initial commit, 4.5 stable

core/templates/ring_buffer.h

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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.                 */
+/**************************************************************************/
+
+#pragma once
+
+#include "core/templates/local_vector.h"
+
+template <typename T>
+class RingBuffer {
+	LocalVector<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[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[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(int64_t(1) << int64_t(p_power));
+		if (old_size < new_size && read_pos > write_pos) {
+			for (int i = 0; i < write_pos; i++) {
+				data[(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(int p_power = 0) {
+		resize(p_power);
+	}
+	~RingBuffer() {}
+};