src/include/common/shortest_dec.h

   1 /*---------------------------------------------------------------------------
   2  *
   3  * Ryu floating-point output.
   4  *
   5  * Portions Copyright (c) 2018-2022, PostgreSQL Global Development Group
   6  *
   7  * IDENTIFICATION
   8  *        src/include/common/shortest_dec.h
   9  *
  10  * This is a modification of code taken from github.com/ulfjack/ryu under the
  11  * terms of the Boost license (not the Apache license). The original copyright
  12  * notice follows:
  13  *
  14  * Copyright 2018 Ulf Adams
  15  *
  16  * The contents of this file may be used under the terms of the Apache
  17  * License, Version 2.0.
  18  *
  19  *     (See accompanying file LICENSE-Apache or copy at
  20  *      http://www.apache.org/licenses/LICENSE-2.0)
  21  *
  22  * Alternatively, the contents of this file may be used under the terms of the
  23  * Boost Software License, Version 1.0.
  24  *
  25  *     (See accompanying file LICENSE-Boost or copy at
  26  *      https://www.boost.org/LICENSE_1_0.txt)
  27  *
  28  * Unless required by applicable law or agreed to in writing, this software is
  29  * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  30  * KIND, either express or implied.
  31  *
  32  *---------------------------------------------------------------------------
  33  */
  34 #ifndef SHORTEST_DEC_H
  35 #define SHORTEST_DEC_H
  36
  37 /*----
  38  * The length of 25 comes from:
  39  *
  40  * Case 1: -9.9999999999999999e-299  = 24 bytes, plus 1 for null
  41  *
  42  * Case 2: -0.00099999999999999999   = 23 bytes, plus 1 for null
  43  */
  44 #define DOUBLE_SHORTEST_DECIMAL_LEN 25
  45
  46 int                     double_to_shortest_decimal_bufn(double f, char *result);
  47 int                     double_to_shortest_decimal_buf(double f, char *result);
  48 char       *double_to_shortest_decimal(double f);
  49
  50 /*
  51  * The length of 16 comes from:
  52  *
  53  * Case 1: -9.99999999e+29  = 15 bytes, plus 1 for null
  54  *
  55  * Case 2: -0.000999999999  = 15 bytes, plus 1 for null
  56  */
  57 #define FLOAT_SHORTEST_DECIMAL_LEN 16
  58
  59 int                     float_to_shortest_decimal_bufn(float f, char *result);
  60 int                     float_to_shortest_decimal_buf(float f, char *result);
  61 char       *float_to_shortest_decimal(float f);
  62
  63 #endif                                                  /* SHORTEST_DEC_H */