57 lines
1.8 KiB
C++
57 lines
1.8 KiB
C++
/*******************************************************************************
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Copyright(C) Jonas 'Sortie' Termansen 2012, 2016.
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This file is part of Sortix.
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Sortix is free software: you can redistribute it and/or modify it under the
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terms of the GNU General Public License as published by the Free Software
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Foundation, either version 3 of the License, or (at your option) any later
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version.
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Sortix is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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details.
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You should have received a copy of the GNU General Public License along
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with Sortix. If not, see <http://www.gnu.org/licenses/>.
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crc32.cpp
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Calculates a CRC32 Checksum on binary data.
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*******************************************************************************/
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// TODO: Remove this file and this feature after releasing Sortix 1.0. Change
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// the checksum algorithm in the initrd header to say none.
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#include <stdlib.h>
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#include <stdint.h>
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#include <unistd.h>
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#include <errno.h>
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#include <error.h>
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#include "crc32.h"
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#include "zcrc32.h"
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bool CRC32File(uint32_t* result, const char* name, int fd, off_t offset,
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off_t length)
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{
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uint32_t crc = crc32(0, NULL, 0);
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const size_t BUFFER_SIZE = 16UL * 1024UL;
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uint8_t buffer[BUFFER_SIZE];
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off_t sofar = 0;
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ssize_t amount = 0;
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while ( sofar < length &&
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0 < (amount = pread(fd, buffer, BUFFER_SIZE, offset + sofar)) )
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{
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if ( length - sofar < amount ) { amount = length - sofar; }
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crc = crc32(crc, buffer, amount);
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sofar += amount;
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}
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if ( amount < 0 ) { error(0, errno, "read: %s", name); return false; }
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if ( sofar < length ) { error(0, EIO, "read: %s", name); return false; }
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*result = crc;
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return true;
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}
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