/*
  * (c) 2002 Fabrice Bellard
  *

  * This file is part of FFmpeg.
  *
  * FFmpeg 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.

  *

  * FFmpeg 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 FFmpeg; if not, write to the Free Software

  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 

 /**

  * @file

  * FFT and MDCT tests.
  */
 

 #include "libavutil/cpu.h"

 #include "libavutil/mathematics.h"

 #include "libavutil/lfg.h"

 #include "libavutil/log.h"

 #include "libavutil/time.h"

 #include "fft.h"

 #if CONFIG_FFT_FLOAT

 #include "dct.h"
 #include "rdft.h"

 #endif

 #include <math.h>

 #if HAVE_UNISTD_H

 #include <unistd.h>

 #endif

 #include <stdlib.h>
 #include <string.h>

 
 /* reference fft */
 
 #define MUL16(a,b) ((a) * (b))
 
 #define CMAC(pre, pim, are, aim, bre, bim) \
 {\
    pre += (MUL16(are, bre) - MUL16(aim, bim));\
    pim += (MUL16(are, bim) + MUL16(bre, aim));\
 }
 

 #if CONFIG_FFT_FLOAT
 #   define RANGE 1.0
 #   define REF_SCALE(x, bits)  (x)
 #   define FMT "%10.6f"
 #else
 #   define RANGE 16384
 #   define REF_SCALE(x, bits) ((x) / (1<<(bits)))
 #   define FMT "%6d"
 #endif
 
 struct {
     float re, im;
 } *exptab;

 static void fft_ref_init(int nbits, int inverse)

 {
     int n, i;

     double c1, s1, alpha;

 
     n = 1 << nbits;

     exptab = av_malloc((n / 2) * sizeof(*exptab));

     for (i = 0; i < (n/2); i++) {

         alpha = 2 * M_PI * (float)i / (float)n;
         c1 = cos(alpha);
         s1 = sin(alpha);
         if (!inverse)
             s1 = -s1;
         exptab[i].re = c1;
         exptab[i].im = s1;
     }
 }
 

 static void fft_ref(FFTComplex *tabr, FFTComplex *tab, int nbits)

 {
     int n, i, j, k, n2;

     double tmp_re, tmp_im, s, c;

     FFTComplex *q;
 
     n = 1 << nbits;
     n2 = n >> 1;

     for (i = 0; i < n; i++) {

         tmp_re = 0;
         tmp_im = 0;
         q = tab;

         for (j = 0; j < n; j++) {

             k = (i * j) & (n - 1);
             if (k >= n2) {
                 c = -exptab[k - n2].re;
                 s = -exptab[k - n2].im;
             } else {
                 c = exptab[k].re;
                 s = exptab[k].im;
             }
             CMAC(tmp_re, tmp_im, c, s, q->re, q->im);
             q++;
         }

         tabr[i].re = REF_SCALE(tmp_re, nbits);
         tabr[i].im = REF_SCALE(tmp_im, nbits);

     }
 }
 

 static void imdct_ref(FFTSample *out, FFTSample *in, int nbits)

 {

     int n = 1<<nbits;

     int k, i, a;

     double sum, f;

     for (i = 0; i < n; i++) {

         sum = 0;

         for (k = 0; k < n/2; k++) {

             a = (2 * i + 1 + (n / 2)) * (2 * k + 1);
             f = cos(M_PI * a / (double)(2 * n));
             sum += f * in[k];
         }

         out[i] = REF_SCALE(-sum, nbits - 2);

     }
 }
 
 /* NOTE: no normalisation by 1 / N is done */

 static void mdct_ref(FFTSample *output, FFTSample *input, int nbits)

 {

     int n = 1<<nbits;

     int k, i;

     double a, s;

 
     /* do it by hand */

     for (k = 0; k < n/2; k++) {

         s = 0;

         for (i = 0; i < n; i++) {

             a = (2*M_PI*(2*i+1+n/2)*(2*k+1) / (4 * n));
             s += input[i] * cos(a);
         }

         output[k] = REF_SCALE(s, nbits - 1);

     }
 }
 

 #if CONFIG_FFT_FLOAT

 static void idct_ref(FFTSample *output, FFTSample *input, int nbits)

 {
     int n = 1<<nbits;
     int k, i;
     double a, s;
 
     /* do it by hand */
     for (i = 0; i < n; i++) {
         s = 0.5 * input[0];
         for (k = 1; k < n; k++) {
             a = M_PI*k*(i+0.5) / n;
             s += input[k] * cos(a);
         }
         output[i] = 2 * s / n;
     }
 }

 static void dct_ref(FFTSample *output, FFTSample *input, int nbits)

 {
     int n = 1<<nbits;
     int k, i;
     double a, s;
 
     /* do it by hand */
     for (k = 0; k < n; k++) {
         s = 0;
         for (i = 0; i < n; i++) {
             a = M_PI*k*(i+0.5) / n;
             s += input[i] * cos(a);
         }
         output[k] = s;
     }
 }

 #endif

 static FFTSample frandom(AVLFG *prng)

 {

     return (int16_t)av_lfg_get(prng) / 32768.0 * RANGE;

 }
 

 static int check_diff(FFTSample *tab1, FFTSample *tab2, int n, double scale)

 {
     int i;

     double max= 0;
     double error= 0;

     int err = 0;

     for (i = 0; i < n; i++) {

         double e = fabsf(tab1[i] - (tab2[i] / scale)) / RANGE;

         if (e >= 1e-3) {

             av_log(NULL, AV_LOG_ERROR, "ERROR %5d: "FMT" "FMT"\n",

                    i, tab1[i], tab2[i]);

             err = 1;

         }

         error+= e*e;
         if(e>max) max= e;

     }

     av_log(NULL, AV_LOG_INFO, "max:%f e:%g\n", max, sqrt(error/n));

     return err;

 }
 
 

 static void help(void)

 {

     av_log(NULL, AV_LOG_INFO,"usage: fft-test [-h] [-s] [-i] [-n b]\n"

            "-h     print this help\n"
            "-s     speed test\n"
            "-m     (I)MDCT test\n"

            "-d     (I)DCT test\n"

            "-r     (I)RDFT test\n"

            "-i     inverse transform test\n"
            "-n b   set the transform size to 2^b\n"

            "-f x   set scale factor for output data of (I)MDCT to x\n"

            );
 }
 

 enum tf_transform {
     TRANSFORM_FFT,
     TRANSFORM_MDCT,

     TRANSFORM_RDFT,

     TRANSFORM_DCT,

 };

 #if !HAVE_GETOPT
 #include "compat/getopt.c"
 #endif
 

 int main(int argc, char **argv)
 {
     FFTComplex *tab, *tab1, *tab_ref;

     FFTSample *tab2;

     int it, i, c;

     int cpuflags;

     int do_speed = 0;

     int err = 1;

     enum tf_transform transform = TRANSFORM_FFT;

     int do_inverse = 0;
     FFTContext s1, *s = &s1;

     FFTContext m1, *m = &m1;

 #if CONFIG_FFT_FLOAT

     RDFTContext r1, *r = &r1;

     DCTContext d1, *d = &d1;

     int fft_size_2;

 #endif

     int fft_nbits, fft_size;

     double scale = 1.0;

     AVLFG prng;
     av_lfg_init(&prng, 1);

 
     fft_nbits = 9;
     for(;;) {

         c = getopt(argc, argv, "hsimrdn:f:c:");

         if (c == -1)
             break;
         switch(c) {
         case 'h':
             help();

             return 1;

         case 's':
             do_speed = 1;
             break;
         case 'i':
             do_inverse = 1;
             break;
         case 'm':

             transform = TRANSFORM_MDCT;

             break;

         case 'r':
             transform = TRANSFORM_RDFT;
             break;

         case 'd':
             transform = TRANSFORM_DCT;
             break;

         case 'n':
             fft_nbits = atoi(optarg);
             break;

         case 'f':
             scale = atof(optarg);
             break;

         case 'c':

             cpuflags = av_get_cpu_flags();
 
             if (av_parse_cpu_caps(&cpuflags, optarg) < 0)

                 return 1;

 
             av_force_cpu_flags(cpuflags);

             break;

         }
     }
 
     fft_size = 1 << fft_nbits;
     tab = av_malloc(fft_size * sizeof(FFTComplex));
     tab1 = av_malloc(fft_size * sizeof(FFTComplex));
     tab_ref = av_malloc(fft_size * sizeof(FFTComplex));
     tab2 = av_malloc(fft_size * sizeof(FFTSample));
 

     switch (transform) {
     case TRANSFORM_MDCT:

         av_log(NULL, AV_LOG_INFO,"Scale factor is set to %f\n", scale);

         if (do_inverse)

             av_log(NULL, AV_LOG_INFO,"IMDCT");

         else

             av_log(NULL, AV_LOG_INFO,"MDCT");

         ff_mdct_init(m, fft_nbits, do_inverse, scale);

         break;
     case TRANSFORM_FFT:

         if (do_inverse)

             av_log(NULL, AV_LOG_INFO,"IFFT");

         else

             av_log(NULL, AV_LOG_INFO,"FFT");

         ff_fft_init(s, fft_nbits, do_inverse);

         fft_ref_init(fft_nbits, do_inverse);

         break;

 #if CONFIG_FFT_FLOAT

     case TRANSFORM_RDFT:
         if (do_inverse)

             av_log(NULL, AV_LOG_INFO,"IDFT_C2R");

         else

             av_log(NULL, AV_LOG_INFO,"DFT_R2C");
         ff_rdft_init(r, fft_nbits, do_inverse ? IDFT_C2R : DFT_R2C);

         fft_ref_init(fft_nbits, do_inverse);
         break;

     case TRANSFORM_DCT:
         if (do_inverse)

             av_log(NULL, AV_LOG_INFO,"DCT_III");

         else

             av_log(NULL, AV_LOG_INFO,"DCT_II");
         ff_dct_init(d, fft_nbits, do_inverse ? DCT_III : DCT_II);

         break;

 #endif
     default:
         av_log(NULL, AV_LOG_ERROR, "Requested transform not supported\n");
         return 1;

     }

     av_log(NULL, AV_LOG_INFO," %d test\n", fft_size);

 
     /* generate random data */
 

     for (i = 0; i < fft_size; i++) {

         tab1[i].re = frandom(&prng);
         tab1[i].im = frandom(&prng);

     }
 
     /* checking result */

     av_log(NULL, AV_LOG_INFO,"Checking...\n");

     switch (transform) {
     case TRANSFORM_MDCT:

         if (do_inverse) {

             imdct_ref((FFTSample *)tab_ref, (FFTSample *)tab1, fft_nbits);
             m->imdct_calc(m, tab2, (FFTSample *)tab1);
             err = check_diff((FFTSample *)tab_ref, tab2, fft_size, scale);

         } else {

             mdct_ref((FFTSample *)tab_ref, (FFTSample *)tab1, fft_nbits);

             m->mdct_calc(m, tab2, (FFTSample *)tab1);

             err = check_diff((FFTSample *)tab_ref, tab2, fft_size / 2, scale);

         }

         break;
     case TRANSFORM_FFT:

         memcpy(tab, tab1, fft_size * sizeof(FFTComplex));

         s->fft_permute(s, tab);
         s->fft_calc(s, tab);

         fft_ref(tab_ref, tab1, fft_nbits);

         err = check_diff((FFTSample *)tab_ref, (FFTSample *)tab, fft_size * 2, 1.0);

         break;

 #if CONFIG_FFT_FLOAT

     case TRANSFORM_RDFT:

         fft_size_2 = fft_size >> 1;

         if (do_inverse) {
             tab1[         0].im = 0;
             tab1[fft_size_2].im = 0;
             for (i = 1; i < fft_size_2; i++) {
                 tab1[fft_size_2+i].re =  tab1[fft_size_2-i].re;
                 tab1[fft_size_2+i].im = -tab1[fft_size_2-i].im;
             }
 
             memcpy(tab2, tab1, fft_size * sizeof(FFTSample));
             tab2[1] = tab1[fft_size_2].re;
 

             r->rdft_calc(r, tab2);

             fft_ref(tab_ref, tab1, fft_nbits);
             for (i = 0; i < fft_size; i++) {
                 tab[i].re = tab2[i];
                 tab[i].im = 0;
             }

             err = check_diff((float *)tab_ref, (float *)tab, fft_size * 2, 0.5);

         } else {
             for (i = 0; i < fft_size; i++) {
                 tab2[i]    = tab1[i].re;
                 tab1[i].im = 0;
             }

             r->rdft_calc(r, tab2);

             fft_ref(tab_ref, tab1, fft_nbits);
             tab_ref[0].im = tab_ref[fft_size_2].re;

             err = check_diff((float *)tab_ref, (float *)tab2, fft_size, 1.0);

         }

         break;
     case TRANSFORM_DCT:
         memcpy(tab, tab1, fft_size * sizeof(FFTComplex));

         d->dct_calc(d, (FFTSample *)tab);

         if (do_inverse) {

             idct_ref((FFTSample*)tab_ref, (FFTSample *)tab1, fft_nbits);

         } else {

             dct_ref((FFTSample*)tab_ref, (FFTSample *)tab1, fft_nbits);

         }

         err = check_diff((float *)tab_ref, (float *)tab, fft_size, 1.0);

         break;

 #endif

     }
 
     /* do a speed test */
 
     if (do_speed) {

         int64_t time_start, duration;

         int nb_its;
 

         av_log(NULL, AV_LOG_INFO,"Speed test...\n");

         /* we measure during about 1 seconds */
         nb_its = 1;
         for(;;) {

             time_start = av_gettime();

             for (it = 0; it < nb_its; it++) {

                 switch (transform) {
                 case TRANSFORM_MDCT:

                     if (do_inverse) {

                         m->imdct_calc(m, (FFTSample *)tab, (FFTSample *)tab1);

                     } else {

                         m->mdct_calc(m, (FFTSample *)tab, (FFTSample *)tab1);

                     }

                     break;
                 case TRANSFORM_FFT:

                     memcpy(tab, tab1, fft_size * sizeof(FFTComplex));

                     s->fft_calc(s, tab);

                     break;

 #if CONFIG_FFT_FLOAT

                 case TRANSFORM_RDFT:
                     memcpy(tab2, tab1, fft_size * sizeof(FFTSample));

                     r->rdft_calc(r, tab2);

                     break;

                 case TRANSFORM_DCT:
                     memcpy(tab2, tab1, fft_size * sizeof(FFTSample));

                     d->dct_calc(d, tab2);

                     break;

 #endif

                 }
             }

             duration = av_gettime() - time_start;

             if (duration >= 1000000)
                 break;
             nb_its *= 2;
         }

         av_log(NULL, AV_LOG_INFO,"time: %0.1f us/transform [total time=%0.2f s its=%d]\n",
                (double)duration / nb_its,

                (double)duration / 1000000.0,
                nb_its);
     }

     switch (transform) {
     case TRANSFORM_MDCT:

         ff_mdct_end(m);

         break;
     case TRANSFORM_FFT:

         ff_fft_end(s);

         break;

 #if CONFIG_FFT_FLOAT

     case TRANSFORM_RDFT:
         ff_rdft_end(r);
         break;

     case TRANSFORM_DCT:
         ff_dct_end(d);
         break;

 #endif

     }

 
     av_free(tab);
     av_free(tab1);
     av_free(tab2);
     av_free(tab_ref);
     av_free(exptab);
 

     return err;

 }