promisor-remote: skip move_to_tail when no-op
[git/git.git] / ewah / ewok_rlw.h
1 /**
2 * Copyright 2013, GitHub, Inc
3 * Copyright 2009-2013, Daniel Lemire, Cliff Moon,
4 * David McIntosh, Robert Becho, Google Inc. and Veronika Zenz
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version 2
9 * of the License, or (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, see <http://www.gnu.org/licenses/>.
18 */
19 #ifndef __EWOK_RLW_H__
20 #define __EWOK_RLW_H__
21
22 #include "ewok.h"
23
24 #define RLW_RUNNING_BITS (sizeof(eword_t) * 4)
25 #define RLW_LITERAL_BITS (sizeof(eword_t) * 8 - 1 - RLW_RUNNING_BITS)
26
27 #define RLW_LARGEST_RUNNING_COUNT (((eword_t)1 << RLW_RUNNING_BITS) - 1)
28 #define RLW_LARGEST_LITERAL_COUNT (((eword_t)1 << RLW_LITERAL_BITS) - 1)
29
30 #define RLW_LARGEST_RUNNING_COUNT_SHIFT (RLW_LARGEST_RUNNING_COUNT << 1)
31
32 #define RLW_RUNNING_LEN_PLUS_BIT (((eword_t)1 << (RLW_RUNNING_BITS + 1)) - 1)
33
34 static inline int rlw_get_run_bit(const eword_t *word)
35 {
36 return *word & (eword_t)1;
37 }
38
39 static inline void rlw_set_run_bit(eword_t *word, int b)
40 {
41 if (b) {
42 *word |= (eword_t)1;
43 } else {
44 *word &= (eword_t)(~1);
45 }
46 }
47
48 static inline void rlw_xor_run_bit(eword_t *word)
49 {
50 if (*word & 1) {
51 *word &= (eword_t)(~1);
52 } else {
53 *word |= (eword_t)1;
54 }
55 }
56
57 static inline void rlw_set_running_len(eword_t *word, eword_t l)
58 {
59 *word |= RLW_LARGEST_RUNNING_COUNT_SHIFT;
60 *word &= (l << 1) | (~RLW_LARGEST_RUNNING_COUNT_SHIFT);
61 }
62
63 static inline eword_t rlw_get_running_len(const eword_t *word)
64 {
65 return (*word >> 1) & RLW_LARGEST_RUNNING_COUNT;
66 }
67
68 static inline eword_t rlw_get_literal_words(const eword_t *word)
69 {
70 return *word >> (1 + RLW_RUNNING_BITS);
71 }
72
73 static inline void rlw_set_literal_words(eword_t *word, eword_t l)
74 {
75 *word |= ~RLW_RUNNING_LEN_PLUS_BIT;
76 *word &= (l << (RLW_RUNNING_BITS + 1)) | RLW_RUNNING_LEN_PLUS_BIT;
77 }
78
79 static inline eword_t rlw_size(const eword_t *self)
80 {
81 return rlw_get_running_len(self) + rlw_get_literal_words(self);
82 }
83
84 struct rlw_iterator {
85 const eword_t *buffer;
86 size_t size;
87 size_t pointer;
88 size_t literal_word_start;
89
90 struct {
91 const eword_t *word;
92 int literal_words;
93 int running_len;
94 int literal_word_offset;
95 int running_bit;
96 } rlw;
97 };
98
99 void rlwit_init(struct rlw_iterator *it, struct ewah_bitmap *bitmap);
100 void rlwit_discard_first_words(struct rlw_iterator *it, size_t x);
101 size_t rlwit_discharge(
102 struct rlw_iterator *it, struct ewah_bitmap *out, size_t max, int negate);
103
104 static inline size_t rlwit_word_size(struct rlw_iterator *it)
105 {
106 return it->rlw.running_len + it->rlw.literal_words;
107 }
108
109 static inline size_t rlwit_literal_words(struct rlw_iterator *it)
110 {
111 return it->pointer - it->rlw.literal_words;
112 }
113
114 #endif