/src/ghostpdl/brotli/c/enc/find_match_length.h
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1 | | /* Copyright 2010 Google Inc. All Rights Reserved. |
2 | | |
3 | | Distributed under MIT license. |
4 | | See file LICENSE for detail or copy at https://opensource.org/licenses/MIT |
5 | | */ |
6 | | |
7 | | /* Function to find maximal matching prefixes of strings. */ |
8 | | |
9 | | #ifndef BROTLI_ENC_FIND_MATCH_LENGTH_H_ |
10 | | #define BROTLI_ENC_FIND_MATCH_LENGTH_H_ |
11 | | |
12 | | #include "../common/platform.h" |
13 | | |
14 | | #if defined(__cplusplus) || defined(c_plusplus) |
15 | | extern "C" { |
16 | | #endif |
17 | | |
18 | | /* Separate implementation for little-endian 64-bit targets, for speed. */ |
19 | | #if defined(BROTLI_TZCNT64) && BROTLI_64_BITS && BROTLI_LITTLE_ENDIAN |
20 | | static BROTLI_INLINE size_t FindMatchLengthWithLimit(const uint8_t* s1, |
21 | | const uint8_t* s2, |
22 | 0 | size_t limit) { |
23 | 0 | const uint8_t *s1_orig = s1; |
24 | 0 | for (; limit >= 8; limit -= 8) { |
25 | 0 | uint64_t x = BROTLI_UNALIGNED_LOAD64LE(s2) ^ |
26 | 0 | BROTLI_UNALIGNED_LOAD64LE(s1); |
27 | 0 | s2 += 8; |
28 | 0 | if (x != 0) { |
29 | 0 | size_t matching_bits = (size_t)BROTLI_TZCNT64(x); |
30 | 0 | return (size_t)(s1 - s1_orig) + (matching_bits >> 3); |
31 | 0 | } |
32 | 0 | s1 += 8; |
33 | 0 | } |
34 | 0 | while (limit && *s1 == *s2) { |
35 | 0 | limit--; |
36 | 0 | ++s2; |
37 | 0 | ++s1; |
38 | 0 | } |
39 | 0 | return (size_t)(s1 - s1_orig); |
40 | 0 | } Unexecuted instantiation: encode.c:FindMatchLengthWithLimit Unexecuted instantiation: encoder_dict.c:FindMatchLengthWithLimit Unexecuted instantiation: backward_references.c:FindMatchLengthWithLimit Unexecuted instantiation: backward_references_hq.c:FindMatchLengthWithLimit Unexecuted instantiation: compress_fragment.c:FindMatchLengthWithLimit Unexecuted instantiation: compress_fragment_two_pass.c:FindMatchLengthWithLimit Unexecuted instantiation: static_dict.c:FindMatchLengthWithLimit |
41 | | #else |
42 | | static BROTLI_INLINE size_t FindMatchLengthWithLimit(const uint8_t* s1, |
43 | | const uint8_t* s2, |
44 | | size_t limit) { |
45 | | size_t matched = 0; |
46 | | const uint8_t* s2_limit = s2 + limit; |
47 | | const uint8_t* s2_ptr = s2; |
48 | | /* Find out how long the match is. We loop over the data 32 bits at a |
49 | | time until we find a 32-bit block that doesn't match; then we find |
50 | | the first non-matching bit and use that to calculate the total |
51 | | length of the match. */ |
52 | | while (s2_ptr <= s2_limit - 4 && |
53 | | BrotliUnalignedRead32(s2_ptr) == |
54 | | BrotliUnalignedRead32(s1 + matched)) { |
55 | | s2_ptr += 4; |
56 | | matched += 4; |
57 | | } |
58 | | while ((s2_ptr < s2_limit) && (s1[matched] == *s2_ptr)) { |
59 | | ++s2_ptr; |
60 | | ++matched; |
61 | | } |
62 | | return matched; |
63 | | } |
64 | | #endif |
65 | | |
66 | | #if defined(__cplusplus) || defined(c_plusplus) |
67 | | } /* extern "C" */ |
68 | | #endif |
69 | | |
70 | | #endif /* BROTLI_ENC_FIND_MATCH_LENGTH_H_ */ |