1 files changed, 112 insertions, 0 deletions
diff --git a/point.cpp b/point.cpp
new file mode 100644
index 0000000..e31f5de
--- /dev/null
+++ b/point.cpp
@@ -0,0 +1,112 @@
+#include <stdint.h>
+#include <stdbool.h>
+
+struct Point {
+	Page *page;
+	uint16_t index;
+
+	Point() : page(nullptr), index(0) {}
+	Point(Page *page) : page(page), index(0) {}
+	Point(const Point& p) : page(p.page), index(p.index) {}
+
+	uint16_t index_to_offset() {
+		if (index < page->gap_start) {
+			return index;
+		} else {
+			return index + (page->gap_end - page->gap_start);
+		}
+	}
+
+	bool operator==(Point p) {
+		return page == p.page && index == p.index;
+	}
+
+	uint8_t element() {
+		if (index == page->element_count) {
+			return !page->next ? 0 : page->next->elements[0];
+		} else {
+			return page->elements[index_to_offset()];
+		}
+	}
+
+	void operator++(int) {
+		if (index < page->element_count) {
+			index++;
+		} else if (page->next) {
+			index = 1;
+			page = page->next;
+		}
+	}
+
+	void operator--(int) {
+		if (index > 1) {
+			index--;
+		} else if (page->prev) {
+			page = page->prev;
+			index = page->element_count;
+		} else {
+			index = 0;
+		}
+	}
+
+	uint64_t seek(uint8_t c, uint64_t limit) {
+		uint64_t travel_distance = 0;
+		while (element() && element() != c && travel_distance < limit) {
+			(*this)++;
+			travel_distance++;
+		}
+		return travel_distance;
+	}
+
+	uint64_t rseek(uint8_t c, uint64_t limit) {
+		uint64_t travel_distance = 0;
+		while (index != 0 && element() != c && travel_distance < limit) {
+			(*this)--;
+			travel_distance++;
+		}
+		return travel_distance;
+	}
+
+	void align_gap() {
+		while (page->gap_end < index_to_offset()) {
+			(*page)++;
+		}
+		while (page->gap_end > index_to_offset()) {
+			(*page)--;
+		}
+	}
+
+	void push(uint8_t c) {
+		if (page->gap_start == page->gap_end) {
+			page->split();
+			if (index >= PAGE_SIZE / 2) {
+				page = page->next;
+				index -= PAGE_SIZE / 2;
+			}
+		}
+		align_gap();
+		page->push(c);
+		(*this)++;
+	}
+
+	void pop() {
+		if (page->element_count == 1 && index == 1) {
+			if (page->prev) {
+				(*this)--;
+				delete page->next;
+			} else if (page->next) {
+				page->next->copy_to(page);
+				delete page->next;
+				index = 0;
+			} else {
+				page->pop();
+				index = 0;
+			}
+		} else if (index > 0) {
+			align_gap();
+			page->pop();
+			(*this)--;
+		}
+	}
+
+};