mirror of https://gitlab.com/rnger/amath
135 lines
5.8 KiB
C
Executable File
135 lines
5.8 KiB
C
Executable File
/******************************************************************************
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Copyright (c) 2014 Ryan Juckett
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http://www.ryanjuckett.com/
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This software is provided 'as-is', without any express or implied
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warranty. In no event will the authors be held liable for any damages
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arising from the use of this software.
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Permission is granted to anyone to use this software for any purpose,
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including commercial applications, and to alter it and redistribute it
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freely, subject to the following restrictions:
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1. The origin of this software must not be misrepresented; you must not
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claim that you wrote the original software. If you use this software
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in a product, an acknowledgment in the product documentation would be
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appreciated but is not required.
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2. Altered source versions must be plainly marked as such, and must not be
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misrepresented as being the original software.
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3. This notice may not be removed or altered from any source
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distribution.
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*******************************************************************************
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Copyright (c) 2015-2017 Carsten Sonne Larsen <cs@innolan.dk>
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions
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are met:
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1. Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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2. Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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The origin source code can be obtained from:
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http://www.ryanjuckett.com/
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******************************************************************************/
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#ifndef RJX_DRAGON4_H
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#define RJX_DRAGON4_H
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/**
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* @file dragon4.h
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* @brief Convert floating point format to a decimal number in string format.
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*
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* This is an implementation the Dragon4 algorithm to convert a binary number
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* in floating point format to a decimal number in string format. The function
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* returns the number of digits written to the output buffer and the output is
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* not NUL terminated.
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*
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* Downloaded from:<BR>
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* http://www.ryanjuckett.com/
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*
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*/
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#include "dstandard.h"
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//******************************************************************************
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// Different modes for terminating digit output
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//******************************************************************************
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enum tCutoffMode
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{
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CutoffMode_Unique, // as many digits as necessary to print a uniquely identifiable number
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CutoffMode_TotalLength, // up to cutoffNumber significant digits
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CutoffMode_FractionLength, // up to cutoffNumber significant digits past the decimal point
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};
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//******************************************************************************
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// This is an implementation the Dragon4 algorithm to convert a binary number
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// in floating point format to a decimal number in string format. The function
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// returns the number of digits written to the output buffer and the output is
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// not NUL terminated.
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//
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// The floating point input value is (mantissa * 2^exponent).
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//
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// See the following papers for more information on the algorithm:
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// "How to Print Floating-Point Numbers Accurately"
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// Steele and White
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// http://kurtstephens.com/files/p372-steele.pdf
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// "Printing Floating-Point Numbers Quickly and Accurately"
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// Burger and Dybvig
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// http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.72.4656&rep=rep1&type=pdf
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//******************************************************************************
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/**
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* @brief Dragon4 main.
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* @details
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* Downloaded from:<BR>
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* http://www.ryanjuckett.com/
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*
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* This is an implementation the Dragon4 algorithm to convert a binary number
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* in floating point format to a decimal number in string format. The function
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* returns the number of digits written to the output buffer and the output is
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* not NUL terminated.
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*
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* The floating point input value is (mantissa * 2^exponent).
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*
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* See the following papers for more information on the algorithm:<BR>
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* "How to Print Floating-Point Numbers Accurately"<BR>
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* Steele and White<BR>
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* http://kurtstephens.com/files/p372-steele.pdf<BR>
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* "Printing Floating-Point Numbers Quickly and Accurately"<BR>
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* Burger and Dybvig<BR>
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* http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.72.4656&rep=rep1&type=pdf<BR>
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*
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*/
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tU32 Dragon4
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(
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tU64 mantissa, // value significand
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tS32 exponent, // value exponent in base 2
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tU32 mantissaHighBitIdx, // index of the highest set mantissa bit
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tB hasUnequalMargins, // is the high margin twice as large as the low margin
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enum tCutoffMode cutoffMode, // how to determine output length
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tU32 cutoffNumber, // parameter to the selected cutoffMode
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tC8 * pOutBuffer, // buffer to output into
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tU32 bufferSize, // maximum characters that can be printed to pOutBuffer
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tS32 * pOutExponent // the base 10 exponent of the first digit
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);
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#endif
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