/src/h2o/deps/brotli/c/enc/prefix.h
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1 | | /* Copyright 2013 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 | | /* Functions for encoding of integers into prefix codes the amount of extra |
8 | | bits, and the actual values of the extra bits. */ |
9 | | |
10 | | #ifndef BROTLI_ENC_PREFIX_H_ |
11 | | #define BROTLI_ENC_PREFIX_H_ |
12 | | |
13 | | #include "../common/constants.h" |
14 | | #include <brotli/port.h> |
15 | | #include <brotli/types.h> |
16 | | #include "./fast_log.h" |
17 | | |
18 | | #if defined(__cplusplus) || defined(c_plusplus) |
19 | | extern "C" { |
20 | | #endif |
21 | | |
22 | | /* Here distance_code is an intermediate code, i.e. one of the special codes or |
23 | | the actual distance increased by BROTLI_NUM_DISTANCE_SHORT_CODES - 1. */ |
24 | | static BROTLI_INLINE void PrefixEncodeCopyDistance(size_t distance_code, |
25 | | size_t num_direct_codes, |
26 | | size_t postfix_bits, |
27 | | uint16_t* code, |
28 | 0 | uint32_t* extra_bits) { |
29 | 0 | if (distance_code < BROTLI_NUM_DISTANCE_SHORT_CODES + num_direct_codes) { |
30 | 0 | *code = (uint16_t)distance_code; |
31 | 0 | *extra_bits = 0; |
32 | 0 | return; |
33 | 0 | } else { |
34 | 0 | size_t dist = ((size_t)1 << (postfix_bits + 2u)) + |
35 | 0 | (distance_code - BROTLI_NUM_DISTANCE_SHORT_CODES - num_direct_codes); |
36 | 0 | size_t bucket = Log2FloorNonZero(dist) - 1; |
37 | 0 | size_t postfix_mask = (1u << postfix_bits) - 1; |
38 | 0 | size_t postfix = dist & postfix_mask; |
39 | 0 | size_t prefix = (dist >> bucket) & 1; |
40 | 0 | size_t offset = (2 + prefix) << bucket; |
41 | 0 | size_t nbits = bucket - postfix_bits; |
42 | 0 | *code = (uint16_t)( |
43 | 0 | (BROTLI_NUM_DISTANCE_SHORT_CODES + num_direct_codes + |
44 | 0 | ((2 * (nbits - 1) + prefix) << postfix_bits) + postfix)); |
45 | 0 | *extra_bits = (uint32_t)( |
46 | 0 | (nbits << 24) | ((dist - offset) >> postfix_bits)); |
47 | 0 | } |
48 | 0 | } Unexecuted instantiation: backward_references.c:PrefixEncodeCopyDistance Unexecuted instantiation: backward_references_hq.c:PrefixEncodeCopyDistance Unexecuted instantiation: bit_cost.c:PrefixEncodeCopyDistance Unexecuted instantiation: block_splitter.c:PrefixEncodeCopyDistance Unexecuted instantiation: brotli_bit_stream.c:PrefixEncodeCopyDistance Unexecuted instantiation: cluster.c:PrefixEncodeCopyDistance Unexecuted instantiation: compress_fragment.c:PrefixEncodeCopyDistance Unexecuted instantiation: compress_fragment_two_pass.c:PrefixEncodeCopyDistance Unexecuted instantiation: encode.c:PrefixEncodeCopyDistance Unexecuted instantiation: histogram.c:PrefixEncodeCopyDistance Unexecuted instantiation: metablock.c:PrefixEncodeCopyDistance |
49 | | |
50 | | #if defined(__cplusplus) || defined(c_plusplus) |
51 | | } /* extern "C" */ |
52 | | #endif |
53 | | |
54 | | #endif /* BROTLI_ENC_PREFIX_H_ */ |