70 lines
1.8 KiB
C#
70 lines
1.8 KiB
C#
using System;
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using System.Text;
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namespace Ooui
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{
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public static class Utilities
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{
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#if PCL
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static readonly uint[] crcTable;
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static Utilities ()
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{
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uint p = 0x04C11DB7;
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crcTable = new uint[256];
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for (uint c = 0; c <= 0xFF; c++) {
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crcTable[c] = CrcReflect (c, 8) << 24;
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for (uint i = 0; i < 8; i++) {
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crcTable[c] = (crcTable[c] << 1) ^ (((crcTable[c] & (1u << 31)) != 0) ? p : 0);
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}
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crcTable[c] = CrcReflect (crcTable[c], 32);
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}
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}
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static uint CrcReflect (uint r, byte c)
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{
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uint v = 0;
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for (int i = 1; i < (c + 1); i++) {
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if ((r & 1) != 0) {
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v |= (1u << (c - i));
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}
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r >>= 1;
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}
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return v;
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}
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public static string Hash (byte[] bytes)
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{
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uint crc = 0xffffffffu;
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for (var i = 0; i < bytes.Length; i++) {
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crc = (crc >> 8) ^ crcTable[(crc & 0xff) ^ bytes[i]];
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}
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crc ^= 0xffffffffu;
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return crc.ToString ("x8");
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}
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#else
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[ThreadStatic]
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static System.Security.Cryptography.SHA256 sha256;
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public static string Hash (byte[] bytes)
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{
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var sha = sha256;
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if (sha == null) {
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sha = System.Security.Cryptography.SHA256.Create ();
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sha256 = sha;
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}
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var data = sha.ComputeHash (bytes);
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StringBuilder sBuilder = new StringBuilder ();
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for (int i = 0; i < data.Length; i++) {
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sBuilder.Append (data[i].ToString ("x2"));
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}
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return sBuilder.ToString ();
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}
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#endif
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}
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}
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