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66 lines
2.0 KiB
C++
66 lines
2.0 KiB
C++
/*
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* This file is a consolidation of functions required for tfe
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* emulation taken from the following files
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*
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* lib.c - Library functions.
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* util.c - Miscellaneous utility functions.
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* crc32.c
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*
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* Written by
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* Andreas Boose <viceteam@t-online.de>
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* Ettore Perazzoli <ettore@comm2000.it>
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* Andreas Matthies <andreas.matthies@gmx.net>
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* Tibor Biczo <crown@mail.matav.hu>
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* Spiro Trikaliotis <Spiro.Trikaliotis@gmx.de>*
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*
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* This file is part of VICE, the Versatile Commodore Emulator.
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* See README for copyright notice.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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* 02111-1307 USA.
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*
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*/
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#include "tfesupp.h"
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#define CRC32_POLY 0xedb88320
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static unsigned long crc32_table[256];
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static int crc32_is_initialized = 0;
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// crc32 Stuff
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unsigned long crc32_buf(const char *buffer, unsigned int len)
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{
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int i, j;
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unsigned long crc, c;
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const char *p;
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if (!crc32_is_initialized) {
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for (i = 0; i < 256; i++) {
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c = (unsigned long) i;
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for (j = 0; j < 8; j++)
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c = c & 1 ? CRC32_POLY ^ (c >> 1) : c >> 1;
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crc32_table[i] = c;
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}
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crc32_is_initialized = 1;
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}
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crc = 0xffffffff;
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for (p = buffer; len > 0; ++p, --len)
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crc = (crc >> 8) ^ crc32_table[(crc ^ *p) & 0xff];
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return ~crc;
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}
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