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 V8_BIGNUM_DTOA_H_ 29#define V8_BIGNUM_DTOA_H_ 30 31namespace v8 { 32namespace internal { 33 34enum BignumDtoaMode { 35 // Return the shortest correct representation. 36 // For example the output of 0.299999999999999988897 is (the less accurate but 37 // correct) 0.3. 38 BIGNUM_DTOA_SHORTEST, 39 // Return a fixed number of digits after the decimal point. 40 // For instance fixed(0.1, 4) becomes 0.1000 41 // If the input number is big, the output will be big. 42 BIGNUM_DTOA_FIXED, 43 // Return a fixed number of digits, no matter what the exponent is. 44 BIGNUM_DTOA_PRECISION 45}; 46 47// Converts the given double 'v' to ASCII. 48// The result should be interpreted as buffer * 10^(point-length). 49// The buffer will be null-terminated. 50// 51// The input v must be > 0 and different from NaN, and Infinity. 52// 53// The output depends on the given mode: 54// - SHORTEST: produce the least amount of digits for which the internal 55// identity requirement is still satisfied. If the digits are printed 56// (together with the correct exponent) then reading this number will give 57// 'v' again. The buffer will choose the representation that is closest to 58// 'v'. If there are two at the same distance, than the number is round up. 59// In this mode the 'requested_digits' parameter is ignored. 60// - FIXED: produces digits necessary to print a given number with 61// 'requested_digits' digits after the decimal point. The produced digits 62// might be too short in which case the caller has to fill the gaps with '0's. 63// Example: toFixed(0.001, 5) is allowed to return buffer="1", point=-2. 64// Halfway cases are rounded up. The call toFixed(0.15, 2) thus returns 65// buffer="2", point=0. 66// Note: the length of the returned buffer has no meaning wrt the significance 67// of its digits. That is, just because it contains '0's does not mean that 68// any other digit would not satisfy the internal identity requirement. 69// - PRECISION: produces 'requested_digits' where the first digit is not '0'. 70// Even though the length of produced digits usually equals 71// 'requested_digits', the function is allowed to return fewer digits, in 72// which case the caller has to fill the missing digits with '0's. 73// Halfway cases are again rounded up. 74// 'BignumDtoa' expects the given buffer to be big enough to hold all digits 75// and a terminating null-character. 76void BignumDtoa(double v, BignumDtoaMode mode, int requested_digits, 77 Vector<char> buffer, int* length, int* point); 78 79} } // namespace v8::internal 80 81#endif // V8_BIGNUM_DTOA_H_ 82