alexwav.h

#pragma once

#include <string>
#include <cmath>
#include <fstream>
#include <iostream>
using namespace std;

class WAVfile
{
public:
	static const double two_pi;
	static const long max_amplitude;

	WAVfile(const int srate) : sampleRate(srate) {	}

	template <typename Word>
	std::ostream& write_word(std::ostream& outs, Word value, unsigned size = sizeof(Word))
	{
		for (; size; --size, value >>= 8)
			outs.put(static_cast <char> (value & 0xFF));
		return outs;
	}

	void write(string fileName, int *left, int *right, long samplesCount) {
		ofstream f(fileName, ios::binary);

		// Write the file headers
		f << "RIFF----WAVEfmt ";     // (chunk size to be filled in later)
		write_word(f, 16, 4);  // no extension data
		write_word(f, 1, 2);  // PCM - integer samples
		write_word(f, 2, 2);  // two channels (stereo file)
		write_word(f, sampleRate, 4);  // samples per second (Hz)
		write_word(f, sampleRate * 16 * 2 / 8, 4);  // (Sample Rate * BitsPerSample * Channels) / 8
		write_word(f, 4, 2);  // data block size (size of two integer samples, one for each channel, in bytes)
		write_word(f, 16, 2);  // number of bits per sample (use a multiple of 8)

							   // Write the data chunk header
		size_t data_chunk_pos = f.tellp();
		f << "data----";  // (chunk size to be filled in later)


		for (int s = 0; s < samplesCount; s++)
		{
			write_word(f, left[s], 2);
			write_word(f, right[s], 2);
		}

		// (We'll need the final file size to fix the chunk sizes above)
		size_t file_length = f.tellp();

		// Fix the data chunk header to contain the data size
		f.seekp(data_chunk_pos + 4);
		write_word(f, file_length - data_chunk_pos + 8);

		// Fix the file header to contain the proper RIFF chunk size, which is (file size - 8) bytes
		f.seekp(0 + 4);
		write_word(f, file_length - 8, 4);
	}
private:
	const int sampleRate;
};
const long WAVfile::max_amplitude = 32760;
const double WAVfile::two_pi = 6.283185307179586476925286766559;

class SimpleSine {
public:
	double getSampleFor(int sampleRate, long sample, float frequency) {
		return sin((WAVfile::two_pi * sample * frequency) / sampleRate);
	}
};