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/*=============================================================================
This file is part of FLINT.
FLINT is free software; you can redistribute it and/or modify
it under the terms of 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.
FLINT 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 a copy of the GNU General Public License
along with FLINT; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
=============================================================================*/
/******************************************************************************
Copyright (C) 2007 David Howden
Copyright (C) 2010 William Hart
******************************************************************************/
#include <stdlib.h>
#include <gmp.h>
#include "flint.h"
#include "nmod_vec.h"
#include "nmod_poly.h"
#include "fmpz.h"
/* Assumes len > 0, bits > 0. */
void
_nmod_poly_bit_unpack(mp_ptr res, slong len, mp_srcptr mpn, mp_bitcnt_t bits,
nmod_t mod)
{
slong i;
ulong current_bit = 0, current_limb = 0;
mp_limb_t temp_lower, temp_upper, temp_upper2;
if (bits < FLINT_BITS)
{
ulong boundary_limit_bit = FLINT_BITS - bits;
mp_limb_t mask = (WORD(1) << bits) - WORD(1);
for (i = 0; i < len; i++)
{
if (current_bit > boundary_limit_bit)
{
temp_lower = mpn[current_limb++] >> current_bit;
temp_upper = mpn[current_limb] << (FLINT_BITS - current_bit);
temp_upper |= temp_lower;
temp_upper &= mask;
NMOD_RED(res[i], temp_upper, mod);
current_bit += bits - FLINT_BITS;
}
else
{
/* the coeff will fit in the current limb */
temp_upper = (mpn[current_limb] >> current_bit) & mask;
NMOD_RED(res[i], temp_upper, mod);
current_bit += bits;
if (current_bit == FLINT_BITS)
{
current_bit = 0;
current_limb++;
}
}
}
}
else if (bits == FLINT_BITS)
{
for (i = 0; i < len; i++)
NMOD_RED(res[i], mpn[i], mod);
}
else if (bits == 2 * FLINT_BITS)
{
for (i = 0; i < len; i++)
{
NMOD2_RED2(res[i], mpn[current_limb + 1], mpn[current_limb], mod);
current_limb += 2;
}
}
else if (bits < 2 * FLINT_BITS) /* FLINT_BITS < bits < 2*FLINT_BITS */
{
ulong double_boundary_limit_bit = 2 * FLINT_BITS - bits;
mp_limb_t mask = (WORD(1) << (bits - FLINT_BITS)) - WORD(1);
for (i = 0; i < len; i++)
{
if (current_bit == 0)
{
temp_lower = mpn[current_limb++];
temp_upper = mpn[current_limb] & mask;
NMOD2_RED2(res[i], temp_upper, temp_lower, mod);
current_bit = bits - FLINT_BITS;
}
else if (current_bit > double_boundary_limit_bit)
{
/* the coeff will be across two limb boundaries */
temp_lower = mpn[current_limb++] >> current_bit;
temp_lower |=
(mpn[current_limb] << (FLINT_BITS - current_bit));
temp_upper = mpn[current_limb++] >> current_bit;
temp_upper |=
(mpn[current_limb] << (FLINT_BITS - current_bit));
temp_upper &= mask;
NMOD2_RED2(res[i], temp_upper, temp_lower, mod);
current_bit += bits - 2 * FLINT_BITS;
}
else
{
/* the coeff will be across one limb boundary */
temp_lower =
(mpn[current_limb] >> current_bit) | (mpn[current_limb + 1]
<< (FLINT_BITS -
current_bit));
current_limb++;
temp_upper = mpn[current_limb] >> current_bit;
temp_upper &= mask;
NMOD2_RED2(res[i], temp_upper, temp_lower, mod);
current_bit += bits - FLINT_BITS;
if (current_bit == FLINT_BITS)
{
current_bit = 0;
current_limb++;
}
}
}
}
else /* 2*FLINT_BITS < bits < 3*FLINT_BITS */
{
ulong double_boundary_limit_bit = 3 * FLINT_BITS - bits;
mp_limb_t mask = (WORD(1) << (bits - 2 * FLINT_BITS)) - WORD(1);
for (i = 0; i < len; i++)
{
if (current_bit == 0)
{
temp_lower = mpn[current_limb++];
temp_upper = mpn[current_limb++];
temp_upper2 = mpn[current_limb] & mask;
NMOD_RED3(res[i], temp_upper2, temp_upper, temp_lower, mod);
current_bit = bits - 2 * FLINT_BITS;
}
else if (current_bit <= double_boundary_limit_bit)
{
/* the coeff will be across two limb boundaries */
temp_lower = mpn[current_limb++] >> current_bit;
temp_lower |=
(mpn[current_limb] << (FLINT_BITS - current_bit));
temp_upper = mpn[current_limb++] >> current_bit;
temp_upper |=
(mpn[current_limb] << (FLINT_BITS - current_bit));
temp_upper2 = mpn[current_limb] >> current_bit;
temp_upper2 &= mask;
NMOD_RED3(res[i], temp_upper2, temp_upper, temp_lower, mod);
current_bit += bits - 2 * FLINT_BITS;
if (current_bit == FLINT_BITS)
{
current_bit = 0;
current_limb++;
}
}
else
{
/* the coeff will be across three limb boundaries */
temp_lower = mpn[current_limb++] >> current_bit;
temp_lower |=
(mpn[current_limb] << (FLINT_BITS - current_bit));
temp_upper = mpn[current_limb++] >> current_bit;
temp_upper |=
(mpn[current_limb] << (FLINT_BITS - current_bit));
temp_upper2 = mpn[current_limb++] >> current_bit;
temp_upper2 |=
(mpn[current_limb] << (FLINT_BITS - current_bit));
temp_upper2 &= mask;
NMOD_RED3(res[i], temp_upper2, temp_upper, temp_lower, mod);
current_bit += bits - 3 * FLINT_BITS;
}
}
}
}
void
nmod_poly_bit_unpack(nmod_poly_t poly, const fmpz_t f, mp_bitcnt_t bit_size)
{
slong len;
mpz_t tmp;
if (fmpz_sgn(f) < 0)
{
flint_printf("Exception (nmod_poly_bit_unpack). f < 0.\n");
abort();
}
if (bit_size == 0 || fmpz_is_zero(f))
{
nmod_poly_zero(poly);
return;
}
len = (fmpz_bits(f) + bit_size - 1) / bit_size;
mpz_init2(tmp, bit_size*len);
flint_mpn_zero(tmp->_mp_d, tmp->_mp_alloc);
fmpz_get_mpz(tmp, f);
nmod_poly_fit_length(poly, len);
_nmod_poly_bit_unpack(poly->coeffs, len, tmp->_mp_d, bit_size, poly->mod);
poly->length = len;
_nmod_poly_normalise(poly);
mpz_clear(tmp);
}
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