/[dtapublic]/projs/trunk/shared_source/c_datd/esrg_win_int64.c
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Contents of /projs/trunk/shared_source/c_datd/esrg_win_int64.c

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Revision 56 - (show annotations) (download)
Sat Oct 29 01:53:01 2016 UTC (6 years, 3 months ago) by dashley
File MIME type: text/plain
File size: 4433 byte(s)
License and property (keyword) changes.
1 //$Header$
2 //-------------------------------------------------------------------------------------------------
3 //This file is part of "David T. Ashley's Shared Source Code", a set of shared components
4 //integrated into many of David T. Ashley's projects.
5 //-------------------------------------------------------------------------------------------------
6 //This source code and any program in which it is compiled/used is provided under the MIT License,
7 //reproduced below.
8 //-------------------------------------------------------------------------------------------------
9 //Permission is hereby granted, free of charge, to any person obtaining a copy of
10 //this software and associated documentation files(the "Software"), to deal in the
11 //Software without restriction, including without limitation the rights to use,
12 //copy, modify, merge, publish, distribute, sublicense, and / or sell copies of the
13 //Software, and to permit persons to whom the Software is furnished to do so,
14 //subject to the following conditions :
15 //
16 //The above copyright notice and this permission notice shall be included in all
17 //copies or substantial portions of the Software.
18 //
19 //THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
20 //IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
21 //FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
22 //AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
23 //LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
24 //OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
25 //SOFTWARE.
26 //-------------------------------------------------------------------------------------------------
27 #define MODULE_ESRG_WIN_INT64
28
29 #include <assert.h>
30 #include <string.h>
31
32 #include "charfunc.h"
33 #include "esrg_win_int64.h"
34
35
36 void ESRG_WIN_INT64_StringPlainToUi
37 (
38 const char *s,
39 ESRG_WIN_INT64_UI64 *rv,
40 int *err
41 )
42 {
43 int cval;
44 ESRG_WIN_INT64_UI64 mul_10_max = 1844674407370955161;
45 //The maximum value that can be successfully
46 //multiplied by 10 and still stay within 64 bits.
47 ESRG_WIN_INT64_UI64 result;
48
49 assert(s != NULL);
50 assert(rv != NULL);
51 assert(err != NULL);
52
53 //By default, no error on return.
54 *err = 0;
55
56 //Cover the case of an illegal first character or
57 //a zero length string.
58 cval = CHARFUNC_digit_to_val(*s);
59 if (cval == -1)
60 goto err_return;
61
62 //Cover the case of canonical zero.
63 if (cval == 0)
64 {
65 if (s[1] != 0)
66 {
67 //There is a '0', but not a null char trailing.
68 goto err_return;
69 }
70 else
71 {
72 //Canonical zero.
73 *rv = 0;
74 return;
75 }
76 }
77
78 //If we're here, we have a digit which is not a zero,
79 //and presumably more to follow. Iterate through, applying
80 //the standard formula.
81 //
82 //Overflow can occur under two circumstances. Either we
83 //multiply by 10 and overflow that way, or else we add a
84 //digit and overflow that way.
85 //
86 //The multiply by 10 overflow can be prevented by
87 //knowing the maximum constant that can be multiplied by
88 //10 without overflow (we know this at compile-time).
89 //The add overflow can be detected by the observation that
90 //if the result is less than the digit we added, we
91 //overflowed.
92 result = 0;
93 do
94 {
95 if (result > mul_10_max) //Can't mul--already too large.
96 goto err_return;
97
98 result *= 10;
99
100 result += cval;
101
102 if (result < cval) //Overflow.
103 goto err_return;
104
105 s++;
106 if (*s)
107 {
108 cval = CHARFUNC_digit_to_val(*s);
109 }
110 else
111 {
112 cval = 0;
113 }
114
115 if (cval == -1)
116 goto err_return;
117
118 } while (*s);
119
120
121 *rv = result;
122 return;
123
124 //---------
125 err_return:
126 *rv = 0;
127 *err = 1;
128 return;
129 }
130
131
132 const char *ESRG_WIN_INT64_cvcinfo(void)
133 {
134 return("$Header$");
135 }
136
137
138 const char *ESRG_WIN_INT64_hvcinfo(void)
139 {
140 return(ESRG_WIN_INT64_H_VERSION);
141 }
142
143 //End of esrg_win_int64.c.

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