BadVPN – Blame information for rev 1
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1 | office | 1 | /** |
2 | * @file bsize.h |
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3 | * @author Ambroz Bizjak <ambrop7@gmail.com> |
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4 | * |
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5 | * @section LICENSE |
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6 | * |
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7 | * Redistribution and use in source and binary forms, with or without |
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8 | * modification, are permitted provided that the following conditions are met: |
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9 | * 1. Redistributions of source code must retain the above copyright |
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10 | * notice, this list of conditions and the following disclaimer. |
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11 | * 2. Redistributions in binary form must reproduce the above copyright |
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12 | * notice, this list of conditions and the following disclaimer in the |
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13 | * documentation and/or other materials provided with the distribution. |
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14 | * 3. Neither the name of the author nor the |
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15 | * names of its contributors may be used to endorse or promote products |
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16 | * derived from this software without specific prior written permission. |
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17 | * |
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18 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND |
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19 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED |
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20 | * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
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21 | * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY |
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22 | * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES |
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23 | * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
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24 | * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND |
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25 | * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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26 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
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27 | * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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28 | * |
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29 | * @section DESCRIPTION |
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30 | * |
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31 | * Arithmetic with overflow detection. |
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32 | */ |
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33 | |||
34 | #ifndef BADVPN_MISC_BSIZE_H |
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35 | #define BADVPN_MISC_BSIZE_H |
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36 | |||
37 | #include <stddef.h> |
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38 | #include <limits.h> |
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39 | #include <stdint.h> |
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40 | |||
41 | typedef struct { |
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42 | int is_overflow; |
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43 | size_t value; |
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44 | } bsize_t; |
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45 | |||
46 | static bsize_t bsize_fromsize (size_t v); |
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47 | static bsize_t bsize_fromint (int v); |
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48 | static bsize_t bsize_overflow (void); |
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49 | static int bsize_tosize (bsize_t s, size_t *out); |
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50 | static int bsize_toint (bsize_t s, int *out); |
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51 | static bsize_t bsize_add (bsize_t s1, bsize_t s2); |
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52 | static bsize_t bsize_max (bsize_t s1, bsize_t s2); |
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53 | static bsize_t bsize_mul (bsize_t s1, bsize_t s2); |
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54 | |||
55 | bsize_t bsize_fromsize (size_t v) |
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56 | { |
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57 | bsize_t s = {0, v}; |
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58 | return s; |
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59 | } |
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60 | |||
61 | bsize_t bsize_fromint (int v) |
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62 | { |
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63 | bsize_t s = {(v < 0 || v > SIZE_MAX), v}; |
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64 | return s; |
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65 | } |
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66 | |||
67 | static bsize_t bsize_overflow (void) |
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68 | { |
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69 | bsize_t s = {1, 0}; |
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70 | return s; |
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71 | } |
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72 | |||
73 | int bsize_tosize (bsize_t s, size_t *out) |
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74 | { |
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75 | if (s.is_overflow) { |
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76 | return 0; |
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77 | } |
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78 | |||
79 | if (out) { |
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80 | *out = s.value; |
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81 | } |
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82 | |||
83 | return 1; |
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84 | } |
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85 | |||
86 | int bsize_toint (bsize_t s, int *out) |
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87 | { |
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88 | if (s.is_overflow || s.value > INT_MAX) { |
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89 | return 0; |
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90 | } |
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91 | |||
92 | if (out) { |
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93 | *out = s.value; |
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94 | } |
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95 | |||
96 | return 1; |
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97 | } |
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98 | |||
99 | bsize_t bsize_add (bsize_t s1, bsize_t s2) |
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100 | { |
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101 | bsize_t s = {(s1.is_overflow || s2.is_overflow || s2.value > SIZE_MAX - s1.value), (s1.value + s2.value)}; |
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102 | return s; |
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103 | } |
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104 | |||
105 | bsize_t bsize_max (bsize_t s1, bsize_t s2) |
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106 | { |
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107 | bsize_t s = {(s1.is_overflow || s2.is_overflow), ((s1.value > s2.value) * s1.value + (s1.value <= s2.value) * s2.value)}; |
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108 | return s; |
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109 | } |
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110 | |||
111 | bsize_t bsize_mul (bsize_t s1, bsize_t s2) |
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112 | { |
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113 | bsize_t s = {(s1.is_overflow || s2.is_overflow || (s1.value != 0 && s2.value > SIZE_MAX / s1.value)), (s1.value * s2.value)}; |
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114 | return s; |
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115 | } |
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116 | |||
117 | #endif |