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74 lines
1.9 KiB
74 lines
1.9 KiB
namespace com.hitrust.util.Checksums
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{
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using System;
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public sealed class Adler32 : IChecksum
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{
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private static readonly uint BASE = 0xfff1;
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private uint checksum;
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public Adler32()
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{
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this.Reset();
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}
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public void Reset()
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{
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this.checksum = 1;
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}
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public void Update(int bval)
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{
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uint num = this.checksum & 0xffff;
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uint num2 = this.checksum >> 0x10;
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num = (uint) ((num + (bval & 0xff)) % BASE);
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num2 = (num + num2) % BASE;
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this.checksum = (num2 << 0x10) + num;
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}
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public void Update(byte[] buffer)
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{
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this.Update(buffer, 0, buffer.Length);
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}
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public void Update(byte[] buf, int off, int len)
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{
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if (buf == null)
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{
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throw new ArgumentNullException("buf");
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}
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if (((off < 0) || (len < 0)) || ((off + len) > buf.Length))
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{
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throw new ArgumentOutOfRangeException();
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}
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uint num = this.checksum & 0xffff;
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uint num2 = this.checksum >> 0x10;
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while (len > 0)
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{
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int num3 = 0xed8;
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if (num3 > len)
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{
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num3 = len;
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}
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len -= num3;
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while (--num3 >= 0)
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{
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num += (uint) (buf[off++] & 0xff);
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num2 += num;
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}
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num = num % BASE;
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num2 = num2 % BASE;
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}
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this.checksum = (num2 << 0x10) | num;
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}
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public long Value
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{
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get
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{
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return (long) this.checksum;
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}
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}
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}
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}
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