COMMON: Refactoring of FFT class to remove repeated fft<x>() functions.

The repeated functions expanded from the original DECL_FFT macros are
now replaced by a recursive fft() function.

2 files changed, 15 insertions, 147 deletions

diff --git a/common/fft.cpp b/common/fft.cpp
index 2ed9b97edc..a9c58ead9b 100644
--- a/common/fft.cpp
+++ b/common/fft.cpp
@@ -218,104 +218,8 @@ void FFT::fft16(Complex *z) {
 	TRANSFORM(z[3], z[7], z[11], z[15], cosTable[3], cosTable[1]);
 }
 
-void FFT::fft32(Complex *z) {
-	fft16(z);
-	fft8(z + 8 * 2);
-	fft8(z + 8 * 3);
-	assert(_cosTables[1]);
-	pass(z, _cosTables[1]->getTable(), 8 / 2);
-}
-
-void FFT::fft64(Complex *z) {
-	fft32(z);
-	fft16(z + 16 * 2);
-	fft16(z + 16 * 3);
-	assert(_cosTables[2]);
-	pass(z, _cosTables[2]->getTable(), 16 / 2);
-}
-
-void FFT::fft128(Complex *z) {
-	fft64(z);
-	fft32(z + 32 * 2);
-	fft32(z + 32 * 3);
-	assert(_cosTables[3]);
-	pass(z, _cosTables[3]->getTable(), 32 / 2);
-}
-
-void FFT::fft256(Complex *z) {
-	fft128(z);
-	fft64(z + 64 * 2);
-	fft64(z + 64 * 3);
-	assert(_cosTables[4]);
-	pass(z, _cosTables[4]->getTable(), 64 / 2);
-}
-
-void FFT::fft512(Complex *z) {
-	fft256(z);
-	fft128(z + 128 * 2);
-	fft128(z + 128 * 3);
-	assert(_cosTables[5]);
-	pass(z, _cosTables[5]->getTable(), 128 / 2);
-}
-
-void FFT::fft1024(Complex *z) {
-	fft512(z);
-	fft256(z + 256 * 2);
-	fft256(z + 256 * 3);
-	assert(_cosTables[6]);
-	pass_big(z, _cosTables[6]->getTable(), 256 / 2);
-}
-
-void FFT::fft2048(Complex *z) {
-	fft1024(z);
-	fft512(z + 512 * 2);
-	fft512(z + 512 * 3);
-	assert(_cosTables[7]);
-	pass_big(z, _cosTables[7]->getTable(), 512 / 2);
-}
-
-void FFT::fft4096(Complex *z) {
-	fft2048(z);
-	fft1024(z + 1024 * 2);
-	fft1024(z + 1024 * 3);
-	assert(_cosTables[8]);
-	pass_big(z, _cosTables[8]->getTable(), 1024 / 2);
-}
-
-void FFT::fft8192(Complex *z) {
-	fft4096(z);
-	fft2048(z + 2048 * 2);
-	fft2048(z + 2048 * 3);
-	assert(_cosTables[9]);
-	pass_big(z, _cosTables[9]->getTable(), 2048 / 2);
-}
-
-void FFT::fft16384(Complex *z) {
-	fft8192(z);
-	fft4096(z + 4096 * 2);
-	fft4096(z + 4096 * 3);
-	assert(_cosTables[10]);
-	pass_big(z, _cosTables[10]->getTable(), 4096 / 2);
-}
-
-void FFT::fft32768(Complex *z) {
-	fft16384(z);
-	fft8192(z + 8192 * 2);
-	fft8192(z + 8192 * 3);
-	assert(_cosTables[11]);
-	pass_big(z, _cosTables[11]->getTable(), 8192 / 2);
-}
-
-void FFT::fft65536(Complex *z) {
-	fft32768(z);
-	fft16384(z + 16384 * 2);
-	fft16384(z + 16384 * 3);
-	assert(_cosTables[12]);
-	pass_big(z, _cosTables[12]->getTable(), 16384 / 2);
-}
-
-void FFT::calc(Complex *z) {
-	switch (_bits) {
+void FFT::fft(int n, int logn, Complex *z) {
+	switch (logn) {
 	case 2:
 		fft4(z);
 		break;
@@ -325,45 +229,20 @@ void FFT::calc(Complex *z) {
 	case 4:
 		fft16(z);
 		break;
-	case 5:
-		fft32(z);
-		break;
-	case 6:
-		fft64(z);
-		break;
-	case 7:
-		fft128(z);
-		break;
-	case 8:
-		fft256(z);
-		break;
-	case 9:
-		fft512(z);
-		break;
-	case 10:
-		fft1024(z);
-		break;
-	case 11:
-		fft2048(z);
-		break;
-	case 12:
-		fft4096(z);
-		break;
-	case 13:
-		fft8192(z);
-		break;
-	case 14:
-		fft16384(z);
-		break;
-	case 15:
-		fft32768(z);
-		break;
-	case 16:
-		fft65536(z);
-		break;
 	default:
-		error("Should Not Happen!");
+		fft((n / 2), logn - 1, z);
+		fft((n / 4), logn - 2, z + (n / 4) * 2);
+		fft((n / 4), logn - 2, z + (n / 4) * 3);
+		assert(_cosTables[logn - 4]);
+		if (n > 1024)
+			pass_big(z, _cosTables[logn - 4]->getTable(), (n / 4) / 2);
+		else
+			pass(z, _cosTables[logn - 4]->getTable(), (n / 4) / 2);
 	}
 }
 
+void FFT::calc(Complex *z) {
+	fft(1 << _bits, _bits, z);
+}
+
 } // End of namespace Common
diff --git a/common/fft.h b/common/fft.h
index d510e51d9c..bc58f1dded 100644
--- a/common/fft.h
+++ b/common/fft.h
@@ -76,18 +76,7 @@ private:
 	void fft4(Complex *z);
 	void fft8(Complex *z);
 	void fft16(Complex *z);
-	void fft32(Complex *z);
-	void fft64(Complex *z);
-	void fft128(Complex *z);
-	void fft256(Complex *z);
-	void fft512(Complex *z);
-	void fft1024(Complex *z);
-	void fft2048(Complex *z);
-	void fft4096(Complex *z);
-	void fft8192(Complex *z);
-	void fft16384(Complex *z);
-	void fft32768(Complex *z);
-	void fft65536(Complex *z);
+	void fft(int n, int logn, Complex *z);
 };
 
 } // End of namespace Common