/usr/include/libcoyotl/crccalc.h is in libcoyotl-dev 3.1.0-5.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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// Algorithmic Conjurings @ http://www.coyotegulch.com
//
// crccalc.h (libcoyotl)
//
// Defines tools for calculating 32-bit cyclic-redundancy (CRC)
// values from arrays of 8-bit byte data.
//---------------------------------------------------------------------
//
// Copyright 1990-2005 Scott Robert Ladd
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the
// Free Software Foundation, Inc.
// 59 Temple Place - Suite 330
// Boston, MA 02111-1307, USA.
//
//-----------------------------------------------------------------------
//
// For more information on this software package, please visit
// Scott's web site, Coyote Gulch Productions, at:
//
// http://www.coyotegulch.com
//
//-----------------------------------------------------------------------
#if !defined(LIBCOYOTL_CRCCALC_H)
#define LIBCOYOTL_CRCCALC_H
namespace libcoyotl
{
//! 32-bit unsigned value for holding CRC value
typedef unsigned long crc32_t;
//! Calculate 32-bit CRC values from byte data
/*!
Calculates a 32-bit CRC value using the algorithm specified by
ISO 3309, and as used by the PNG graphics specification.
\version 1.1.0
\date 15 June 2002
*/
class crc_calculator
{
// internal class for preclaculated table
private:
class crc_precalc
{
public:
// constructor
crc_precalc();
// return element of table
crc32_t operator [] (int n) const
{
return m_table[n];
}
protected:
// table of precalculated values
crc32_t m_table[256];
};
public:
//! Constrctor
/*!
Constructs a new CRC value with a base value of 0xFFFFFFFF.
*/
crc_calculator();
//! Update CRC for a given data set
/*!
Updates the crc value from the bytes provided in <i>data</i>.
Each time this function is called for a given crc_calculator,
the 32-bit CRC value changes to reflect the new bytes.
\param a_data - Array of bytes to be "added" to the CRC value
\param a_length - Number of bytes in the <i>data</i> array
*/
void update(const unsigned char * a_data, size_t a_length);
//! Get CRC value
/*!
Returns the current 32-bit CRC value. This value will change
with subsequent calls to update.
\return Current 32-bit CRC value
*/
crc32_t get_crc32()
{
return m_crc ^ 0xFFFFFFFFL;
}
private:
// precacluated table
static crc_precalc s_table;
// computed CRC value
crc32_t m_crc;
};
} // end namespace libcoyotl
#endif
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