zUtil.cs

namespace DeflateLib
{
    internal class zUtil
    {
        /// <summary>
        /// Default memLevel
        /// </summary>
        internal const int DEF_MEM_LEVEL = 8;

        /// <summary>
        /// The minimum match lengths
        /// </summary>
        internal const int MIN_MATCH = 3;

        /// <summary>
        /// The maximum match lengths
        /// </summary>
        internal const int MAX_MATCH = 258;

        /// <summary>
        /// Sets the OS code, defaults to windows
        /// </summary>
        internal static readonly byte OS_CODE = 10;

        /// <summary>
        /// Type of blocks
        /// </summary>
        internal const int STORED_BLOCK = 0;
        internal const int STATIC_TREES = 1;
        internal const int DYN_TREES = 2;

        internal static readonly string[] errmsg = new string[]
        {
            "need dictionary",     /* Z_NEED_DICT       2  */
            "stream end",          /* Z_STREAM_END      1  */
            "",                    /* Z_OK              0  */
            "file error",          /* Z_ERRNO         (-1) */
            "stream error",        /* Z_STREAM_ERROR  (-2) */
            "data error",          /* Z_DATA_ERROR    (-3) */
            "insufficient memory", /* Z_MEM_ERROR     (-4) */
            "buffer error",        /* Z_BUF_ERROR     (-5) */
            "incompatible version",/* Z_VERSION_ERROR (-6) */
            ""
        };

        //static zUtil()
        //{
        //    try
        //    {
        //        /* Inject code to determine the OS we're running on */
        //        // Windows = 10
        //        // Apple = 19
        //        // Unix = 3
        //        // Dos = 0
        //    }
        //    catch { }
        //}

        /* Reverse the bytes in a 32-bit value */
        internal static int ZSWAP32(int q)
        {
            return ((((q) >> 24) & 0xff) + (((q) >> 8) & 0xff00) +
                    (((q) & 0xff00) << 8) + (((q) & 0xff) << 24));
        }
        internal static uint ZSWAP32(uint q)
        {
            return ((((q) >> 24) & 0xff) + (((q) >> 8) & 0xff00) +
                    (((q) & 0xff00) << 8) + (((q) & 0xff) << 24));
        }
        internal static long ZSWAP32(long q)
        {
            return ((((q) >> 24) & 0xff) + (((q) >> 8) & 0xff00) +
                    (((q) & 0xff00) << 8) + (((q) & 0xff) << 24));
        }
    }
}