double-conversion-bignum-dtoa.h (4811B)
1 // © 2018 and later: Unicode, Inc. and others. 2 // License & terms of use: http://www.unicode.org/copyright.html 3 // 4 // From the double-conversion library. Original license: 5 // 6 // Copyright 2010 the V8 project authors. All rights reserved. 7 // Redistribution and use in source and binary forms, with or without 8 // modification, are permitted provided that the following conditions are 9 // met: 10 // 11 // * Redistributions of source code must retain the above copyright 12 // notice, this list of conditions and the following disclaimer. 13 // * Redistributions in binary form must reproduce the above 14 // copyright notice, this list of conditions and the following 15 // disclaimer in the documentation and/or other materials provided 16 // with the distribution. 17 // * Neither the name of Google Inc. nor the names of its 18 // contributors may be used to endorse or promote products derived 19 // from this software without specific prior written permission. 20 // 21 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 22 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 23 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 24 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 25 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 26 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 27 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 28 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 29 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 30 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 31 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 32 33 // ICU PATCH: ifdef around UCONFIG_NO_FORMATTING 34 #include "unicode/utypes.h" 35 #if !UCONFIG_NO_FORMATTING 36 37 #ifndef DOUBLE_CONVERSION_BIGNUM_DTOA_H_ 38 #define DOUBLE_CONVERSION_BIGNUM_DTOA_H_ 39 40 // ICU PATCH: Customize header file paths for ICU. 41 42 #include "double-conversion-utils.h" 43 44 // ICU PATCH: Wrap in ICU namespace 45 U_NAMESPACE_BEGIN 46 47 namespace double_conversion { 48 49 enum BignumDtoaMode { 50 // Return the shortest correct representation. 51 // For example the output of 0.299999999999999988897 is (the less accurate but 52 // correct) 0.3. 53 BIGNUM_DTOA_SHORTEST, 54 // Same as BIGNUM_DTOA_SHORTEST but for single-precision floats. 55 BIGNUM_DTOA_SHORTEST_SINGLE, 56 // Return a fixed number of digits after the decimal point. 57 // For instance fixed(0.1, 4) becomes 0.1000 58 // If the input number is big, the output will be big. 59 BIGNUM_DTOA_FIXED, 60 // Return a fixed number of digits, no matter what the exponent is. 61 BIGNUM_DTOA_PRECISION 62 }; 63 64 // Converts the given double 'v' to ascii. 65 // The result should be interpreted as buffer * 10^(point-length). 66 // The buffer will be null-terminated. 67 // 68 // The input v must be > 0 and different from NaN, and Infinity. 69 // 70 // The output depends on the given mode: 71 // - SHORTEST: produce the least amount of digits for which the internal 72 // identity requirement is still satisfied. If the digits are printed 73 // (together with the correct exponent) then reading this number will give 74 // 'v' again. The buffer will choose the representation that is closest to 75 // 'v'. If there are two at the same distance, than the number is round up. 76 // In this mode the 'requested_digits' parameter is ignored. 77 // - FIXED: produces digits necessary to print a given number with 78 // 'requested_digits' digits after the decimal point. The produced digits 79 // might be too short in which case the caller has to fill the gaps with '0's. 80 // Example: toFixed(0.001, 5) is allowed to return buffer="1", point=-2. 81 // Halfway cases are rounded up. The call toFixed(0.15, 2) thus returns 82 // buffer="2", point=0. 83 // Note: the length of the returned buffer has no meaning wrt the significance 84 // of its digits. That is, just because it contains '0's does not mean that 85 // any other digit would not satisfy the internal identity requirement. 86 // - PRECISION: produces 'requested_digits' where the first digit is not '0'. 87 // Even though the length of produced digits usually equals 88 // 'requested_digits', the function is allowed to return fewer digits, in 89 // which case the caller has to fill the missing digits with '0's. 90 // Halfway cases are again rounded up. 91 // 'BignumDtoa' expects the given buffer to be big enough to hold all digits 92 // and a terminating null-character. 93 void BignumDtoa(double v, BignumDtoaMode mode, int requested_digits, 94 Vector<char> buffer, int* length, int* point); 95 96 } // namespace double_conversion 97 98 // ICU PATCH: Close ICU namespace 99 U_NAMESPACE_END 100 101 #endif // DOUBLE_CONVERSION_BIGNUM_DTOA_H_ 102 #endif // ICU PATCH: close #if !UCONFIG_NO_FORMATTING