Add BigTiff support

Author: jayvdb

src/reader.rs

@@ -121,6 +121,7 @@ impl Reader {
             entries: parser.entries,
             entry_map,
             little_endian: parser.little_endian,
+            bigtiff: parser.bigtiff,
         };
         match parser.continue_on_error {
             Some(v) if !v.is_empty() =>
@@ -194,6 +195,8 @@ pub struct Exif {
     entry_map: HashMap<(In, Tag), usize>,
     // True if the TIFF data is little endian.
     little_endian: bool,
+    /// True if the TIFF data is in the BigTIFF format.
+    bigtiff: bool,
 }
 
 impl Exif {
@@ -207,7 +210,9 @@ impl Exif {
     #[inline]
     pub fn fields(&self) -> impl ExactSizeIterator<Item = &Field> {
         self.entries.iter()
-            .map(move |e| e.ref_field(&self.buf, self.little_endian))
+            .map(move |e| {
+                e.ref_field(&self.buf, self.little_endian)
+        })
     }
 
     /// Returns true if the Exif data (TIFF structure) is in the
@@ -217,6 +222,12 @@ impl Exif {
         self.little_endian
     }
 
+    /// Returns true if the Exif data (TIFF structure) is in BigTIFF format.
+    #[inline]
+    pub fn bigtiff(&self) -> bool {
+        self.bigtiff
+    }
+
     /// Returns a reference to the Exif field specified by the tag
     /// and the IFD number.
     #[inline]

src/tag.rs

@@ -1442,9 +1442,14 @@ fn d_default(w: &mut dyn fmt::Write, value: &Value) -> fmt::Result {
         Value::SRational(ref v) => d_sub_comma(w, v),
         Value::Float(ref v) => d_sub_comma(w, v),
         Value::Double(ref v) => d_sub_comma(w, v),
+        Value::Long8(ref v) => d_sub_comma(w, v),
+        Value::SLong8(ref v) => d_sub_comma(w, v),
         Value::Unknown(t, c, o) =>
             write!(w, "unknown value (type={}, count={}, offset={:#x})",
                    t, c, o),
+        Value::UnknownBigTiff(t, c, o) =>
+            write!(w, "unknown value (type={}, count={}, offset={:#x})",
+                   t, c, o),
     }
 }
 

src/tiff.rs

@@ -39,8 +39,11 @@ use crate::value::get_type_info;
 const TIFF_BE: u16 = 0x4d4d;
 const TIFF_LE: u16 = 0x4949;
 const TIFF_FORTY_TWO: u16 = 0x002a;
+const TIFF_FORTY_THREE: u16 = 0x002b;
 pub const TIFF_BE_SIG: [u8; 4] = [0x4d, 0x4d, 0x00, 0x2a];
 pub const TIFF_LE_SIG: [u8; 4] = [0x49, 0x49, 0x2a, 0x00];
+pub const BIGTIFF_BE_SIG: [u8; 4] = [0x4d, 0x4d, 0x00, 0x2b];
+pub const BIGTIFF_LE_SIG: [u8; 4] = [0x49, 0x49, 0x2b, 0x00];
 
 // Partially parsed TIFF field (IFD entry).
 // Value::Unknown is abused to represent a partially parsed value.
@@ -63,34 +66,48 @@ impl IfdEntry {
         }
     }
 
+    /// Obtain a reference to the field.
+    /// Only supports regular TIFF.
     pub fn ref_field<'a>(&'a self, data: &[u8], le: bool) -> &'a Field {
-        self.parse(data, le);
+        self.ref_field_any(data, le, false)
+    }
+
+    /// Obtain a reference to the field.
+    /// Supports regular TIFF and BigTiff.
+    pub fn ref_field_any<'a>(&'a self, data: &[u8], le: bool, bigtiff: bool) -> &'a Field {
+        self.parse(data, le, bigtiff);
         self.field.get_ref()
     }
 
-    fn into_field(self, data: &[u8], le: bool) -> Field {
-        self.parse(data, le);
+    fn into_field(self, data: &[u8], le: bool, bigtiff: bool) -> Field {
+        self.parse(data, le, bigtiff);
         self.field.into_inner()
     }
 
-    fn parse(&self, data: &[u8], le: bool) {
+    fn parse(&self, data: &[u8], le: bool, bigtiff: bool) {
         if !self.field.is_fixed() {
             let mut field = self.field.get_mut();
             if le {
-                Self::parse_value::<LittleEndian>(&mut field.value, data);
+                Self::parse_value::<LittleEndian>(&mut field.value, data, bigtiff);
             } else {
-                Self::parse_value::<BigEndian>(&mut field.value, data);
+                Self::parse_value::<BigEndian>(&mut field.value, data, bigtiff);
             }
         }
     }
 
     // Converts a partially parsed value into a real one.
-    fn parse_value<E>(value: &mut Value, data: &[u8]) where E: Endian {
+    fn parse_value<E>(value: &mut Value, data: &[u8], bigtiff: bool) where E: Endian {
         match *value {
             Value::Unknown(typ, cnt, ofs) => {
                 let (unitlen, parser) = get_type_info::<E>(typ);
                 if unitlen != 0 {
-                    *value = parser(data, ofs as usize, cnt as usize);
+                    *value = parser(data, ofs as usize, cnt as usize, bigtiff);
+                }
+            },
+            Value::UnknownBigTiff(typ, cnt, ofs) => {
+                let (unitlen, parser) = get_type_info::<E>(typ);
+                if unitlen != 0 {
+                    *value = parser(data, ofs as usize, cnt as usize, bigtiff);
                 }
             },
             _ => panic!("value is already parsed"),
@@ -153,14 +170,15 @@ impl fmt::Display for In {
 pub fn parse_exif(data: &[u8]) -> Result<(Vec<Field>, bool), Error> {
     let mut parser = Parser::new();
     parser.parse(data)?;
-    let (entries, le) = (parser.entries, parser.little_endian);
-    Ok((entries.into_iter().map(|e| e.into_field(data, le)).collect(), le))
+    let (entries, le, bigtiff) = (parser.entries, parser.little_endian, parser.bigtiff);
+    Ok((entries.into_iter().map(|e| e.into_field(data, le, bigtiff)).collect(), le))
 }
 
-#[derive(Debug)]
+#[derive(Debug, Default)]
 pub struct Parser {
     pub entries: Vec<IfdEntry>,
     pub little_endian: bool,
+    pub bigtiff: bool,
     // `Some<Vec>` to enable the option and `None` to disable it.
     pub continue_on_error: Option<Vec<Error>>,
 }
@@ -170,6 +188,7 @@ impl Parser {
         Self {
             entries: Vec::new(),
             little_endian: false,
+            bigtiff: false,
             continue_on_error: None,
         }
     }
@@ -194,11 +213,31 @@ impl Parser {
 
     fn parse_header<E>(&mut self, data: &[u8])
                        -> Result<(), Error> where E: Endian {
-        // Parse the rest of the header (42 and the IFD offset).
-        if E::loadu16(data, 2) != TIFF_FORTY_TWO {
-            return Err(Error::InvalidFormat("Invalid forty two"));
-        }
-        let ifd_offset = E::loadu32(data, 4) as usize;
+        // Parse the rest of the header:
+        // - 42 and the IFD offset for regular TIFF.
+        // - 43, a constant, and the u64 IFD offset for BigTIFF.
+        let tiff_type = E::loadu16(data, 2);
+        self.bigtiff = if tiff_type == TIFF_FORTY_TWO {
+            false
+        } else if tiff_type == TIFF_FORTY_THREE {
+            // http://bigtiff.org/ describes the BigTIFF header additions as constants 8 and 0.
+            let offset_bytesize = E::loadu16(data, 4);
+            if offset_bytesize != 8 {
+                return Err(Error::InvalidFormat("Invalid BigTIFF offset byte size"));
+            }
+            let extra_field = E::loadu16(data, 6);
+            if extra_field != 0 {
+                return Err(Error::InvalidFormat("Invalid BigTIFF header"));
+            }
+            true
+        } else {
+            return Err(Error::InvalidFormat("Invalid TIFF magic number 42 or 43"));
+        };
+        let ifd_offset = if self.bigtiff {
+            E::loadu64(data, 8) as usize
+        } else {
+            E::loadu32(data, 4) as usize
+        };
         self.parse_body::<E>(data, ifd_offset)
             .or_else(|e| self.check_error(e))
     }
@@ -226,19 +265,31 @@ impl Parser {
                     mut offset: usize, ctx: Context, ifd_num: u16)
                     -> Result<usize, Error> where E: Endian {
         // Count (the number of the entries).
-        if data.len() < offset || data.len() - offset < 2 {
+        if !self.bigtiff && (data.len() < offset || data.len() - offset < 2) {
             return Err(Error::InvalidFormat("Truncated IFD count"));
         }
-        let count = E::loadu16(data, offset) as usize;
-        offset += 2;
+        let count = if self.bigtiff {
+            E::loadu64(data, offset) as usize
+        } else {
+            E::loadu16(data, offset) as usize
+        };
+        if self.bigtiff {
+            offset += 8;
+        } else {
+            offset += 2;
+        }
 
         // Array of entries.
         for _ in 0..count {
-            if data.len() - offset < 12 {
+            if !self.bigtiff && data.len() - offset < 12 { // fixme
                 return Err(Error::InvalidFormat("Truncated IFD"));
             }
-            let entry = Self::parse_ifd_entry::<E>(data, offset);
-            offset += 12;
+            let entry = self.parse_ifd_entry::<E>(data, offset);
+            if self.bigtiff {
+                offset += 20;
+            } else {
+                offset += 12;
+            }
             let (tag, value) = match entry {
                 Ok(x) => x,
                 Err(e) => {
@@ -265,31 +316,53 @@ impl Parser {
         }
 
         // Offset to the next IFD.
-        if data.len() - offset < 4 {
+        if !self.bigtiff && data.len() - offset < 4 { // fixme
             return Err(Error::InvalidFormat("Truncated next IFD offset"));
         }
-        let next_ifd_offset = E::loadu32(data, offset);
-        Ok(next_ifd_offset as usize)
+        let next_ifd_offset = if self.bigtiff {
+            E::loadu64(data, offset) as usize
+        } else {
+            E::loadu32(data, offset) as usize
+        };
+        Ok(next_ifd_offset)
     }
 
-    fn parse_ifd_entry<E>(data: &[u8], offset: usize)
+    fn parse_ifd_entry<E>(&self, data: &[u8], offset: usize)
                           -> Result<(u16, Value), Error> where E: Endian {
         // The size of entry has been checked in parse_ifd().
         let tag = E::loadu16(data, offset);
         let typ = E::loadu16(data, offset + 2);
-        let cnt = E::loadu32(data, offset + 4);
-        let valofs_at = offset + 8;
+
+        let (cnt, valofs_at) = if self.bigtiff {
+            (E::loadu64(data, offset + 4) as usize, offset + 12)
+        } else {
+            (E::loadu32(data, offset + 4) as usize, offset + 8)
+        };
+
         let (unitlen, _parser) = get_type_info::<E>(typ);
-        let vallen = unitlen.checked_mul(cnt as usize).ok_or(
+        let vallen = unitlen.checked_mul(cnt).ok_or(
             Error::InvalidFormat("Invalid entry count"))?;
-        let val = if vallen <= 4 {
-            Value::Unknown(typ, cnt, valofs_at as u32)
+        let max_inline_len = if self.bigtiff { 8 } else { 4 };
+        let val = if vallen <= max_inline_len {
+            if self.bigtiff {
+                Value::UnknownBigTiff(typ, cnt as u64, valofs_at as u64)
+            } else {
+                Value::Unknown(typ, cnt as u32, valofs_at as u32)
+            }
         } else {
-            let ofs = E::loadu32(data, valofs_at) as usize;
-            if data.len() < ofs || data.len() - ofs < vallen {
+            let ofs = if self.bigtiff {
+                E::loadu64(data, valofs_at) as usize
+            } else {
+                E::loadu32(data, valofs_at) as usize
+            };
+            if !self.bigtiff && (data.len() < ofs || data.len() - ofs < vallen) { // fixme
                 return Err(Error::InvalidFormat("Truncated field value"));
             }
-            Value::Unknown(typ, cnt, ofs as u32)
+            if self.bigtiff {
+                Value::UnknownBigTiff(typ, cnt as u64, ofs as u64)
+            } else {
+                Value::Unknown(typ, cnt as u32, ofs as u32)
+            }
         };
         Ok((tag, val))
     }
@@ -298,7 +371,7 @@ impl Parser {
                           mut pointer: Value, ctx: Context, ifd_num: u16)
                           -> Result<(), Error> where E: Endian {
         // The pointer is not yet parsed, so do it here.
-        IfdEntry::parse_value::<E>(&mut pointer, data);
+        IfdEntry::parse_value::<E>(&mut pointer, data, self.bigtiff);
 
         // A pointer field has type == LONG and count == 1, so the
         // value (IFD offset) must be embedded in the "value offset"
@@ -323,7 +396,9 @@ impl Parser {
 }
 
 pub fn is_tiff(buf: &[u8]) -> bool {
-    buf.starts_with(&TIFF_BE_SIG) || buf.starts_with(&TIFF_LE_SIG)
+    buf.starts_with(&TIFF_BE_SIG) || buf.starts_with(&TIFF_LE_SIG) ||
+    buf.starts_with(&BIGTIFF_BE_SIG) || buf.starts_with(&BIGTIFF_LE_SIG)
+
 }
 
 /// A struct used to parse a DateTime field.
@@ -633,29 +708,30 @@ mod tests {
     fn parse_ifd_entry() {
         // BYTE (type == 1)
         let data = b"\x02\x03\x00\x01\0\0\0\x04ABCD";
-        assert_pat!(Parser::parse_ifd_entry::<BigEndian>(data, 0).unwrap(),
+        let parser = Parser::default();
+        assert_pat!(parser.parse_ifd_entry::<BigEndian>(data, 0).unwrap(),
                     (0x0203, Value::Unknown(1, 4, 8)));
         let data = b"\x02\x03\x00\x01\0\0\0\x05\0\0\0\x0cABCDE";
-        assert_pat!(Parser::parse_ifd_entry::<BigEndian>(data, 0).unwrap(),
+        assert_pat!(Parser::default().parse_ifd_entry::<BigEndian>(data, 0).unwrap(),
                     (0x0203, Value::Unknown(1, 5, 12)));
         let data = b"\x02\x03\x00\x01\0\0\0\x05\0\0\0\x0cABCD";
-        assert_err_pat!(Parser::parse_ifd_entry::<BigEndian>(data, 0),
+        assert_err_pat!(Parser::default().parse_ifd_entry::<BigEndian>(data, 0),
                         Error::InvalidFormat("Truncated field value"));
 
         // SHORT (type == 3)
         let data = b"X\x04\x05\x00\x03\0\0\0\x02ABCD";
-        assert_pat!(Parser::parse_ifd_entry::<BigEndian>(data, 1).unwrap(),
+        assert_pat!(Parser::default().parse_ifd_entry::<BigEndian>(data, 1).unwrap(),
                     (0x0405, Value::Unknown(3, 2, 9)));
         let data = b"X\x04\x05\x00\x03\0\0\0\x03\0\0\0\x0eXABCDEF";
-        assert_pat!(Parser::parse_ifd_entry::<BigEndian>(data, 1).unwrap(),
+        assert_pat!(Parser::default().parse_ifd_entry::<BigEndian>(data, 1).unwrap(),
                     (0x0405, Value::Unknown(3, 3, 14)));
         let data = b"X\x04\x05\x00\x03\0\0\0\x03\0\0\0\x0eXABCDE";
-        assert_err_pat!(Parser::parse_ifd_entry::<BigEndian>(data, 1),
+        assert_err_pat!(Parser::default().parse_ifd_entry::<BigEndian>(data, 1),
                         Error::InvalidFormat("Truncated field value"));
 
         // Really unknown
         let data = b"X\x01\x02\x03\x04\x05\x06\x07\x08ABCD";
-        assert_pat!(Parser::parse_ifd_entry::<BigEndian>(data, 1).unwrap(),
+        assert_pat!(Parser::default().parse_ifd_entry::<BigEndian>(data, 1).unwrap(),
                     (0x0102, Value::Unknown(0x0304, 0x05060708, 9)));
     }