feat(SimpleFileOptions): const DEFAULT implementation

src/compression.rs

@@ -138,6 +138,15 @@ impl CompressionMethod {
     pub const AES: Self = CompressionMethod::Aes;
     #[cfg(not(feature = "aes-crypto"))]
     pub const AES: Self = CompressionMethod::Unsupported(99);
+
+    #[cfg(feature = "_deflate-any")]
+    pub const DEFAULT: Self = CompressionMethod::Deflated;
+
+    #[cfg(all(not(feature = "_deflate-any"), feature = "bzip2"))]
+    pub const DEFAULT: Self = CompressionMethod::Bzip2;
+
+    #[cfg(all(not(feature = "_deflate-any"), not(feature = "bzip2")))]
+    pub const DEFAULT: Self = CompressionMethod::Stored;
 }
 impl CompressionMethod {
     pub(crate) const fn parse_from_u16(val: u16) -> Self {
@@ -228,11 +237,7 @@ impl CompressionMethod {
 
 impl Default for CompressionMethod {
     fn default() -> Self {
-        #[cfg(feature = "_deflate-any")]
-        return CompressionMethod::Deflated;
-
-        #[cfg(not(feature = "_deflate-any"))]
-        return CompressionMethod::Stored;
+        Self::DEFAULT
     }
 }
 

src/types.rs

@@ -136,6 +136,12 @@ impl PartialOrd for DateTime {
 }
 
 impl DateTime {
+    /// Constructs a default datetime of 1980-01-01 00:00:00.
+    pub const DEFAULT: Self = DateTime {
+        datepart: 0b0000000000100001,
+        timepart: 0,
+    };
+
     /// Returns the current time if possible, otherwise the default of 1980-01-01.
     #[cfg(feature = "time")]
     pub fn default_for_write() -> Self {
@@ -256,10 +262,7 @@ impl From<DateTime> for (u16, u16) {
 impl Default for DateTime {
     /// Constructs an 'default' datetime of 1980-01-01 00:00:00
     fn default() -> DateTime {
-        DateTime {
-            datepart: 0b0000000000100001,
-            timepart: 0,
-        }
+        DateTime::DEFAULT
     }
 }
 

src/write.rs

@@ -432,10 +432,9 @@ impl<T: FileOptionExtension> FileOptions<'_, T> {
 
     /// Set the compression method for the new file
     ///
-    /// The default is `CompressionMethod::Deflated` if it is enabled. If not,
-    /// `CompressionMethod::Bzip2` is the default if it is enabled. If neither `bzip2` nor `deflate`
-    /// is enabled, `CompressionMethod::Zlib` is the default. If all else fails,
-    /// `CompressionMethod::Stored` becomes the default and files are written uncompressed.
+    /// The default is [`CompressionMethod::Deflated`] if it is enabled. If not,
+    /// [`CompressionMethod::Bzip2`] is the default if it is enabled. If neither `bzip2` nor `deflate`
+    /// is enabled, [`CompressionMethod::Stored`] becomes the default and files are written uncompressed.
     #[must_use]
     pub const fn compression_method(mut self, method: CompressionMethod) -> Self {
         self.compression_method = method;
@@ -559,6 +558,28 @@ impl FileOptions<'_, ExtendedFileOptions> {
         self
     }
 }
+impl FileOptions<'static, ()> {
+    /// Constructs a const FileOptions object.
+    ///
+    /// Note: This value is different than the return value of [`FileOptions::default()`]:
+    ///
+    /// - The `last_modified_time` is [`DateTime::DEFAULT`]. This corresponds to 1980-01-01 00:00:00
+    pub const DEFAULT: Self = Self {
+        compression_method: CompressionMethod::DEFAULT,
+        compression_level: None,
+        last_modified_time: DateTime::DEFAULT,
+        large_file: false,
+        permissions: None,
+        encrypt_with: None,
+        extended_options: (),
+        alignment: 1,
+        #[cfg(feature = "deflate-zopfli")]
+        zopfli_buffer_size: Some(1 << 15),
+        #[cfg(feature = "aes-crypto")]
+        aes_mode: None,
+    };
+}
+
 impl<T: FileOptionExtension> Default for FileOptions<'_, T> {
     /// Construct a new FileOptions object
     fn default() -> Self {