161 lines
2.8 KiB
C
161 lines
2.8 KiB
C
/**
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* \file crc32.h
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*/
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#if defined(__i386__) /* { */
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#define partial_crc32 __z_partial_crc32
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#define partial_crc32_copy __z_partial_crc32_copy
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struct __crc32_fool_gcc {
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char x[32768];
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};
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#if 0
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#define PREFETCH(p) __asm__ __volatile__("prefetch %0": : "m" (*(struct __crc32_fool_gcc *)(p)))
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#else
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#define PREFETCH(p) (*(long *)(struct __crc32_fool_gcc *)(p))
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#endif
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#if 0
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#define PREFETCH(p) do ; while (0)
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#endif
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static inline void partial_crc32_prep(uLong *crcp)
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/*@modifies *crcp @*/
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{
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*crcp ^= 0xffffffffL;
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}
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static inline void partial_crc32_finish(uLong *crcp)
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/*@modifies *crcp @*/
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{
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*crcp ^= 0xffffffffL;
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}
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static inline uLong get_crc_from_partial(uLong *crcp)
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/*@modifies *crcp @*/
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{
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return *crcp ^ 0xffffffffL;
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}
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/*@observer@*/ /*@unchecked@*/
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extern const uLongf crc_table[256];
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#define DO1(buf) crc = crc_table[((int)crc ^ (*buf++)) & 0xff] ^ (crc >> 8);
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static __inline__ uLong __partial_crc32(uLong crc, const Bytef *buf, uInt len, int copy, Bytef *dst)
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/*@modifies *dst @*/
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{
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uInt n = len / 4;
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#if 1 /* { */
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#define DOlong(p, d) do { \
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crc ^= *(p); \
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if (copy) \
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*(d) = *(p); \
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crc = crc_table[crc & 0xff] ^ (crc >> 8); \
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crc = crc_table[crc & 0xff] ^ (crc >> 8); \
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crc = crc_table[crc & 0xff] ^ (crc >> 8); \
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crc = crc_table[crc & 0xff] ^ (crc >> 8); \
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} while(0)
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#if 0 /* { */
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#define UPDcrc(x) crc =
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#define DOlong(p) \
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__asm__ __volatile__( \
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"xorl %1,%0;" \
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: "=a" (crc) \
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: "0" (crc) \
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: "ebx" \
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)
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#endif /* } */
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if (n) {
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long *x = (long *)buf;
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long *y;
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PREFETCH(x);
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PREFETCH(x+8);
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PREFETCH(x+16);
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if (copy)
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y = (long *)dst;
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while (n >= 8) {
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PREFETCH(x+24);
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/* I hate gcc. If I turn on loop unrolling,
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* everything else is slowed down. */
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DOlong(x+0, y+0);
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DOlong(x+1, y+1);
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DOlong(x+2, y+2);
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DOlong(x+3, y+3);
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DOlong(x+4, y+4);
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DOlong(x+5, y+5);
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DOlong(x+6, y+6);
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DOlong(x+7, y+7);
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x += 8;
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y += 8;
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n -= 8;
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}
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while (n--) {
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DOlong(x, y);
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x++;
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y++;
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}
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buf = (Bytef *)x;
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if (copy)
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dst = (Bytef *)y;
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}
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len &= 3;
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while (len--) {
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if (copy)
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*dst++ = *buf;
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DO1(buf);
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}
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#else /* } { */
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if (n) {
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do {
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DO4(buf);
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} while (--n);
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}
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len &= 3;
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switch(len) {
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case 3:
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if (copy)
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*dst++ = *buf;
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DO1(buf);
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case 2:
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if (copy)
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*dst++ = *buf;
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DO1(buf);
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case 1:
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if (copy)
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*dst++ = *buf;
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DO1(buf);
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}
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#endif /* } */
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return crc;
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}
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#undef DO1
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#undef DOlong
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#if 0
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#define partial_crc32(crc,buf,len) __partial_crc32(crc, buf, len, 0, 0)
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#define partial_crc32_copy(crc,buf,len,dst) __partial_crc32((crc), (buf), (len), 1, (dst))
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#endif
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extern uLong partial_crc32(uLong crc, const Bytef *buf, uInt len) __attribute__((regparm(3)));
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extern uLong partial_crc32_copy(uLong crcp, const Bytef *buf, uInt len, Bytef *dst) __attribute__((regparm(3)));
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#endif /* } */
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