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//! Module containing the DICOM Transfer Syntax data structure and related methods. //! Similar to the DcmCodec in DCMTK, the `TransferSyntax` contains all of the necessary //! algorithms for decoding and encoding DICOM data in a certain transfer syntax. //! //! This crate does not host specific transfer syntaxes. Instead, they are created in //! other crates and registered in the global transfer syntax registry. For more //! information, please see the `dicom-transfer-syntax-registry` crate. pub mod explicit_be; pub mod explicit_le; pub mod implicit_le; use crate::decode::basic::BasicDecoder; use crate::decode::Decode; use crate::encode::Encode; use std::io::{Read, Write}; pub use byteordered::Endianness; /// A decoder with its type erased. pub type DynDecoder = Box<dyn Decode<Source = dyn Read>>; /// An encoder with its type erased. pub type DynEncoder = Box<dyn Encode<Writer = dyn Write>>; /// A DICOM transfer syntax specifier. The data RW adapter `A` specifies /// custom codec capabilities when required. #[derive(Debug)] pub struct TransferSyntax<A = DynDataRWAdapter> { /// The unique identifier of the transfer syntax. uid: &'static str, /// The name of the transfer syntax. name: &'static str, /// The byte order of data. byte_order: Endianness, /// Whether the transfer syntax mandates an explicit value representation, /// or the VR is implicit. explicit_vr: bool, /// The transfer syntax' requirements and implemented capabilities. codec: Codec<A>, } // Collect transfer syntax specifiers from other crates. inventory::collect!(TransferSyntax); #[macro_export] /// Submit a transfer syntax specifier to be supported by the /// program's runtime. This is to be used by crates wishing to provide /// additional support for a certain transfer syntax. /// /// This macro does actually "run" anything, so place it outside of a /// function body at the root of the crate. macro_rules! submit_transfer_syntax { ($ts: expr) => { inventory::submit! { ($ts).erased() } }; } /// Description regarding the encoding and decoding requirements of a transfer /// syntax. This is also used as a means to describe whether pixel data is /// encapsulated and whether this implementation supports it. #[derive(Debug, Clone, PartialEq)] pub enum Codec<A> { /// No codec is given, nor is it required. None, /// Custom encoding and decoding of the entire data set is required, but /// not supported. This could be used by a stub of /// _Deflated Explicit VR Little Endian_, for example. Unsupported, /// Custom encoding and decoding of the pixel data set is required, but /// not supported. The program should still be able to parse DICOM /// data sets and fetch the pixel data in its encapsulated form. EncapsulatedPixelData, /// A pixel data encapsulation codec is required and provided for reading /// and writing pixel data. PixelData(A), /// A full, custom data set codec is required and provided. Dataset(A), } /// An alias for a transfer syntax specifier with no pixel data encapsulation /// nor data set deflating. pub type AdapterFreeTransferSyntax = TransferSyntax<NeverAdapter>; /// An adapter of byte read and write streams. pub trait DataRWAdapter<R, W> { type Reader: Read; type Writer: Write; /// Adapt a byte reader. fn adapt_reader(&self, reader: R) -> Self::Reader where R: Read; /// Adapt a byte writer. fn adapt_writer(&self, writer: W) -> Self::Writer where W: Write; } pub type DynDataRWAdapter = Box< dyn DataRWAdapter< Box<dyn Read>, Box<dyn Write>, Reader = Box<dyn Read>, Writer = Box<dyn Write>, > + Send + Sync, >; impl<'a, T, R, W> DataRWAdapter<R, W> for &'a T where T: DataRWAdapter<R, W>, R: Read, W: Write, { type Reader = <T as DataRWAdapter<R, W>>::Reader; type Writer = <T as DataRWAdapter<R, W>>::Writer; /// Adapt a byte reader. fn adapt_reader(&self, reader: R) -> Self::Reader where R: Read, { (**self).adapt_reader(reader) } /// Adapt a byte writer. fn adapt_writer(&self, writer: W) -> Self::Writer where W: Write, { (**self).adapt_writer(writer) } } #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord)] pub enum NeverAdapter {} impl<R, W> DataRWAdapter<R, W> for NeverAdapter { type Reader = Box<dyn Read>; type Writer = Box<dyn Write>; fn adapt_reader(&self, _reader: R) -> Self::Reader where R: Read, { unreachable!() } fn adapt_writer(&self, _writer: W) -> Self::Writer where W: Write, { unreachable!() } } impl<A> TransferSyntax<A> { pub const fn new( uid: &'static str, name: &'static str, byte_order: Endianness, explicit_vr: bool, codec: Codec<A>, ) -> Self { TransferSyntax { uid, name, byte_order, explicit_vr, codec, } } /// Obtain this transfer syntax' unique identifier. pub const fn uid(&self) -> &'static str { self.uid } /// Obtain the name of this transfer syntax. pub const fn name(&self) -> &'static str { self.name } /// Obtain this transfer syntax' expected endianness. pub const fn endianness(&self) -> Endianness { self.byte_order } /// Obtain this transfer syntax' codec specification. pub fn codec(&self) -> &Codec<A> { &self.codec } /// Check whether this transfer syntax specifier provides a complete /// implementation. pub fn fully_supported(&self) -> bool { match self.codec { Codec::None | Codec::Dataset(_) | Codec::PixelData(_) => true, _ => false, } } /// Check whether reading and writing of data sets is unsupported. /// If this is `true`, encoding and decoding will not be available. pub fn unsupported(&self) -> bool { match self.codec { Codec::Unsupported => true, _ => false, } } /// Check whether reading and writing the pixel data is unsupported. /// If this is `true`, encoding and decoding of the data set will still /// be possible, but the pixel data will only be available in its /// encapsulated form. pub fn unsupported_pixel_encapsulation(&self) -> bool { match self.codec { Codec::Unsupported | Codec::EncapsulatedPixelData => true, _ => false, } } /// Retrieve the appropriate data element decoder for this transfer syntax. /// Can yield none if decoding is not supported. /// /// The resulting decoder does not consider pixel data encapsulation or /// data set compression rules. This means that the consumer of this method /// needs to adapt the reader before using the decoder. pub fn get_decoder(&self) -> Option<DynDecoder> { match (self.byte_order, self.explicit_vr) { (Endianness::Little, false) => Some(Box::new( implicit_le::ImplicitVRLittleEndianDecoder::default(), )), (Endianness::Little, true) => Some(Box::new( explicit_le::ExplicitVRLittleEndianDecoder::default(), )), (Endianness::Big, true) => { Some(Box::new(explicit_be::ExplicitVRBigEndianDecoder::default())) } _ => None, } } /// Retrieve the appropriate data element encoder for this transfer syntax. /// Can yield none if encoding is not supported. The resulting encoder does not /// consider pixel data encapsulation or data set compression rules. pub fn get_encoder(&self) -> Option<DynEncoder> { match (self.byte_order, self.explicit_vr) { (Endianness::Little, false) => Some(Box::new( implicit_le::ImplicitVRLittleEndianEncoder::default(), )), (Endianness::Little, true) => Some(Box::new( explicit_le::ExplicitVRLittleEndianEncoder::default(), )), (Endianness::Big, true) => { Some(Box::new(explicit_be::ExplicitVRBigEndianEncoder::default())) } _ => None, } } /// Obtain a dynamic basic decoder, based on this transfer syntax' expected endianness. pub fn get_basic_decoder(&self) -> BasicDecoder { BasicDecoder::from(self.endianness()) } /// Type-erase the pixel data or data set codec. pub fn erased(self) -> TransferSyntax where A: Send + Sync + 'static, A: DataRWAdapter< Box<dyn Read>, Box<dyn Write>, Reader = Box<dyn Read>, Writer = Box<dyn Write>, >, { let codec = match self.codec { Codec::Dataset(a) => Codec::Dataset(Box::new(a) as DynDataRWAdapter), Codec::PixelData(a) => Codec::PixelData(Box::new(a) as DynDataRWAdapter), Codec::EncapsulatedPixelData => Codec::EncapsulatedPixelData, Codec::Unsupported => Codec::Unsupported, Codec::None => Codec::None, }; TransferSyntax { uid: self.uid, name: self.name, byte_order: self.byte_order, explicit_vr: self.explicit_vr, codec, } } }