expose version string in the header

Author: s3bk

pdf/examples/metadata.rs

@@ -12,13 +12,17 @@ fn main() -> Result<(), PdfError> {
         .expect("Please provide a file path to the PDF you want to explore.");
 
     let file = FileOptions::cached().open(&path).unwrap();
+    dbg!(file.version());
     let resolver = file.resolver();
 
     if let Some(ref info) = file.trailer.info_dict {
         dbg!(info);
     }
 
-    if let Some(ref forms) = file.get_root().forms {
+    let catalog = file.get_root();
+    dbg!(&catalog.version);
+
+    if let Some(ref forms) = catalog.forms {
         for field in forms.fields.iter() {
             print_field(field, &resolver);
         }
@@ -35,4 +39,4 @@ fn print_field(field: &FieldDictionary, resolve: &impl Resolve) {
         let child = resolve.get(kid).unwrap();
         print_field(&child, resolve);
     }
-}
+}

pdf/src/file.rs

@@ -118,12 +118,17 @@ where
     pub fn into_inner(self) -> B {
         self.backend
     }
+    pub fn version(&self) -> Result<String> {
+        Ok(String::from_utf8(self.backend.read(self.start_offset+1..self.start_offset+8)?.to_owned())?)
+    }
     pub fn resolver(&self) -> impl Resolve + '_ {
         StorageResolver::new(self)
     }
     pub fn with_cache(backend: B, options: ParseOptions, object_cache: OC, stream_cache: SC, log: L) -> Result<Self> {
+        let start_offset = backend.locate_start_offset()?;
+
         Ok(Storage {
-            start_offset: backend.locate_start_offset()?,
+            start_offset,
             backend,
             refs: XRefTable::new(0),
             cache: object_cache,
@@ -656,6 +661,12 @@ where
     pub fn log(&self) -> &L {
         &self.storage.log
     }
+
+    /// the version string in the file header.
+    /// if the version field in the Catalog is set, this should be used instead.
+    pub fn version(&self) -> Result<String> {
+        self.storage.version()
+    }
 }
 
 #[derive(Object, ObjectWrite, DataSize)]