using System;
using System.IO;
using System.IO.Compression;
//using ICSharpCode.SharpZipLib.Zip;

namespace AllBase
{
    public static class ZipHelper
    {
        /// <summary>
        /// GZip压缩
        /// </summary>
        /// <param name="rawData"></param>
        /// <returns></returns>
        public static byte[] Compress(byte[] rawData)
        {
            if (rawData == null || rawData.Length < 1000)
                return rawData;
            MemoryStream ms = new MemoryStream();
            GZipStream compressedzipStream = new GZipStream(ms, CompressionMode.Compress, true);
            compressedzipStream.Write(rawData, 0, rawData.Length);
            compressedzipStream.Close();
            return ms.ToArray();
        }

        /// <summary>
        /// ZIP解压
        /// </summary>
        /// <param name="zippedData"></param>
        /// <returns></returns>
        public static byte[] Decompress(byte[] zippedData)
        {
            if (zippedData == null || zippedData.Length == 0)
                return null;
            if (zippedData.Length < 100)
                return zippedData;
            if (zippedData[2] != 0x8 || zippedData[3] != 0x0 || zippedData[4] != 0x0 
                || zippedData[5] != 0x0 || zippedData[6] != 0x0 || zippedData[7] != 0x0
                || zippedData[0] != 31 || zippedData[1] != 139)//软加速判断头尾是否正确
                return zippedData;
            try
            {
                MemoryStream ms = new MemoryStream(zippedData);
                GZipStream compressedzipStream = new GZipStream(ms, CompressionMode.Decompress);
                MemoryStream outBuffer = new MemoryStream();
                byte[] block = new byte[1024];
                while (true)
                {
                    int bytesRead = compressedzipStream.Read(block, 0, block.Length);
                    if (bytesRead < 1)
                        break;
                    outBuffer.Write(block, 0, bytesRead);
                }
                compressedzipStream.Close();
                return outBuffer.ToArray();
            }
            catch
            {
            }
            return zippedData;
        }
        /// <summary>
        /// 解压文件到指定文件夹
        /// </summary>
        /// <param name="sourceFile">压缩文件</param>
        /// <param name="destinationDirectory">目标文件夹，如果为空则解压到当前文件夹下</param>
        /// <param name="password">密码</param>
        /// <returns></returns>
        //public static bool DecomparessFile(string sourceFile, string destinationDirectory = null, string password = null)
        //{
        //    bool result = false;
        //    int BufferSize = 1024*128;
        //    if (!File.Exists(sourceFile))
        //    {
        //        return false;
        //    }

        //    if (string.IsNullOrWhiteSpace(destinationDirectory))
        //    {
        //        destinationDirectory = Path.GetDirectoryName(sourceFile);
        //    }

        //    try
        //    {
        //        if (!Directory.Exists(destinationDirectory))
        //        {
        //            Directory.CreateDirectory(destinationDirectory);
        //        }

        //        using (ZipInputStream zipStream = new ZipInputStream(File.Open(sourceFile, FileMode.Open,
        //            FileAccess.Read, FileShare.Read)))
        //        {
        //            zipStream.Password = password;
        //            ZipEntry zipEntry = zipStream.GetNextEntry();

        //            while (zipEntry != null)
        //            {
        //                if (zipEntry.IsDirectory)//如果是文件夹则创建
        //                {
        //                    Directory.CreateDirectory(Path.Combine(destinationDirectory,
        //                        Path.GetDirectoryName(zipEntry.Name)));
        //                }
        //                else
        //                {
        //                    string fileName = Path.GetFileName(zipEntry.Name);
        //                    if (!string.IsNullOrEmpty(fileName) && fileName.Trim().Length > 0)
        //                    {
        //                        FileInfo fileItem = new FileInfo(Path.Combine(destinationDirectory, zipEntry.Name));
        //                        using (FileStream writeStream = fileItem.Create())
        //                        {
        //                            byte[] buffer = new byte[BufferSize];
        //                            int readLength = 0;

        //                            do
        //                            {
        //                                readLength = zipStream.Read(buffer, 0, BufferSize);
        //                                writeStream.Write(buffer, 0, readLength);
        //                            } while (readLength == BufferSize);

        //                            writeStream.Flush();
        //                            writeStream.Close();
        //                        }
        //                        fileItem.LastWriteTime = zipEntry.DateTime;
        //                    }
        //                }
        //                zipEntry = zipStream.GetNextEntry();//获取下一个文件
        //            }

        //            zipStream.Close();
        //        }
        //        result = true;
        //    }
        //    catch (System.Exception ex)
        //    {
        //        throw new Exception("文件解压发生错误", ex);
        //    }

        //    return result;
        //}
    }
}