56 lines
1.6 KiB
Rust
56 lines
1.6 KiB
Rust
// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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#![allow(dead_code)]
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use fmt::{Formatter, Result, Write};
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use core::str::lossy::{Utf8Lossy, Utf8LossyChunk};
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pub fn debug_fmt_bytestring(slice: &[u8], f: &mut Formatter) -> Result {
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// Writes out a valid unicode string with the correct escape sequences
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fn write_str_escaped(f: &mut Formatter, s: &str) -> Result {
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for c in s.chars().flat_map(|c| c.escape_debug()) {
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f.write_char(c)?
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}
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Ok(())
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}
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f.write_str("\"")?;
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for Utf8LossyChunk { valid, broken } in Utf8Lossy::from_bytes(slice).chunks() {
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write_str_escaped(f, valid)?;
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for b in broken {
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write!(f, "\\x{:02X}", b)?;
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}
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}
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f.write_str("\"")
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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use fmt::{Formatter, Result, Debug};
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#[test]
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fn smoke() {
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struct Helper<'a>(&'a [u8]);
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impl<'a> Debug for Helper<'a> {
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fn fmt(&self, f: &mut Formatter) -> Result {
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debug_fmt_bytestring(self.0, f)
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}
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}
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let input = b"\xF0hello,\tworld";
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let expected = r#""\xF0hello,\tworld""#;
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let output = format!("{:?}", Helper(input));
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assert!(output == expected);
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}
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}
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