Improve read.

1 files changed, 7 insertions, 9 deletions

diff --git a/bytecode/src/main.rs b/bytecode/src/main.rs
index 6ccd4b8..ccb7c9a 100644
--- a/bytecode/src/main.rs
+++ b/bytecode/src/main.rs
@@ -6,7 +6,7 @@ use encoding::{Arg, Op};
 use heap::Heap;
 use std::error::Error;
 use std::ffi::OsString;
-use std::io::{stdin, BufWriter, Read, Write};
+use std::io::{stdin, BufRead, BufWriter, Write};
 use value::Value;
 
 trait ReadArg {
@@ -183,16 +183,14 @@ impl State {
                 let Ok(len) = usize::try_from(ilen) else {
                     return Err(Box::from("read: len is negative"));
                 };
-                let mut n = 0;
-                for byte in stdin().lock().bytes().take(len) {
-                    let byte = byte?;
+                let mut stdin = stdin().lock();
+                let buf = stdin.fill_buf()?;
+                let n = std::cmp::min(len, buf.len());
+                for (i, &byte) in buf[..n].iter().enumerate() {
                     self.heap
-                        .poke(ptr, off + n, Value::from_int(i64::from(byte)))?;
-                    n += 1;
-                    if byte == b'\n' {
-                        break;
-                    }
+                        .poke(ptr, off + i, Value::from_int(i64::from(byte)))?;
                 }
+                stdin.consume(n);
                 self.heap.locals[usize::from(op.out)] = Value::from_int(
                     i64::try_from(n)
                         .expect("we can never read more than len bytes, and len fit in an i64"),