '0'; 139 140 return next - buffer; 141 } 142 143 // 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> 146 147 if (m_sign) 148 *next++ = '-'; 149 for (unsigned i = 0; i < digitsBeforeDecimalPoint; ++i) 150 *next++ = m_significand[i]; 151 *next++ = '.'; 152 for (unsigned i = digitsBeforeDecimalPoint; i < m_precision; ++i) 153 *next++ = m_significand[i]; 154 155 return next - buffer; 156 } 157 158 unsigned DecimalNumber::toStringExponential(UChar* buffer, unsigned bufferLength) const 159 { 160 ASSERT_UNUSED(bufferLength, bufferLength >= bufferLengthForStringExponential()); 161 162 // Should always be at least one digit to add to the string! 163 ASSERT(m_precision); 164 UChar* next = buffer; 165 166 // Add the sign 167 if (m_sign) 168 *next++ = '-'; 169 170 // Add the significand 171 *next++ = m_significand[0]; 172 if (m_precision > 1) { 173 *next++ = '.'; 174 for (unsigned i = 1; i < m_precision; ++i) 175 *next++ = m_significand[i]; 176 } 177 178 // Add "e+" or "e-" 179 *next++ = 'e'; 180 int exponent; 181 if (m_exponent >= 0) { 182 *next++ = '+'; 183 exponent = m_exponent; 184 } else { 185 *next++ = '-'; 186 exponent = -m_exponent; 187 } 188 189 // Add the exponent 190 if (exponent >= 100) 191 *next++ = '0' + exponent / 100; 192 if (exponent >= 10) 193 *next++ = '0' + (exponent % 100) / 10; 194 *next++ = '0' + exponent % 10; 195 196 return next - buffer; 197 } 198 199 } // namespace WTF 200