using System.IO;
using System.Text;
using System.IO.Compression;


namespace Sog.IO
{
    /// <summary>
    /// zip压缩算法
    /// </summary>
    public static class ZipUtils
    {

        public static byte[] CompressString(string inputString)
        {
            byte[] input = Encoding.UTF8.GetBytes(inputString);
            return CompressBytes(input);
        }

        public static byte[] CompressStringGZip(string inputString)
        {
            byte[] input = Encoding.UTF8.GetBytes(inputString);
            return CompressBytesGzip(input);
        }


        public static byte[] CompressBytes(byte[] bytes)
        {
            var ms = new MemoryStream();
            using (var cprs = new DeflateStream(ms, CompressionMode.Compress))
            {
                cprs.Write(bytes, 0, bytes.Length);
            }
            return ms.ToArray();
        }

        // size表示bytes的有效长度
        public static byte[] CompressBytes(byte[] bytes, int size)
        {
            var ms = new MemoryStream();
            using (var cprs = new DeflateStream(ms, CompressionMode.Compress))
            {
                cprs.Write(bytes, 0, size);
            }
            return ms.ToArray();
        }

        public static byte[] DecompressBytes(byte[] bytes)
        {
            return DecompressBytes(bytes, 0, bytes.Length);
        }

        public static byte[] DecompressBytes(byte[] bytes, int start, int length)
        {
            var ms = new MemoryStream(bytes, start, length);
            var outms = new MemoryStream();
            using (var deflateStream = new DeflateStream(ms, CompressionMode.Decompress, true))
            {
                var buf = new byte[1024];
                int len;
                while ((len = deflateStream.Read(buf, 0, buf.Length)) > 0)
                {
                    outms.Write(buf, 0, len);
                }
            }
            return outms.ToArray();
        }

        public static byte[] CompressBytesGzip(byte[] bytes)
        {
            var ms = new MemoryStream();
            using (var cprs = new GZipStream(ms, CompressionMode.Compress))
            {
                cprs.Write(bytes, 0, bytes.Length);
            }
            return ms.ToArray();
        }

        public static byte[] DecompressBytesGzip(byte[] bytes)
        {
            var ms = new MemoryStream(bytes) { Position = 0 };
            var outms = new MemoryStream();
            using (var deflateStream = new GZipStream(ms, CompressionMode.Decompress, true))
            {
                var buf = new byte[1024];
                int len;
                while ((len = deflateStream.Read(buf, 0, buf.Length)) > 0)
                {
                    outms.Write(buf, 0, len);
                }
            }
            return outms.ToArray();
        }
    }
}