Enum Value 

pub enum Value {
    Byte(Vec<u8>),
    Ascii(String),
    Short(Vec<u16>),
    Long(Vec<u32>),
    Rational(Vec<(u32, u32)>),
    SByte(Vec<i8>),
    Undefined(Vec<u8>),
    SShort(Vec<i16>),
    SLong(Vec<i32>),
    SRational(Vec<(i32, i32)>),
    Float(Vec<f32>),
    Double(Vec<f64>),
    Long8(Vec<u64>),
    SLong8(Vec<i64>),
    Ifd8(Vec<u64>),
}

The decoded value(s) of one IFD entry, one variant per crate::FieldType.

A TIFF entry always stores a count of values of a single type; even a scalar is a 1-element vector here. On disk the values sit inline in the entry’s value/offset field when they fit, or at a file offset otherwise — a distinction the reader/writer resolve, leaving this type purely the logical value. The BigTIFF 64-bit variants (Long8/SLong8/Ifd8) appear only when the bigtiff feature is enabled.

Variants

Byte(Vec<u8>)

BYTE — unsigned 8-bit integers.

Ascii(String)

ASCII — a NUL-terminated 7-bit ASCII string (the terminator is not stored here).

Short(Vec<u16>)

SHORT — unsigned 16-bit integers.

Long(Vec<u32>)

LONG — unsigned 32-bit integers.

Rational(Vec<(u32, u32)>)

RATIONAL — unsigned fractions as (numerator, denominator) pairs.

SByte(Vec<i8>)

SBYTE — signed 8-bit integers.

Undefined(Vec<u8>)

UNDEFINED — raw bytes whose interpretation depends on the field.

SShort(Vec<i16>)

SSHORT — signed 16-bit integers.

SLong(Vec<i32>)

SLONG — signed 32-bit integers.

SRational(Vec<(i32, i32)>)

SRATIONAL — signed fractions as (numerator, denominator) pairs.

Float(Vec<f32>)

FLOAT — IEEE single-precision floats.

Double(Vec<f64>)

DOUBLE — IEEE double-precision floats.

Long8(Vec<u64>)

LONG8 — BigTIFF 64-bit unsigned integers.

SLong8(Vec<i64>)

SLONG8 — BigTIFF 64-bit signed integers.

Ifd8(Vec<u64>)

IFD8 — BigTIFF 64-bit IFD offsets.

Implementations

impl Value

pub fn field_type(&self) -> FieldType

The field type of this value.

pub fn count(&self) -> usize

The Count of this value: the number of elements, or for ASCII the number of bytes including the terminating NUL.

pub fn byte_len(&self) -> usize

The number of bytes this value occupies on disk (count * type size).

pub fn as_u32(&self) -> Option<u32>

Coerces a single unsigned-integer value (BYTE, SHORT, LONG, or — with bigtiff — LONG8/IFD8) to u32.

TIFF readers accept any of these types for an integer field (TIFF 6.0 §2); returns None if the value is not a single unsigned integer or a LONG8/IFD8 exceeds u32::MAX (only possible past the 4 GiB classic-TIFF limit, which an in-memory decode cannot reach anyway).

pub fn as_u32_vec(&self) -> Option<Vec<u32>>

Coerces an array of unsigned integers (BYTE, SHORT, LONG, or — with bigtiff — LONG8/IFD8) to Vec<u32>.

Returns None for any other type, or if a LONG8/IFD8 element exceeds u32::MAX. This lets a decoder read BigTIFF StripOffsets/StripByteCounts, which libtiff writes as LONG8.

pub fn encode(&self, order: ByteOrder) -> Vec<u8>

Serialises the value’s elements to bytes in order (without any inline/offset padding).

pub fn decode( ty: FieldType, count: usize, bytes: &[u8], order: ByteOrder, ) -> Result<Value, Error>

Parses count values of ty from bytes (which must hold at least count * ty.size() bytes) in order.

Errors

Returns Error::InvalidInput if bytes is too short for the declared count.

Trait Implementations

impl Clone for Value

fn clone(&self) -> Value

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Value

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl PartialEq for Value

fn eq(&self, other: &Value) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for Value