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Viewing changes to src/adler32.cpp

  • Committer: Package Import Robot
  • Author(s): Laszlo Boszormenyi (GCS)
  • Date: 2018-03-01 22:23:25 UTC
  • mfrom: (1.2.2)
  • Revision ID: package-import@ubuntu.com-20180301222325-7p7vc45gu3hta34d
Tags: 2.4.0-2
* Don't remove .doctrees from the manual if it doesn't exist.
* Don't specify parallel to debhelper.

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src/adler32.cpp
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/*************************************************
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* Adler32 Source File                            *
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* (C) 1999-2007 The Botan Project                *
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*************************************************/
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#include <botan/adler32.h>
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#include <botan/bit_ops.h>
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namespace Botan {
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/*************************************************
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* Adler32 Checksum                               *
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*************************************************/
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void Adler32::hash(const byte input[], u32bit length)
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   {
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   u32bit S1x = S1, S2x = S2;
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   while(length >= 16)
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      {
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      S1x += input[ 0]; S2x += S1x;
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      S1x += input[ 1]; S2x += S1x;
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      S1x += input[ 2]; S2x += S1x;
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      S1x += input[ 3]; S2x += S1x;
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      S1x += input[ 4]; S2x += S1x;
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      S1x += input[ 5]; S2x += S1x;
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      S1x += input[ 6]; S2x += S1x;
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      S1x += input[ 7]; S2x += S1x;
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      S1x += input[ 8]; S2x += S1x;
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      S1x += input[ 9]; S2x += S1x;
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      S1x += input[10]; S2x += S1x;
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      S1x += input[11]; S2x += S1x;
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      S1x += input[12]; S2x += S1x;
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      S1x += input[13]; S2x += S1x;
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      S1x += input[14]; S2x += S1x;
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      S1x += input[15]; S2x += S1x;
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      input += 16;
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      length -= 16;
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      }
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   for(u32bit j = 0; j != length; ++j)
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      {
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      S1x += input[j]; S2x += S1x;
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      }
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   S1x %= 65521;
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   S2x %= 65521;
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   S1 = S1x;
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   S2 = S2x;
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   }
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/*************************************************
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* Update an Adler32 Checksum                     *
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*************************************************/
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void Adler32::add_data(const byte input[], u32bit length)
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   {
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   const u32bit PROCESS_AMOUNT = 5552;
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   while(length >= PROCESS_AMOUNT)
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      {
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      hash(input, PROCESS_AMOUNT);
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      input += PROCESS_AMOUNT;
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      length -= PROCESS_AMOUNT;
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      }
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   hash(input, length);
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   }
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/*************************************************
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* Finalize an Adler32 Checksum                   *
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*************************************************/
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void Adler32::final_result(byte output[])
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   {
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   output[0] = get_byte(2, S2);
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   output[1] = get_byte(3, S2);
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   output[2] = get_byte(2, S1);
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   output[3] = get_byte(3, S1);
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   clear();
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   }
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}