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use {
crate::{NullOrd, Value},
std::cmp::Ordering,
};
pub enum JoinType {
Inner,
Outer,
Left,
Right,
}
macro_rules! unwrap_or_break {
($unwrap: expr) => {
match $unwrap {
Some(value) => value,
None => {
break;
}
}
};
}
pub fn join_iters(join_type: JoinType, a: Vec<Value>, b: Vec<Value>) -> Vec<Value> {
let mut a = a.into_iter().peekable();
let mut b = b.into_iter().peekable();
let mut results = vec![];
match join_type {
JoinType::Inner => loop {
match unwrap_or_break!(a.peek())
.null_cmp(unwrap_or_break!(&b.peek()))
.unwrap_or(Ordering::Equal)
{
Ordering::Equal => {
results.push(a.next().unwrap());
b.next();
}
Ordering::Less => {
a.next();
}
Ordering::Greater => {
b.next();
}
}
},
JoinType::Outer => {
loop {
match unwrap_or_break!(a.peek())
.null_cmp(unwrap_or_break!(&b.peek()))
.unwrap_or(Ordering::Equal)
{
Ordering::Less => {
results.push(a.next().unwrap());
}
Ordering::Greater => {
results.push(b.next().unwrap());
}
Ordering::Equal => {
results.push(a.next().unwrap());
b.next();
}
}
}
results.extend(a);
results.extend(b);
}
JoinType::Left => {
loop {
match unwrap_or_break!(a.peek())
.null_cmp(unwrap_or_break!(b.peek()))
.unwrap_or(Ordering::Equal)
{
Ordering::Less => {
results.push(a.next().unwrap());
}
Ordering::Equal => {
results.push(a.next().unwrap());
b.next();
}
Ordering::Greater => {
b.next();
}
}
}
results.extend(a);
}
JoinType::Right => {
loop {
match unwrap_or_break!(a.peek())
.null_cmp(unwrap_or_break!(&b.peek()))
.unwrap_or(Ordering::Equal)
{
Ordering::Greater => {
results.push(b.next().unwrap());
}
Ordering::Equal => {
results.push(a.next().unwrap());
b.next();
}
Ordering::Less => {
a.next();
}
}
}
results.extend(b);
}
}
results
}
