feat: helper function

src/xlsx/mod.rs

@@ -1117,6 +1117,130 @@ fn check_for_password_protected<RS: Read + Seek>(reader: &mut RS) -> Result<(),
  Ok(())
 }
 
+/// check if a char vector is a valid cell name 
+/// column name must be between A and XFD,
+/// last char must be digit
+fn valid_cell_name(name: &[char]) -> bool {
+ if name.is_empty() {
+ return false;
+ }
+ if name.len() < 2 {
+ return false;
+ }
+ if name.len() > 3 {
+ if name[3].is_ascii_alphabetic() {
+ return false;
+ }
+ if name[2].is_alphabetic() {
+ if "YZ".contains(name[0]) {
+ return false;
+ } else if name[0] == 'X' {
+ if name[1] == 'F' {
+ if !"ABCD".contains(name[2]) {
+ return false;
+ };
+ } else if !"ABCDE".contains(name[1]) {
+ return false;
+ }
+ }
+ }
+ }
+ match name.last() {
+ Some(c) => c.is_ascii_digit(),
+ _ => false,
+ }
+}
+
+/// advance the cell name by the offset
+fn replace_cell(name: &[char], offset: (i64, i64)) -> Result<Vec<u8>, XlsxError> {
+ let cell = get_row_column(
+ name.into_iter()
+ .map(|c| *c as u8)
+ .collect::<Vec<_>>()
+ .as_slice(),
+ )?;
+ coordinate_to_name((
+ (cell.0 as i64 + offset.0) as u32,
+ (cell.1 as i64 + offset.1) as u32,
+ ))
+}
+
+/// advance all valid cell names in the string by the offset
+fn replace_cell_names(s: &str, offset: (i64, i64)) -> Result<String, XlsxError> {
+ let mut res: Vec<u8> = Vec::new();
+ let mut cell: Vec<char> = Vec::new();
+ let mut is_cell_row = false;
+ let mut in_quote = false;
+ for c in s.chars() {
+ if c == '"' {
+ in_quote = !in_quote;
+ }
+ if in_quote {
+ res.push(c as u8);
+ continue;
+ }
+ if c.is_ascii_alphabetic() {
+ if is_cell_row {
+ // two cell not possible stick togather in formula
+ res.extend(cell.iter().map(|c| *c as u8));
+ cell.clear();
+ is_cell_row = false;
+ }
+ cell.push(c);
+ } else if c.is_ascii_digit() {
+ is_cell_row = true;
+ cell.push(c);
+ } else {
+ if valid_cell_name(cell.as_ref()) {
+ res.extend(replace_cell(cell.as_ref(), offset)?);
+ } else {
+ res.extend(cell.iter().map(|c| *c as u8));
+ }
+ cell.clear();
+ is_cell_row = false;
+ res.push(c as u8);
+ }
+ }
+ if !cell.is_empty() {
+ if valid_cell_name(cell.as_ref()) {
+ res.extend(replace_cell(cell.as_ref(), offset)?);
+ } else {
+ res.extend(cell.iter().map(|c| *c as u8));
+ }
+ }
+ match String::from_utf8(res) {
+ Ok(s) => Ok(s),
+ Err(_) => Err(XlsxError::Unexpected("fail to convert cell name")),
+ }
+}
+
+/// Convert the integer to Excelsheet column title. 
+/// If the column number not in 1~16384, an Error is returned.
+pub(crate) fn column_number_to_name(num: u32) -> Result<Vec<u8>, XlsxError> {
+ if num >= MAX_COLUMNS {
+ return Err(XlsxError::Unexpected("column number overflow"));
+ }
+ let mut col: Vec<u8> = Vec::new();
+ let mut num = num + 1;
+ while num > 0 {
+ let integer = ((num - 1) % 26 + 65) as u8;
+ col.push(integer);
+ num = (num - 1) / 26;
+ }
+ col.reverse();
+ Ok(col)
+}
+
+/// Convert a cell coordinate to Excelsheet cell name. 
+/// If the column number not in 1~16384, an Error is returned.
+pub(crate) fn coordinate_to_name(cell: (u32, u32)) -> Result<Vec<u8>, XlsxError> {
+ let cell = &[
+ column_number_to_name(cell.1)?,
+ (cell.0 + 1).to_string().into_bytes(),
+ ];
+ Ok(cell.concat())
+}
+
 #[cfg(test)]
 mod tests {
  use super::*;
@@ -1178,4 +1302,39 @@ mod tests {
  CellErrorType::Value
  );
  }
+
+ #[test]
+ fn test_column_number_to_name() {
+ assert_eq!(column_number_to_name(0).unwrap(), b"A");
+ assert_eq!(column_number_to_name(25).unwrap(), b"Z");
+ assert_eq!(column_number_to_name(26).unwrap(), b"AA");
+ assert_eq!(column_number_to_name(27).unwrap(), b"AB");
+ assert_eq!(column_number_to_name(MAX_COLUMNS - 1).unwrap(), b"XFD");
+ }
+
+ #[test]
+ fn test_coordinate_to_name() {
+ assert_eq!(coordinate_to_name((0, 0)).unwrap(), b"A1");
+ assert_eq!(
+ coordinate_to_name((MAX_ROWS - 1, MAX_COLUMNS - 1)).unwrap(),
+ b"XFD1048576"
+ );
+ }
+
+ #[test]
+ fn test_replace_cell_names() {
+ assert_eq!(replace_cell_names("A1", (1, 0)).unwrap(), "A2".to_owned());
+ assert_eq!(
+ replace_cell_names("CONCATENATE(A1, \"a\")", (1, 0)).unwrap(),
+ "CONCATENATE(A2, \"a\")".to_owned()
+ );
+ assert_eq!(
+ replace_cell_names(
+ "A1 is a cell, B1 is another, also C107, but XFE123 is not and \"A3\" in quote wont change.",
+ (1, 0)
+ )
+ .unwrap(),
+ "A2 is a cell, B2 is another, also C108, but XFE123 is not and \"A3\" in quote wont change.".to_owned()
+ );
+ }
 }