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libtgvoip/webrtc_dsp/common_audio/third_party/fft4g/fft4g.c
Grishka 5caaaafa42 Updated WebRTC APM 
I'm now using the entire audio processing module from WebRTC as opposed to individual DSP algorithms pulled from there before. Seems to work better this way.
2018-11-23 04:02:53 +03:00

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/*
* http://www.kurims.kyoto-u.ac.jp/~ooura/fft.html
* Copyright Takuya OOURA, 1996-2001
*
* You may use, copy, modify and distribute this code for any purpose (include
* commercial use) and without fee. Please refer to this package when you modify
* this code.
*
* Changes:
* Trivial type modifications by the WebRTC authors.
*/
/*
Fast Fourier/Cosine/Sine Transform
dimension :one
data length :power of 2
decimation :frequency
radix :4, 2
data :inplace
table :use
functions
cdft: Complex Discrete Fourier Transform
rdft: Real Discrete Fourier Transform
ddct: Discrete Cosine Transform
ddst: Discrete Sine Transform
dfct: Cosine Transform of RDFT (Real Symmetric DFT)
dfst: Sine Transform of RDFT (Real Anti-symmetric DFT)
function prototypes
void cdft(int, int, float *, int *, float *);
void rdft(size_t, int, float *, size_t *, float *);
void ddct(int, int, float *, int *, float *);
void ddst(int, int, float *, int *, float *);
void dfct(int, float *, float *, int *, float *);
void dfst(int, float *, float *, int *, float *);
-------- Complex DFT (Discrete Fourier Transform) --------
[definition]
<case1>
X[k] = sum_j=0^n-1 x[j]*exp(2*pi*i*j*k/n), 0<=k<n
<case2>
X[k] = sum_j=0^n-1 x[j]*exp(-2*pi*i*j*k/n), 0<=k<n
(notes: sum_j=0^n-1 is a summation from j=0 to n-1)
[usage]
<case1>
ip[0] = 0; // first time only
cdft(2*n, 1, a, ip, w);
<case2>
ip[0] = 0; // first time only
cdft(2*n, -1, a, ip, w);
[parameters]
2*n :data length (int)
n >= 1, n = power of 2
a[0...2*n-1] :input/output data (float *)
input data
a[2*j] = Re(x[j]),
a[2*j+1] = Im(x[j]), 0<=j<n
output data
a[2*k] = Re(X[k]),
a[2*k+1] = Im(X[k]), 0<=k<n
ip[0...*] :work area for bit reversal (int *)
length of ip >= 2+sqrt(n)
strictly,
length of ip >=
2+(1<<(int)(log(n+0.5)/log(2))/2).
ip[0],ip[1] are pointers of the cos/sin table.
w[0...n/2-1] :cos/sin table (float *)
w[],ip[] are initialized if ip[0] == 0.
[remark]
Inverse of
cdft(2*n, -1, a, ip, w);
is
cdft(2*n, 1, a, ip, w);
for (j = 0; j <= 2 * n - 1; j++) {
a[j] *= 1.0 / n;
}
.
-------- Real DFT / Inverse of Real DFT --------
[definition]
<case1> RDFT
R[k] = sum_j=0^n-1 a[j]*cos(2*pi*j*k/n), 0<=k<=n/2
I[k] = sum_j=0^n-1 a[j]*sin(2*pi*j*k/n), 0<k<n/2
<case2> IRDFT (excluding scale)
a[k] = (R[0] + R[n/2]*cos(pi*k))/2 +
sum_j=1^n/2-1 R[j]*cos(2*pi*j*k/n) +
sum_j=1^n/2-1 I[j]*sin(2*pi*j*k/n), 0<=k<n
[usage]
<case1>
ip[0] = 0; // first time only
rdft(n, 1, a, ip, w);
<case2>
ip[0] = 0; // first time only
rdft(n, -1, a, ip, w);
[parameters]
n :data length (size_t)
n >= 2, n = power of 2
a[0...n-1] :input/output data (float *)
<case1>
output data
a[2*k] = R[k], 0<=k<n/2
a[2*k+1] = I[k], 0<k<n/2
a[1] = R[n/2]
<case2>
input data
a[2*j] = R[j], 0<=j<n/2
a[2*j+1] = I[j], 0<j<n/2
a[1] = R[n/2]
ip[0...*] :work area for bit reversal (size_t *)
length of ip >= 2+sqrt(n/2)
strictly,
length of ip >=
2+(1<<(int)(log(n/2+0.5)/log(2))/2).
ip[0],ip[1] are pointers of the cos/sin table.
w[0...n/2-1] :cos/sin table (float *)
w[],ip[] are initialized if ip[0] == 0.
[remark]
Inverse of
rdft(n, 1, a, ip, w);
is
rdft(n, -1, a, ip, w);
for (j = 0; j <= n - 1; j++) {
a[j] *= 2.0 / n;
}
.
-------- DCT (Discrete Cosine Transform) / Inverse of DCT --------
[definition]
<case1> IDCT (excluding scale)
C[k] = sum_j=0^n-1 a[j]*cos(pi*j*(k+1/2)/n), 0<=k<n
<case2> DCT
C[k] = sum_j=0^n-1 a[j]*cos(pi*(j+1/2)*k/n), 0<=k<n
[usage]
<case1>
ip[0] = 0; // first time only
ddct(n, 1, a, ip, w);
<case2>
ip[0] = 0; // first time only
ddct(n, -1, a, ip, w);
[parameters]
n :data length (int)
n >= 2, n = power of 2
a[0...n-1] :input/output data (float *)
output data
a[k] = C[k], 0<=k<n
ip[0...*] :work area for bit reversal (int *)
length of ip >= 2+sqrt(n/2)
strictly,
length of ip >=
2+(1<<(int)(log(n/2+0.5)/log(2))/2).
ip[0],ip[1] are pointers of the cos/sin table.
w[0...n*5/4-1] :cos/sin table (float *)
w[],ip[] are initialized if ip[0] == 0.
[remark]
Inverse of
ddct(n, -1, a, ip, w);
is
a[0] *= 0.5;
ddct(n, 1, a, ip, w);
for (j = 0; j <= n - 1; j++) {
a[j] *= 2.0 / n;
}
.
-------- DST (Discrete Sine Transform) / Inverse of DST --------
[definition]
<case1> IDST (excluding scale)
S[k] = sum_j=1^n A[j]*sin(pi*j*(k+1/2)/n), 0<=k<n
<case2> DST
S[k] = sum_j=0^n-1 a[j]*sin(pi*(j+1/2)*k/n), 0<k<=n
[usage]
<case1>
ip[0] = 0; // first time only
ddst(n, 1, a, ip, w);
<case2>
ip[0] = 0; // first time only
ddst(n, -1, a, ip, w);
[parameters]
n :data length (int)
n >= 2, n = power of 2
a[0...n-1] :input/output data (float *)
<case1>
input data
a[j] = A[j], 0<j<n
a[0] = A[n]
output data
a[k] = S[k], 0<=k<n
<case2>
output data
a[k] = S[k], 0<k<n
a[0] = S[n]
ip[0...*] :work area for bit reversal (int *)
length of ip >= 2+sqrt(n/2)
strictly,
length of ip >=
2+(1<<(int)(log(n/2+0.5)/log(2))/2).
ip[0],ip[1] are pointers of the cos/sin table.
w[0...n*5/4-1] :cos/sin table (float *)
w[],ip[] are initialized if ip[0] == 0.
[remark]
Inverse of
ddst(n, -1, a, ip, w);
is
a[0] *= 0.5;
ddst(n, 1, a, ip, w);
for (j = 0; j <= n - 1; j++) {
a[j] *= 2.0 / n;
}
.
-------- Cosine Transform of RDFT (Real Symmetric DFT) --------
[definition]
C[k] = sum_j=0^n a[j]*cos(pi*j*k/n), 0<=k<=n
[usage]
ip[0] = 0; // first time only
dfct(n, a, t, ip, w);
[parameters]
n :data length - 1 (int)
n >= 2, n = power of 2
a[0...n] :input/output data (float *)
output data
a[k] = C[k], 0<=k<=n
t[0...n/2] :work area (float *)
ip[0...*] :work area for bit reversal (int *)
length of ip >= 2+sqrt(n/4)
strictly,
length of ip >=
2+(1<<(int)(log(n/4+0.5)/log(2))/2).
ip[0],ip[1] are pointers of the cos/sin table.
w[0...n*5/8-1] :cos/sin table (float *)
w[],ip[] are initialized if ip[0] == 0.
[remark]
Inverse of
a[0] *= 0.5;
a[n] *= 0.5;
dfct(n, a, t, ip, w);
is
a[0] *= 0.5;
a[n] *= 0.5;
dfct(n, a, t, ip, w);
for (j = 0; j <= n; j++) {
a[j] *= 2.0 / n;
}
.
-------- Sine Transform of RDFT (Real Anti-symmetric DFT) --------
[definition]
S[k] = sum_j=1^n-1 a[j]*sin(pi*j*k/n), 0<k<n
[usage]
ip[0] = 0; // first time only
dfst(n, a, t, ip, w);
[parameters]
n :data length + 1 (int)
n >= 2, n = power of 2
a[0...n-1] :input/output data (float *)
output data
a[k] = S[k], 0<k<n
(a[0] is used for work area)
t[0...n/2-1] :work area (float *)
ip[0...*] :work area for bit reversal (int *)
length of ip >= 2+sqrt(n/4)
strictly,
length of ip >=
2+(1<<(int)(log(n/4+0.5)/log(2))/2).
ip[0],ip[1] are pointers of the cos/sin table.
w[0...n*5/8-1] :cos/sin table (float *)
w[],ip[] are initialized if ip[0] == 0.
[remark]
Inverse of
dfst(n, a, t, ip, w);
is
dfst(n, a, t, ip, w);
for (j = 1; j <= n - 1; j++) {
a[j] *= 2.0 / n;
}
.
Appendix :
The cos/sin table is recalculated when the larger table required.
w[] and ip[] are compatible with all routines.
*/
#include <stddef.h>
static void makewt(size_t nw, size_t *ip, float *w);
static void makect(size_t nc, size_t *ip, float *c);
static void bitrv2(size_t n, size_t *ip, float *a);
#if 0 // Not used.
static void bitrv2conj(int n, int *ip, float *a);
#endif
static void cftfsub(size_t n, float *a, float *w);
static void cftbsub(size_t n, float *a, float *w);
static void cft1st(size_t n, float *a, float *w);
static void cftmdl(size_t n, size_t l, float *a, float *w);
static void rftfsub(size_t n, float *a, size_t nc, float *c);
static void rftbsub(size_t n, float *a, size_t nc, float *c);
#if 0 // Not used.
static void dctsub(int n, float *a, int nc, float *c)
static void dstsub(int n, float *a, int nc, float *c)
#endif
#if 0 // Not used.
void WebRtc_cdft(int n, int isgn, float *a, int *ip, float *w)
{
if (n > (ip[0] << 2)) {
makewt(n >> 2, ip, w);
}
if (n > 4) {
if (isgn >= 0) {
bitrv2(n, ip + 2, a);
cftfsub(n, a, w);
} else {
bitrv2conj(n, ip + 2, a);
cftbsub(n, a, w);
}
} else if (n == 4) {
cftfsub(n, a, w);
}
}
#endif
void WebRtc_rdft(size_t n, int isgn, float *a, size_t *ip, float *w)
{
size_t nw, nc;
float xi;
nw = ip[0];
if (n > (nw << 2)) {
nw = n >> 2;
makewt(nw, ip, w);
}
nc = ip[1];
if (n > (nc << 2)) {
nc = n >> 2;
makect(nc, ip, w + nw);
}
if (isgn >= 0) {
if (n > 4) {
bitrv2(n, ip + 2, a);
cftfsub(n, a, w);
rftfsub(n, a, nc, w + nw);
} else if (n == 4) {
cftfsub(n, a, w);
}
xi = a[0] - a[1];
a[0] += a[1];
a[1] = xi;
} else {
a[1] = 0.5f * (a[0] - a[1]);
a[0] -= a[1];
if (n > 4) {
rftbsub(n, a, nc, w + nw);
bitrv2(n, ip + 2, a);
cftbsub(n, a, w);
} else if (n == 4) {
cftfsub(n, a, w);
}
}
}
#if 0 // Not used.
static void ddct(int n, int isgn, float *a, int *ip, float *w)
{
int j, nw, nc;
float xr;
nw = ip[0];
if (n > (nw << 2)) {
nw = n >> 2;
makewt(nw, ip, w);
}
nc = ip[1];
if (n > nc) {
nc = n;
makect(nc, ip, w + nw);
}
if (isgn < 0) {
xr = a[n - 1];
for (j = n - 2; j >= 2; j -= 2) {
a[j + 1] = a[j] - a[j - 1];
a[j] += a[j - 1];
}
a[1] = a[0] - xr;
a[0] += xr;
if (n > 4) {
rftbsub(n, a, nc, w + nw);
bitrv2(n, ip + 2, a);
cftbsub(n, a, w);
} else if (n == 4) {
cftfsub(n, a, w);
}
}
dctsub(n, a, nc, w + nw);
if (isgn >= 0) {
if (n > 4) {
bitrv2(n, ip + 2, a);
cftfsub(n, a, w);
rftfsub(n, a, nc, w + nw);
} else if (n == 4) {
cftfsub(n, a, w);
}
xr = a[0] - a[1];
a[0] += a[1];
for (j = 2; j < n; j += 2) {
a[j - 1] = a[j] - a[j + 1];
a[j] += a[j + 1];
}
a[n - 1] = xr;
}
}
static void ddst(int n, int isgn, float *a, int *ip, float *w)
{
int j, nw, nc;
float xr;
nw = ip[0];
if (n > (nw << 2)) {
nw = n >> 2;
makewt(nw, ip, w);
}
nc = ip[1];
if (n > nc) {
nc = n;
makect(nc, ip, w + nw);
}
if (isgn < 0) {
xr = a[n - 1];
for (j = n - 2; j >= 2; j -= 2) {
a[j + 1] = -a[j] - a[j - 1];
a[j] -= a[j - 1];
}
a[1] = a[0] + xr;
a[0] -= xr;
if (n > 4) {
rftbsub(n, a, nc, w + nw);
bitrv2(n, ip + 2, a);
cftbsub(n, a, w);
} else if (n == 4) {
cftfsub(n, a, w);
}
}
dstsub(n, a, nc, w + nw);
if (isgn >= 0) {
if (n > 4) {
bitrv2(n, ip + 2, a);
cftfsub(n, a, w);
rftfsub(n, a, nc, w + nw);
} else if (n == 4) {
cftfsub(n, a, w);
}
xr = a[0] - a[1];
a[0] += a[1];
for (j = 2; j < n; j += 2) {
a[j - 1] = -a[j] - a[j + 1];
a[j] -= a[j + 1];
}
a[n - 1] = -xr;
}
}
static void dfct(int n, float *a, float *t, int *ip, float *w)
{
int j, k, l, m, mh, nw, nc;
float xr, xi, yr, yi;
nw = ip[0];
if (n > (nw << 3)) {
nw = n >> 3;
makewt(nw, ip, w);
}
nc = ip[1];
if (n > (nc << 1)) {
nc = n >> 1;
makect(nc, ip, w + nw);
}
m = n >> 1;
yi = a[m];
xi = a[0] + a[n];
a[0] -= a[n];
t[0] = xi - yi;
t[m] = xi + yi;
if (n > 2) {
mh = m >> 1;
for (j = 1; j < mh; j++) {
k = m - j;
xr = a[j] - a[n - j];
xi = a[j] + a[n - j];
yr = a[k] - a[n - k];
yi = a[k] + a[n - k];
a[j] = xr;
a[k] = yr;
t[j] = xi - yi;
t[k] = xi + yi;
}
t[mh] = a[mh] + a[n - mh];
a[mh] -= a[n - mh];
dctsub(m, a, nc, w + nw);
if (m > 4) {
bitrv2(m, ip + 2, a);
cftfsub(m, a, w);
rftfsub(m, a, nc, w + nw);
} else if (m == 4) {
cftfsub(m, a, w);
}
a[n - 1] = a[0] - a[1];
a[1] = a[0] + a[1];
for (j = m - 2; j >= 2; j -= 2) {
a[2 * j + 1] = a[j] + a[j + 1];
a[2 * j - 1] = a[j] - a[j + 1];
}
l = 2;
m = mh;
while (m >= 2) {
dctsub(m, t, nc, w + nw);
if (m > 4) {
bitrv2(m, ip + 2, t);
cftfsub(m, t, w);
rftfsub(m, t, nc, w + nw);
} else if (m == 4) {
cftfsub(m, t, w);
}
a[n - l] = t[0] - t[1];
a[l] = t[0] + t[1];
k = 0;
for (j = 2; j < m; j += 2) {
k += l << 2;
a[k - l] = t[j] - t[j + 1];
a[k + l] = t[j] + t[j + 1];
}
l <<= 1;
mh = m >> 1;
for (j = 0; j < mh; j++) {
k = m - j;
t[j] = t[m + k] - t[m + j];
t[k] = t[m + k] + t[m + j];
}
t[mh] = t[m + mh];
m = mh;
}
a[l] = t[0];
a[n] = t[2] - t[1];
a[0] = t[2] + t[1];
} else {
a[1] = a[0];
a[2] = t[0];
a[0] = t[1];
}
}
static void dfst(int n, float *a, float *t, int *ip, float *w)
{
int j, k, l, m, mh, nw, nc;
float xr, xi, yr, yi;
nw = ip[0];
if (n > (nw << 3)) {
nw = n >> 3;
makewt(nw, ip, w);
}
nc = ip[1];
if (n > (nc << 1)) {
nc = n >> 1;
makect(nc, ip, w + nw);
}
if (n > 2) {
m = n >> 1;
mh = m >> 1;
for (j = 1; j < mh; j++) {
k = m - j;
xr = a[j] + a[n - j];
xi = a[j] - a[n - j];
yr = a[k] + a[n - k];
yi = a[k] - a[n - k];
a[j] = xr;
a[k] = yr;
t[j] = xi + yi;
t[k] = xi - yi;
}
t[0] = a[mh] - a[n - mh];
a[mh] += a[n - mh];
a[0] = a[m];
dstsub(m, a, nc, w + nw);
if (m > 4) {
bitrv2(m, ip + 2, a);
cftfsub(m, a, w);
rftfsub(m, a, nc, w + nw);
} else if (m == 4) {
cftfsub(m, a, w);
}
a[n - 1] = a[1] - a[0];
a[1] = a[0] + a[1];
for (j = m - 2; j >= 2; j -= 2) {
a[2 * j + 1] = a[j] - a[j + 1];
a[2 * j - 1] = -a[j] - a[j + 1];
}
l = 2;
m = mh;
while (m >= 2) {
dstsub(m, t, nc, w + nw);
if (m > 4) {
bitrv2(m, ip + 2, t);
cftfsub(m, t, w);
rftfsub(m, t, nc, w + nw);
} else if (m == 4) {
cftfsub(m, t, w);
}
a[n - l] = t[1] - t[0];
a[l] = t[0] + t[1];
k = 0;
for (j = 2; j < m; j += 2) {
k += l << 2;
a[k - l] = -t[j] - t[j + 1];
a[k + l] = t[j] - t[j + 1];
}
l <<= 1;
mh = m >> 1;
for (j = 1; j < mh; j++) {
k = m - j;
t[j] = t[m + k] + t[m + j];
t[k] = t[m + k] - t[m + j];
}
t[0] = t[m + mh];
m = mh;
}
a[l] = t[0];
}
a[0] = 0;
}
#endif // Not used.
/* -------- initializing routines -------- */
#include <math.h>
static void makewt(size_t nw, size_t *ip, float *w)
{
size_t j, nwh;
float delta, x, y;
ip[0] = nw;
ip[1] = 1;
if (nw > 2) {
nwh = nw >> 1;
delta = atanf(1.0f) / nwh;
w[0] = 1;
w[1] = 0;
w[nwh] = (float)cos(delta * nwh);
w[nwh + 1] = w[nwh];
if (nwh > 2) {
for (j = 2; j < nwh; j += 2) {
x = (float)cos(delta * j);
y = (float)sin(delta * j);
w[j] = x;
w[j + 1] = y;
w[nw - j] = y;
w[nw - j + 1] = x;
}
bitrv2(nw, ip + 2, w);
}
}
}
static void makect(size_t nc, size_t *ip, float *c)
{
size_t j, nch;
float delta;
ip[1] = nc;
if (nc > 1) {
nch = nc >> 1;
delta = atanf(1.0f) / nch;
c[0] = (float)cos(delta * nch);
c[nch] = 0.5f * c[0];
for (j = 1; j < nch; j++) {
c[j] = 0.5f * (float)cos(delta * j);
c[nc - j] = 0.5f * (float)sin(delta * j);
}
}
}
/* -------- child routines -------- */
static void bitrv2(size_t n, size_t *ip, float *a)
{
size_t j, j1, k, k1, l, m, m2;
float xr, xi, yr, yi;
ip[0] = 0;
l = n;
m = 1;
while ((m << 3) < l) {
l >>= 1;
for (j = 0; j < m; j++) {
ip[m + j] = ip[j] + l;
}
m <<= 1;
}
m2 = 2 * m;
if ((m << 3) == l) {
for (k = 0; k < m; k++) {
for (j = 0; j < k; j++) {
j1 = 2 * j + ip[k];
k1 = 2 * k + ip[j];
xr = a[j1];
xi = a[j1 + 1];
yr = a[k1];
yi = a[k1 + 1];
a[j1] = yr;
a[j1 + 1] = yi;
a[k1] = xr;
a[k1 + 1] = xi;
j1 += m2;
k1 += 2 * m2;
xr = a[j1];
xi = a[j1 + 1];
yr = a[k1];
yi = a[k1 + 1];
a[j1] = yr;
a[j1 + 1] = yi;
a[k1] = xr;
a[k1 + 1] = xi;
j1 += m2;
k1 -= m2;
xr = a[j1];
xi = a[j1 + 1];
yr = a[k1];
yi = a[k1 + 1];
a[j1] = yr;
a[j1 + 1] = yi;
a[k1] = xr;
a[k1 + 1] = xi;
j1 += m2;
k1 += 2 * m2;
xr = a[j1];
xi = a[j1 + 1];
yr = a[k1];
yi = a[k1 + 1];
a[j1] = yr;
a[j1 + 1] = yi;
a[k1] = xr;
a[k1 + 1] = xi;
}
j1 = 2 * k + m2 + ip[k];
k1 = j1 + m2;
xr = a[j1];
xi = a[j1 + 1];
yr = a[k1];
yi = a[k1 + 1];
a[j1] = yr;
a[j1 + 1] = yi;
a[k1] = xr;
a[k1 + 1] = xi;
}
} else {
for (k = 1; k < m; k++) {
for (j = 0; j < k; j++) {
j1 = 2 * j + ip[k];
k1 = 2 * k + ip[j];
xr = a[j1];
xi = a[j1 + 1];
yr = a[k1];
yi = a[k1 + 1];
a[j1] = yr;
a[j1 + 1] = yi;
a[k1] = xr;
a[k1 + 1] = xi;
j1 += m2;
k1 += m2;
xr = a[j1];
xi = a[j1 + 1];
yr = a[k1];
yi = a[k1 + 1];
a[j1] = yr;
a[j1 + 1] = yi;
a[k1] = xr;
a[k1 + 1] = xi;
}
}
}
}
#if 0 // Not used.
static void bitrv2conj(int n, int *ip, float *a)
{
int j, j1, k, k1, l, m, m2;
float xr, xi, yr, yi;
ip[0] = 0;
l = n;
m = 1;
while ((m << 3) < l) {
l >>= 1;
for (j = 0; j < m; j++) {
ip[m + j] = ip[j] + l;
}
m <<= 1;
}
m2 = 2 * m;
if ((m << 3) == l) {
for (k = 0; k < m; k++) {
for (j = 0; j < k; j++) {
j1 = 2 * j + ip[k];
k1 = 2 * k + ip[j];
xr = a[j1];
xi = -a[j1 + 1];
yr = a[k1];
yi = -a[k1 + 1];
a[j1] = yr;
a[j1 + 1] = yi;
a[k1] = xr;
a[k1 + 1] = xi;
j1 += m2;
k1 += 2 * m2;
xr = a[j1];
xi = -a[j1 + 1];
yr = a[k1];
yi = -a[k1 + 1];
a[j1] = yr;
a[j1 + 1] = yi;
a[k1] = xr;
a[k1 + 1] = xi;
j1 += m2;
k1 -= m2;
xr = a[j1];
xi = -a[j1 + 1];
yr = a[k1];
yi = -a[k1 + 1];
a[j1] = yr;
a[j1 + 1] = yi;
a[k1] = xr;
a[k1 + 1] = xi;
j1 += m2;
k1 += 2 * m2;
xr = a[j1];
xi = -a[j1 + 1];
yr = a[k1];
yi = -a[k1 + 1];
a[j1] = yr;
a[j1 + 1] = yi;
a[k1] = xr;
a[k1 + 1] = xi;
}
k1 = 2 * k + ip[k];
a[k1 + 1] = -a[k1 + 1];
j1 = k1 + m2;
k1 = j1 + m2;
xr = a[j1];
xi = -a[j1 + 1];
yr = a[k1];
yi = -a[k1 + 1];
a[j1] = yr;
a[j1 + 1] = yi;
a[k1] = xr;
a[k1 + 1] = xi;
k1 += m2;
a[k1 + 1] = -a[k1 + 1];
}
} else {
a[1] = -a[1];
a[m2 + 1] = -a[m2 + 1];
for (k = 1; k < m; k++) {
for (j = 0; j < k; j++) {
j1 = 2 * j + ip[k];
k1 = 2 * k + ip[j];
xr = a[j1];
xi = -a[j1 + 1];
yr = a[k1];
yi = -a[k1 + 1];
a[j1] = yr;
a[j1 + 1] = yi;
a[k1] = xr;
a[k1 + 1] = xi;
j1 += m2;
k1 += m2;
xr = a[j1];
xi = -a[j1 + 1];
yr = a[k1];
yi = -a[k1 + 1];
a[j1] = yr;
a[j1 + 1] = yi;
a[k1] = xr;
a[k1 + 1] = xi;
}
k1 = 2 * k + ip[k];
a[k1 + 1] = -a[k1 + 1];
a[k1 + m2 + 1] = -a[k1 + m2 + 1];
}
}
}
#endif
static void cftfsub(size_t n, float *a, float *w)
{
size_t j, j1, j2, j3, l;
float x0r, x0i, x1r, x1i, x2r, x2i, x3r, x3i;
l = 2;
if (n > 8) {
cft1st(n, a, w);
l = 8;
while ((l << 2) < n) {
cftmdl(n, l, a, w);
l <<= 2;
}
}
if ((l << 2) == n) {
for (j = 0; j < l; j += 2) {
j1 = j + l;
j2 = j1 + l;
j3 = j2 + l;
x0r = a[j] + a[j1];
x0i = a[j + 1] + a[j1 + 1];
x1r = a[j] - a[j1];
x1i = a[j + 1] - a[j1 + 1];
x2r = a[j2] + a[j3];
x2i = a[j2 + 1] + a[j3 + 1];
x3r = a[j2] - a[j3];
x3i = a[j2 + 1] - a[j3 + 1];
a[j] = x0r + x2r;
a[j + 1] = x0i + x2i;
a[j2] = x0r - x2r;
a[j2 + 1] = x0i - x2i;
a[j1] = x1r - x3i;
a[j1 + 1] = x1i + x3r;
a[j3] = x1r + x3i;
a[j3 + 1] = x1i - x3r;
}
} else {
for (j = 0; j < l; j += 2) {
j1 = j + l;
x0r = a[j] - a[j1];
x0i = a[j + 1] - a[j1 + 1];
a[j] += a[j1];
a[j + 1] += a[j1 + 1];
a[j1] = x0r;
a[j1 + 1] = x0i;
}
}
}
static void cftbsub(size_t n, float *a, float *w)
{
size_t j, j1, j2, j3, l;
float x0r, x0i, x1r, x1i, x2r, x2i, x3r, x3i;
l = 2;
if (n > 8) {
cft1st(n, a, w);
l = 8;
while ((l << 2) < n) {
cftmdl(n, l, a, w);
l <<= 2;
}
}
if ((l << 2) == n) {
for (j = 0; j < l; j += 2) {
j1 = j + l;
j2 = j1 + l;
j3 = j2 + l;
x0r = a[j] + a[j1];
x0i = -a[j + 1] - a[j1 + 1];
x1r = a[j] - a[j1];
x1i = -a[j + 1] + a[j1 + 1];
x2r = a[j2] + a[j3];
x2i = a[j2 + 1] + a[j3 + 1];
x3r = a[j2] - a[j3];
x3i = a[j2 + 1] - a[j3 + 1];
a[j] = x0r + x2r;
a[j + 1] = x0i - x2i;
a[j2] = x0r - x2r;
a[j2 + 1] = x0i + x2i;
a[j1] = x1r - x3i;
a[j1 + 1] = x1i - x3r;
a[j3] = x1r + x3i;
a[j3 + 1] = x1i + x3r;
}
} else {
for (j = 0; j < l; j += 2) {
j1 = j + l;
x0r = a[j] - a[j1];
x0i = -a[j + 1] + a[j1 + 1];
a[j] += a[j1];
a[j + 1] = -a[j + 1] - a[j1 + 1];
a[j1] = x0r;
a[j1 + 1] = x0i;
}
}
}
static void cft1st(size_t n, float *a, float *w)
{
size_t j, k1, k2;
float wk1r, wk1i, wk2r, wk2i, wk3r, wk3i;
float x0r, x0i, x1r, x1i, x2r, x2i, x3r, x3i;
x0r = a[0] + a[2];
x0i = a[1] + a[3];
x1r = a[0] - a[2];
x1i = a[1] - a[3];
x2r = a[4] + a[6];
x2i = a[5] + a[7];
x3r = a[4] - a[6];
x3i = a[5] - a[7];
a[0] = x0r + x2r;
a[1] = x0i + x2i;
a[4] = x0r - x2r;
a[5] = x0i - x2i;
a[2] = x1r - x3i;
a[3] = x1i + x3r;
a[6] = x1r + x3i;
a[7] = x1i - x3r;
wk1r = w[2];
x0r = a[8] + a[10];
x0i = a[9] + a[11];
x1r = a[8] - a[10];
x1i = a[9] - a[11];
x2r = a[12] + a[14];
x2i = a[13] + a[15];
x3r = a[12] - a[14];
x3i = a[13] - a[15];
a[8] = x0r + x2r;
a[9] = x0i + x2i;
a[12] = x2i - x0i;
a[13] = x0r - x2r;
x0r = x1r - x3i;
x0i = x1i + x3r;
a[10] = wk1r * (x0r - x0i);
a[11] = wk1r * (x0r + x0i);
x0r = x3i + x1r;
x0i = x3r - x1i;
a[14] = wk1r * (x0i - x0r);
a[15] = wk1r * (x0i + x0r);
k1 = 0;
for (j = 16; j < n; j += 16) {
k1 += 2;
k2 = 2 * k1;
wk2r = w[k1];
wk2i = w[k1 + 1];
wk1r = w[k2];
wk1i = w[k2 + 1];
wk3r = wk1r - 2 * wk2i * wk1i;
wk3i = 2 * wk2i * wk1r - wk1i;
x0r = a[j] + a[j + 2];
x0i = a[j + 1] + a[j + 3];
x1r = a[j] - a[j + 2];
x1i = a[j + 1] - a[j + 3];
x2r = a[j + 4] + a[j + 6];
x2i = a[j + 5] + a[j + 7];
x3r = a[j + 4] - a[j + 6];
x3i = a[j + 5] - a[j + 7];
a[j] = x0r + x2r;
a[j + 1] = x0i + x2i;
x0r -= x2r;
x0i -= x2i;
a[j + 4] = wk2r * x0r - wk2i * x0i;
a[j + 5] = wk2r * x0i + wk2i * x0r;
x0r = x1r - x3i;
x0i = x1i + x3r;
a[j + 2] = wk1r * x0r - wk1i * x0i;
a[j + 3] = wk1r * x0i + wk1i * x0r;
x0r = x1r + x3i;
x0i = x1i - x3r;
a[j + 6] = wk3r * x0r - wk3i * x0i;
a[j + 7] = wk3r * x0i + wk3i * x0r;
wk1r = w[k2 + 2];
wk1i = w[k2 + 3];
wk3r = wk1r - 2 * wk2r * wk1i;
wk3i = 2 * wk2r * wk1r - wk1i;
x0r = a[j + 8] + a[j + 10];
x0i = a[j + 9] + a[j + 11];
x1r = a[j + 8] - a[j + 10];
x1i = a[j + 9] - a[j + 11];
x2r = a[j + 12] + a[j + 14];
x2i = a[j + 13] + a[j + 15];
x3r = a[j + 12] - a[j + 14];
x3i = a[j + 13] - a[j + 15];
a[j + 8] = x0r + x2r;
a[j + 9] = x0i + x2i;
x0r -= x2r;
x0i -= x2i;
a[j + 12] = -wk2i * x0r - wk2r * x0i;
a[j + 13] = -wk2i * x0i + wk2r * x0r;
x0r = x1r - x3i;
x0i = x1i + x3r;
a[j + 10] = wk1r * x0r - wk1i * x0i;
a[j + 11] = wk1r * x0i + wk1i * x0r;
x0r = x1r + x3i;
x0i = x1i - x3r;
a[j + 14] = wk3r * x0r - wk3i * x0i;
a[j + 15] = wk3r * x0i + wk3i * x0r;
}
}
static void cftmdl(size_t n, size_t l, float *a, float *w)
{
size_t j, j1, j2, j3, k, k1, k2, m, m2;
float wk1r, wk1i, wk2r, wk2i, wk3r, wk3i;
float x0r, x0i, x1r, x1i, x2r, x2i, x3r, x3i;
m = l << 2;
for (j = 0; j < l; j += 2) {
j1 = j + l;
j2 = j1 + l;
j3 = j2 + l;
x0r = a[j] + a[j1];
x0i = a[j + 1] + a[j1 + 1];
x1r = a[j] - a[j1];
x1i = a[j + 1] - a[j1 + 1];
x2r = a[j2] + a[j3];
x2i = a[j2 + 1] + a[j3 + 1];
x3r = a[j2] - a[j3];
x3i = a[j2 + 1] - a[j3 + 1];
a[j] = x0r + x2r;
a[j + 1] = x0i + x2i;
a[j2] = x0r - x2r;
a[j2 + 1] = x0i - x2i;
a[j1] = x1r - x3i;
a[j1 + 1] = x1i + x3r;
a[j3] = x1r + x3i;
a[j3 + 1] = x1i - x3r;
}
wk1r = w[2];
for (j = m; j < l + m; j += 2) {
j1 = j + l;
j2 = j1 + l;
j3 = j2 + l;
x0r = a[j] + a[j1];
x0i = a[j + 1] + a[j1 + 1];
x1r = a[j] - a[j1];
x1i = a[j + 1] - a[j1 + 1];
x2r = a[j2] + a[j3];
x2i = a[j2 + 1] + a[j3 + 1];
x3r = a[j2] - a[j3];
x3i = a[j2 + 1] - a[j3 + 1];
a[j] = x0r + x2r;
a[j + 1] = x0i + x2i;
a[j2] = x2i - x0i;
a[j2 + 1] = x0r - x2r;
x0r = x1r - x3i;
x0i = x1i + x3r;
a[j1] = wk1r * (x0r - x0i);
a[j1 + 1] = wk1r * (x0r + x0i);
x0r = x3i + x1r;
x0i = x3r - x1i;
a[j3] = wk1r * (x0i - x0r);
a[j3 + 1] = wk1r * (x0i + x0r);
}
k1 = 0;
m2 = 2 * m;
for (k = m2; k < n; k += m2) {
k1 += 2;
k2 = 2 * k1;
wk2r = w[k1];
wk2i = w[k1 + 1];
wk1r = w[k2];
wk1i = w[k2 + 1];
wk3r = wk1r - 2 * wk2i * wk1i;
wk3i = 2 * wk2i * wk1r - wk1i;
for (j = k; j < l + k; j += 2) {
j1 = j + l;
j2 = j1 + l;
j3 = j2 + l;
x0r = a[j] + a[j1];
x0i = a[j + 1] + a[j1 + 1];
x1r = a[j] - a[j1];
x1i = a[j + 1] - a[j1 + 1];
x2r = a[j2] + a[j3];
x2i = a[j2 + 1] + a[j3 + 1];
x3r = a[j2] - a[j3];
x3i = a[j2 + 1] - a[j3 + 1];
a[j] = x0r + x2r;
a[j + 1] = x0i + x2i;
x0r -= x2r;
x0i -= x2i;
a[j2] = wk2r * x0r - wk2i * x0i;
a[j2 + 1] = wk2r * x0i + wk2i * x0r;
x0r = x1r - x3i;
x0i = x1i + x3r;
a[j1] = wk1r * x0r - wk1i * x0i;
a[j1 + 1] = wk1r * x0i + wk1i * x0r;
x0r = x1r + x3i;
x0i = x1i - x3r;
a[j3] = wk3r * x0r - wk3i * x0i;
a[j3 + 1] = wk3r * x0i + wk3i * x0r;
}
wk1r = w[k2 + 2];
wk1i = w[k2 + 3];
wk3r = wk1r - 2 * wk2r * wk1i;
wk3i = 2 * wk2r * wk1r - wk1i;
for (j = k + m; j < l + (k + m); j += 2) {
j1 = j + l;
j2 = j1 + l;
j3 = j2 + l;
x0r = a[j] + a[j1];
x0i = a[j + 1] + a[j1 + 1];
x1r = a[j] - a[j1];
x1i = a[j + 1] - a[j1 + 1];
x2r = a[j2] + a[j3];
x2i = a[j2 + 1] + a[j3 + 1];
x3r = a[j2] - a[j3];
x3i = a[j2 + 1] - a[j3 + 1];
a[j] = x0r + x2r;
a[j + 1] = x0i + x2i;
x0r -= x2r;
x0i -= x2i;
a[j2] = -wk2i * x0r - wk2r * x0i;
a[j2 + 1] = -wk2i * x0i + wk2r * x0r;
x0r = x1r - x3i;
x0i = x1i + x3r;
a[j1] = wk1r * x0r - wk1i * x0i;
a[j1 + 1] = wk1r * x0i + wk1i * x0r;
x0r = x1r + x3i;
x0i = x1i - x3r;
a[j3] = wk3r * x0r - wk3i * x0i;
a[j3 + 1] = wk3r * x0i + wk3i * x0r;
}
}
}
static void rftfsub(size_t n, float *a, size_t nc, float *c)
{
size_t j, k, kk, ks, m;
float wkr, wki, xr, xi, yr, yi;
m = n >> 1;
ks = 2 * nc / m;
kk = 0;
for (j = 2; j < m; j += 2) {
k = n - j;
kk += ks;
wkr = 0.5f - c[nc - kk];
wki = c[kk];
xr = a[j] - a[k];
xi = a[j + 1] + a[k + 1];
yr = wkr * xr - wki * xi;
yi = wkr * xi + wki * xr;
a[j] -= yr;
a[j + 1] -= yi;
a[k] += yr;
a[k + 1] -= yi;
}
}
static void rftbsub(size_t n, float *a, size_t nc, float *c)
{
size_t j, k, kk, ks, m;
float wkr, wki, xr, xi, yr, yi;
a[1] = -a[1];
m = n >> 1;
ks = 2 * nc / m;
kk = 0;
for (j = 2; j < m; j += 2) {
k = n - j;
kk += ks;
wkr = 0.5f - c[nc - kk];
wki = c[kk];
xr = a[j] - a[k];
xi = a[j + 1] + a[k + 1];
yr = wkr * xr + wki * xi;
yi = wkr * xi - wki * xr;
a[j] -= yr;
a[j + 1] = yi - a[j + 1];
a[k] += yr;
a[k + 1] = yi - a[k + 1];
}
a[m + 1] = -a[m + 1];
}
#if 0 // Not used.
static void dctsub(int n, float *a, int nc, float *c)
{
int j, k, kk, ks, m;
float wkr, wki, xr;
m = n >> 1;
ks = nc / n;
kk = 0;
for (j = 1; j < m; j++) {
k = n - j;
kk += ks;
wkr = c[kk] - c[nc - kk];
wki = c[kk] + c[nc - kk];
xr = wki * a[j] - wkr * a[k];
a[j] = wkr * a[j] + wki * a[k];
a[k] = xr;
}
a[m] *= c[0];
}
static void dstsub(int n, float *a, int nc, float *c)
{
int j, k, kk, ks, m;
float wkr, wki, xr;
m = n >> 1;
ks = nc / n;
kk = 0;
for (j = 1; j < m; j++) {
k = n - j;
kk += ks;
wkr = c[kk] - c[nc - kk];
wki = c[kk] + c[nc - kk];
xr = wki * a[k] - wkr * a[j];
a[k] = wkr * a[k] + wki * a[j];
a[j] = xr;
}
a[m] *= c[0];
}
#endif // Not used.
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