php&.net对称压缩解压缩探讨

C#客户端访问PHP SOAP WebService，当传输大量文本数据时，可以通过压缩减少网络传输。

C#在System.IO.Compression命名空间下提供了两个类GZipStream 类和DeflateStream类来进行数据的压缩和解压缩。经本人实验，在C#下使用GZipStream压缩的字符串在PHP下使用gzuncompress函数无法解压缩，有人说可以使用gzdecode解开，但本人的PHP不支持gzdecode函数，但有gzencode函数（why?原因未明，据说是PHP的BUG，可能到PHP6才提供此函数）。

C#下使用DeflateStream类压缩文本后，可以在PHP下用gzinflate解压缩。示例代码如下：

客户端C#（在头4个字节增加了原文本的长度，方便在C#中解压缩，对于在PHP端解压缩这个没有用处）：

public static string Compress(string text)
        {
            byte[] buffer = Encoding.UTF8.GetBytes(text);
            MemoryStream ms = new MemoryStream();
            using (DeflateStream zip = new DeflateStream(ms, CompressionMode.Compress, true))
            {
                zip.Write(buffer, 0, buffer.Length);
            }
            ms.Position = 0;
            MemoryStream outStream = new MemoryStream();
            byte[] compressed = new byte[ms.Length];
            ms.Read(compressed, 0, compressed.Length);
            byte[] gzBuffer = new byte[compressed.Length + 4];
            System.Buffer.BlockCopy(compressed, 0, gzBuffer, 4, compressed.Length);
            System.Buffer.BlockCopy(BitConverter.GetBytes(buffer.Length), 0, gzBuffer, 0, 4);
            return Convert.ToBase64String(gzBuffer);
        }

 服务端PHP：

function Decompress($strSource)
{
    $strTemp = base64_decode($strSource);
    $strTemp = substr($strTemp, 4);
    return gzinflate($strTemp);
}

 支持中文，编码为UTF8.

/// <summary>
    /// 简单的压缩
    /// </summary>
    public static class CompressHelper
    {
        /// <summary>
        /// 压缩字符串
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public static byte[] CompressString(string str)
        {
            return CompressBytes(Encoding.UTF8.GetBytes(str));
        }

        /// <summary>
        /// 压缩二进制
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public static byte[] CompressBytes(byte[] str)
        {
            var ms = new MemoryStream(str) {Position = 0};
            var outms = new MemoryStream();
            using (var deflateStream = new DeflateStream(outms, CompressionMode.Compress, true))
            {
                var buf = new byte[1024];
                int len;
                while ((len = ms.Read(buf, 0, buf.Length)) > 0)
                    deflateStream.Write(buf, 0, len);
            }
            return outms.ToArray();
        }
        /// <summary>
        /// 解压字符串
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public static string DecompressString(byte[] str)
        {
            return Encoding.UTF8.GetString(DecompressBytes(str));
        }
        /// <summary>
        /// 解压二进制
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public static byte[] DecompressBytes(byte[] str)
        {
            var ms = new MemoryStream(str) {Position = 0};
            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();
        }
    }