42 lines
751 B
C
42 lines
751 B
C
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/*
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* XZ decompressor - CRC64
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*
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* Based on xz-embedded by Lasse Collin (public domain).
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* CRC64 with polynomial 0xC96C5795D7870F42 (ECMA-182).
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*/
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#include "xz_private.h"
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uint64_t xz_crc64_table[256];
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void xz_crc64_init(void)
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{
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static int done = 0;
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uint64_t i, j, r;
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if (done)
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return;
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for (i = 0; i < 256; ++i) {
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r = i;
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for (j = 0; j < 8; ++j)
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r = (r >> 1) ^ (UINT64_C(0xC96C5795D7870F42) & ~((r & 1) - 1));
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xz_crc64_table[i] = r;
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}
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done = 1;
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}
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uint64_t xz_crc64(const uint8_t *buf, size_t size, uint64_t crc)
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{
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crc = ~crc;
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while (size > 0) {
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crc = xz_crc64_table[(crc ^ *buf) & 0xFF] ^ (crc >> 8);
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++buf;
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--size;
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}
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return ~crc;
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}
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