diff --git a/src/lib.rs b/src/lib.rs index 206adcd..98384ab 100644 --- a/src/lib.rs +++ b/src/lib.rs @@ -32,7 +32,7 @@ pub use tag::Tag; pub use tiff::Field; pub use tiff::parse_exif; pub use value::Value; -pub use value::Rational; +pub use value::{Rational, SRational}; #[cfg(test)] #[macro_use] diff --git a/src/value.rs b/src/value.rs index 0a4a58c..12fab3b 100644 --- a/src/value.rs +++ b/src/value.rs @@ -52,6 +52,9 @@ pub enum Value<'a> { SShort(Vec), /// Vector of 32-bit signed integers. SLong(Vec), + /// Vector of signed rationals. + /// A signed rational number is a pair of 32-bit signed integers. + SRational(Vec), /// The type is unknown to this implementation. /// The associated values are the type and the count, and the /// offset of the "Value Offset" element. @@ -67,6 +70,15 @@ impl fmt::Debug for Rational { } } +/// A signed rational number, which is a pair of 32-bit signed integers. +pub struct SRational { pub num: i32, pub denom: i32 } + +impl fmt::Debug for SRational { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + write!(f, "SRational({}/{})", self.num, self.denom) + } +} + type Parser<'a> = fn(&'a [u8], usize, usize) -> Value<'a>; // Return the length of a single value and the parser of the type. @@ -82,6 +94,7 @@ pub fn get_type_info<'a, E>(typecode: u16) 7 => (1, parse_undefined), 8 => (2, parse_sshort::), 9 => (4, parse_slong::), + 10 => (8, parse_srational::), _ => (0, parse_unknown), } } @@ -164,6 +177,18 @@ fn parse_slong<'a, E>(data: &'a [u8], offset: usize, count: usize) Value::SLong(val) } +fn parse_srational<'a, E>(data: &'a [u8], offset: usize, count: usize) + -> Value<'a> where E: Endian { + let mut val = Vec::with_capacity(count); + for i in 0..count { + val.push(SRational { + num: E::loadu32(data, offset + i * 8) as i32, + denom: E::loadu32(data, offset + i * 8 + 4) as i32, + }); + } + Value::SRational(val) +} + // This is a dummy function and will never be called. #[allow(unused_variables)] fn parse_unknown<'a>(data: &'a [u8], offset: usize, count: usize) @@ -334,4 +359,28 @@ mod tests { } } } + + #[test] + fn srational() { + let sets: &[(&[u8], Vec)] = &[ + (b"x", vec![]), + (b"x\xa1\x02\x03\x04\x05\x06\x07\x08\ + \x09\x0a\x0b\x0c\xbd\x0e\x0f\x10", + vec![SRational { num: -0x5efdfcfc, denom: 0x05060708 }, + SRational { num: 0x090a0b0c, denom: -0x42f1f0f0 }]), + ]; + let (unitlen, parser) = get_type_info::(10); + for &(data, ref ans) in sets { + assert!((data.len() - 1) % unitlen == 0); + match parser(data, 1, (data.len() - 1) / unitlen) { + Value::SRational(v) => { + assert_eq!(v.len(), ans.len()); + for (x, y) in v.iter().zip(ans.iter()) { + assert!(x.num == y.num && x.denom == y.denom); + } + }, + v => panic!("wrong variant {:?}", v), + } + } + } }