74 lines
1.9 KiB
C++
74 lines
1.9 KiB
C++
// $package. http://www.slack.net/~ant/
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#include "Upsampler.h"
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/* Copyright (C) 2004-2008 Shay Green. This module is free software; you
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can redistribute it and/or modify it under the terms of the GNU Lesser
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General Public License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version. This
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module is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
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details. You should have received a copy of the GNU Lesser General Public
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License along with this module; if not, write to the Free Software Foundation,
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Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */
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#include "blargg_source.h"
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int const shift = 15;
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int const unit = 1 << shift;
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void Upsampler::clear_()
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{
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pos = 0;
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Resampler::clear_();
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}
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Upsampler::Upsampler()
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{
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clear();
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}
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blargg_err_t Upsampler::set_rate_( double new_factor )
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{
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step = (int) (new_factor * unit + 0.5);
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return Resampler::set_rate_( 1.0 / unit * step );
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}
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Resampler::sample_t const* Upsampler::resample_( sample_t** out_, sample_t const* out_end,
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sample_t const in [], int in_size )
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{
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in_size -= write_offset;
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if ( in_size > 0 )
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{
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sample_t* BLARGG_RESTRICT out = *out_;
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sample_t const* const in_end = in + in_size;
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int const step = this->step;
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int pos = this->pos;
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do
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{
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#define INTERP( i, out )\
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{\
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int t = in [0 + i] * (unit - pos) + in [stereo + i] * pos;\
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out = t >> shift;\
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}
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int out_0;
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INTERP( 0, out_0 )
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INTERP( 1, out [0] = out_0; out [1] )
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out += stereo;
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pos += step;
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in += ((unsigned) pos >> shift) * stereo;
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pos &= unit - 1;
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}
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while ( in < in_end && out < out_end );
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this->pos = pos;
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*out_ = out;
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}
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return in;
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}
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