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22 lines
537 B
C++
22 lines
537 B
C++
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#include "mathlib/crc32.h"
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// Karl Malbrain's compact CRC-32, with pre and post conditioning.
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// See "A compact CCITT crc16 and crc32 C implementation that balances processor cache usage against speed":
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// http://www.geocities.com/malbrain/
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uint32_t crc32::update(uint32_t crc, const uint8_t* ptr, size_t buf_len)
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{
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if (!ptr)
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{
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return NULL;
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}
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crc = ~crc;
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while (buf_len--)
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{
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uint8_t b = *ptr++;
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crc = (crc >> 4) ^ s_crc32[(crc & 0xF) ^ (b & 0xF)];
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crc = (crc >> 4) ^ s_crc32[(crc & 0xF) ^ (b >> 4)];
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}
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return ~crc;
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}
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