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author | jan.nijtmans <nijtmans@users.sourceforge.net> | 2016-11-17 10:46:09 (GMT) |
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committer | jan.nijtmans <nijtmans@users.sourceforge.net> | 2016-11-17 10:46:09 (GMT) |
commit | c011864b3411bd607efb52ffd86bb9b91e8e1bf3 (patch) | |
tree | 5ae27db53133eec3cea2523f3df4c28df354b71e /libtommath/bn_mp_export.c | |
parent | 68111aa5bf7fc228dcfda8beb9de265734925b56 (diff) | |
parent | 3dd86e6ebc0137c3a2c02d3a046de046571e3789 (diff) | |
download | tcl-c011864b3411bd607efb52ffd86bb9b91e8e1bf3.zip tcl-c011864b3411bd607efb52ffd86bb9b91e8e1bf3.tar.gz tcl-c011864b3411bd607efb52ffd86bb9b91e8e1bf3.tar.bz2 |
Merge trunk. Re-generate tclTomMath.h. Use faster exponentiation-function from libtommath 1.0 (in tclExecute.c).
Diffstat (limited to 'libtommath/bn_mp_export.c')
-rw-r--r-- | libtommath/bn_mp_export.c | 88 |
1 files changed, 88 insertions, 0 deletions
diff --git a/libtommath/bn_mp_export.c b/libtommath/bn_mp_export.c new file mode 100644 index 0000000..ac4c2f9 --- /dev/null +++ b/libtommath/bn_mp_export.c @@ -0,0 +1,88 @@ +#include <tommath_private.h> +#ifdef BN_MP_EXPORT_C +/* LibTomMath, multiple-precision integer library -- Tom St Denis + * + * LibTomMath is a library that provides multiple-precision + * integer arithmetic as well as number theoretic functionality. + * + * The library was designed directly after the MPI library by + * Michael Fromberger but has been written from scratch with + * additional optimizations in place. + * + * The library is free for all purposes without any express + * guarantee it works. + * + * Tom St Denis, tstdenis82@gmail.com, http://libtom.org + */ + +/* based on gmp's mpz_export. + * see http://gmplib.org/manual/Integer-Import-and-Export.html + */ +int mp_export(void* rop, size_t* countp, int order, size_t size, + int endian, size_t nails, mp_int* op) { + int result; + size_t odd_nails, nail_bytes, i, j, bits, count; + unsigned char odd_nail_mask; + + mp_int t; + + if ((result = mp_init_copy(&t, op)) != MP_OKAY) { + return result; + } + + if (endian == 0) { + union { + unsigned int i; + char c[4]; + } lint; + lint.i = 0x01020304; + + endian = (lint.c[0] == 4) ? -1 : 1; + } + + odd_nails = (nails % 8); + odd_nail_mask = 0xff; + for (i = 0; i < odd_nails; ++i) { + odd_nail_mask ^= (1 << (7 - i)); + } + nail_bytes = nails / 8; + + bits = mp_count_bits(&t); + count = (bits / ((size * 8) - nails)) + (((bits % ((size * 8) - nails)) != 0) ? 1 : 0); + + for (i = 0; i < count; ++i) { + for (j = 0; j < size; ++j) { + unsigned char* byte = ( + (unsigned char*)rop + + (((order == -1) ? i : ((count - 1) - i)) * size) + + ((endian == -1) ? j : ((size - 1) - j)) + ); + + if (j >= (size - nail_bytes)) { + *byte = 0; + continue; + } + + *byte = (unsigned char)((j == ((size - nail_bytes) - 1)) ? (t.dp[0] & odd_nail_mask) : (t.dp[0] & 0xFF)); + + if ((result = mp_div_2d(&t, ((j == ((size - nail_bytes) - 1)) ? (8 - odd_nails) : 8), &t, NULL)) != MP_OKAY) { + mp_clear(&t); + return result; + } + } + } + + mp_clear(&t); + + if (countp != NULL) { + *countp = count; + } + + return MP_OKAY; +} + +#endif + +/* $Source$ */ +/* $Revision$ */ +/* $Date$ */ |