1/*
2 * This file is part of Libav.
3 *
4 * Libav is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2.1 of the License, or (at your option) any later version.
8 *
9 * Libav is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
12 * Lesser General Public License for more details.
13 *
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with Libav; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17 */
18
19#define CONFIG_FFT_FLOAT 0
20#include "mdct.c"
21
22/* same as ff_mdct_calcw_c with double-width unscaled output */
23void ff_mdct_calcw_c(FFTContext *s, FFTDouble *out, const FFTSample *input)
24{
25    int i, j, n, n8, n4, n2, n3;
26    FFTDouble re, im;
27    const uint16_t *revtab = s->revtab;
28    const FFTSample *tcos = s->tcos;
29    const FFTSample *tsin = s->tsin;
30    FFTComplex *x = s->tmp_buf;
31    FFTDComplex *o = (FFTDComplex *)out;
32
33    n = 1 << s->mdct_bits;
34    n2 = n >> 1;
35    n4 = n >> 2;
36    n8 = n >> 3;
37    n3 = 3 * n4;
38
39    /* pre rotation */
40    for(i=0;i<n8;i++) {
41        re = RSCALE(-input[2*i+n3] - input[n3-1-2*i]);
42        im = RSCALE(-input[n4+2*i] + input[n4-1-2*i]);
43        j = revtab[i];
44        CMUL(x[j].re, x[j].im, re, im, -tcos[i], tsin[i]);
45
46        re = RSCALE( input[2*i]    - input[n2-1-2*i]);
47        im = RSCALE(-input[n2+2*i] - input[ n-1-2*i]);
48        j = revtab[n8 + i];
49        CMUL(x[j].re, x[j].im, re, im, -tcos[n8 + i], tsin[n8 + i]);
50    }
51
52    s->fft_calc(s, x);
53
54    /* post rotation */
55    for(i=0;i<n8;i++) {
56        FFTDouble r0, i0, r1, i1;
57        CMULL(i1, r0, x[n8-i-1].re, x[n8-i-1].im, -tsin[n8-i-1], -tcos[n8-i-1]);
58        CMULL(i0, r1, x[n8+i  ].re, x[n8+i  ].im, -tsin[n8+i  ], -tcos[n8+i  ]);
59        o[n8-i-1].re = r0;
60        o[n8-i-1].im = i0;
61        o[n8+i  ].re = r1;
62        o[n8+i  ].im = i1;
63    }
64}
65