#[derive(Default)]
pub struct TextCache {
pub text_strings: Vec<Option<String>>,
pub next_free_slot: usize,
pub slot_generations: Vec<u64>,
pub generation: u64,
}
impl TextCache {
pub fn new() -> Self {
Self {
text_strings: Vec::new(),
next_free_slot: 0,
slot_generations: Vec::new(),
generation: 0,
}
}
pub fn add_text(&mut self, content: impl Into<String>) -> usize {
let content = content.into();
self.generation += 1;
if self.next_free_slot < self.text_strings.len() {
let slot = self.next_free_slot;
self.text_strings[slot] = Some(content);
self.slot_generations[slot] += 1;
self.next_free_slot = self.find_next_free_slot();
slot
} else {
let slot = self.text_strings.len();
self.text_strings.push(Some(content));
self.slot_generations.push(1);
self.next_free_slot = slot + 1;
slot
}
}
pub fn get_text(&self, index: usize) -> Option<&str> {
self.text_strings.get(index).and_then(|opt| opt.as_deref())
}
pub fn set_text(&mut self, index: usize, content: impl Into<String>) -> bool {
if let Some(text_opt) = self.text_strings.get_mut(index) {
*text_opt = Some(content.into());
self.slot_generations[index] += 1;
self.generation += 1;
true
} else {
false
}
}
pub fn remove_text(&mut self, index: usize) -> bool {
if let Some(text_opt) = self.text_strings.get_mut(index) {
if text_opt.is_some() {
*text_opt = None;
self.slot_generations[index] += 1;
if index < self.next_free_slot {
self.next_free_slot = index;
}
true
} else {
false
}
} else {
false
}
}
pub fn is_slot_valid(&self, index: usize) -> bool {
self.text_strings
.get(index)
.is_some_and(|opt| opt.is_some())
}
pub fn get_all_text_with_indices(&self) -> Vec<(usize, &str)> {
self.text_strings
.iter()
.enumerate()
.filter_map(|(i, opt)| opt.as_deref().map(|s| (i, s)))
.collect()
}
pub fn get_valid_slots(&self) -> Vec<usize> {
self.text_strings
.iter()
.enumerate()
.filter_map(|(i, opt)| if opt.is_some() { Some(i) } else { None })
.collect()
}
pub fn compact(&mut self) -> Vec<(usize, usize)> {
let mut new_strings = Vec::new();
let mut new_generations = Vec::new();
let mut index_mapping = Vec::new();
for (old_index, opt) in self.text_strings.iter().enumerate() {
if let Some(text) = opt {
index_mapping.push((old_index, new_strings.len()));
new_strings.push(Some(text.clone()));
new_generations.push(self.slot_generations.get(old_index).copied().unwrap_or(1));
}
}
self.text_strings = new_strings;
self.slot_generations = new_generations;
self.next_free_slot = self.text_strings.len();
index_mapping
}
fn find_next_free_slot(&self) -> usize {
for (i, opt) in self.text_strings.iter().enumerate() {
if opt.is_none() {
return i;
}
}
self.text_strings.len()
}
}