1 | // Copyright 2012 the V8 project authors. All rights reserved. |
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27 | |
28 | #ifndef DOUBLE_CONVERSION_STRING_TO_DOUBLE_H_ |
29 | #define DOUBLE_CONVERSION_STRING_TO_DOUBLE_H_ |
30 | |
31 | #include "utils.h" |
32 | |
33 | namespace double_conversion { |
34 | |
35 | class StringToDoubleConverter { |
36 | public: |
37 | // Enumeration for allowing octals and ignoring junk when converting |
38 | // strings to numbers. |
39 | enum Flags { |
40 | NO_FLAGS = 0, |
41 | ALLOW_HEX = 1, |
42 | ALLOW_OCTALS = 2, |
43 | ALLOW_TRAILING_JUNK = 4, |
44 | ALLOW_LEADING_SPACES = 8, |
45 | ALLOW_TRAILING_SPACES = 16, |
46 | ALLOW_SPACES_AFTER_SIGN = 32, |
47 | ALLOW_CASE_INSENSITIVITY = 64, |
48 | ALLOW_CASE_INSENSIBILITY = 64, // Deprecated |
49 | ALLOW_HEX_FLOATS = 128, |
50 | }; |
51 | |
52 | static const uc16 kNoSeparator = '\0'; |
53 | |
54 | // Flags should be a bit-or combination of the possible Flags-enum. |
55 | // - NO_FLAGS: no special flags. |
56 | // - ALLOW_HEX: recognizes the prefix "0x". Hex numbers may only be integers. |
57 | // Ex: StringToDouble("0x1234") -> 4660.0 |
58 | // In StringToDouble("0x1234.56") the characters ".56" are trailing |
59 | // junk. The result of the call is hence dependent on |
60 | // the ALLOW_TRAILING_JUNK flag and/or the junk value. |
61 | // With this flag "0x" is a junk-string. Even with ALLOW_TRAILING_JUNK, |
62 | // the string will not be parsed as "0" followed by junk. |
63 | // |
64 | // - ALLOW_OCTALS: recognizes the prefix "0" for octals: |
65 | // If a sequence of octal digits starts with '0', then the number is |
66 | // read as octal integer. Octal numbers may only be integers. |
67 | // Ex: StringToDouble("01234") -> 668.0 |
68 | // StringToDouble("012349") -> 12349.0 // Not a sequence of octal |
69 | // // digits. |
70 | // In StringToDouble("01234.56") the characters ".56" are trailing |
71 | // junk. The result of the call is hence dependent on |
72 | // the ALLOW_TRAILING_JUNK flag and/or the junk value. |
73 | // In StringToDouble("01234e56") the characters "e56" are trailing |
74 | // junk, too. |
75 | // - ALLOW_TRAILING_JUNK: ignore trailing characters that are not part of |
76 | // a double literal. |
77 | // - ALLOW_LEADING_SPACES: skip over leading whitespace, including spaces, |
78 | // new-lines, and tabs. |
79 | // - ALLOW_TRAILING_SPACES: ignore trailing whitespace. |
80 | // - ALLOW_SPACES_AFTER_SIGN: ignore whitespace after the sign. |
81 | // Ex: StringToDouble("- 123.2") -> -123.2. |
82 | // StringToDouble("+ 123.2") -> 123.2 |
83 | // - ALLOW_CASE_INSENSITIVITY: ignore case of characters for special values: |
84 | // infinity and nan. |
85 | // - ALLOW_HEX_FLOATS: allows hexadecimal float literals. |
86 | // This *must* start with "0x" and separate the exponent with "p". |
87 | // Examples: 0x1.2p3 == 9.0 |
88 | // 0x10.1p0 == 16.0625 |
89 | // ALLOW_HEX and ALLOW_HEX_FLOATS are indented. |
90 | // |
91 | // empty_string_value is returned when an empty string is given as input. |
92 | // If ALLOW_LEADING_SPACES or ALLOW_TRAILING_SPACES are set, then a string |
93 | // containing only spaces is converted to the 'empty_string_value', too. |
94 | // |
95 | // junk_string_value is returned when |
96 | // a) ALLOW_TRAILING_JUNK is not set, and a junk character (a character not |
97 | // part of a double-literal) is found. |
98 | // b) ALLOW_TRAILING_JUNK is set, but the string does not start with a |
99 | // double literal. |
100 | // |
101 | // infinity_symbol and nan_symbol are strings that are used to detect |
102 | // inputs that represent infinity and NaN. They can be null, in which case |
103 | // they are ignored. |
104 | // The conversion routine first reads any possible signs. Then it compares the |
105 | // following character of the input-string with the first character of |
106 | // the infinity, and nan-symbol. If either matches, the function assumes, that |
107 | // a match has been found, and expects the following input characters to match |
108 | // the remaining characters of the special-value symbol. |
109 | // This means that the following restrictions apply to special-value symbols: |
110 | // - they must not start with signs ('+', or '-'), |
111 | // - they must not have the same first character. |
112 | // - they must not start with digits. |
113 | // |
114 | // If the separator character is not kNoSeparator, then that specific |
115 | // character is ignored when in between two valid digits of the significant. |
116 | // It is not allowed to appear in the exponent. |
117 | // It is not allowed to lead or trail the number. |
118 | // It is not allowed to appear twice next to each other. |
119 | // |
120 | // Examples: |
121 | // flags = ALLOW_HEX | ALLOW_TRAILING_JUNK, |
122 | // empty_string_value = 0.0, |
123 | // junk_string_value = NaN, |
124 | // infinity_symbol = "infinity", |
125 | // nan_symbol = "nan": |
126 | // StringToDouble("0x1234") -> 4660.0. |
127 | // StringToDouble("0x1234K") -> 4660.0. |
128 | // StringToDouble("") -> 0.0 // empty_string_value. |
129 | // StringToDouble(" ") -> NaN // junk_string_value. |
130 | // StringToDouble(" 1") -> NaN // junk_string_value. |
131 | // StringToDouble("0x") -> NaN // junk_string_value. |
132 | // StringToDouble("-123.45") -> -123.45. |
133 | // StringToDouble("--123.45") -> NaN // junk_string_value. |
134 | // StringToDouble("123e45") -> 123e45. |
135 | // StringToDouble("123E45") -> 123e45. |
136 | // StringToDouble("123e+45") -> 123e45. |
137 | // StringToDouble("123E-45") -> 123e-45. |
138 | // StringToDouble("123e") -> 123.0 // trailing junk ignored. |
139 | // StringToDouble("123e-") -> 123.0 // trailing junk ignored. |
140 | // StringToDouble("+NaN") -> NaN // NaN string literal. |
141 | // StringToDouble("-infinity") -> -inf. // infinity literal. |
142 | // StringToDouble("Infinity") -> NaN // junk_string_value. |
143 | // |
144 | // flags = ALLOW_OCTAL | ALLOW_LEADING_SPACES, |
145 | // empty_string_value = 0.0, |
146 | // junk_string_value = NaN, |
147 | // infinity_symbol = NULL, |
148 | // nan_symbol = NULL: |
149 | // StringToDouble("0x1234") -> NaN // junk_string_value. |
150 | // StringToDouble("01234") -> 668.0. |
151 | // StringToDouble("") -> 0.0 // empty_string_value. |
152 | // StringToDouble(" ") -> 0.0 // empty_string_value. |
153 | // StringToDouble(" 1") -> 1.0 |
154 | // StringToDouble("0x") -> NaN // junk_string_value. |
155 | // StringToDouble("0123e45") -> NaN // junk_string_value. |
156 | // StringToDouble("01239E45") -> 1239e45. |
157 | // StringToDouble("-infinity") -> NaN // junk_string_value. |
158 | // StringToDouble("NaN") -> NaN // junk_string_value. |
159 | // |
160 | // flags = NO_FLAGS, |
161 | // separator = ' ': |
162 | // StringToDouble("1 2 3 4") -> 1234.0 |
163 | // StringToDouble("1 2") -> NaN // junk_string_value |
164 | // StringToDouble("1 000 000.0") -> 1000000.0 |
165 | // StringToDouble("1.000 000") -> 1.0 |
166 | // StringToDouble("1.0e1 000") -> NaN // junk_string_value |
167 | StringToDoubleConverter(int flags, |
168 | double empty_string_value, |
169 | double junk_string_value, |
170 | const char* infinity_symbol, |
171 | const char* nan_symbol, |
172 | uc16 separator = kNoSeparator) |
173 | : flags_(flags), |
174 | empty_string_value_(empty_string_value), |
175 | junk_string_value_(junk_string_value), |
176 | infinity_symbol_(infinity_symbol), |
177 | nan_symbol_(nan_symbol), |
178 | separator_(separator) { |
179 | } |
180 | |
181 | // Performs the conversion. |
182 | // The output parameter 'processed_characters_count' is set to the number |
183 | // of characters that have been processed to read the number. |
184 | // Spaces than are processed with ALLOW_{LEADING|TRAILING}_SPACES are included |
185 | // in the 'processed_characters_count'. Trailing junk is never included. |
186 | double StringToDouble(const char* buffer, |
187 | int length, |
188 | int* processed_characters_count) const; |
189 | |
190 | // Same as StringToDouble above but for 16 bit characters. |
191 | double StringToDouble(const uc16* buffer, |
192 | int length, |
193 | int* processed_characters_count) const; |
194 | |
195 | // Same as StringToDouble but reads a float. |
196 | // Note that this is not equivalent to static_cast<float>(StringToDouble(...)) |
197 | // due to potential double-rounding. |
198 | float StringToFloat(const char* buffer, |
199 | int length, |
200 | int* processed_characters_count) const; |
201 | |
202 | // Same as StringToFloat above but for 16 bit characters. |
203 | float StringToFloat(const uc16* buffer, |
204 | int length, |
205 | int* processed_characters_count) const; |
206 | |
207 | // Same as StringToDouble for T = double, and StringToFloat for T = float. |
208 | template <typename T> |
209 | T StringTo(const char* buffer, |
210 | int length, |
211 | int* processed_characters_count) const; |
212 | |
213 | // Same as StringTo above but for 16 bit characters. |
214 | template <typename T> |
215 | T StringTo(const uc16* buffer, |
216 | int length, |
217 | int* processed_characters_count) const; |
218 | |
219 | private: |
220 | const int flags_; |
221 | const double empty_string_value_; |
222 | const double junk_string_value_; |
223 | const char* const infinity_symbol_; |
224 | const char* const nan_symbol_; |
225 | const uc16 separator_; |
226 | |
227 | template <class Iterator> |
228 | double StringToIeee(Iterator start_pointer, |
229 | int length, |
230 | bool read_as_double, |
231 | int* processed_characters_count) const; |
232 | |
233 | DOUBLE_CONVERSION_DISALLOW_IMPLICIT_CONSTRUCTORS(StringToDoubleConverter); |
234 | }; |
235 | |
236 | } // namespace double_conversion |
237 | |
238 | #endif // DOUBLE_CONVERSION_STRING_TO_DOUBLE_H_ |
239 | |