1 files changed, 139 insertions, 0 deletions
diff --git a/src/server/point.cpp b/src/server/point.cpp
new file mode 100644
index 0000000..ab9f70f
--- /dev/null
+++ b/src/server/point.cpp
@@ -0,0 +1,139 @@
+#include <stdint.h>
+#include <stdbool.h>
+
+struct Point {
+	Page *page;
+	uint16_t index;
+
+	uint16_t index_to_offset() {
+		if (index < page->gap_start) {
+			return index;
+		} else {
+			return index + (page->gap_end - page->gap_start);
+		}
+	}
+
+	uint8_t prev_byte() {
+		if (index == 0) {
+			if (page->prev) {
+				return page->prev->elements[Point(page->prev, page->prev->element_count - 1).index_to_offset()];
+			} else {
+				return 0;
+			}
+		} else {
+			return page->elements[Point(page, index - 1).index_to_offset()];
+		}
+	}
+
+	uint8_t next_byte() {
+		if (index == page->element_count) {
+			if (page->next) {
+				return page->next->elements[Point(page->next, 0).index_to_offset()];
+			} else {
+				return 0;
+			}
+		} else {
+			return page->elements[index_to_offset()];
+		}
+	}
+
+	void move_forward() {
+		if (index < page->element_count) {
+			index++;
+		} else if (page->next) {
+			page = page->next;
+			index = 0;
+		}
+	}
+
+	void move_backward() {
+		if (index > 0) {
+			index--;
+		} else if (page->prev) {
+			page = page->prev;
+			index = page->element_count;
+		}
+	}
+
+
+	public:
+
+	Point() : page(0), index(0) {}
+	Point(Page* page, uint16_t index) : page(page), index(index) {}
+	Point(const Buffer &b) : page(b.storage), index(0) {}
+	Point(const Point &p) : page(p.page), index(p.index) {}
+
+	bool operator==(Point p) {
+		return page == p.page && index == p.index;
+	}
+
+	bool operator!=(Point p) {
+		return page != p.page || index != p.index;
+	}
+
+	bool at_start() {
+		return index == 0 && !page->prev;
+	}
+
+	bool at_end() {
+		return index == page->element_count && !page->next;
+	}
+
+	void operator++(int) {
+		if (index == page->element_count) move_forward();
+		move_forward();
+	}
+
+	void operator--(int) {
+		move_backward();
+		if (index == 0) move_backward();
+	}
+
+	char element() {
+		return next_byte();
+	}
+
+	void align_gap() {
+		while (page->gap_end < index_to_offset()) {
+			page->move_gap_forward();
+		}
+		while (page->gap_end > index_to_offset()) {
+			page->move_gap_backward();
+		}
+	}
+
+	void push(uint8_t c) {
+		if (page->is_full()) {
+			page->split();
+			if (index >= PAGE_SIZE / 2) {
+				page = page->next;
+				index -= PAGE_SIZE / 2;
+			}
+		}
+		align_gap();
+		page->push(c);
+		move_forward();
+	}
+
+	void pop() {
+		if (!at_start()) {
+			align_gap();
+			page->pop();
+			move_backward();
+			if (index == 0) {
+				move_backward();
+			}
+		}
+		if (page->is_empty()) {
+			if (page->prev) {
+				move_backward();
+				delete page->next;
+			} else if (page->next) {
+				page->next->copy_to(page);
+				delete page->next;
+				index = 0;
+			}
+		}
+	}
+
+};