Added some (small) performance helpers

perf.h

@@ -0,0 +1,42 @@
+#ifndef SIGNALSMITH_DSP_PERF_H
+#define SIGNALSMITH_DSP_PERF_H
+
+
+namespace signalsmith {
+namespace perf {
+	/**	@defgroup Performance Performance helpers
+		@brief Nothing serious, just some `#defines` and helpers
+		
+		@{
+		@file
+	*/
+
+	/// *Really* insist that a function/method is inlined
+	#ifndef SIGNALSMITH_INLINE
+	#ifdef __GNUC__
+	#define SIGNALSMITH_INLINE __attribute__((always_inline)) inline
+	#elif defined(__MSVC__)
+	#define SIGNALSMITH_INLINE __forceinline inline
+	#else
+	#define SIGNALSMITH_INLINE inline
+	#endif
+	#endif
+
+	/** @brief Complex-multiplication (with optional conjugate second-arg), without handling NaN/Infinity
+		The `std::complex` multiplication has edge-cases around NaNs which slow things down and prevent auto-vectorisation.
+	*/
+	template <bool conjugateSecond=false, typename V>
+	static SIGNALSMITH_INLINE std::complex<V> mul(const std::complex<V> &a, const std::complex<V> &b) {
+		return conjugateSecond ? std::complex<V>{
+			b.real()*a.real() + b.imag()*a.imag(),
+			b.real()*a.imag() - b.imag()*a.real()
+		} : std::complex<V>{
+			a.real()*b.real() - a.imag()*b.imag(),
+			a.real()*b.imag() + a.imag()*b.real()
+		};
+	}
+
+/** @} */
+}} // signalsmith::perf::
+
+#endif // include guard

spectral.h

@@ -127,7 +127,7 @@ namespace spectral {
 		
 		\diagram{stft-buffer-validity.svg}
 		
-		You move the valid index along using `.ensureValid()`, passing in a functor which provides spectra (using `.analyse()` and/or direct modification through `.spectrum(c)`):
+		You move the valid index along using `.ensureValid()`, passing in a functor which provides spectra (using `.analyse()` and/or direct modification through `.spectrum[c]`):
 
 		\code
 			void processSample(...) {
@@ -302,7 +302,7 @@ namespace spectral {
 
 		/** Analyse a multi-channel input, for any type where `data[channel][index]` returns samples
  
-		Results can be read/edited using `.spectrum()`. */
+		Results can be read/edited using `.spectrum`. */
 		template<class Data>
 		void analyse(Data &&data) {
 			for (int c = 0; c < channels; ++c) {

windows.h

@@ -69,7 +69,7 @@ namespace windows {
 
 	/**@brief Forces STFT perfect-reconstruction (WOLA) on an existing window by direct calculation.
 	For example, here are perfect-reconstruction versions of the approximately-optimal @ref Kaiser windows:
-	\diagram{kaiser-windows-heuristic-pr.svg,Note the lower overall energy\, and the pointy top for 2x bandwidth}
+	\diagram{kaiser-windows-heuristic-pr.svg,Note the lower overall energy\, and the pointy top for 2x bandwidth. Spectral performance is about the same, though.}
 	*/
 	template<typename Data>
 	void forcePerfectReconstruction(Data &data, int size, int stride) {