wip: allow arbitrary Read + Seek as file source

ekiwi · Oct 9, 2024 · e6b7230 · e6b7230
1 parent 245b1c8
commit e6b7230
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Showing 2 changed files with 34 additions and 26 deletions.
diff --git a/wellen/src/fst.rs b/wellen/src/fst.rs
@@ -15,12 +15,11 @@ use std::io::{BufRead, Seek};
 
 pub type Result<T> = std::result::Result<T, WellenError>;
 
-pub fn read_header(
-    filename: &str,
+pub fn read_header<R: BufRead + Seek>(
+    input: R,
     _options: &LoadOptions,
 ) -> Result<(Hierarchy, ReadBodyContinuation)> {
-    let input = std::fs::File::open(filename)?;
-    let mut reader = FstReader::open_and_read_time_table(std::io::BufReader::new(input))?;
+    let mut reader = FstReader::open_and_read_time_table(input)?;
     let hierarchy = read_hierarchy(&mut reader)?;
     let cont = ReadBodyContinuation {
         reader: Reader::File(reader),

diff --git a/wellen/src/viewers.rs b/wellen/src/viewers.rs
@@ -58,7 +58,8 @@ pub fn read_header(filename: &str, options: &LoadOptions) -> Result<HeaderResult
             })
         }
         FileFormat::Fst => {
-            let (hierarchy, body) = crate::fst::read_header(filename, options)?;
+            let input = std::io::BufReader::new(std::fs::File::open(filename)?);
+            let (hierarchy, body) = crate::fst::read_header(input, options)?;
             let body = ReadBodyContinuation::new(ReadBodyData::Fst(body));
             Ok(HeaderResult {
                 hierarchy,
@@ -71,34 +72,42 @@ pub fn read_header(filename: &str, options: &LoadOptions) -> Result<HeaderResult
 }
 
 pub fn read_header_from_bytes(bytes: Vec<u8>, options: &LoadOptions) -> Result<HeaderResult> {
-    let file_format = {
-        let mut cursor = &mut std::io::Cursor::new(&bytes);
-        detect_file_format(&mut cursor)
-    };
+    read_header_from_reader(std::io::Cursor::new(bytes), options)
+}
+
+pub fn read_header_from_reader<R>(mut input: R, options: &LoadOptions) -> Result<HeaderResult>
+where
+    R: std::io::BufRead + std::io::Seek,
+{
+    // remember where we are supposed to start reading
+    let start = input.stream_position()?;
+    let file_format = { detect_file_format(&mut input) };
     match file_format {
         FileFormat::Unknown => Err(WellenError::UnknownFileFormat),
         FileFormat::Vcd => {
-            let (hierarchy, body, body_len) = crate::vcd::read_header_from_bytes(bytes, options)?;
-            let body = ReadBodyContinuation::new(ReadBodyData::Vcd(body));
-            Ok(HeaderResult {
-                hierarchy,
-                file_format,
-                body_len,
-                body,
-            })
+            todo!()
+            // let (hierarchy, body, body_len) = crate::vcd::read_header_from_bytes(bytes, options)?;
+            // let body = ReadBodyContinuation::new(ReadBodyData::Vcd(body));
+            // Ok(HeaderResult {
+            //     hierarchy,
+            //     file_format,
+            //     body_len,
+            //     body,
+            // })
         }
         FileFormat::Ghw => {
-            let (hierarchy, body, body_len) = crate::ghw::read_header_from_bytes(bytes, options)?;
-            let body = ReadBodyContinuation::new(ReadBodyData::Ghw(body));
-            Ok(HeaderResult {
-                hierarchy,
-                file_format,
-                body_len,
-                body,
-            })
+            todo!()
+            // let (hierarchy, body, body_len) = crate::ghw::read_header_from_bytes(bytes, options)?;
+            // let body = ReadBodyContinuation::new(ReadBodyData::Ghw(body));
+            // Ok(HeaderResult {
+            //     hierarchy,
+            //     file_format,
+            //     body_len,
+            //     body,
+            // })
         }
         FileFormat::Fst => {
-            let (hierarchy, body) = crate::fst::read_header_from_bytes(bytes, options)?;
+            let (hierarchy, body) = crate::fst::read_header(input, options)?;
             let body = ReadBodyContinuation::new(ReadBodyData::Fst(body));
             Ok(HeaderResult {
                 hierarchy,