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Remove LevEditType::Keep variant (#27)

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This commit is contained in:
Nick Condron
2023-01-22 13:20:50 -05:00
committed by GitHub
parent 319b1c35c0
commit 019493f944
2 changed files with 41 additions and 75 deletions
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110
src/editops.rs
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@@ -27,7 +27,6 @@
#[derive(Debug, PartialEq, Eq, Copy, Clone)]
pub enum LevEditType {
Keep,
Replace,
Insert,
Delete,
@@ -77,19 +76,10 @@ where T: PartialEq {
cache_matrix[current + 1 + p] = x;
}
}
editops_from_cost_matrix(
first_string,
second_string,
matrix_columns,
matrix_rows,
prefix_len,
cache_matrix,
)
editops_from_cost_matrix::<T>(matrix_columns, matrix_rows, prefix_len, cache_matrix)
}
fn editops_from_cost_matrix<T>(
string1: &[T],
string2: &[T],
len1: usize,
len2: usize,
prefix_len: usize,
@@ -98,77 +88,57 @@ fn editops_from_cost_matrix<T>(
where
T: PartialEq,
{
let mut ops = Vec::with_capacity(cache_matrix[len1 * len2 - 1]);
let mut dir = 0;
let mut ops: Vec<LevEditOp> = vec![];
ops.reserve(cache_matrix[len1 * len2 - 1]);
let mut i = len1 - 1;
let mut j = len2 - 1;
let mut p = len1 * len2 - 1;
// let string1_chars: Vec<char> = string1.chars().collect();
// let string2_chars: Vec<char> = string2.chars().collect();
//TODO this is still pretty ugly
while i > 0 || j > 0 {
let current_value = cache_matrix[p];
let op_type;
// More than one operation can be possible at a time. We use `dir` to
// decide when ambiguous.
let is_insert = j > 0 && current_value == cache_matrix[p - 1] + 1;
let is_delete = i > 0 && current_value == cache_matrix[p - len2] + 1;
let is_replace = i > 0 && j > 0 && current_value == cache_matrix[p - len2 - 1] + 1;
if dir == -1 && j > 0 && current_value == cache_matrix[p - 1] + 1 {
op_type = LevEditType::Insert;
} else if dir == 1 && i > 0 && current_value == cache_matrix[p - len2] + 1 {
op_type = LevEditType::Delete;
} else if i > 0
&& j > 0
&& current_value == cache_matrix[p - len2 - 1]
&& string1[i - 1] == string2[j - 1]
{
op_type = LevEditType::Keep;
} else if i > 0 && j > 0 && current_value == cache_matrix[p - len2 - 1] + 1 {
op_type = LevEditType::Replace;
}
/* we can't turn directly from -1 to 1, in this case it would be better
* to go diagonally, but check it (dir == 0) */
else if dir == 0 && j > 0 && current_value == cache_matrix[p - 1] + 1 {
op_type = LevEditType::Insert;
} else if dir == 0 && i > 0 && current_value == cache_matrix[p - len2] + 1 {
op_type = LevEditType::Delete;
} else {
panic!("something went terribly wrong");
}
match op_type {
LevEditType::Insert => {
j -= 1;
p -= 1;
dir = -1;
}
LevEditType::Delete => {
i -= 1;
p -= len2;
dir = 1;
}
LevEditType::Replace => {
i -= 1;
j -= 1;
p -= len2 + 1;
dir = 0;
}
LevEditType::Keep => {
i -= 1;
j -= 1;
p -= len2 + 1;
dir = 0;
/* LevEditKeep does not has to be stored */
continue;
}
let (op_type, new_dir) = match (dir, is_insert, is_delete, is_replace) {
(_, false, false, false) => (None, 0),
(-1, true, _, _) => (Some(LevEditType::Insert), -1),
(1, _, true, _) => (Some(LevEditType::Delete), 1),
(_, _, _, true) => (Some(LevEditType::Replace), 0),
(0, true, _, _) => (Some(LevEditType::Insert), -1),
(0, _, true, _) => (Some(LevEditType::Delete), 1),
_ => panic!("something went terribly wrong"),
};
let edit_op =
LevEditOp { op_type, first_start: i + prefix_len, second_start: j + prefix_len };
ops.insert(0, edit_op);
match new_dir {
-1 => {
j -= 1;
p -= 1;
}
1 => {
i -= 1;
p -= len2;
}
0 => {
i -= 1;
j -= 1;
p -= len2 + 1;
}
_ => panic!("something went terribly wrong"),
};
dir = new_dir;
if let Some(op_type) = op_type {
ops.insert(0, LevEditOp {
op_type,
first_start: i + prefix_len,
second_start: j + prefix_len,
});
}
}
ops