private static async Task WriteOutputFileAsync(FileProperties properties, StreamReader reader, long linesPerFile, string outputPath, bool isLastFile)
{
using (var outputStream = new FileStream(outputPath, FileMode.Create))
{
Stream writeStream = outputStream;
if (properties.IsGzipped)
{
writeStream = new GZipStream(writeStream, CompressionLevel.Optimal);
}
var lineIndex = 0;
using (var writer = new StreamWriter(writeStream, properties.Encoding))
{
string line;
while (((!isLastFile && lineIndex < linesPerFile) || isLastFile) &&
(line = await reader.ReadLineAsync()) != null)
{
lineIndex++;
await writer.WriteLineAsync(line);
}
}
}
}
private static async Task <int> MainAsync(string[] args)
{
if (args.Length == 0)
{
Console.WriteLine("The first parameter should be the path to the large file to split.");
return(1);
}
var inputPath = args[0];
Console.WriteLine("Input parameters:");
Console.WriteLine();
Console.WriteLine($" Desired outout file size (bytes): {DesiredFileSize}");
Console.WriteLine($" Input path: {inputPath}");
Console.WriteLine();
if (!File.Exists(inputPath))
{
Console.WriteLine("The input file does not exist.");
return(1);
}
using (var inputStream = new FileStream(inputPath, FileMode.Open))
{
Console.Write("Gathering data about the input file...");
var properties = await FileProperties.FromFileStreamAsync(inputStream);
Console.WriteLine(" done.");
// Generate the output path format.
var outputPathFormat = GenerateOutputPathFormat(inputPath, properties.IsGzipped);
// This is a rough estimate assuming that each line compresses to the same length.
var fileCount = properties.Size / DesiredFileSize;
if (fileCount == 0)
{
fileCount = 1;
}
var linesPerFile = properties.LineCount / fileCount;
Console.WriteLine();
Console.WriteLine($" Output path format: {outputPathFormat}");
Console.WriteLine();
Console.WriteLine($" Input File encoding: {properties.Encoding}");
Console.WriteLine($" Is gzipped: {properties.IsGzipped}");
Console.WriteLine($" Input file size (bytes): {properties.Size}");
Console.WriteLine($" Input file line count: {properties.LineCount}");
Console.WriteLine();
Console.WriteLine($" Output file count: {fileCount}");
Console.WriteLine($" Output file line count: {linesPerFile}");
Console.WriteLine();
Console.WriteLine("Splitting up files...");
Stream readStream = inputStream;
if (properties.IsGzipped)
{
readStream = new GZipStream(inputStream, CompressionMode.Decompress);
}
using (var reader = new StreamReader(readStream, properties.Encoding))
{
for (var fileIndex = 0; fileIndex < fileCount; fileIndex++)
{
var isLastFile = fileIndex >= fileCount - 1;
var outputPath = string.Format(outputPathFormat, fileIndex);
Console.Write($"[{fileIndex + 1}/{fileCount}] Writing {outputPath}...");
await WriteOutputFileAsync(properties, reader, linesPerFile, outputPath, isLastFile);
Console.WriteLine(" done.");
}
}
}
Console.WriteLine();
Console.WriteLine("The file has been split up.");
return(0);
}