153 lines
5.0 KiB
C
153 lines
5.0 KiB
C
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/* $NoKeywords: $ */
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/*
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//
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// Copyright (c) 1993-2012 Robert McNeel & Associates. All rights reserved.
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// OpenNURBS, Rhinoceros, and Rhino3D are registered trademarks of Robert
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// McNeel & Associates.
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//
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// THIS SOFTWARE IS PROVIDED "AS IS" WITHOUT EXPRESS OR IMPLIED WARRANTY.
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// ALL IMPLIED WARRANTIES OF FITNESS FOR ANY PARTICULAR PURPOSE AND OF
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// MERCHANTABILITY ARE HEREBY DISCLAIMED.
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//
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// For complete openNURBS copyright information see <http://www.opennurbs.org>.
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//
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////////////////////////////////////////////////////////////////
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*/
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#if !defined(OPENNURBS_CRC_INC_)
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#define OPENNURBS_CRC_INC_
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ON_BEGIN_EXTERNC
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/*
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Description:
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Continues 16 bit CRC calulation to include the buffer.
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Parameters:
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current_remainder - [in]
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sizeof_buffer - [in] number of bytes in buffer
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buffer - [in]
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Example:
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16 bit CRC calculations are typically done something like this:
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const ON__UINT16 crc_seed = 0; // or 1, or your favorite starting value
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// Compute CRC on "good" data
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unsigned ON__UINT16 first_crc = crc_seed;
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first_crc = ON_CRC16( first_crc, size1, buffer1 );
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...
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first_crc = ON_CRC16( first_crc, sizeN, bufferN );
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unsigned char two_zero_bytes[2] = (0,0);
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first_crc = ON_CRC16( first_crc, 2, two_zero_bytes );
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// make sure 16 bit CRC calculation is valid
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ON__UINT16 check_crc_calculation = ON_CRC16( first_crc, 2, &first_crc );
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if ( check_crc_calculation != 0 )
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{
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printf("ON_CRC16() calculated a bogus 16 bit CRC\n");
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}
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// Do something that may potentially change the values in
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// the buffers (like storing them on a faulty disk).
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// Compute CRC on "suspect" data
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ON__UINT16 second_crc = crc_seed;
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second_crc = ON_CRC16( second_crc, size1, buffer1 );
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...
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second_crc = ON_CRC16( second_crc, sizeN, bufferN );
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if ( 0 != ON_CRC16( second_crc, 2, &first_crc ) )
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{
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printf( "The value of at least one byte has changed.\n" );
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}
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*/
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ON_DECL
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ON__UINT16 ON_CRC16(
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ON__UINT16 current_remainder,
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std::size_t sizeof_buffer,
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const void* buffer
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);
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/*
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Description:
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Continues 32 bit CRC calulation to include the buffer
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ON_CRC32() is a slightly altered version of zlib 1.3.3's crc32()
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and the zlib "legal stuff" is reproduced below.
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ON_CRC32() and zlib's crc32() compute the same values. ON_CRC32()
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was renamed so it wouldn't clash with the other crc32()'s that are
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out there and the argument order was switched to match that used by
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the legacy ON_CRC16().
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Parameters:
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current_remainder - [in]
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sizeof_buffer - [in] number of bytes in buffer
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buffer - [in]
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Example:
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32 bit CRC calculations are typically done something like this:
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const ON__UINT32 crc_seed = 0; // or 1, or your favorite starting value
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//Compute CRC on "good" data
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ON__UINT32 first_crc = crc_seed;
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first_crc = ON_CRC32( first_crc, size1, buffer1 );
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...
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first_crc = ON_CRC32( first_crc, sizeN, bufferN );
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// Do something that may potentially change the values in
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// the buffers (like storing them on a faulty disk).
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// Compute CRC on "suspect" data
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ON__UINT32 second_crc = crc_seed;
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second_crc = ON_CRC32( second_crc, size1, buffer1 );
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...
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second_crc = ON_CRC32( second_crc, sizeN, bufferN );
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if ( second_crc != first_crc )
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{
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printf( "The value of at least one byte has changed.\n" );
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}
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*/
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ON_DECL
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ON__UINT32 ON_CRC32(
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ON__UINT32 current_remainder,
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std::size_t sizeof_buffer,
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const void* buffer
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);
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/*
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zlib.h -- interface of the 'zlib' general purpose compression library
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version 1.1.3, July 9th, 1998
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Copyright (C) 1995-1998 Jean-loup Gailly and Mark Adler
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This software is provided 'as-is', without any express or implied
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warranty. In no event will the authors be held liable for any damages
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arising from the use of this software.
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Permission is granted to anyone to use this software for any purpose,
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including commercial applications, and to alter it and redistribute it
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freely, subject to the following restrictions:
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1. The origin of this software must not be misrepresented; you must not
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claim that you wrote the original software. If you use this software
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in a product, an acknowledgment in the product documentation would be
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appreciated but is not required.
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2. Altered source versions must be plainly marked as such, and must not be
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misrepresented as being the original software.
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3. This notice may not be removed or altered from any source distribution.
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Jean-loup Gailly Mark Adler
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jloup@gzip.org madler@alumni.caltech.edu
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The data format used by the zlib library is described by RFCs (Request for
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Comments) 1950 to 1952 in the files ftp://ds.internic.net/rfc/rfc1950.txt
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(zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format).
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*/
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ON_END_EXTERNC
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#endif
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