opencv

1
/* crc32_acle.c -- compute the CRC-32 of a data stream
2
 * Copyright (C) 1995-2006, 2010, 2011, 2012 Mark Adler
3
 * Copyright (C) 2016 Yang Zhang
4
 * For conditions of distribution and use, see copyright notice in zlib.h
5
 *
6
*/
7

8
#ifdef ARM_ACLE
9
#include "acle_intrins.h"
10
#include "../../zbuild.h"
11

12
Z_INTERNAL Z_TARGET_CRC uint32_t crc32_acle(uint32_t crc, const uint8_t *buf, size_t len) {
13
    Z_REGISTER uint32_t c;
14
    Z_REGISTER const uint16_t *buf2;
15
    Z_REGISTER const uint32_t *buf4;
16
    Z_REGISTER const uint64_t *buf8;
17

18
    c = ~crc;
19

20
    if (UNLIKELY(len == 1)) {
21
        c = __crc32b(c, *buf);
22
        c = ~c;
23
        return c;
24
    }
25

26
    if ((ptrdiff_t)buf & (sizeof(uint64_t) - 1)) {
27
        if (len && ((ptrdiff_t)buf & 1)) {
28
            c = __crc32b(c, *buf++);
29
            len--;
30
        }
31

32
        if ((len >= sizeof(uint16_t)) && ((ptrdiff_t)buf & sizeof(uint16_t))) {
33
            buf2 = (const uint16_t *) buf;
34
            c = __crc32h(c, *buf2++);
35
            len -= sizeof(uint16_t);
36
            buf4 = (const uint32_t *) buf2;
37
        } else {
38
            buf4 = (const uint32_t *) buf;
39
        }
40

41
        if ((len >= sizeof(uint32_t)) && ((ptrdiff_t)buf & sizeof(uint32_t))) {
42
            c = __crc32w(c, *buf4++);
43
            len -= sizeof(uint32_t);
44
        }
45

46
        buf8 = (const uint64_t *) buf4;
47
    } else {
48
        buf8 = (const uint64_t *) buf;
49
    }
50

51
    while (len >= sizeof(uint64_t)) {
52
        c = __crc32d(c, *buf8++);
53
        len -= sizeof(uint64_t);
54
    }
55

56
    if (len >= sizeof(uint32_t)) {
57
        buf4 = (const uint32_t *) buf8;
58
        c = __crc32w(c, *buf4++);
59
        len -= sizeof(uint32_t);
60
        buf2 = (const uint16_t *) buf4;
61
    } else {
62
        buf2 = (const uint16_t *) buf8;
63
    }
64

65
    if (len >= sizeof(uint16_t)) {
66
        c = __crc32h(c, *buf2++);
67
        len -= sizeof(uint16_t);
68
    }
69

70
    buf = (const unsigned char *) buf2;
71
    if (len) {
72
        c = __crc32b(c, *buf);
73
    }
74

75
    c = ~c;
76
    return c;
77
}
78
#endif
79