[25] | 1 | #include <tommath.h> |
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| 2 | #ifdef BN_MP_GROW_C |
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| 3 | /* LibTomMath, multiple-precision integer library -- Tom St Denis |
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| 4 | * |
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| 5 | * LibTomMath is a library that provides multiple-precision |
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| 6 | * integer arithmetic as well as number theoretic functionality. |
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| 7 | * |
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| 8 | * The library was designed directly after the MPI library by |
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| 9 | * Michael Fromberger but has been written from scratch with |
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| 10 | * additional optimizations in place. |
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| 11 | * |
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| 12 | * The library is free for all purposes without any express |
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| 13 | * guarantee it works. |
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| 14 | * |
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| 15 | * Tom St Denis, tomstdenis@gmail.com, http://math.libtomcrypt.com |
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| 16 | */ |
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| 17 | |
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| 18 | /* grow as required */ |
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| 19 | int mp_grow (mp_int * a, int size) |
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| 20 | { |
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| 21 | int i; |
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| 22 | mp_digit *tmp; |
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| 23 | |
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| 24 | /* if the alloc size is smaller alloc more ram */ |
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| 25 | if (a->alloc < size) { |
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| 26 | /* ensure there are always at least MP_PREC digits extra on top */ |
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| 27 | size += (MP_PREC * 2) - (size % MP_PREC); |
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| 28 | |
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| 29 | /* reallocate the array a->dp |
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| 30 | * |
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| 31 | * We store the return in a temporary variable |
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| 32 | * in case the operation failed we don't want |
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| 33 | * to overwrite the dp member of a. |
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| 34 | */ |
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| 35 | tmp = OPT_CAST(mp_digit) XREALLOC (a->dp, sizeof (mp_digit) * size); |
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| 36 | if (tmp == NULL) { |
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| 37 | /* reallocation failed but "a" is still valid [can be freed] */ |
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| 38 | return MP_MEM; |
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| 39 | } |
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| 40 | |
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| 41 | /* reallocation succeeded so set a->dp */ |
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| 42 | a->dp = tmp; |
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| 43 | |
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| 44 | /* zero excess digits */ |
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| 45 | i = a->alloc; |
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| 46 | a->alloc = size; |
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| 47 | for (; i < a->alloc; i++) { |
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| 48 | a->dp[i] = 0; |
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| 49 | } |
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| 50 | } |
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| 51 | return MP_OKAY; |
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| 52 | } |
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| 53 | #endif |
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| 54 | |
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| 55 | /* $Source: /cvsroot/tcl/libtommath/bn_mp_grow.c,v $ */ |
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| 56 | /* $Revision: 1.1.1.3 $ */ |
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| 57 | /* $Date: 2006/12/01 00:08:11 $ */ |
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