Find loop points in a wave file.

FindLoop.cpp

#include<iostream>
#include<fstream>
#include<string>
struct DataStructure_16BitStereo
{
	short var_left, var_right;
};
struct WaveStructure
{
	char strRIFF[4];
	int chunkSize;
	char strFormat[4];
	char strFmt[4];
	int subchunk1Size;
	short audioFormat;
	short numChannels;
	int sampleRate;
	int byteRate;
	short blockAlign;
	short bpsample;//Bits per sample
	char strData[4];
	int subchunk2Size;//Data size
	DataStructure_16BitStereo *eachSample;//Length is subchunk2Size/sizeof(Struct)
};
int FindLoop(DataStructure_16BitStereo* pdata, int a, int b, int rsearch, int psearch, int rsum, int psum, bool atend)
{
	int minpos = 0;
	int64_t minsquaresum = 0x7FFFFFFFFFFFFFFF, cur_sum;
	int64_t tempa;
	if (atend)
	{
		std::cout << "位置\t双通道方差累计" << std::endl;
		for (int j = -rsearch; j < rsearch; j += psearch)
		{
			cur_sum = 0;
			for (int i = -rsum; i < rsum; i += psum)
			{
				tempa = (pdata[a + i].var_left - pdata[b + j + i].var_left);
				cur_sum += tempa*tempa;
				tempa = (pdata[a + i].var_right - pdata[b + j + i].var_right);
				cur_sum += tempa*tempa;
			}
			if (cur_sum < minsquaresum)
			{
				minsquaresum = cur_sum;
				minpos = b + j;
			}
			std::cout << b + j << "\t" << cur_sum << std::endl;
		}
		std::cout << "查找[" << b - rsearch << "," << b + rsearch << "]完毕，符合条件的位置：" << minpos <<
			", 方差累计：" << minsquaresum << std::endl;
	}
	else
		std::cout << "未实现。" << std::endl;
	return minpos;
}
int main(int argc,char *argv[])
{
	WaveStructure wf;
	std::ifstream f;
	if (argc > 1)
		f.open(argv[1], std::ios::binary);
	else
	{
		std::string path;
		std::cout << "文件名：" << std::endl;
		std::cin >> path;
		f.open(path, std::ios::binary);
	}
	if (!f)
	{
		std::cout << "文件打开失败。" << std::endl;
		return -1;
	}
	f.read((char*)&wf, 44);
	if (wf.numChannels == 2 && wf.bpsample == 16)
	{
		wf.eachSample = reinterpret_cast<DataStructure_16BitStereo*>(new char[wf.subchunk2Size]);
		f.read((char*)wf.eachSample, wf.subchunk2Size);
		int input;
		int loopa, loopb;
		int radiussearch = 230, precisesearch = 1, rsum = 250, precsum = 10;
		bool findatend = true;
		do
		{
			std::cout << "1=查找,2=定头,3=定尾,4=搜索半径（" << radiussearch << "）,5=搜索精度(" << precisesearch << "),6=计算范围(" << rsum << "),7=计算精度（" << precsum << "）,0=退出：";
			std::cin >> input;
			switch (input)
			{
			case 1:
				std::cout << "输入起止Sample：";
				std::cin >> loopa >> loopb;
				FindLoop(wf.eachSample, loopa, loopb, radiussearch, precisesearch, rsum, precsum, findatend);
				break;
			case 2:findatend = true; break;
			case 3:findatend = false; break;
			case 4:std::cin >> radiussearch; break;
			case 5:std::cin >> precisesearch; break;
			case 6:std::cin >> rsum; break;
			case 7:std::cin >> precsum; break;
			}
		} while (input);
		delete[]wf.eachSample;
	}
	else
	{
		std::cout << "不支持的格式：" << wf.numChannels << "通道，" << wf.bpsample << "位。" << std::endl;
	}
	f.close();
}