diff options
Diffstat (limited to 'Build/source/libs/gmp/gmp-6.0.0/mpz/gcdext.c')
-rw-r--r-- | Build/source/libs/gmp/gmp-6.0.0/mpz/gcdext.c | 124 |
1 files changed, 124 insertions, 0 deletions
diff --git a/Build/source/libs/gmp/gmp-6.0.0/mpz/gcdext.c b/Build/source/libs/gmp/gmp-6.0.0/mpz/gcdext.c new file mode 100644 index 00000000000..01b1f8379ae --- /dev/null +++ b/Build/source/libs/gmp/gmp-6.0.0/mpz/gcdext.c @@ -0,0 +1,124 @@ +/* mpz_gcdext(g, s, t, a, b) -- Set G to gcd(a, b), and S and T such that + g = as + bt. + +Copyright 1991, 1993-1997, 2000, 2001, 2005, 2011, 2012 Free Software +Foundation, Inc. + +This file is part of the GNU MP Library. + +The GNU MP Library is free software; you can redistribute it and/or modify +it under the terms of either: + + * the GNU Lesser General Public License as published by the Free + Software Foundation; either version 3 of the License, or (at your + option) any later version. + +or + + * the GNU General Public License as published by the Free Software + Foundation; either version 2 of the License, or (at your option) any + later version. + +or both in parallel, as here. + +The GNU MP Library is distributed in the hope that it will be useful, but +WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY +or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License +for more details. + +You should have received copies of the GNU General Public License and the +GNU Lesser General Public License along with the GNU MP Library. If not, +see https://www.gnu.org/licenses/. */ + +#include <stdio.h> /* for NULL */ +#include "gmp.h" +#include "gmp-impl.h" + +void +mpz_gcdext (mpz_ptr g, mpz_ptr s, mpz_ptr t, mpz_srcptr a, mpz_srcptr b) +{ + mp_size_t asize, bsize; + mp_ptr tmp_ap, tmp_bp; + mp_size_t gsize, ssize, tmp_ssize; + mp_ptr gp, tmp_gp, tmp_sp; + TMP_DECL; + + /* mpn_gcdext requires that Usize >= Vsize. Therefore, we often + have to swap U and V. The computed cofactor will be the + "smallest" one, which is faster to produce. The wanted one will + be computed here; this is needed anyway when both are requested. */ + + asize = ABSIZ (a); + bsize = ABSIZ (b); + + if (asize < bsize) + { + MPZ_SRCPTR_SWAP (a, b); + MP_SIZE_T_SWAP (asize, bsize); + MPZ_PTR_SWAP (s, t); + } + + if (bsize == 0) + { + /* g = |a|, s = sgn(a), t = 0. */ + ssize = SIZ (a) >= 0 ? (asize != 0) : -1; + + gp = MPZ_REALLOC (g, asize); + MPN_COPY (gp, PTR (a), asize); + SIZ (g) = asize; + + if (t != NULL) + SIZ (t) = 0; + if (s != NULL) + { + SIZ (s) = ssize; + PTR (s)[0] = 1; + } + return; + } + + TMP_MARK; + + TMP_ALLOC_LIMBS_2 (tmp_ap, asize, tmp_bp, bsize); + MPN_COPY (tmp_ap, PTR (a), asize); + MPN_COPY (tmp_bp, PTR (b), bsize); + + TMP_ALLOC_LIMBS_2 (tmp_gp, bsize, tmp_sp, bsize + 1); + + gsize = mpn_gcdext (tmp_gp, tmp_sp, &tmp_ssize, tmp_ap, asize, tmp_bp, bsize); + + ssize = ABS (tmp_ssize); + tmp_ssize = SIZ (a) >= 0 ? tmp_ssize : -tmp_ssize; + + if (t != NULL) + { + mpz_t x; + __mpz_struct gtmp, stmp; + + PTR (>mp) = tmp_gp; + SIZ (>mp) = gsize; + + PTR (&stmp) = tmp_sp; + SIZ (&stmp) = tmp_ssize; + + MPZ_TMP_INIT (x, ssize + asize + 1); + mpz_mul (x, &stmp, a); + mpz_sub (x, >mp, x); + mpz_divexact (t, x, b); + } + + if (s != NULL) + { + mp_ptr sp; + + sp = MPZ_REALLOC (s, ssize); + MPN_COPY (sp, tmp_sp, ssize); + SIZ (s) = tmp_ssize; + } + + gp = MPZ_REALLOC (g, gsize); + MPN_COPY (gp, tmp_gp, gsize); + SIZ (g) = gsize; + + TMP_FREE; +} |