diff options
Diffstat (limited to 'gnu/lib/libgmp/mpq/inv.c')
-rw-r--r-- | gnu/lib/libgmp/mpq/inv.c | 75 |
1 files changed, 75 insertions, 0 deletions
diff --git a/gnu/lib/libgmp/mpq/inv.c b/gnu/lib/libgmp/mpq/inv.c new file mode 100644 index 0000000..745c78d --- /dev/null +++ b/gnu/lib/libgmp/mpq/inv.c @@ -0,0 +1,75 @@ +/* mpq_inv(dest,src) -- invert a rational number, i.e. set DEST to SRC + with the numerator and denominator swapped. + +Copyright (C) 1991, 1994, 1995 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 the GNU Library General Public License as published by +the Free Software Foundation; either version 2 of the License, or (at your +option) any later version. + +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 Library General Public +License for more details. + +You should have received a copy of the GNU Library General Public License +along with the GNU MP Library; see the file COPYING.LIB. If not, write to +the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, +MA 02111-1307, USA. */ + +#include "gmp.h" +#include "gmp-impl.h" + +void +#if __STDC__ +mpq_inv (MP_RAT *dest, const MP_RAT *src) +#else +mpq_inv (dest, src) + MP_RAT *dest; + const MP_RAT *src; +#endif +{ + mp_size_t num_size = src->_mp_num._mp_size; + mp_size_t den_size = src->_mp_den._mp_size; + + if (num_size == 0) + num_size = 1 / num_size; /* Divide by zero! */ + + if (num_size < 0) + { + num_size = -num_size; + den_size = -den_size; + } + dest->_mp_den._mp_size = num_size; + dest->_mp_num._mp_size = den_size; + + /* If dest == src we may just swap the numerator and denominator, but + we have to ensure the new denominator is positive. */ + + if (dest == src) + { + mp_size_t alloc = dest->_mp_num._mp_alloc; + mp_ptr limb_ptr = dest->_mp_num._mp_d; + + dest->_mp_num._mp_alloc = dest->_mp_den._mp_alloc; + dest->_mp_num._mp_d = dest->_mp_den._mp_d; + + dest->_mp_den._mp_alloc = alloc; + dest->_mp_den._mp_d = limb_ptr; + } + else + { + den_size = ABS (den_size); + if (dest->_mp_num._mp_alloc < den_size) + _mpz_realloc (&(dest->_mp_num), den_size); + + if (dest->_mp_den._mp_alloc < num_size) + _mpz_realloc (&(dest->_mp_den), num_size); + + MPN_COPY (dest->_mp_num._mp_d, src->_mp_den._mp_d, den_size); + MPN_COPY (dest->_mp_den._mp_d, src->_mp_num._mp_d, num_size); + } +} |