56 lines
1.3 KiB
Rust
56 lines
1.3 KiB
Rust
use crate::{
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op_tree::OpTreeNode,
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types::{ElemId, Key},
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};
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use super::{QueryResult, TreeQuery};
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/// Lookup the index in the list that this elemid occupies.
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pub(crate) struct ElemIdPos {
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elemid: ElemId,
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pos: usize,
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found: bool,
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}
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impl ElemIdPos {
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pub(crate) fn new(elemid: ElemId) -> Self {
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Self {
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elemid,
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pos: 0,
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found: false,
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}
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}
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pub(crate) fn index(&self) -> Option<usize> {
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if self.found {
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Some(self.pos)
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} else {
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None
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}
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}
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}
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impl<'a> TreeQuery<'a> for ElemIdPos {
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fn query_node(&mut self, child: &OpTreeNode) -> QueryResult {
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// if index has our element then we can continue
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if child.index.has_visible(&Key::Seq(self.elemid)) {
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// element is in this node somewhere
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QueryResult::Descend
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} else {
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// not in this node, try the next one
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self.pos += child.index.visible_len();
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QueryResult::Next
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}
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}
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fn query_element(&mut self, element: &crate::types::Op) -> QueryResult {
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if element.elemid() == Some(self.elemid) {
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// this is it
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self.found = true;
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return QueryResult::Finish;
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} else if element.visible() {
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self.pos += 1;
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}
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QueryResult::Next
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}
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}
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