From 103b677d218a3916439d5c966fe5e75b7b110d59 Mon Sep 17 00:00:00 2001
From: Dmitry <b4tm4n@mail.ru>
Date: Tue, 28 Mar 2023 15:01:14 +0300
Subject: [PATCH] into_iter() for reader
---
lib/src/db.rs | 124 ++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 124 insertions(+)
diff --git a/lib/src/db.rs b/lib/src/db.rs
index d2b5396..73b121b 100644
--- a/lib/src/db.rs
+++ b/lib/src/db.rs
@@ -226,6 +226,10 @@ where
pub fn iter(&self) -> ReaderIter<'_, T> {
ReaderIter::new(self)
}
+
+ pub fn into_iter(self) -> ReaderIntoIter<T> {
+ ReaderIntoIter::new(self)
+ }
}
pub struct ReaderIter<'a, T>
@@ -310,6 +314,100 @@ where
}
}
+pub struct ReaderIntoIter<T>
+where
+ T: bincode::Decode,
+{
+ reader: Reader<T>,
+ index: Option<usize>,
+}
+
+impl<T> ReaderIntoIter<T>
+where
+ T: bincode::Decode,
+{
+ fn new(reader: Reader<T>) -> Self {
+ Self {
+ reader,
+ index: None,
+ }
+ }
+}
+
+impl<T> Iterator for ReaderIntoIter<T>
+where
+ T: bincode::Decode,
+{
+ type Item = T;
+
+ fn next(&mut self) -> Option<Self::Item> {
+ if self.index.is_none() && !self.reader.is_empty() {
+ self.index = Some(0);
+ }
+
+ match self.index {
+ Some(i) if i < self.reader.len() => self.nth(i),
+ _ => None,
+ }
+ }
+
+ fn nth(&mut self, n: usize) -> Option<Self::Item> {
+ if self.reader.len() <= n {
+ return None;
+ }
+ self.index = Some(n + 1);
+
+ let item = self.reader.get(n);
+ match item {
+ Ok(item) => Some(item),
+ Err(_) => None,
+ }
+ }
+
+ fn size_hint(&self) -> (usize, Option<usize>) {
+ let len = self.reader.len();
+ if self.index.is_none() {
+ return (len, Some(len));
+ }
+
+ let index = self.index.unwrap();
+ let rem = if len > index + 1 {
+ len - (index + 1)
+ } else {
+ 0
+ };
+ (rem, Some(rem))
+ }
+
+ fn count(self) -> usize
+ where
+ Self: Sized,
+ {
+ self.reader.len()
+ }
+}
+
+impl<T> ExactSizeIterator for ReaderIntoIter<T>
+where
+ T: bincode::Decode,
+{
+ fn len(&self) -> usize {
+ self.reader.len()
+ }
+}
+
+impl<T> IntoIterator for Reader<T>
+where
+ T: bincode::Decode,
+{
+ type Item = T;
+ type IntoIter = ReaderIntoIter<Self::Item>;
+
+ fn into_iter(self) -> Self::IntoIter {
+ self.into_iter()
+ }
+}
+
#[cfg(test)]
mod test {
use super::*;
@@ -380,4 +478,30 @@ mod test {
assert_eq!(pair.0, pair.1);
});
}
+
+ #[test]
+ fn test_write_read_into_iter() {
+ let dir = tempdir().expect("tempdir");
+ let tmpfile = dir.path().join("test.tmp");
+ let opts = WriterOpts {
+ compress_lvl: 1,
+ data_buf_size: 10 * 1024 * 1024,
+ out_buf_size: 10 * 1024 * 1024,
+ current_buf_size: 4096,
+ };
+ let mut writer: Writer<TestData> = Writer::new(&tmpfile, opts).expect("new writer");
+
+ let items_iter = gen_data(10);
+ let items: Vec<TestData> = items_iter.collect();
+
+ writer.load(&mut items.clone().into_iter()).expect("load");
+ writer.finish().expect("finish write");
+
+ let reader: Reader<TestData> = Reader::new(&tmpfile, 2048).expect("new reader");
+ assert_eq!(items.len(), reader.len());
+
+ items.into_iter().zip(reader).for_each(|pair| {
+ assert_eq!(pair.0, pair.1);
+ });
+ }
}