bcf/lazy/record/value: Borrow string value

noodles-bcf/src/lazy/record/value.rs

@@ -8,11 +8,11 @@ mod ty;
 pub use self::{array::Array, float::Float, int16::Int16, int32::Int32, int8::Int8, ty::Type};
 
 #[derive(Clone, Debug, PartialEq)]
-pub enum Value {
+pub enum Value<'a> {
     Int8(Option<Int8>),
     Int16(Option<Int16>),
     Int32(Option<Int32>),
     Float(Option<Float>),
-    String(Option<String>),
+    String(Option<&'a str>),
     Array(Array),
 }

noodles-bcf/src/record/codec/decoder.rs

@@ -121,7 +121,7 @@ pub fn read_ref_alt(src: &mut &[u8], len: usize) -> io::Result<(ReferenceBases,
 
     for _ in 0..len {
         match read_value(src)? {
-            Some(Value::String(Some(s))) => alleles.push(s),
+            Some(Value::String(Some(s))) => alleles.push(s.into()),
             Some(Value::String(None)) => alleles.push(String::from(".")),
             v => {
                 return Err(io::Error::new(

noodles-bcf/src/record/codec/decoder/value.rs

@@ -2,7 +2,7 @@ mod ty;
 
 pub use self::ty::read_type;
 
-use std::io::{self, Read};
+use std::{io, str};
 
 use byteorder::{LittleEndian, ReadBytesExt};
 
@@ -11,7 +11,7 @@ use crate::lazy::record::{
     Value,
 };
 
-pub fn read_value(src: &mut &[u8]) -> io::Result<Option<Value>> {
+pub fn read_value<'a>(src: &mut &'a [u8]) -> io::Result<Option<Value<'a>>> {
     let ty = read_type(src)?;
 
     match ty {
@@ -111,10 +111,16 @@ fn read_float_array(src: &mut &[u8], len: usize) -> io::Result<Vec<f32>> {
     Ok(buf)
 }
 
-fn read_string(src: &mut &[u8], len: usize) -> io::Result<String> {
-    let mut buf = vec![0; len];
-    src.read_exact(&mut buf)?;
-    String::from_utf8(buf).map_err(|e| io::Error::new(io::ErrorKind::InvalidData, e))
+fn read_string<'a>(src: &mut &'a [u8], len: usize) -> io::Result<&'a str> {
+    if src.len() < len {
+        return Err(io::Error::from(io::ErrorKind::UnexpectedEof));
+    }
+
+    let (buf, rest) = src.split_at(len);
+    let s = str::from_utf8(buf).map_err(|e| io::Error::new(io::ErrorKind::InvalidData, e))?;
+    *src = rest;
+
+    Ok(s)
 }
 
 #[cfg(test)]

noodles-bcf/src/record/codec/encoder/site.rs

@@ -180,13 +180,14 @@ pub(crate) fn write_id<W>(writer: &mut W, ids: &vcf::record::Ids) -> io::Result<
 where
     W: Write,
 {
-    let value = if ids.is_empty() {
-        Some(Value::String(None))
+    if ids.is_empty() {
+        let value = Some(Value::String(None));
+        write_value(writer, value)
     } else {
-        Some(Value::String(Some(ids.to_string())))
-    };
-
-    write_value(writer, value)
+        let s = ids.to_string();
+        let value = Some(Value::String(Some(&s)));
+        write_value(writer, value)
+    }
 }
 
 pub(crate) fn write_ref_alt<W>(
@@ -198,12 +199,13 @@ where
     W: Write,
 {
     let r#ref = reference_bases.to_string();
-    let ref_value = Some(Value::String(Some(r#ref)));
+    let ref_value = Some(Value::String(Some(&r#ref)));
     write_value(writer, ref_value)?;
 
     if !alternate_bases.is_empty() {
         for allele in alternate_bases.iter() {
-            let alt_value = Some(Value::String(Some(allele.to_string())));
+            let alt = allele.to_string();
+            let alt_value = Some(Value::String(Some(&alt)));
             write_value(writer, alt_value)?;
         }
     }

noodles-bcf/src/record/codec/encoder/site/info.rs

@@ -140,14 +140,15 @@ fn write_info_field_character_value<W>(writer: &mut W, c: char) -> io::Result<()
 where
     W: Write,
 {
-    write_value(writer, Some(Value::String(Some(c.into()))))
+    let s = c.to_string();
+    write_value(writer, Some(Value::String(Some(&s))))
 }
 
 fn write_info_field_string_value<W>(writer: &mut W, s: &str) -> io::Result<()>
 where
     W: Write,
 {
-    write_value(writer, Some(Value::String(Some(s.into()))))
+    write_value(writer, Some(Value::String(Some(s))))
 }
 
 fn write_info_field_integer_array_value<W>(writer: &mut W, values: &[Option<i32>]) -> io::Result<()>
@@ -297,7 +298,7 @@ where
         s.push(c);
     }
 
-    write_value(writer, Some(Value::String(Some(s))))
+    write_value(writer, Some(Value::String(Some(&s))))
 }
 
 fn write_info_field_string_array_value<W>(
@@ -321,7 +322,7 @@ where
         }
     }
 
-    write_value(writer, Some(Value::String(Some(s))))
+    write_value(writer, Some(Value::String(Some(&s))))
 }
 
 #[cfg(test)]

noodles-bcf/src/record/codec/encoder/value.rs

@@ -8,7 +8,7 @@ use byteorder::{LittleEndian, WriteBytesExt};
 
 use crate::lazy::record::value::{Array, Float, Int16, Int32, Int8, Type, Value};
 
-pub fn write_value<W>(writer: &mut W, value: Option<Value>) -> io::Result<()>
+pub fn write_value<W>(writer: &mut W, value: Option<Value<'_>>) -> io::Result<()>
 where
     W: Write,
 {
@@ -153,7 +153,7 @@ where
     Ok(())
 }
 
-fn write_string<W>(writer: &mut W, value: Option<String>) -> io::Result<()>
+fn write_string<W>(writer: &mut W, value: Option<&str>) -> io::Result<()>
 where
     W: Write,
 {
@@ -238,11 +238,11 @@ mod tests {
         assert_eq!(buf, [0x07]);
 
         buf.clear();
-        write_value(&mut buf, Some(Value::String(Some(String::from("n")))))?;
+        write_value(&mut buf, Some(Value::String(Some("n"))))?;
         assert_eq!(buf, [0x17, 0x6e]);
 
         buf.clear();
-        write_value(&mut buf, Some(Value::String(Some(String::from("ndls")))))?;
+        write_value(&mut buf, Some(Value::String(Some("ndls"))))?;
         assert_eq!(buf, [0x47, 0x6e, 0x64, 0x6c, 0x73]);
 
         Ok(())