feat: add option to set header row

README.md

@@ -103,6 +103,26 @@ if let Some(Ok(r)) = excel.worksheet_range("Sheet1") {
 }
 ```
 
+### Reader: With header row
+
+```rs
+use calamine::{Reader, Xlsx, open_workbook};
+
+let mut excel: Xlsx<_> = open_workbook("file.xlsx").unwrap();
+
+let sheet1 = excel
+    .with_header_row(Some(3))
+    .worksheet_range("Sheet1")
+    .unwrap();
+```
+
+Note that `xlsx` and `xlsb` files support lazy loading, so specifying a
+header row takes effect immediately when reading a sheet range.
+In contrast, for `xls` and `ods` files, all sheets are loaded at once when
+opening the workbook with default settings.
+As a result, setting the header row only applies afterward and does not
+provide any performance benefits.
+
 ### Reader: More complex
 
 Let's assume
@@ -190,7 +210,7 @@ The programs are all structured to follow the same constructs:
 use calamine::{open_workbook, Reader, Xlsx};
 
 fn main() {
-    // Open workbook 
+    // Open workbook
     let mut excel: Xlsx<_> =
         open_workbook("NYC_311_SR_2010-2020-sample-1M.xlsx").expect("failed to find file");
 

src/auto.rs

@@ -3,8 +3,8 @@
 use crate::errors::Error;
 use crate::vba::VbaProject;
 use crate::{
-    open_workbook, open_workbook_from_rs, Data, DataRef, Metadata, Ods, Range, Reader, ReaderRef,
-    Xls, Xlsb, Xlsx,
+    open_workbook, open_workbook_from_rs, Data, DataRef, HeaderRow, Metadata, Ods, Range, Reader,
+    ReaderRef, Xls, Xlsb, Xlsx,
 };
 use std::borrow::Cow;
 use std::fs::File;
@@ -85,9 +85,27 @@ where
         Err(Error::Msg("Sheets must be created from a Path"))
     }
 
+    fn with_header_row(&mut self, header_row: HeaderRow) -> &mut Self {
+        match self {
+            Sheets::Xls(ref mut e) => {
+                e.with_header_row(header_row);
+            }
+            Sheets::Xlsx(ref mut e) => {
+                e.with_header_row(header_row);
+            }
+            Sheets::Xlsb(ref mut e) => {
+                e.with_header_row(header_row);
+            }
+            Sheets::Ods(ref mut e) => {
+                e.with_header_row(header_row);
+            }
+        }
+        self
+    }
+
     /// Gets `VbaProject`
     fn vba_project(&mut self) -> Option<Result<Cow<'_, VbaProject>, Self::Error>> {
-        match *self {
+        match self {
             Sheets::Xls(ref mut e) => e.vba_project().map(|vba| vba.map_err(Error::Xls)),
             Sheets::Xlsx(ref mut e) => e.vba_project().map(|vba| vba.map_err(Error::Xlsx)),
             Sheets::Xlsb(ref mut e) => e.vba_project().map(|vba| vba.map_err(Error::Xlsb)),
@@ -97,7 +115,7 @@ where
 
     /// Initialize
     fn metadata(&self) -> &Metadata {
-        match *self {
+        match self {
             Sheets::Xls(ref e) => e.metadata(),
             Sheets::Xlsx(ref e) => e.metadata(),
             Sheets::Xlsb(ref e) => e.metadata(),
@@ -107,7 +125,7 @@ where
 
     /// Read worksheet data in corresponding worksheet path
     fn worksheet_range(&mut self, name: &str) -> Result<Range<Data>, Self::Error> {
-        match *self {
+        match self {
             Sheets::Xls(ref mut e) => e.worksheet_range(name).map_err(Error::Xls),
             Sheets::Xlsx(ref mut e) => e.worksheet_range(name).map_err(Error::Xlsx),
             Sheets::Xlsb(ref mut e) => e.worksheet_range(name).map_err(Error::Xlsb),
@@ -117,7 +135,7 @@ where
 
     /// Read worksheet formula in corresponding worksheet path
     fn worksheet_formula(&mut self, name: &str) -> Result<Range<String>, Self::Error> {
-        match *self {
+        match self {
             Sheets::Xls(ref mut e) => e.worksheet_formula(name).map_err(Error::Xls),
             Sheets::Xlsx(ref mut e) => e.worksheet_formula(name).map_err(Error::Xlsx),
             Sheets::Xlsb(ref mut e) => e.worksheet_formula(name).map_err(Error::Xlsb),
@@ -126,7 +144,7 @@ where
     }
 
     fn worksheets(&mut self) -> Vec<(String, Range<Data>)> {
-        match *self {
+        match self {
             Sheets::Xls(ref mut e) => e.worksheets(),
             Sheets::Xlsx(ref mut e) => e.worksheets(),
             Sheets::Xlsb(ref mut e) => e.worksheets(),
@@ -136,7 +154,7 @@ where
 
     #[cfg(feature = "picture")]
     fn pictures(&self) -> Option<Vec<(String, Vec<u8>)>> {
-        match *self {
+        match self {
             Sheets::Xls(ref e) => e.pictures(),
             Sheets::Xlsx(ref e) => e.pictures(),
             Sheets::Xlsb(ref e) => e.pictures(),
@@ -153,7 +171,7 @@ where
         &'a mut self,
         name: &str,
     ) -> Result<Range<DataRef<'a>>, Self::Error> {
-        match *self {
+        match self {
             Sheets::Xlsx(ref mut e) => e.worksheet_range_ref(name).map_err(Error::Xlsx),
             Sheets::Xlsb(ref mut e) => e.worksheet_range_ref(name).map_err(Error::Xlsb),
             Sheets::Xls(_) => unimplemented!(),

src/lib.rs

@@ -215,6 +215,23 @@ pub struct Sheet {
     pub visible: SheetVisible,
 }
 
+/// Row to use as header
+/// By default, the first non-empty row is used as header
+#[derive(Debug, Clone, Copy)]
+#[non_exhaustive]
+pub enum HeaderRow {
+    /// First non-empty row
+    FirstNonEmptyRow,
+    /// Index of the header row
+    Row(u32),
+}
+
+impl Default for HeaderRow {
+    fn default() -> Self {
+        HeaderRow::FirstNonEmptyRow
+    }
+}
+
 // FIXME `Reader` must only be seek `Seek` for `Xls::xls`. Because of the present API this limits
 // the kinds of readers (other) data in formats can be read from.
 /// A trait to share spreadsheets reader functions across different `FileType`s
@@ -228,6 +245,10 @@ where
     /// Creates a new instance.
     fn new(reader: RS) -> Result<Self, Self::Error>;
 
+    /// Set header row (i.e. first row to be read)
+    /// If `header_row` is `None`, the first non-empty row will be used as header row
+    fn with_header_row(&mut self, header_row: HeaderRow) -> &mut Self;
+
     /// Gets `VbaProject`
     fn vba_project(&mut self) -> Option<Result<Cow<'_, VbaProject>, Self::Error>>;
 

src/ods.rs

@@ -16,7 +16,7 @@ use zip::read::{ZipArchive, ZipFile};
 use zip::result::ZipError;
 
 use crate::vba::VbaProject;
-use crate::{Data, DataType, Metadata, Range, Reader, Sheet, SheetType, SheetVisible};
+use crate::{Data, DataType, HeaderRow, Metadata, Range, Reader, Sheet, SheetType, SheetVisible};
 use std::marker::PhantomData;
 
 const MIMETYPE: &[u8] = b"application/vnd.oasis.opendocument.spreadsheet";
@@ -62,6 +62,13 @@ pub enum OdsError {
     WorksheetNotFound(String),
 }
 
+/// Ods reader options
+#[derive(Debug, Default)]
+#[non_exhaustive]
+struct OdsOptions {
+    pub header_row: HeaderRow,
+}
+
 from_err!(std::io::Error, OdsError, Io);
 from_err!(zip::result::ZipError, OdsError, Zip);
 from_err!(quick_xml::Error, OdsError, Xml);
@@ -116,6 +123,8 @@ pub struct Ods<RS> {
     marker: PhantomData<RS>,
     #[cfg(feature = "picture")]
     pictures: Option<Vec<(String, Vec<u8>)>>,
+    /// Reader options
+    options: OdsOptions,
 }
 
 impl<RS> Reader<RS> for Ods<RS>
@@ -161,9 +170,15 @@ where
             sheets,
             #[cfg(feature = "picture")]
             pictures,
+            options: OdsOptions::default(),
         })
     }
 
+    fn with_header_row(&mut self, header_row: HeaderRow) -> &mut Self {
+        self.options.header_row = header_row;
+        self
+    }
+
     /// Gets `VbaProject`
     fn vba_project(&mut self) -> Option<Result<Cow<'_, VbaProject>, OdsError>> {
         None
@@ -176,10 +191,24 @@ where
 
     /// Read worksheet data in corresponding worksheet path
     fn worksheet_range(&mut self, name: &str) -> Result<Range<Data>, OdsError> {
-        self.sheets
+        let sheet = self
+            .sheets
             .get(name)
-            .ok_or_else(|| OdsError::WorksheetNotFound(name.into()))
-            .map(|r| r.0.to_owned())
+            .ok_or_else(|| OdsError::WorksheetNotFound(name.into()))?
+            .0
+            .to_owned();
+
+        match self.options.header_row {
+            HeaderRow::FirstNonEmptyRow => Ok(sheet),
+            HeaderRow::Row(header_row_idx) => {
+                // If `header_row` is a row index, adjust the range
+                if let (Some(start), Some(end)) = (sheet.start(), sheet.end()) {
+                    Ok(sheet.range((header_row_idx, start.1), end))
+                } else {
+                    Ok(sheet)
+                }
+            }
+        }
     }
 
     fn worksheets(&mut self) -> Vec<(String, Range<Data>)> {

src/xls.rs

@@ -17,7 +17,8 @@ use crate::utils::read_usize;
 use crate::utils::{push_column, read_f64, read_i16, read_i32, read_u16, read_u32};
 use crate::vba::VbaProject;
 use crate::{
-    Cell, CellErrorType, Data, Dimensions, Metadata, Range, Reader, Sheet, SheetType, SheetVisible,
+    Cell, CellErrorType, Data, Dimensions, HeaderRow, Metadata, Range, Reader, Sheet, SheetType,
+    SheetVisible,
 };
 
 #[derive(Debug)]
@@ -136,6 +137,8 @@ pub struct XlsOptions {
     ///
     /// [code page]: https://docs.microsoft.com/en-us/windows/win32/intl/code-page-identifiers
     pub force_codepage: Option<u16>,
+    /// Row to use as header
+    pub header_row: HeaderRow,
 }
 
 struct SheetData {
@@ -231,6 +234,11 @@ impl<RS: Read + Seek> Reader<RS> for Xls<RS> {
         Self::new_with_options(reader, XlsOptions::default())
     }
 
+    fn with_header_row(&mut self, header_row: HeaderRow) -> &mut Self {
+        self.options.header_row = header_row;
+        self
+    }
+
     fn vba_project(&mut self) -> Option<Result<Cow<'_, VbaProject>, XlsError>> {
         self.vba.as_ref().map(|vba| Ok(Cow::Borrowed(vba)))
     }
@@ -241,10 +249,23 @@ impl<RS: Read + Seek> Reader<RS> for Xls<RS> {
     }
 
     fn worksheet_range(&mut self, name: &str) -> Result<Range<Data>, XlsError> {
-        self.sheets
+        let sheet = self
+            .sheets
             .get(name)
             .map(|r| r.range.clone())
-            .ok_or_else(|| XlsError::WorksheetNotFound(name.into()))
+            .ok_or_else(|| XlsError::WorksheetNotFound(name.into()))?;
+
+        match self.options.header_row {
+            HeaderRow::FirstNonEmptyRow => Ok(sheet),
+            HeaderRow::Row(header_row_idx) => {
+                // If `header_row` is a row index, adjust the range
+                if let (Some(start), Some(end)) = (sheet.start(), sheet.end()) {
+                    Ok(sheet.range((header_row_idx, start.1), end))
+                } else {
+                    Ok(sheet)
+                }
+            }
+        }
     }
 
     fn worksheets(&mut self) -> Vec<(String, Range<Data>)> {