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1 /* LibTomMath, multiple-precision integer library -- Tom St Denis |
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2 * |
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3 * LibTomMath is a library that provides multiple-precision |
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4 * integer arithmetic as well as number theoretic functionality. |
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5 * |
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6 * The library was designed directly after the MPI library by |
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7 * Michael Fromberger but has been written from scratch with |
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8 * additional optimizations in place. |
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9 * |
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10 * The library is free for all purposes without any express |
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11 * guarantee it works. |
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12 * |
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13 * Tom St Denis, [email protected], http://math.libtomcrypt.org |
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14 */ |
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15 #include <tommath.h> |
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16 |
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17 /* read signed bin, big endian, first byte is 0==positive or 1==negative */ |
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18 int |
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19 mp_read_signed_bin (mp_int * a, unsigned char *b, int c) |
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20 { |
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21 int res; |
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22 |
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23 /* read magnitude */ |
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24 if ((res = mp_read_unsigned_bin (a, b + 1, c - 1)) != MP_OKAY) { |
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25 return res; |
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26 } |
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27 |
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28 /* first byte is 0 for positive, non-zero for negative */ |
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29 if (b[0] == 0) { |
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30 a->sign = MP_ZPOS; |
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31 } else { |
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32 a->sign = MP_NEG; |
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33 } |
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34 |
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35 return MP_OKAY; |
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36 } |
