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pub mod str { use std::io::{Result, Write}; #[derive(Debug)] pub struct StringWriter { buf: Vec<u8>, } impl Default for StringWriter { fn default() -> Self { Self::new() } } impl StringWriter { pub fn new() -> StringWriter { StringWriter { buf: Vec::with_capacity(8 * 1024), } } pub fn into_string(self) -> String { if let Ok(s) = String::from_utf8(self.buf) { s } else { String::new() } } } impl Write for StringWriter { fn write(&mut self, buf: &[u8]) -> Result<usize> { self.buf.extend_from_slice(buf); Ok(buf.len()) } fn flush(&mut self) -> Result<()> { Ok(()) } } #[cfg(test)] mod test { use std::io::Write; use support::str::StringWriter; #[test] fn test_string_writer() { let mut sw = StringWriter::new(); let _ = sw.write("hello".to_owned().into_bytes().as_ref()); let _ = sw.write("world".to_owned().into_bytes().as_ref()); let s = sw.into_string(); assert_eq!(s, "helloworld".to_string()); } } }