1/**************************************************************************/
2/* ring_buffer.h */
3/**************************************************************************/
4/* This file is part of: */
5/* GODOT ENGINE */
6/* https://godotengine.org */
7/**************************************************************************/
8/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
9/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur. */
10/* */
11/* Permission is hereby granted, free of charge, to any person obtaining */
12/* a copy of this software and associated documentation files (the */
13/* "Software"), to deal in the Software without restriction, including */
14/* without limitation the rights to use, copy, modify, merge, publish, */
15/* distribute, sublicense, and/or sell copies of the Software, and to */
16/* permit persons to whom the Software is furnished to do so, subject to */
17/* the following conditions: */
18/* */
19/* The above copyright notice and this permission notice shall be */
20/* included in all copies or substantial portions of the Software. */
21/* */
22/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
23/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
24/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. */
25/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
26/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
27/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
28/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
29/**************************************************************************/
30
31#ifndef RING_BUFFER_H
32#define RING_BUFFER_H
33
34#include "core/templates/vector.h"
35
36template <typename T>
37class RingBuffer {
38 Vector<T> data;
39 int read_pos = 0;
40 int write_pos = 0;
41 int size_mask;
42
43 inline int inc(int &p_var, int p_size) const {
44 int ret = p_var;
45 p_var += p_size;
46 p_var = p_var & size_mask;
47 return ret;
48 }
49
50public:
51 T read() {
52 ERR_FAIL_COND_V(space_left() < 1, T());
53 return data.ptr()[inc(read_pos, 1)];
54 }
55
56 int read(T *p_buf, int p_size, bool p_advance = true) {
57 int left = data_left();
58 p_size = MIN(left, p_size);
59 int pos = read_pos;
60 int to_read = p_size;
61 int dst = 0;
62 while (to_read) {
63 int end = pos + to_read;
64 end = MIN(end, size());
65 int total = end - pos;
66 const T *read = data.ptr();
67 for (int i = 0; i < total; i++) {
68 p_buf[dst++] = read[pos + i];
69 }
70 to_read -= total;
71 pos = 0;
72 }
73 if (p_advance) {
74 inc(read_pos, p_size);
75 }
76 return p_size;
77 }
78
79 int copy(T *p_buf, int p_offset, int p_size) const {
80 int left = data_left();
81 if ((p_offset + p_size) > left) {
82 p_size -= left - p_offset;
83 if (p_size <= 0) {
84 return 0;
85 }
86 }
87 p_size = MIN(left, p_size);
88 int pos = read_pos;
89 inc(pos, p_offset);
90 int to_read = p_size;
91 int dst = 0;
92 while (to_read) {
93 int end = pos + to_read;
94 end = MIN(end, size());
95 int total = end - pos;
96 for (int i = 0; i < total; i++) {
97 p_buf[dst++] = data[pos + i];
98 }
99 to_read -= total;
100 pos = 0;
101 }
102 return p_size;
103 }
104
105 int find(const T &t, int p_offset, int p_max_size) const {
106 int left = data_left();
107 if ((p_offset + p_max_size) > left) {
108 p_max_size -= left - p_offset;
109 if (p_max_size <= 0) {
110 return 0;
111 }
112 }
113 p_max_size = MIN(left, p_max_size);
114 int pos = read_pos;
115 inc(pos, p_offset);
116 int to_read = p_max_size;
117 while (to_read) {
118 int end = pos + to_read;
119 end = MIN(end, size());
120 int total = end - pos;
121 for (int i = 0; i < total; i++) {
122 if (data[pos + i] == t) {
123 return i + (p_max_size - to_read);
124 }
125 }
126 to_read -= total;
127 pos = 0;
128 }
129 return -1;
130 }
131
132 inline int advance_read(int p_n) {
133 p_n = MIN(p_n, data_left());
134 inc(read_pos, p_n);
135 return p_n;
136 }
137
138 inline int decrease_write(int p_n) {
139 p_n = MIN(p_n, data_left());
140 inc(write_pos, size_mask + 1 - p_n);
141 return p_n;
142 }
143
144 Error write(const T &p_v) {
145 ERR_FAIL_COND_V(space_left() < 1, FAILED);
146 data.write[inc(write_pos, 1)] = p_v;
147 return OK;
148 }
149
150 int write(const T *p_buf, int p_size) {
151 int left = space_left();
152 p_size = MIN(left, p_size);
153
154 int pos = write_pos;
155 int to_write = p_size;
156 int src = 0;
157 while (to_write) {
158 int end = pos + to_write;
159 end = MIN(end, size());
160 int total = end - pos;
161
162 for (int i = 0; i < total; i++) {
163 data.write[pos + i] = p_buf[src++];
164 }
165 to_write -= total;
166 pos = 0;
167 }
168
169 inc(write_pos, p_size);
170 return p_size;
171 }
172
173 inline int space_left() const {
174 int left = read_pos - write_pos;
175 if (left < 0) {
176 return size() + left - 1;
177 }
178 if (left == 0) {
179 return size() - 1;
180 }
181 return left - 1;
182 }
183 inline int data_left() const {
184 return size() - space_left() - 1;
185 }
186
187 inline int size() const {
188 return data.size();
189 }
190
191 inline void clear() {
192 read_pos = 0;
193 write_pos = 0;
194 }
195
196 void resize(int p_power) {
197 int old_size = size();
198 int new_size = 1 << p_power;
199 int mask = new_size - 1;
200 data.resize(1 << p_power);
201 if (old_size < new_size && read_pos > write_pos) {
202 for (int i = 0; i < write_pos; i++) {
203 data.write[(old_size + i) & mask] = data[i];
204 }
205 write_pos = (old_size + write_pos) & mask;
206 } else {
207 read_pos = read_pos & mask;
208 write_pos = write_pos & mask;
209 }
210
211 size_mask = mask;
212 }
213
214 RingBuffer<T>(int p_power = 0) {
215 resize(p_power);
216 }
217 ~RingBuffer<T>() {}
218};
219
220#endif // RING_BUFFER_H
221