/* mpq_set_d(mpq_t q, double d) -- Set q to d without rounding. Copyright 2000, 2002 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 Lesser General Public License as published by the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details. You should have received a copy of the GNU Lesser 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" #include "longlong.h" #if BITS_PER_MP_LIMB != 32 && BITS_PER_MP_LIMB != 64 choke me #endif void mpq_set_d (mpq_ptr dest, double d) { int negative; mp_exp_t exp; mp_limb_t tp[LIMBS_PER_DOUBLE]; mp_ptr np, dp; mp_size_t nn, dn; int c; negative = d < 0; d = ABS (d); exp = __gmp_extract_double (tp, d); /* There are two main version of the conversion. The `then' arm handles things that have a fractional part, while the `else' part handles only integers. */ #if BITS_PER_MP_LIMB == 32 if (exp <= 1 || (exp == 2 && tp[0] != 0)) #else if (exp <= 1) #endif { if (d == 0.0) { SIZ(&(dest->_mp_num)) = 0; SIZ(&(dest->_mp_den)) = 1; PTR(&(dest->_mp_den))[0] = 1; return; } dn = -exp; if (dest->_mp_num._mp_alloc < 3) _mpz_realloc (&(dest->_mp_num), 3); np = PTR(&(dest->_mp_num)); #if BITS_PER_MP_LIMB == 32 if ((tp[0] | tp[1]) == 0) np[0] = tp[2], nn = 1; else if (tp[0] == 0) np[1] = tp[2], np[0] = tp[1], nn = 2; else np[2] = tp[2], np[1] = tp[1], np[0] = tp[0], nn = 3; #else if (tp[0] == 0) np[0] = tp[1], nn = 1; else np[1] = tp[1], np[0] = tp[0], nn = 2; #endif dn += nn + 1; if (dest->_mp_den._mp_alloc < dn) _mpz_realloc (&(dest->_mp_den), dn); dp = PTR(&(dest->_mp_den)); MPN_ZERO (dp, dn - 1); dp[dn - 1] = 1; count_trailing_zeros (c, np[0] | dp[0]); if (c != 0) { mpn_rshift (np, np, nn, c); nn -= np[nn - 1] == 0; mpn_rshift (dp, dp, dn, c); dn -= dp[dn - 1] == 0; } SIZ(&(dest->_mp_den)) = dn; SIZ(&(dest->_mp_num)) = negative ? -nn : nn; } else { nn = exp; if (dest->_mp_num._mp_alloc < nn) _mpz_realloc (&(dest->_mp_num), nn); np = PTR(&(dest->_mp_num)); #if BITS_PER_MP_LIMB == 32 switch (nn) { default: MPN_ZERO (np, nn - 3); np += nn - 3; /* fall through */ case 3: np[2] = tp[2], np[1] = tp[1], np[0] = tp[0]; break; case 2: np[1] = tp[2], np[0] = tp[1]; break; } #else switch (nn) { default: MPN_ZERO (np, nn - 2); np += nn - 2; /* fall through */ case 2: np[1] = tp[1], np[0] = tp[0]; break; } #endif dp = PTR(&(dest->_mp_den)); dp[0] = 1; SIZ(&(dest->_mp_den)) = 1; SIZ(&(dest->_mp_num)) = negative ? -nn : nn; } }