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1 : // Output __int128 or unsigned __int128 to an iostream
2 : // Copyright (c) 2021 Made to Order Software Corp. All Rights Reserved
3 : //
4 : // This program is free software; you can redistribute it and/or modify
5 : // it under the terms of the GNU General Public License as published by
6 : // the Free Software Foundation; either version 2 of the License, or
7 : // (at your option) any later version.
8 : //
9 : // This program is distributed in the hope that it will be useful,
10 : // but WITHOUT ANY WARRANTY; without even the implied warranty of
11 : // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 : // GNU General Public License for more details.
13 : //
14 : // You should have received a copy of the GNU General Public License
15 : // along with this program; if not, write to the Free Software
16 : // Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
17 : #pragma once
18 :
19 : /** \file
20 : * \brief Print large integers to any iostream.
21 : *
22 : * This function prints large integers (128 bits) to the specified iostream.
23 : */
24 :
25 : // C++ lib
26 : //
27 : #include <ostream>
28 : #include <sstream>
29 :
30 :
31 : namespace snap
32 : {
33 :
34 : /** \brief Convert an __int128 to a string.
35 : *
36 : * This function converts an __int128 to a string.
37 : *
38 : * \param[in] x An __int128 number.
39 : *
40 : * \return A string representing that __int128 number.
41 : */
42 : #pragma GCC diagnostic push
43 : #pragma GCC diagnostic ignored "-Wpedantic"
44 : #pragma GCC diagnostic ignored "-Wstrict-overflow"
45 2022 : std::string to_string(__int128 x)
46 : {
47 2022 : char buf[42];
48 :
49 2022 : int idx(sizeof(buf));
50 2022 : unsigned __int128 y(x < 0
51 2022 : ? static_cast<unsigned __int128>(-x)
52 : : static_cast<unsigned __int128>(x));
53 2022 : constexpr unsigned __int128 const limit(9);
54 36086 : while(y > limit)
55 : {
56 17032 : --idx;
57 17032 : buf[idx] = y % 10 + '0';
58 17032 : y /= 10;
59 : }
60 2022 : --idx;
61 2022 : buf[idx] = y + '0';
62 2022 : if(x < 0)
63 : {
64 1011 : --idx;
65 1011 : buf[idx] = '-';
66 : }
67 :
68 2022 : return std::string(buf + idx, sizeof(buf) - idx);
69 : }
70 : #pragma GCC diagnostic pop
71 :
72 :
73 : /** \brief Convert an unsigned __int128 to a string.
74 : *
75 : * This function converts an unsigned __int128 to a string.
76 : *
77 : * \param[in] x An unsigned __int128 number.
78 : *
79 : * \return A string representing that unsigned __int128 number.
80 : */
81 : #pragma GCC diagnostic push
82 : #pragma GCC diagnostic ignored "-Wpedantic"
83 1 : std::string to_string(unsigned __int128 x)
84 : {
85 1 : char buf[42];
86 :
87 1 : int idx(sizeof(buf));
88 77 : while(x > 9)
89 : {
90 38 : --idx;
91 38 : buf[idx] = x % 10 + '0';
92 38 : x /= 10;
93 : }
94 1 : --idx;
95 1 : buf[idx] = x + '0';
96 :
97 1 : return std::string(buf + idx, sizeof(buf) - idx);
98 : }
99 : #pragma GCC diagnostic pop
100 :
101 : }
102 :
103 :
104 :
105 : //namespace snap -- no namespace for such definitions, it works better that way
106 :
107 :
108 : /** \brief Output an __int128 number.
109 : *
110 : * \warning
111 : * This implementation does not offer proper formatting.
112 : * It will first generate a string then output that string
113 : * which means the result is not what you'd expect if you
114 : * used formatting such as std::hex and std::setw().
115 : *
116 : * \param[in] os The output stream.
117 : * \param[in] x The value to be output in \p os.
118 : *
119 : * \return A reference to \p os.
120 : */
121 : #pragma GCC diagnostic push
122 : #pragma GCC diagnostic ignored "-Wpedantic"
123 2022 : std::ostream & operator << (std::ostream & os, __int128 x)
124 : {
125 2022 : return os << snap::to_string(x);
126 : }
127 : #pragma GCC diagnostic pop
128 :
129 :
130 : /** \brief Output an unsigned __int128 number.
131 : *
132 : * \warning
133 : * This implementation does not offer proper formatting.
134 : * It will first generate a string then output that string
135 : * which means the result is not what you'd expect if you
136 : * used formatting such as std::hex and std::setw().
137 : *
138 : * \param[in] os The output stream.
139 : * \param[in] x The value to be output in \p os.
140 : *
141 : * \return A reference to \p os.
142 : */
143 : #pragma GCC diagnostic push
144 : #pragma GCC diagnostic ignored "-Wpedantic"
145 1 : std::ostream & operator << (std::ostream & os, unsigned __int128 x)
146 : {
147 1 : return os << snap::to_string(x);
148 : }
149 : #pragma GCC diagnostic pop
150 :
151 :
152 : // vim: ts=4 sw=4 et
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