serde_json/
iter.rs

1use crate::io;
2
3pub struct LineColIterator<I> {
4    iter: I,
5
6    /// Index of the current line. Characters in the first line of the input
7    /// (before the first newline character) are in line 1.
8    line: usize,
9
10    /// Index of the current column. The first character in the input and any
11    /// characters immediately following a newline character are in column 1.
12    /// The column is 0 immediately after a newline character has been read.
13    col: usize,
14
15    /// Byte offset of the start of the current line. This is the sum of lengths
16    /// of all previous lines. Keeping track of things this way allows efficient
17    /// computation of the current line, column, and byte offset while only
18    /// updating one of the counters in `next()` in the common case.
19    start_of_line: usize,
20}
21
22impl<I> LineColIterator<I>
23where
24    I: Iterator<Item = io::Result<u8>>,
25{
26    pub fn new(iter: I) -> LineColIterator<I> {
27        LineColIterator {
28            iter,
29            line: 1,
30            col: 0,
31            start_of_line: 0,
32        }
33    }
34
35    pub fn line(&self) -> usize {
36        self.line
37    }
38
39    pub fn col(&self) -> usize {
40        self.col
41    }
42
43    pub fn byte_offset(&self) -> usize {
44        self.start_of_line + self.col
45    }
46}
47
48impl<I> Iterator for LineColIterator<I>
49where
50    I: Iterator<Item = io::Result<u8>>,
51{
52    type Item = io::Result<u8>;
53
54    fn next(&mut self) -> Option<io::Result<u8>> {
55        match self.iter.next() {
56            None => None,
57            Some(Ok(b'\n')) => {
58                self.start_of_line += self.col + 1;
59                self.line += 1;
60                self.col = 0;
61                Some(Ok(b'\n'))
62            }
63            Some(Ok(c)) => {
64                self.col += 1;
65                Some(Ok(c))
66            }
67            Some(Err(e)) => Some(Err(e)),
68        }
69    }
70}
serde_json/iter.rs

serde_json/
iter.rs
