Files
image-tiff/src/encoder/tiff_value.rs
T

688 lines
17 KiB
Rust

use std::{borrow::Cow, io::Write, slice::from_ref};
use crate::{bytecast, tags, tags::Type, TiffError, TiffFormatError, TiffResult};
use super::writer::TiffWriter;
/// Trait for types that can be encoded in a tiff file
#[diagnostic::on_unimplemented(
message = "the type `{Self}` does not implement `TiffValue`",
note = "the trait is implemented for primitive types (`u8`, `i16`, `f32`, etc.)",
note = "the trait is implemented for shared references to values",
note = "the trait is implemented for slices, pass them by reference (e.g. `&[u8]`)",
note = "the trait is implemented for arrays if it is implemented for a slice",
note = "values in a `Vec` or `Box` should be dereferenced, e.g. `&vec[..]`"
)]
pub trait TiffValue {
const BYTE_LEN: u8;
const FIELD_TYPE: Type;
// FIXME: If we want this to mean 'count' in the sense of `Entry` it should return `u32` or
// `u64`, probably the latter with `convert_offset` taking care of the check against `u32::MAX`
// for classic tiff.
fn count(&self) -> usize;
fn bytes(&self) -> usize {
self.count() * usize::from(Self::BYTE_LEN)
}
/// Access this value as an contiguous sequence of bytes.
/// If their is no trivial representation, allocate it on the heap.
fn data(&self) -> Cow<'_, [u8]>;
/// Write this value to a TiffWriter.
/// While the default implementation will work in all cases, it may require unnecessary allocations.
/// The written bytes of any custom implementation MUST be the same as yielded by `self.data()`.
fn write<W: Write>(&self, writer: &mut TiffWriter<W>) -> TiffResult<()> {
writer.write_bytes(&self.data())?;
Ok(())
}
}
impl TiffValue for [u8] {
const BYTE_LEN: u8 = 1;
const FIELD_TYPE: Type = Type::BYTE;
fn count(&self) -> usize {
self.len()
}
fn data(&self) -> Cow<'_, [u8]> {
Cow::Borrowed(self)
}
}
impl TiffValue for [i8] {
const BYTE_LEN: u8 = 1;
const FIELD_TYPE: Type = Type::SBYTE;
fn count(&self) -> usize {
self.len()
}
fn data(&self) -> Cow<'_, [u8]> {
Cow::Borrowed(bytecast::i8_as_ne_bytes(self))
}
}
impl TiffValue for [u16] {
const BYTE_LEN: u8 = 2;
const FIELD_TYPE: Type = Type::SHORT;
fn count(&self) -> usize {
self.len()
}
fn data(&self) -> Cow<'_, [u8]> {
Cow::Borrowed(bytecast::u16_as_ne_bytes(self))
}
}
impl TiffValue for [i16] {
const BYTE_LEN: u8 = 2;
const FIELD_TYPE: Type = Type::SSHORT;
fn count(&self) -> usize {
self.len()
}
fn data(&self) -> Cow<'_, [u8]> {
Cow::Borrowed(bytecast::i16_as_ne_bytes(self))
}
}
impl TiffValue for [u32] {
const BYTE_LEN: u8 = 4;
const FIELD_TYPE: Type = Type::LONG;
fn count(&self) -> usize {
self.len()
}
fn data(&self) -> Cow<'_, [u8]> {
Cow::Borrowed(bytecast::u32_as_ne_bytes(self))
}
}
impl TiffValue for [i32] {
const BYTE_LEN: u8 = 4;
const FIELD_TYPE: Type = Type::SLONG;
fn count(&self) -> usize {
self.len()
}
fn data(&self) -> Cow<'_, [u8]> {
Cow::Borrowed(bytecast::i32_as_ne_bytes(self))
}
}
impl TiffValue for [u64] {
const BYTE_LEN: u8 = 8;
const FIELD_TYPE: Type = Type::LONG8;
fn count(&self) -> usize {
self.len()
}
fn data(&self) -> Cow<'_, [u8]> {
Cow::Borrowed(bytecast::u64_as_ne_bytes(self))
}
}
impl TiffValue for [i64] {
const BYTE_LEN: u8 = 8;
const FIELD_TYPE: Type = Type::SLONG8;
fn count(&self) -> usize {
self.len()
}
fn data(&self) -> Cow<'_, [u8]> {
Cow::Borrowed(bytecast::i64_as_ne_bytes(self))
}
}
impl TiffValue for [f32] {
const BYTE_LEN: u8 = 4;
const FIELD_TYPE: Type = Type::FLOAT;
fn count(&self) -> usize {
self.len()
}
fn data(&self) -> Cow<'_, [u8]> {
// We write using native endian so this should be safe
Cow::Borrowed(bytecast::f32_as_ne_bytes(self))
}
}
impl TiffValue for [f64] {
const BYTE_LEN: u8 = 8;
const FIELD_TYPE: Type = Type::DOUBLE;
fn count(&self) -> usize {
self.len()
}
fn data(&self) -> Cow<'_, [u8]> {
// We write using native endian so this should be safe
Cow::Borrowed(bytecast::f64_as_ne_bytes(self))
}
}
impl TiffValue for u8 {
const BYTE_LEN: u8 = 1;
const FIELD_TYPE: Type = Type::BYTE;
fn count(&self) -> usize {
1
}
fn write<W: Write>(&self, writer: &mut TiffWriter<W>) -> TiffResult<()> {
writer.write_u8(*self)?;
Ok(())
}
fn data(&self) -> Cow<'_, [u8]> {
Cow::Borrowed(from_ref(self))
}
}
impl TiffValue for i8 {
const BYTE_LEN: u8 = 1;
const FIELD_TYPE: Type = Type::SBYTE;
fn count(&self) -> usize {
1
}
fn write<W: Write>(&self, writer: &mut TiffWriter<W>) -> TiffResult<()> {
writer.write_i8(*self)?;
Ok(())
}
fn data(&self) -> Cow<'_, [u8]> {
Cow::Borrowed(bytecast::i8_as_ne_bytes(from_ref(self)))
}
}
impl TiffValue for u16 {
const BYTE_LEN: u8 = 2;
const FIELD_TYPE: Type = Type::SHORT;
fn count(&self) -> usize {
1
}
fn write<W: Write>(&self, writer: &mut TiffWriter<W>) -> TiffResult<()> {
writer.write_u16(*self)?;
Ok(())
}
fn data(&self) -> Cow<'_, [u8]> {
Cow::Borrowed(bytecast::u16_as_ne_bytes(from_ref(self)))
}
}
impl TiffValue for i16 {
const BYTE_LEN: u8 = 2;
const FIELD_TYPE: Type = Type::SSHORT;
fn count(&self) -> usize {
1
}
fn write<W: Write>(&self, writer: &mut TiffWriter<W>) -> TiffResult<()> {
writer.write_i16(*self)?;
Ok(())
}
fn data(&self) -> Cow<'_, [u8]> {
Cow::Borrowed(bytecast::i16_as_ne_bytes(from_ref(self)))
}
}
impl TiffValue for u32 {
const BYTE_LEN: u8 = 4;
const FIELD_TYPE: Type = Type::LONG;
fn count(&self) -> usize {
1
}
fn write<W: Write>(&self, writer: &mut TiffWriter<W>) -> TiffResult<()> {
writer.write_u32(*self)?;
Ok(())
}
fn data(&self) -> Cow<'_, [u8]> {
Cow::Borrowed(bytecast::u32_as_ne_bytes(from_ref(self)))
}
}
impl TiffValue for i32 {
const BYTE_LEN: u8 = 4;
const FIELD_TYPE: Type = Type::SLONG;
fn count(&self) -> usize {
1
}
fn write<W: Write>(&self, writer: &mut TiffWriter<W>) -> TiffResult<()> {
writer.write_i32(*self)?;
Ok(())
}
fn data(&self) -> Cow<'_, [u8]> {
Cow::Borrowed(bytecast::i32_as_ne_bytes(from_ref(self)))
}
}
impl TiffValue for u64 {
const BYTE_LEN: u8 = 8;
const FIELD_TYPE: Type = Type::LONG8;
fn count(&self) -> usize {
1
}
fn write<W: Write>(&self, writer: &mut TiffWriter<W>) -> TiffResult<()> {
writer.write_u64(*self)?;
Ok(())
}
fn data(&self) -> Cow<'_, [u8]> {
Cow::Borrowed(bytecast::u64_as_ne_bytes(from_ref(self)))
}
}
impl TiffValue for i64 {
const BYTE_LEN: u8 = 8;
const FIELD_TYPE: Type = Type::SLONG8;
fn count(&self) -> usize {
1
}
fn write<W: Write>(&self, writer: &mut TiffWriter<W>) -> TiffResult<()> {
writer.write_i64(*self)?;
Ok(())
}
fn data(&self) -> Cow<'_, [u8]> {
Cow::Borrowed(bytecast::i64_as_ne_bytes(from_ref(self)))
}
}
impl TiffValue for f32 {
const BYTE_LEN: u8 = 4;
const FIELD_TYPE: Type = Type::FLOAT;
fn count(&self) -> usize {
1
}
fn write<W: Write>(&self, writer: &mut TiffWriter<W>) -> TiffResult<()> {
writer.write_f32(*self)?;
Ok(())
}
fn data(&self) -> Cow<'_, [u8]> {
Cow::Borrowed(bytecast::f32_as_ne_bytes(from_ref(self)))
}
}
impl TiffValue for f64 {
const BYTE_LEN: u8 = 8;
const FIELD_TYPE: Type = Type::DOUBLE;
fn count(&self) -> usize {
1
}
fn write<W: Write>(&self, writer: &mut TiffWriter<W>) -> TiffResult<()> {
writer.write_f64(*self)?;
Ok(())
}
fn data(&self) -> Cow<'_, [u8]> {
Cow::Borrowed(bytecast::f64_as_ne_bytes(from_ref(self)))
}
}
impl TiffValue for Ifd {
const BYTE_LEN: u8 = 4;
const FIELD_TYPE: Type = Type::IFD;
fn count(&self) -> usize {
1
}
fn write<W: Write>(&self, writer: &mut TiffWriter<W>) -> TiffResult<()> {
writer.write_u32(self.0)?;
Ok(())
}
fn data(&self) -> Cow<'_, [u8]> {
Cow::Borrowed(bytecast::u32_as_ne_bytes(from_ref(&self.0)))
}
}
impl TiffValue for Ifd8 {
const BYTE_LEN: u8 = 8;
const FIELD_TYPE: Type = Type::IFD8;
fn count(&self) -> usize {
1
}
fn write<W: Write>(&self, writer: &mut TiffWriter<W>) -> TiffResult<()> {
writer.write_u64(self.0)?;
Ok(())
}
fn data(&self) -> Cow<'_, [u8]> {
Cow::Borrowed(bytecast::u64_as_ne_bytes(from_ref(&self.0)))
}
}
impl TiffValue for Rational {
const BYTE_LEN: u8 = 8;
const FIELD_TYPE: Type = Type::RATIONAL;
fn count(&self) -> usize {
1
}
fn write<W: Write>(&self, writer: &mut TiffWriter<W>) -> TiffResult<()> {
writer.write_u32(self.n)?;
writer.write_u32(self.d)?;
Ok(())
}
fn data(&self) -> Cow<'_, [u8]> {
Cow::Owned({
let first_dword = bytecast::u32_as_ne_bytes(from_ref(&self.n));
let second_dword = bytecast::u32_as_ne_bytes(from_ref(&self.d));
[first_dword, second_dword].concat()
})
}
}
impl TiffValue for SRational {
const BYTE_LEN: u8 = 8;
const FIELD_TYPE: Type = Type::SRATIONAL;
fn count(&self) -> usize {
1
}
fn write<W: Write>(&self, writer: &mut TiffWriter<W>) -> TiffResult<()> {
writer.write_i32(self.n)?;
writer.write_i32(self.d)?;
Ok(())
}
fn data(&self) -> Cow<'_, [u8]> {
Cow::Owned({
let first_dword = bytecast::i32_as_ne_bytes(from_ref(&self.n));
let second_dword = bytecast::i32_as_ne_bytes(from_ref(&self.d));
[first_dword, second_dword].concat()
})
}
}
impl TiffValue for str {
const BYTE_LEN: u8 = 1;
const FIELD_TYPE: Type = Type::ASCII;
fn count(&self) -> usize {
self.len() + 1
}
fn write<W: Write>(&self, writer: &mut TiffWriter<W>) -> TiffResult<()> {
if self.is_ascii() && !self.bytes().any(|b| b == 0) {
writer.write_bytes(self.as_bytes())?;
writer.write_u8(0)?;
Ok(())
} else {
Err(TiffError::FormatError(TiffFormatError::InvalidTag))
}
}
fn data(&self) -> Cow<'_, [u8]> {
Cow::Owned({
if self.is_ascii() && !self.bytes().any(|b| b == 0) {
let bytes: &[u8] = self.as_bytes();
[bytes, &[0]].concat()
} else {
vec![]
}
})
}
}
// FIXME: held up on reading the discriminant for all but the unknown variant.
//
// It needs to have `repr(u16)` to have a defined layout and then we may read the tag from its
// value representation by casting a u16 pointer to a pointer to the enum type.
// unsafe { *<*const _>::from(self).cast::<u16>() }
// But that is quite unsafe and needs careful review to maintain the safety requirements. Maybe we
// could get `bytemuck` to add a trait for this (it has `TransparentWrapper`) with a derive for
// enum types that have an explicit repr.
//
// This would allow returning borrowed data in more cases. For all types without an unknown, in all
// cases including as slices, and for all types with and unknown variant when we have a single
// value (either returning a borrowed discriminant or a borrowed value within `Unknown`).
impl TiffValue for tags::CompressionMethod {
const BYTE_LEN: u8 = <u16 as TiffValue>::BYTE_LEN;
const FIELD_TYPE: Type = Type::SHORT;
fn count(&self) -> usize {
1
}
fn data(&self) -> Cow<'_, [u8]> {
let bytes = self.to_u16().to_ne_bytes();
Cow::Owned(bytes.to_vec())
}
}
impl TiffValue for tags::PhotometricInterpretation {
const BYTE_LEN: u8 = <u16 as TiffValue>::BYTE_LEN;
const FIELD_TYPE: Type = Type::SHORT;
fn count(&self) -> usize {
1
}
fn data(&self) -> Cow<'_, [u8]> {
self.to_u16().to_ne_bytes().to_vec().into()
}
}
impl TiffValue for tags::PlanarConfiguration {
const BYTE_LEN: u8 = 2;
const FIELD_TYPE: Type = Type::SHORT;
fn count(&self) -> usize {
1
}
fn data(&self) -> Cow<'_, [u8]> {
self.to_u16().to_ne_bytes().to_vec().into()
}
}
impl TiffValue for tags::Predictor {
const BYTE_LEN: u8 = <u16 as TiffValue>::BYTE_LEN;
const FIELD_TYPE: Type = Type::SHORT;
fn count(&self) -> usize {
1
}
fn data(&self) -> Cow<'_, [u8]> {
self.to_u16().to_ne_bytes().to_vec().into()
}
}
impl TiffValue for tags::ResolutionUnit {
const BYTE_LEN: u8 = <u16 as TiffValue>::BYTE_LEN;
const FIELD_TYPE: Type = Type::SHORT;
fn count(&self) -> usize {
1
}
fn data(&self) -> Cow<'_, [u8]> {
self.to_u16().to_ne_bytes().to_vec().into()
}
}
/// This is implemented for slices as the `SampleFormat` tag takes a count of `N`.
///
/// Use `core::slice::from_ref` if you really need to write a single element.
///
/// See: <https://web.archive.org/web/20191120220815/https://www.awaresystems.be/imaging/tiff/tifftags/sampleformat.html>
impl TiffValue for [tags::SampleFormat] {
const BYTE_LEN: u8 = <u16 as TiffValue>::BYTE_LEN;
const FIELD_TYPE: Type = Type::SHORT;
fn count(&self) -> usize {
self.len()
}
fn data(&self) -> Cow<'_, [u8]> {
let mut buf: Vec<u8> = Vec::with_capacity(self.len() * 2);
for x in self {
buf.extend_from_slice(&x.to_u16().to_ne_bytes());
}
Cow::Owned(buf)
}
}
/// This is implemented for slices as the `ExtraSamples` tag takes a count of `N`.
///
/// Use `core::slice::from_ref` if you really need to write a single element.
///
/// See: <https://web.archive.org/web/20191120220815/https://www.awaresystems.be/imaging/tiff/tifftags/extrasamples.html>
impl TiffValue for [tags::ExtraSamples] {
const BYTE_LEN: u8 = <u16 as TiffValue>::BYTE_LEN;
const FIELD_TYPE: Type = Type::SHORT;
fn count(&self) -> usize {
self.len()
}
fn data(&self) -> Cow<'_, [u8]> {
let mut buf: Vec<u8> = Vec::with_capacity(self.len() * 2);
for x in self {
buf.extend_from_slice(&x.to_u16().to_ne_bytes());
}
Cow::Owned(buf)
}
}
// If you pass `&Vec<_>` then you'd get at first sight the complaint:
//
// `Vec<T>` does not implement `TiffValue`
//
// and a list of implementations of `TiffValue` that are quite unrelated. That is not very helpful.
// We do not *want* `Vec` to implement the trait as an owning type, instead you should pass a
// reference to a slice. The error message is further customized in the diagnostics of the trait.
#[diagnostic::do_not_recommend]
impl<T: TiffValue + ?Sized> TiffValue for &'_ T {
const BYTE_LEN: u8 = T::BYTE_LEN;
const FIELD_TYPE: Type = T::FIELD_TYPE;
fn count(&self) -> usize {
(*self).count()
}
fn write<W: Write>(&self, writer: &mut TiffWriter<W>) -> TiffResult<()> {
(*self).write(writer)
}
fn data(&self) -> Cow<'_, [u8]> {
T::data(self)
}
}
/// An array is treated like a slice of the same length.
impl<T, const N: usize> TiffValue for [T; N]
where
[T]: TiffValue,
{
const BYTE_LEN: u8 = <[T]>::BYTE_LEN;
const FIELD_TYPE: Type = <[T]>::FIELD_TYPE;
fn count(&self) -> usize {
self.as_slice().count()
}
fn write<W: Write>(&self, writer: &mut TiffWriter<W>) -> TiffResult<()> {
self.as_slice().write(writer)
}
fn data(&self) -> Cow<'_, [u8]> {
self.as_slice().data()
}
}
macro_rules! impl_tiff_value_for_contiguous_sequence {
($inner_type:ty; $bytes:expr; $field_type:expr) => {
impl $crate::encoder::TiffValue for [$inner_type] {
const BYTE_LEN: u8 = $bytes;
const FIELD_TYPE: Type = $field_type;
fn count(&self) -> usize {
self.len()
}
fn write<W: Write>(&self, writer: &mut TiffWriter<W>) -> TiffResult<()> {
for x in self {
x.write(writer)?;
}
Ok(())
}
fn data(&self) -> Cow<'_, [u8]> {
let mut buf: Vec<u8> = Vec::with_capacity(Self::BYTE_LEN as usize * self.len());
for x in self {
buf.extend_from_slice(&x.data());
}
Cow::Owned(buf)
}
}
};
}
impl_tiff_value_for_contiguous_sequence!(Ifd; 4; Type::IFD);
impl_tiff_value_for_contiguous_sequence!(Ifd8; 8; Type::IFD8);
impl_tiff_value_for_contiguous_sequence!(Rational; 8; Type::RATIONAL);
impl_tiff_value_for_contiguous_sequence!(SRational; 8; Type::SRATIONAL);
/// Type to represent tiff values of type `IFD`
#[derive(Debug, Copy, Clone, PartialEq, Eq)]
pub struct Ifd(pub u32);
/// Type to represent tiff values of type `IFD8`
#[derive(Debug, Copy, Clone, PartialEq, Eq)]
pub struct Ifd8(pub u64);
/// Type to represent tiff values of type `RATIONAL`
#[derive(Debug, Copy, Clone)]
pub struct Rational {
pub n: u32,
pub d: u32,
}
/// Type to represent tiff values of type `SRATIONAL`
#[derive(Debug, Copy, Clone)]
pub struct SRational {
pub n: i32,
pub d: i32,
}