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#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)--;
}
}
};
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