fasta/fai: Add writer

noodles-fasta/src/fai.rs

@@ -1,4 +1,5 @@
 mod reader;
 mod record;
+mod writer;
 
-pub use self::{reader::Reader, record::Record};
+pub use self::{reader::Reader, record::Record, writer::Writer};

noodles-fasta/src/fai/writer.rs

@@ -0,0 +1,50 @@
+use std::io::{self, Write};
+
+use super::Record;
+
+pub struct Writer<W> {
+    inner: W,
+}
+
+impl<W> Writer<W>
+where
+    W: Write,
+{
+    pub fn new(inner: W) -> Self {
+        Self { inner }
+    }
+
+    pub fn get_ref(&self) -> &W {
+        &self.inner
+    }
+
+    pub fn write_record(&mut self, record: &Record) -> io::Result<()> {
+        writeln!(
+            self.inner,
+            "{name}\t{len}\t{offset}\t{line_bases}\t{line_width}",
+            name = record.name(),
+            len = record.len(),
+            offset = record.offset(),
+            line_bases = record.line_bases(),
+            line_width = record.line_width(),
+        )
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_write_record() -> io::Result<()> {
+        let mut writer = Writer::new(Vec::new());
+
+        let record = Record::new(String::from("sq0"), 10946, 4, 80, 81);
+        writer.write_record(&record)?;
+
+        let expected = b"sq0\t10946\t4\t80\t81\n";
+        assert_eq!(writer.get_ref(), expected);
+
+        Ok(())
+    }
+}