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Remove LevEditType::Keep variant #27

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Merged
merged 1 commit into from
Jan 22, 2023
Merged

Remove LevEditType::Keep variant #27

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6 changes: 1 addition & 5 deletions src/diff.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -133,7 +133,6 @@ pub fn diff_code(
right_diff.push(ObjInsDiff::default());
cur_left = left_iter.next();
}
LevEditType::Keep => unreachable!(),
}
} else {
break;
Expand Down Expand Up @@ -511,13 +510,12 @@ fn diff_data(left: &mut ObjSection, right: &mut ObjSection) {
let mut right_diff = Vec::<ObjDataDiff>::new();
let mut left_cur = 0usize;
let mut right_cur = 0usize;
let mut cur_op = LevEditType::Keep;
let mut cur_op = LevEditType::Replace;
Comment on lines -514 to +513
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This was the only change where I wasn't really sure on the semantics. Based on my reading of the code, the initial value of this variable doesn't really matter because it's always set on the first iteration of the following loop.

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Correct, initial value doesn't matter.

let mut cur_left_data = Vec::<u8>::new();
let mut cur_right_data = Vec::<u8>::new();
for op in edit_ops {
if cur_op != op.op_type || left_cur < op.first_start || right_cur < op.second_start {
match cur_op {
LevEditType::Keep => {}
LevEditType::Replace => {
let left_data = take(&mut cur_left_data);
let right_data = take(&mut cur_right_data);
Expand Down Expand Up @@ -603,7 +601,6 @@ fn diff_data(left: &mut ObjSection, right: &mut ObjSection) {
cur_left_data.push(left.data[left_cur]);
left_cur += 1;
}
LevEditType::Keep => unreachable!(),
}
cur_op = op.op_type;
}
Expand All @@ -627,7 +624,6 @@ fn diff_data(left: &mut ObjSection, right: &mut ObjSection) {

// TODO: merge with above
match cur_op {
LevEditType::Keep => {}
LevEditType::Replace => {
let left_data = take(&mut cur_left_data);
let right_data = take(&mut cur_right_data);
Expand Down
92 changes: 31 additions & 61 deletions src/editops.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -27,7 +27,6 @@

#[derive(Debug, PartialEq, Eq, Copy, Clone)]
pub enum LevEditType {
Keep,
Replace,
Insert,
Delete,
Expand Down Expand Up @@ -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,
Expand All @@ -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;

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");
}
// 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;

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"),
};

match op_type {
LevEditType::Insert => {
match new_dir {
-1 => {
j -= 1;
p -= 1;
dir = -1;
}
LevEditType::Delete => {
1 => {
i -= 1;
p -= len2;
dir = 1;
}
LevEditType::Replace => {
0 => {
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;
}
_ => 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);
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
Expand Down