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| 1 // Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file | 1 // Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file |
| 2 // for details. All rights reserved. Use of this source code is governed by a | 2 // for details. All rights reserved. Use of this source code is governed by a |
| 3 // BSD-style license that can be found in the LICENSE file. | 3 // BSD-style license that can be found in the LICENSE file. |
| 4 // Dart core library. | 4 // Dart core library. |
| 5 | 5 |
| 6 // VM implementation of double. | 6 // VM implementation of double. |
| 7 | 7 |
| 8 @patch class double { | 8 @patch |
| 9 | 9 class double { |
| 10 static double _nativeParse(String str, | 10 static double _nativeParse(String str, int start, int end) |
| 11 int start, int end) native "Double_parse"; | 11 native "Double_parse"; |
| 12 | 12 |
| 13 static double _tryParseDouble(var str, var start, var end) { | 13 static double _tryParseDouble(var str, var start, var end) { |
| 14 assert(start < end); | 14 assert(start < end); |
| 15 const int _DOT = 0x2e; // '.' | 15 const int _DOT = 0x2e; // '.' |
| 16 const int _ZERO = 0x30; // '0' | 16 const int _ZERO = 0x30; // '0' |
| 17 const int _MINUS = 0x2d; // '-' | 17 const int _MINUS = 0x2d; // '-' |
| 18 const int _N = 0x4e; // 'N' | 18 const int _N = 0x4e; // 'N' |
| 19 const int _a = 0x61; // 'a' | 19 const int _a = 0x61; // 'a' |
| 20 const int _I = 0x49; // 'I' | 20 const int _I = 0x49; // 'I' |
| 21 const int _e = 0x65; // 'e' | 21 const int _e = 0x65; // 'e' |
| 22 int exponent = 0; | 22 int exponent = 0; |
| 23 // Set to non-zero if a digit is seen. Avoids accepting ".". | 23 // Set to non-zero if a digit is seen. Avoids accepting ".". |
| 24 bool digitsSeen = false; | 24 bool digitsSeen = false; |
| 25 // Added to exponent for each digit. Set to -1 when seeing '.'. | 25 // Added to exponent for each digit. Set to -1 when seeing '.'. |
| 26 int exponentDelta = 0; | 26 int exponentDelta = 0; |
| 27 double doubleValue = 0.0; | 27 double doubleValue = 0.0; |
| 28 double sign = 1.0; | 28 double sign = 1.0; |
| 29 int firstChar = str.codeUnitAt(start); | 29 int firstChar = str.codeUnitAt(start); |
| 30 if (firstChar == _MINUS) { | 30 if (firstChar == _MINUS) { |
| 31 sign = -1.0; | 31 sign = -1.0; |
| (...skipping 17 matching lines...) Expand all Loading... |
| 49 } | 49 } |
| 50 | 50 |
| 51 int firstDigit = firstChar ^ _ZERO; | 51 int firstDigit = firstChar ^ _ZERO; |
| 52 if (firstDigit <= 9) { | 52 if (firstDigit <= 9) { |
| 53 start++; | 53 start++; |
| 54 doubleValue = firstDigit.toDouble(); | 54 doubleValue = firstDigit.toDouble(); |
| 55 digitsSeen = true; | 55 digitsSeen = true; |
| 56 } | 56 } |
| 57 for (int i = start; i < end; i++) { | 57 for (int i = start; i < end; i++) { |
| 58 int c = str.codeUnitAt(i); | 58 int c = str.codeUnitAt(i); |
| 59 int digit = c ^ _ZERO; // '0'-'9' characters are now 0-9 integers. | 59 int digit = c ^ _ZERO; // '0'-'9' characters are now 0-9 integers. |
| 60 if (digit <= 9) { | 60 if (digit <= 9) { |
| 61 doubleValue = 10.0 * doubleValue + digit; | 61 doubleValue = 10.0 * doubleValue + digit; |
| 62 // Doubles at or above this value (2**53) might have lost precission. | 62 // Doubles at or above this value (2**53) might have lost precission. |
| 63 const double MAX_EXACT_DOUBLE = 9007199254740992.0; | 63 const double MAX_EXACT_DOUBLE = 9007199254740992.0; |
| 64 if (doubleValue >= MAX_EXACT_DOUBLE) return null; | 64 if (doubleValue >= MAX_EXACT_DOUBLE) return null; |
| 65 exponent += exponentDelta; | 65 exponent += exponentDelta; |
| 66 digitsSeen = true; | 66 digitsSeen = true; |
| 67 } else if (c == _DOT && exponentDelta == 0) { | 67 } else if (c == _DOT && exponentDelta == 0) { |
| 68 exponentDelta = -1; | 68 exponentDelta = -1; |
| 69 } else if ((c | 0x20) == _e) { | 69 } else if ((c | 0x20) == _e) { |
| 70 i++; | 70 i++; |
| 71 if (i == end) return null; | 71 if (i == end) return null; |
| 72 // int._tryParseSmi treats its end argument as inclusive. | 72 // int._tryParseSmi treats its end argument as inclusive. |
| 73 int expPart = int._tryParseSmi(str, i, end - 1); | 73 int expPart = int._tryParseSmi(str, i, end - 1); |
| 74 if (expPart == null) return null; | 74 if (expPart == null) return null; |
| 75 exponent += expPart; | 75 exponent += expPart; |
| 76 break; | 76 break; |
| 77 } else { | 77 } else { |
| 78 return null; | 78 return null; |
| 79 } | 79 } |
| 80 } | 80 } |
| 81 if (!digitsSeen) return null; // No digits. | 81 if (!digitsSeen) return null; // No digits. |
| 82 if (exponent == 0) return sign * doubleValue; | 82 if (exponent == 0) return sign * doubleValue; |
| 83 const P10 = POWERS_OF_TEN; // From shared library | 83 const P10 = POWERS_OF_TEN; // From shared library |
| 84 if (exponent < 0) { | 84 if (exponent < 0) { |
| 85 int negExponent = -exponent; | 85 int negExponent = -exponent; |
| 86 if (negExponent >= P10.length) return null; | 86 if (negExponent >= P10.length) return null; |
| 87 return sign * (doubleValue / P10[negExponent]); | 87 return sign * (doubleValue / P10[negExponent]); |
| 88 } | 88 } |
| 89 if (exponent >= P10.length) return null; | 89 if (exponent >= P10.length) return null; |
| 90 return sign * (doubleValue * P10[exponent]); | 90 return sign * (doubleValue * P10[exponent]); |
| 91 } | 91 } |
| 92 | 92 |
| 93 static double _parse(var str) { | 93 static double _parse(var str) { |
| 94 int len = str.length; | 94 int len = str.length; |
| 95 int start = str._firstNonWhitespace(); | 95 int start = str._firstNonWhitespace(); |
| 96 if (start == len) return null; // All whitespace. | 96 if (start == len) return null; // All whitespace. |
| 97 int end = str._lastNonWhitespace() + 1; | 97 int end = str._lastNonWhitespace() + 1; |
| 98 assert(start < end); | 98 assert(start < end); |
| 99 var result = _tryParseDouble(str, start, end); | 99 var result = _tryParseDouble(str, start, end); |
| 100 if (result != null) return result; | 100 if (result != null) return result; |
| 101 return _nativeParse(str, start, end); | 101 return _nativeParse(str, start, end); |
| 102 } | 102 } |
| 103 | 103 |
| 104 @patch | 104 @patch |
| 105 static double parse(String source, [double onError(String source)]) { | 105 static double parse(String source, [double onError(String source)]) { |
| 106 var result = _parse(source); | 106 var result = _parse(source); |
| 107 if (result == null) { | 107 if (result == null) { |
| 108 if (onError == null) throw new FormatException("Invalid double", source); | 108 if (onError == null) throw new FormatException("Invalid double", source); |
| 109 return onError(source); | 109 return onError(source); |
| 110 } | 110 } |
| 111 return result; | 111 return result; |
| 112 } | 112 } |
| 113 } | 113 } |
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