spielwiese
Last change
on this file since 82e0a7 was
16f511,
checked in by Oleksandr Motsak <motsak@…>, 11 years ago
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Fixed the usage of "config.h" (if defined HAVE_CONFIG_H)
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-
Property mode set to
100644
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File size:
1.8 KB
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1 | /* emacs edit mode for this file is -*- C++ -*- */ |
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2 | |
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3 | #ifdef HAVE_CONFIG_H |
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4 | #include "config.h" |
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5 | #endif /* HAVE_CONFIG_H */ |
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6 | |
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7 | #include <string.h> |
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8 | |
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9 | #include "cf_assert.h" |
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10 | |
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11 | #include "cf_defs.h" |
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12 | #include "ffops.h" |
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13 | |
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14 | int ff_prime = 0; |
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15 | int ff_halfprime = 0; |
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16 | bool ff_big = false; |
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17 | short * ff_invtab = new short [32767]; |
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18 | |
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19 | void ff_setprime ( const int p ) |
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20 | { |
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21 | if ( p != ff_prime ) { |
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22 | ff_prime = p; |
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23 | ff_halfprime = ff_prime / 2; |
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24 | if ( ! ff_big ) |
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25 | memset( ff_invtab, 0, ff_prime*sizeof(short) ); |
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26 | } |
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27 | } |
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28 | |
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29 | int ff_newinv ( const int a ) |
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30 | { |
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31 | int p, q, r1, r2, y1, y2; |
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32 | if (a < 2) |
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33 | return (ff_invtab[a] = a); |
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34 | r1 = p = ff_prime; |
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35 | q = r1 / a; |
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36 | y1 = -q; |
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37 | r1 -= a * q; |
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38 | if (r1 == 1) |
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39 | { |
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40 | y1 += p; |
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41 | ff_invtab[y1] = a; |
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42 | return (ff_invtab[a] = y1); |
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43 | } |
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44 | r2 = a; |
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45 | y2 = 1; |
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46 | for (;;) |
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47 | { |
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48 | q = r2 / r1; |
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49 | y2 -= y1 * q; |
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50 | r2 -= r1 * q; |
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51 | if (r2 == 1) |
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52 | { |
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53 | if (y2 < 0) |
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54 | y2 += p; |
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55 | ff_invtab[y2] = a; |
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56 | return (ff_invtab[a] = y2); |
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57 | } |
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58 | q = r1 / r2; |
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59 | y1 -= y2 * q; |
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60 | r1 -= r2 * q; |
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61 | if (r1 == 1) |
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62 | { |
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63 | if (y1 < 0) |
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64 | y1 += p; |
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65 | ff_invtab[y1] = a; |
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66 | return (ff_invtab[a] = y1); |
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67 | } |
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68 | } |
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69 | } |
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70 | |
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71 | int ff_biginv ( const int a ) |
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72 | { |
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73 | int p, q, r1, r2, y1, y2; |
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74 | if (a < 2) |
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75 | return a; |
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76 | r1 = p = ff_prime; |
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77 | q = r1 / a; |
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78 | y1 = -q; |
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79 | r1 -= a * q; |
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80 | if (r1 == 1) |
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81 | return p + y1; |
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82 | r2 = a; |
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83 | y2 = 1; |
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84 | for (;;) |
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85 | { |
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86 | q = r2 / r1; |
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87 | y2 -= y1 * q; |
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88 | r2 -= r1 * q; |
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89 | if (r2 == 1) |
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90 | { |
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91 | if (y2 > 0) |
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92 | return y2; |
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93 | else |
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94 | return p + y2; |
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95 | } |
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96 | q = r1 / r2; |
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97 | y1 -= y2 * q; |
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98 | r1 -= r2 * q; |
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99 | if (r1 == 1) |
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100 | { |
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101 | if (y1 > 0) |
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102 | return y1; |
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103 | else |
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104 | return p + y1; |
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105 | } |
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106 | } |
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107 | } |
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