Fix incorrect col calculate for pair.line_col method.

Author: huacnlee

pest/src/iterators/pairs.rs

@@ -249,14 +249,7 @@ impl<'i, R: RuleType> Pairs<'i, R> {
         let (prev_line, prev_col) = (self.cursor.line, self.cursor.col);
 
         let part = &input[self.cursor.end..end];
-        let (l, c) = position::line_col(part, part.len());
-
-        // Because the `original_line_col` returns (line, col) is start from 1
-        let l = l - 1;
-        let mut c = c - 1;
-        if c < 1 {
-            c = 1
-        }
+        let (l, c) = position::line_col(part, part.len(), (0, 0));
 
         self.cursor.line += l;
         // Has new line

pest/src/position.rs

@@ -139,7 +139,7 @@ impl<'i> Position<'i> {
             panic!("position out of bounds");
         }
 
-        line_col(self.input, self.pos)
+        line_col(self.input, self.pos, (1, 1))
     }
 
     /// Returns the entire line of the input that contains this `Position`.
@@ -452,25 +452,30 @@ impl<'i> Hash for Position<'i> {
     }
 }
 
-pub(crate) fn line_col(input: &str, pos: usize) -> (usize, usize) {
+/// Returns the line and column of the given `pos` in `input`.
+pub(crate) fn line_col(input: &str, pos: usize, start: (usize, usize)) -> (usize, usize) {
     #[cfg(feature = "fast-line-col")]
     {
-        fast_line_col(input, pos)
+        fast_line_col(input, pos, start)
     }
     #[cfg(not(feature = "fast-line-col"))]
     {
-        original_line_col(input, pos)
+        original_line_col(input, pos, start)
     }
 }
 
 #[inline]
 #[cfg(not(feature = "fast-line-col"))]
-fn original_line_col(input: &str, mut pos: usize) -> (usize, usize) {
+pub(crate) fn original_line_col(
+    input: &str,
+    mut pos: usize,
+    start: (usize, usize),
+) -> (usize, usize) {
     // Position's pos is always a UTF-8 border.
     let slice = &input[..pos];
     let mut chars = slice.chars().peekable();
 
-    let mut line_col = (1, 1);
+    let mut line_col = start;
 
     while pos != 0 {
         match chars.next() {
@@ -507,16 +512,16 @@ fn original_line_col(input: &str, mut pos: usize) -> (usize, usize) {
 
 #[inline]
 #[cfg(feature = "fast-line-col")]
-fn fast_line_col(input: &str, pos: usize) -> (usize, usize) {
+fn fast_line_col(input: &str, pos: usize, start: (usize, usize)) -> (usize, usize) {
     // Position's pos is always a UTF-8 border.
     let slice = &input[..pos];
 
     let prec_ln = memchr::memrchr(b'\n', slice.as_bytes());
     if let Some(prec_nl_pos) = prec_ln {
-        let lines = bytecount::count(slice[..=prec_nl_pos].as_bytes(), b'\n') + 1;
+        let lines = bytecount::count(slice[..=prec_nl_pos].as_bytes(), b'\n') + start.0;
         (lines, slice[prec_nl_pos..].chars().count())
     } else {
-        (1, slice.chars().count() + 1)
+        (start.0, slice.chars().count() + start.1)
     }
 }