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//! Possible ZIP compression methods.
use std::fmt;
#[allow(deprecated)]
/// Identifies the storage format used to compress a file within a ZIP archive.
///
/// Each file's compression method is stored alongside it, allowing the
/// contents to be read without context.
///
/// When creating ZIP files, you may choose the method to use with
/// [`crate::write::FileOptions::compression_method`]
#[derive(Copy, Clone, PartialEq, Eq, Debug)]
#[non_exhaustive]
pub enum CompressionMethod {
/// Store the file as is
Stored,
/// Compress the file using Deflate
#[cfg(any(
feature = "deflate",
feature = "deflate-miniz",
feature = "deflate-zlib"
))]
Deflated,
/// Compress the file using BZIP2
#[cfg(feature = "bzip2")]
Bzip2,
/// Encrypted using AES.
///
/// The actual compression method has to be taken from the AES extra data field
/// or from `ZipFileData`.
#[cfg(feature = "aes-crypto")]
Aes,
/// Compress the file using ZStandard
#[cfg(feature = "zstd")]
Zstd,
/// Unsupported compression method
#[deprecated(since = "0.5.7", note = "use the constants instead")]
Unsupported(u16),
}
#[allow(deprecated, missing_docs)]
/// All compression methods defined for the ZIP format
impl CompressionMethod {
pub const STORE: Self = CompressionMethod::Stored;
pub const SHRINK: Self = CompressionMethod::Unsupported(1);
pub const REDUCE_1: Self = CompressionMethod::Unsupported(2);
pub const REDUCE_2: Self = CompressionMethod::Unsupported(3);
pub const REDUCE_3: Self = CompressionMethod::Unsupported(4);
pub const REDUCE_4: Self = CompressionMethod::Unsupported(5);
pub const IMPLODE: Self = CompressionMethod::Unsupported(6);
#[cfg(any(
feature = "deflate",
feature = "deflate-miniz",
feature = "deflate-zlib"
))]
pub const DEFLATE: Self = CompressionMethod::Deflated;
#[cfg(not(any(
feature = "deflate",
feature = "deflate-miniz",
feature = "deflate-zlib"
)))]
pub const DEFLATE: Self = CompressionMethod::Unsupported(8);
pub const DEFLATE64: Self = CompressionMethod::Unsupported(9);
pub const PKWARE_IMPLODE: Self = CompressionMethod::Unsupported(10);
#[cfg(feature = "bzip2")]
pub const BZIP2: Self = CompressionMethod::Bzip2;
#[cfg(not(feature = "bzip2"))]
pub const BZIP2: Self = CompressionMethod::Unsupported(12);
pub const LZMA: Self = CompressionMethod::Unsupported(14);
pub const IBM_ZOS_CMPSC: Self = CompressionMethod::Unsupported(16);
pub const IBM_TERSE: Self = CompressionMethod::Unsupported(18);
pub const ZSTD_DEPRECATED: Self = CompressionMethod::Unsupported(20);
#[cfg(feature = "zstd")]
pub const ZSTD: Self = CompressionMethod::Zstd;
#[cfg(not(feature = "zstd"))]
pub const ZSTD: Self = CompressionMethod::Unsupported(93);
pub const MP3: Self = CompressionMethod::Unsupported(94);
pub const XZ: Self = CompressionMethod::Unsupported(95);
pub const JPEG: Self = CompressionMethod::Unsupported(96);
pub const WAVPACK: Self = CompressionMethod::Unsupported(97);
pub const PPMD: Self = CompressionMethod::Unsupported(98);
#[cfg(feature = "aes-crypto")]
pub const AES: Self = CompressionMethod::Aes;
#[cfg(not(feature = "aes-crypto"))]
pub const AES: Self = CompressionMethod::Unsupported(99);
}
impl CompressionMethod {
/// Converts an u16 to its corresponding CompressionMethod
#[deprecated(
since = "0.5.7",
note = "use a constant to construct a compression method"
)]
pub fn from_u16(val: u16) -> CompressionMethod {
#[allow(deprecated)]
match val {
0 => CompressionMethod::Stored,
#[cfg(any(
feature = "deflate",
feature = "deflate-miniz",
feature = "deflate-zlib"
))]
8 => CompressionMethod::Deflated,
#[cfg(feature = "bzip2")]
12 => CompressionMethod::Bzip2,
#[cfg(feature = "zstd")]
93 => CompressionMethod::Zstd,
#[cfg(feature = "aes-crypto")]
99 => CompressionMethod::Aes,
v => CompressionMethod::Unsupported(v),
}
}
/// Converts a CompressionMethod to a u16
#[deprecated(
since = "0.5.7",
note = "to match on other compression methods, use a constant"
)]
pub fn to_u16(self) -> u16 {
#[allow(deprecated)]
match self {
CompressionMethod::Stored => 0,
#[cfg(any(
feature = "deflate",
feature = "deflate-miniz",
feature = "deflate-zlib"
))]
CompressionMethod::Deflated => 8,
#[cfg(feature = "bzip2")]
CompressionMethod::Bzip2 => 12,
#[cfg(feature = "aes-crypto")]
CompressionMethod::Aes => 99,
#[cfg(feature = "zstd")]
CompressionMethod::Zstd => 93,
CompressionMethod::Unsupported(v) => v,
}
}
}
impl fmt::Display for CompressionMethod {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
// Just duplicate what the Debug format looks like, i.e, the enum key:
write!(f, "{self:?}")
}
}
/// The compression methods which have been implemented.
pub const SUPPORTED_COMPRESSION_METHODS: &[CompressionMethod] = &[
CompressionMethod::Stored,
#[cfg(any(
feature = "deflate",
feature = "deflate-miniz",
feature = "deflate-zlib"
))]
CompressionMethod::Deflated,
#[cfg(feature = "bzip2")]
CompressionMethod::Bzip2,
#[cfg(feature = "zstd")]
CompressionMethod::Zstd,
];
#[cfg(test)]
mod test {
use super::{CompressionMethod, SUPPORTED_COMPRESSION_METHODS};
#[test]
fn from_eq_to() {
for v in 0..(u16::MAX as u32 + 1) {
#[allow(deprecated)]
let from = CompressionMethod::from_u16(v as u16);
#[allow(deprecated)]
let to = from.to_u16() as u32;
assert_eq!(v, to);
}
}
#[test]
fn to_eq_from() {
fn check_match(method: CompressionMethod) {
#[allow(deprecated)]
let to = method.to_u16();
#[allow(deprecated)]
let from = CompressionMethod::from_u16(to);
#[allow(deprecated)]
let back = from.to_u16();
assert_eq!(to, back);
}
for &method in SUPPORTED_COMPRESSION_METHODS {
check_match(method);
}
}
#[test]
fn to_display_fmt() {
fn check_match(method: CompressionMethod) {
let debug_str = format!("{method:?}");
let display_str = format!("{method}");
assert_eq!(debug_str, display_str);
}
for &method in SUPPORTED_COMPRESSION_METHODS {
check_match(method);
}
}
}