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/*
Copyright (C) 2008, 2009 William Hart
Copyright (C) 2010 Sebastian Pancratz
Copyright (C) 2013 Fredrik Johansson
This file is part of FLINT.
FLINT is free software: you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License (LGPL) as published
by the Free Software Foundation; either version 3 of the License, or
(at your option) any later version. See <https://www.gnu.org/licenses/>.
*/
#include "arb_poly.h"
void
_arb_poly_shift_left(arb_ptr res, arb_srcptr poly, slong len, slong n)
{
slong i;
/* Copy in reverse to avoid writing over unshifted coefficients */
if (res != poly)
{
for (i = len; i--; )
arb_set(res + n + i, poly + i);
}
else
{
for (i = len; i--; )
arb_swap(res + n + i, res + i);
}
for (i = 0; i < n; i++)
arb_zero(res + i);
}
void
arb_poly_shift_left(arb_poly_t res, const arb_poly_t poly, slong n)
{
if (n == 0)
{
arb_poly_set(res, poly);
return;
}
if (poly->length == 0)
{
arb_poly_zero(res);
return;
}
arb_poly_fit_length(res, poly->length + n);
_arb_poly_shift_left(res->coeffs, poly->coeffs, poly->length, n);
_arb_poly_set_length(res, poly->length + n);
}