diff --git a/implementations/rust/preserves-tools/src/bin/preserves-tool.rs b/implementations/rust/preserves-tools/src/bin/preserves-tool.rs
index 4046d4c..1c17d84 100644
--- a/implementations/rust/preserves-tools/src/bin/preserves-tool.rs
+++ b/implementations/rust/preserves-tools/src/bin/preserves-tool.rs
@@ -215,6 +215,7 @@ impl<R: io::Read> io::Read for RollingBuffer<R> {
 
 fn convert(c: Convert) -> io::Result<()> {
     let mut r = RollingBuffer::new(io::stdin());
+    let mut source = IOBinarySource::new(&mut r);
     let mut count = 0;
     let mut w: Box<dyn FnMut(&IOValue) -> io::Result<()>> = match c.output_format {
         OutputFormat::Text => {
@@ -235,7 +236,7 @@ fn convert(c: Convert) -> io::Result<()> {
     };
     loop {
         let is_text = {
-            let peek_buf = r.peek_buf()?;
+            let peek_buf = source.read.peek_buf()?;
             if peek_buf.is_empty() {
                 return Ok(());
             }
@@ -248,7 +249,7 @@ fn convert(c: Convert) -> io::Result<()> {
                 InputFormat::Binary => return Err(io::Error::new(
                     io::ErrorKind::InvalidData, "Expected binary input, saw text input")),
             }
-            TextReader::new(&mut IOBinarySource::new(&mut r), ViaCodec::new(IOValueDomainCodec))
+            TextReader::new(&mut source, ViaCodec::new(IOValueDomainCodec))
                 .next(c.annotations.into())?
         } else {
             match c.input_format {
@@ -256,7 +257,7 @@ fn convert(c: Convert) -> io::Result<()> {
                 InputFormat::Text => return Err(io::Error::new(
                     io::ErrorKind::InvalidData, "Expected text input, saw binary input")),
             }
-            PackedReader::new(&mut IOBinarySource::new(&mut r), IOValueDomainCodec)
+            PackedReader::new(&mut source, IOValueDomainCodec)
                 .next(c.annotations.into())?
         };
 
@@ -264,7 +265,7 @@ fn convert(c: Convert) -> io::Result<()> {
             None => return Ok(()),
             Some(value) => {
                 w(&value)?;
-                r.discard_to_pos();
+                source.read.discard_to_pos();
                 count += 1;
                 if let Some(limit) = c.limit {
                     if count >= limit {