Struct ChunkType 

pub struct ChunkType(/* private fields */);

A 4-byte chunk type code.

PNA uses a chunk-based format inspired by PNG. Each chunk has a 4-character type code that determines how the chunk should be interpreted.

Chunk Type Naming Convention

The case of each letter in the chunk type encodes important properties:

Position	Uppercase	Lowercase
1st	Critical (must understand)	Ancillary (can ignore)
2nd	Public (standardized)	Private (application-specific)
3rd	Reserved (must be uppercase)	-
4th	Unsafe to copy	Safe to copy if unknown

Critical Chunks

These chunks are essential for reading the archive structure:

• Archive structure: AHED (header), AEND (end), ANXT (next part)
• Entry structure: FHED (header), FDAT (data), FEND (end)
• Solid mode: SHED (header), SDAT (data), SEND (end)
• Encryption: PHSF (password hash string format)

Ancillary Chunks

These chunks contain optional metadata that can be safely ignored:

• Timestamps: cTIM, mTIM, aTIM (seconds), cTNS, mTNS, aTNS (nanoseconds)
• File info: fSIZ (size), fPRM (permissions)
• Extended attributes: xATR

Creating Private Chunks

Use ChunkType::private to create application-specific chunk types:

use libpna::ChunkType;

// Private chunk type must have lowercase second letter
let my_chunk = ChunkType::private(*b"myTy").unwrap();
assert!(my_chunk.is_private());

Implementations

impl ChunkType

pub const AHED: ChunkType

Archive header

pub const AEND: ChunkType

Archive end marker

pub const ANXT: ChunkType

Archive next part marker

pub const FHED: ChunkType

Entry header

pub const PHSF: ChunkType

Password hash string format

pub const FDAT: ChunkType

Entry data stream

pub const FEND: ChunkType

Entry data stream end marker

pub const SHED: ChunkType

Solid mode data header

pub const SDAT: ChunkType

Solid mode data stream

pub const SEND: ChunkType

Solid mode data stream end marker

pub const fSIZ: ChunkType

Raw file size

pub const cTIM: ChunkType

Creation datetime

pub const mTIM: ChunkType

Last modified datetime

pub const aTIM: ChunkType

Last accessed datetime

pub const cTNS: ChunkType

Nanoseconds for creation datetime

pub const mTNS: ChunkType

Nanoseconds for last modified datetime

pub const aTNS: ChunkType

Nanoseconds for last accessed datetime

pub const fPRM: ChunkType

Entry permissions

pub const xATR: ChunkType

Extended attribute

pub const fn len(&self) -> usize

Returns the length of the chunk type code.

Returns

An integer value representing the length of the chunk type code.

Examples

use libpna::ChunkType;

let chunk_type = ChunkType::AHED;

assert_eq!(chunk_type.len(), 4);

pub const fn private(ty: [u8; 4]) -> Result<Self, ChunkTypeError>

Creates private ChunkType.

Errors

This function will return an error in the following cases:

• Value contains non-ASCII alphabet characters
• The second character is not lowercase
• The third character is not uppercase

Examples

assert!(ChunkType::private(*b"myTy").is_ok());
assert_eq!(
    ChunkType::private(*b"zeR\0").unwrap_err(),
    ChunkTypeError::NonAsciiAlphabetic
);
assert_eq!(
    ChunkType::private(*b"pRIv").unwrap_err(),
    ChunkTypeError::NonPrivateChunkType
);
assert_eq!(
    ChunkType::private(*b"rese").unwrap_err(),
    ChunkTypeError::Reserved
);

pub const unsafe fn from_unchecked(ty: [u8; 4]) -> Self

Creates a custom ChunkType without validation.

Panics

Panics if the chunk type contains non-UTF-8 characters and it is formatted with Display.

let custom_chunk_type = unsafe { ChunkType::from_unchecked([0xe3, 0x81, 0x82, 0xe3]) };
format!("{}", custom_chunk_type);

Safety

Callers must ensure the value consists only of ASCII alphabetic characters (‘a’..‘z’ and ‘A’..‘Z’).

let custom_chunk_type = unsafe { ChunkType::from_unchecked(*b"myTy") };
format!("{}", custom_chunk_type);

pub const fn is_critical(&self) -> bool

Returns true if the chunk is critical.

pub const fn is_private(&self) -> bool

Returns true if the chunk is private.

pub const fn is_set_reserved(&self) -> bool

Checks whether the reserved bit of the chunk name is set. If it is set, the chunk name is invalid.

pub const fn is_safe_to_copy(&self) -> bool

Returns true if the chunk is safe to copy if unknown.

Trait Implementations

impl Clone for ChunkType

fn clone(&self) -> ChunkType

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ChunkType

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

Formats the value using the given formatter.

impl Display for ChunkType

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

Formats the value using the given formatter.

impl Hash for ChunkType

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for ChunkType

fn cmp(&self, other: &ChunkType) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for ChunkType

fn eq(&self, other: &ChunkType) -> 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 PartialOrd for ChunkType

fn partial_cmp(&self, other: &ChunkType) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

Tests less than (for self and other) and is used by the < operator.

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

Tests less than or equal to (for self and other) and is used by the <= operator.

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

Tests greater than (for self and other) and is used by the > operator.

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

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl Copy for ChunkType

impl Eq for ChunkType

impl StructuralPartialEq for ChunkType