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/**************************************************************************/
/* ring_buffer.h */
/**************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* https://godotengine.org */
/**************************************************************************/
/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur. */
/* */
/* Permission is hereby granted, free of charge, to any person obtaining */
/* a copy of this software and associated documentation files (the */
/* "Software"), to deal in the Software without restriction, including */
/* without limitation the rights to use, copy, modify, merge, publish, */
/* distribute, sublicense, and/or sell copies of the Software, and to */
/* permit persons to whom the Software is furnished to do so, subject to */
/* the following conditions: */
/* */
/* The above copyright notice and this permission notice shall be */
/* included in all copies or substantial portions of the Software. */
/* */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. */
/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
/**************************************************************************/
#ifndef RING_BUFFER_H
#define RING_BUFFER_H
#include "core/templates/vector.h"
template <typename T>
class RingBuffer {
Vector<T> data;
int read_pos = 0;
int write_pos = 0;
int size_mask;
inline int inc(int &p_var, int p_size) const {
int ret = p_var;
p_var += p_size;
p_var = p_var & size_mask;
return ret;
}
public:
T read() {
ERR_FAIL_COND_V(space_left() < 1, T());
return data.ptr()[inc(read_pos, 1)];
}
int read(T *p_buf, int p_size, bool p_advance = true) {
int left = data_left();
p_size = MIN(left, p_size);
int pos = read_pos;
int to_read = p_size;
int dst = 0;
while (to_read) {
int end = pos + to_read;
end = MIN(end, size());
int total = end - pos;
const T *read = data.ptr();
for (int i = 0; i < total; i++) {
p_buf[dst++] = read[pos + i];
}
to_read -= total;
pos = 0;
}
if (p_advance) {
inc(read_pos, p_size);
}
return p_size;
}
int copy(T *p_buf, int p_offset, int p_size) const {
int left = data_left();
if ((p_offset + p_size) > left) {
p_size -= left - p_offset;
if (p_size <= 0) {
return 0;
}
}
p_size = MIN(left, p_size);
int pos = read_pos;
inc(pos, p_offset);
int to_read = p_size;
int dst = 0;
while (to_read) {
int end = pos + to_read;
end = MIN(end, size());
int total = end - pos;
for (int i = 0; i < total; i++) {
p_buf[dst++] = data[pos + i];
}
to_read -= total;
pos = 0;
}
return p_size;
}
int find(const T &t, int p_offset, int p_max_size) const {
int left = data_left();
if ((p_offset + p_max_size) > left) {
p_max_size -= left - p_offset;
if (p_max_size <= 0) {
return 0;
}
}
p_max_size = MIN(left, p_max_size);
int pos = read_pos;
inc(pos, p_offset);
int to_read = p_max_size;
while (to_read) {
int end = pos + to_read;
end = MIN(end, size());
int total = end - pos;
for (int i = 0; i < total; i++) {
if (data[pos + i] == t) {
return i + (p_max_size - to_read);
}
}
to_read -= total;
pos = 0;
}
return -1;
}
inline int advance_read(int p_n) {
p_n = MIN(p_n, data_left());
inc(read_pos, p_n);
return p_n;
}
inline int decrease_write(int p_n) {
p_n = MIN(p_n, data_left());
inc(write_pos, size_mask + 1 - p_n);
return p_n;
}
Error write(const T &p_v) {
ERR_FAIL_COND_V(space_left() < 1, FAILED);
data.write[inc(write_pos, 1)] = p_v;
return OK;
}
int write(const T *p_buf, int p_size) {
int left = space_left();
p_size = MIN(left, p_size);
int pos = write_pos;
int to_write = p_size;
int src = 0;
while (to_write) {
int end = pos + to_write;
end = MIN(end, size());
int total = end - pos;
for (int i = 0; i < total; i++) {
data.write[pos + i] = p_buf[src++];
}
to_write -= total;
pos = 0;
}
inc(write_pos, p_size);
return p_size;
}
inline int space_left() const {
int left = read_pos - write_pos;
if (left < 0) {
return size() + left - 1;
}
if (left == 0) {
return size() - 1;
}
return left - 1;
}
inline int data_left() const {
return size() - space_left() - 1;
}
inline int size() const {
return data.size();
}
inline void clear() {
read_pos = 0;
write_pos = 0;
}
void resize(int p_power) {
int old_size = size();
int new_size = 1 << p_power;
int mask = new_size - 1;
data.resize(1 << p_power);
if (old_size < new_size && read_pos > write_pos) {
for (int i = 0; i < write_pos; i++) {
data.write[(old_size + i) & mask] = data[i];
}
write_pos = (old_size + write_pos) & mask;
} else {
read_pos = read_pos & mask;
write_pos = write_pos & mask;
}
size_mask = mask;
}
RingBuffer<T>(int p_power = 0) {
resize(p_power);
}
~RingBuffer<T>() {}
};
#endif // RING_BUFFER_H
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