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Diffstat (limited to 'vendor/bumpalo/src/collections/str/lossy.rs')
| -rw-r--r-- | vendor/bumpalo/src/collections/str/lossy.rs | 209 |
1 files changed, 209 insertions, 0 deletions
diff --git a/vendor/bumpalo/src/collections/str/lossy.rs b/vendor/bumpalo/src/collections/str/lossy.rs new file mode 100644 index 000000000..b1012a412 --- /dev/null +++ b/vendor/bumpalo/src/collections/str/lossy.rs @@ -0,0 +1,209 @@ +// Copyright 2012-2017 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or +// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license +// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +use crate::collections::str as core_str; +use core::char; +use core::fmt; +use core::fmt::Write; +use core::str; + +/// Lossy UTF-8 string. +pub struct Utf8Lossy<'a> { + bytes: &'a [u8], +} + +impl<'a> Utf8Lossy<'a> { + pub fn from_bytes(bytes: &'a [u8]) -> Utf8Lossy<'a> { + Utf8Lossy { bytes } + } + + pub fn chunks(&self) -> Utf8LossyChunksIter<'a> { + Utf8LossyChunksIter { + source: &self.bytes, + } + } +} + +/// Iterator over lossy UTF-8 string +#[allow(missing_debug_implementations)] +pub struct Utf8LossyChunksIter<'a> { + source: &'a [u8], +} + +#[derive(PartialEq, Eq, Debug)] +pub struct Utf8LossyChunk<'a> { + /// Sequence of valid chars. + /// Can be empty between broken UTF-8 chars. + pub valid: &'a str, + /// Single broken char, empty if none. + /// Empty iff iterator item is last. + pub broken: &'a [u8], +} + +impl<'a> Iterator for Utf8LossyChunksIter<'a> { + type Item = Utf8LossyChunk<'a>; + + fn next(&mut self) -> Option<Utf8LossyChunk<'a>> { + if self.source.is_empty() { + return None; + } + + const TAG_CONT_U8: u8 = 128; + fn unsafe_get(xs: &[u8], i: usize) -> u8 { + unsafe { *xs.get_unchecked(i) } + } + fn safe_get(xs: &[u8], i: usize) -> u8 { + if i >= xs.len() { + 0 + } else { + unsafe_get(xs, i) + } + } + + let mut i = 0; + while i < self.source.len() { + let i_ = i; + + let byte = unsafe_get(self.source, i); + i += 1; + + if byte < 128 { + } else { + let w = core_str::utf8_char_width(byte); + + macro_rules! error { + () => {{ + unsafe { + let r = Utf8LossyChunk { + valid: str::from_utf8_unchecked(&self.source[0..i_]), + broken: &self.source[i_..i], + }; + self.source = &self.source[i..]; + return Some(r); + } + }}; + } + + match w { + 2 => { + if safe_get(self.source, i) & 192 != TAG_CONT_U8 { + error!(); + } + i += 1; + } + 3 => { + match (byte, safe_get(self.source, i)) { + (0xE0, 0xA0..=0xBF) => (), + (0xE1..=0xEC, 0x80..=0xBF) => (), + (0xED, 0x80..=0x9F) => (), + (0xEE..=0xEF, 0x80..=0xBF) => (), + _ => { + error!(); + } + } + i += 1; + if safe_get(self.source, i) & 192 != TAG_CONT_U8 { + error!(); + } + i += 1; + } + 4 => { + match (byte, safe_get(self.source, i)) { + (0xF0, 0x90..=0xBF) => (), + (0xF1..=0xF3, 0x80..=0xBF) => (), + (0xF4, 0x80..=0x8F) => (), + _ => { + error!(); + } + } + i += 1; + if safe_get(self.source, i) & 192 != TAG_CONT_U8 { + error!(); + } + i += 1; + if safe_get(self.source, i) & 192 != TAG_CONT_U8 { + error!(); + } + i += 1; + } + _ => { + error!(); + } + } + } + } + + let r = Utf8LossyChunk { + valid: unsafe { str::from_utf8_unchecked(self.source) }, + broken: &[], + }; + self.source = &[]; + Some(r) + } +} + +impl<'a> fmt::Display for Utf8Lossy<'a> { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + // If we're the empty string then our iterator won't actually yield + // anything, so perform the formatting manually + if self.bytes.is_empty() { + return "".fmt(f); + } + + for Utf8LossyChunk { valid, broken } in self.chunks() { + // If we successfully decoded the whole chunk as a valid string then + // we can return a direct formatting of the string which will also + // respect various formatting flags if possible. + if valid.len() == self.bytes.len() { + assert!(broken.is_empty()); + return valid.fmt(f); + } + + f.write_str(valid)?; + if !broken.is_empty() { + f.write_char(char::REPLACEMENT_CHARACTER)?; + } + } + Ok(()) + } +} + +impl<'a> fmt::Debug for Utf8Lossy<'a> { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + f.write_char('"')?; + + for Utf8LossyChunk { valid, broken } in self.chunks() { + // Valid part. + // Here we partially parse UTF-8 again which is suboptimal. + { + let mut from = 0; + for (i, c) in valid.char_indices() { + let esc = c.escape_debug(); + // If char needs escaping, flush backlog so far and write, else skip + if esc.len() != 1 { + f.write_str(&valid[from..i])?; + for c in esc { + f.write_char(c)?; + } + from = i + c.len_utf8(); + } + } + f.write_str(&valid[from..])?; + } + + // Broken parts of string as hex escape. + for &b in broken { + write!(f, "\\x{:02x}", b)?; + } + } + + f.write_char('"') + } +} |