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comparison: mfbt/double-conversion/bignum-dtoa.h
mfbt/double-conversion/bignum-dtoa.h
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| 1 // Copyright 2010 the V8 project authors. All rights reserved. | |
| 2 // Redistribution and use in source and binary forms, with or without | |
| 3 // modification, are permitted provided that the following conditions are | |
| 4 // met: | |
| 5 // | |
| 6 // * Redistributions of source code must retain the above copyright | |
| 7 // notice, this list of conditions and the following disclaimer. | |
| 8 // * Redistributions in binary form must reproduce the above | |
| 9 // copyright notice, this list of conditions and the following | |
| 10 // disclaimer in the documentation and/or other materials provided | |
| 11 // with the distribution. | |
| 12 // * Neither the name of Google Inc. nor the names of its | |
| 13 // contributors may be used to endorse or promote products derived | |
| 14 // from this software without specific prior written permission. | |
| 15 // | |
| 16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | |
| 17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT | |
| 18 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR | |
| 19 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT | |
| 20 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, | |
| 21 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT | |
| 22 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
| 23 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
| 24 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
| 25 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE | |
| 26 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
| 27 | |
| 28 #ifndef DOUBLE_CONVERSION_BIGNUM_DTOA_H_ | |
| 29 #define DOUBLE_CONVERSION_BIGNUM_DTOA_H_ | |
| 30 | |
| 31 #include "utils.h" | |
| 32 | |
| 33 namespace double_conversion { | |
| 34 | |
| 35 enum BignumDtoaMode { | |
| 36 // Return the shortest correct representation. | |
| 37 // For example the output of 0.299999999999999988897 is (the less accurate but | |
| 38 // correct) 0.3. | |
| 39 BIGNUM_DTOA_SHORTEST, | |
| 40 // Same as BIGNUM_DTOA_SHORTEST but for single-precision floats. | |
| 41 BIGNUM_DTOA_SHORTEST_SINGLE, | |
| 42 // Return a fixed number of digits after the decimal point. | |
| 43 // For instance fixed(0.1, 4) becomes 0.1000 | |
| 44 // If the input number is big, the output will be big. | |
| 45 BIGNUM_DTOA_FIXED, | |
| 46 // Return a fixed number of digits, no matter what the exponent is. | |
| 47 BIGNUM_DTOA_PRECISION | |
| 48 }; | |
| 49 | |
| 50 // Converts the given double 'v' to ascii. | |
| 51 // The result should be interpreted as buffer * 10^(point-length). | |
| 52 // The buffer will be null-terminated. | |
| 53 // | |
| 54 // The input v must be > 0 and different from NaN, and Infinity. | |
| 55 // | |
| 56 // The output depends on the given mode: | |
| 57 // - SHORTEST: produce the least amount of digits for which the internal | |
| 58 // identity requirement is still satisfied. If the digits are printed | |
| 59 // (together with the correct exponent) then reading this number will give | |
| 60 // 'v' again. The buffer will choose the representation that is closest to | |
| 61 // 'v'. If there are two at the same distance, than the number is round up. | |
| 62 // In this mode the 'requested_digits' parameter is ignored. | |
| 63 // - FIXED: produces digits necessary to print a given number with | |
| 64 // 'requested_digits' digits after the decimal point. The produced digits | |
| 65 // might be too short in which case the caller has to fill the gaps with '0's. | |
| 66 // Example: toFixed(0.001, 5) is allowed to return buffer="1", point=-2. | |
| 67 // Halfway cases are rounded up. The call toFixed(0.15, 2) thus returns | |
| 68 // buffer="2", point=0. | |
| 69 // Note: the length of the returned buffer has no meaning wrt the significance | |
| 70 // of its digits. That is, just because it contains '0's does not mean that | |
| 71 // any other digit would not satisfy the internal identity requirement. | |
| 72 // - PRECISION: produces 'requested_digits' where the first digit is not '0'. | |
| 73 // Even though the length of produced digits usually equals | |
| 74 // 'requested_digits', the function is allowed to return fewer digits, in | |
| 75 // which case the caller has to fill the missing digits with '0's. | |
| 76 // Halfway cases are again rounded up. | |
| 77 // 'BignumDtoa' expects the given buffer to be big enough to hold all digits | |
| 78 // and a terminating null-character. | |
| 79 void BignumDtoa(double v, BignumDtoaMode mode, int requested_digits, | |
| 80 Vector<char> buffer, int* length, int* point); | |
| 81 | |
| 82 } // namespace double_conversion | |
| 83 | |
| 84 #endif // DOUBLE_CONVERSION_BIGNUM_DTOA_H_ |
