make BigInt::new, BigUint::new, and DateTime::new const fns (#539)

* make BigInt::new, BigUint::new, and DateTime::new const fns

* changelog

* bump for 0.21.2 release

Author: reaperhulk

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "asn1"
-version = "0.21.1"
+version = "0.21.2"
 authors = ["Alex Gaynor <[email protected]>"]
 repository = "https://github.com/alex/rust-asn1"
 keywords = ["asn1"]
@@ -17,7 +17,7 @@ default = ["std"]
 std = []
 
 [dependencies]
-asn1_derive = { path = "asn1_derive/", version = "0.21.1" }
+asn1_derive = { path = "asn1_derive/", version = "0.21.2" }
 itoa = "1.0.11"
 
 [dev-dependencies]

README.md

@@ -23,6 +23,13 @@ $ cargo add asn1 --no-default-features
 
 ## Changelog
 
+### [0.21.2]
+
+#### Added
+
+- `BigInt::new`, `BigUint::new`, and `DateTime::new` are now `const fn`.
+
+
 ### [0.21.1]
 
 #### Added

asn1_derive/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "asn1_derive"
-version = "0.21.1"
+version = "0.21.2"
 authors = ["Alex Gaynor <[email protected]>"]
 repository = "https://github.com/alex/rust-asn1"
 license = "BSD-3-Clause"

src/parser.rs

@@ -62,7 +62,7 @@ pub struct ParseError {
 }
 
 impl ParseError {
-    pub fn new(kind: ParseErrorKind) -> ParseError {
+    pub const fn new(kind: ParseErrorKind) -> ParseError {
         ParseError {
             kind,
             parse_locations: [None, None, None, None],

src/types.rs

@@ -568,7 +568,7 @@ impl SimpleAsn1Writable for UniversalString<'_> {
     }
 }
 
-fn validate_integer(data: &[u8], signed: bool) -> ParseResult<()> {
+const fn validate_integer(data: &[u8], signed: bool) -> ParseResult<()> {
     if data.is_empty() {
         return Err(ParseError::new(ParseErrorKind::InvalidValue));
     }
@@ -656,9 +656,11 @@ impl<'a> BigUint<'a> {
     /// as required by DER: minimally and if the high bit would be set in the
     /// first octet, a leading `\x00` should be prepended (to disambiguate from
     /// negative values).
-    pub fn new(data: &'a [u8]) -> Option<Self> {
-        validate_integer(data, false).ok()?;
-        Some(BigUint { data })
+    pub const fn new(data: &'a [u8]) -> Option<Self> {
+        match validate_integer(data, false) {
+            Ok(()) => Some(BigUint { data }),
+            Err(_) => None,
+        }
     }
 
     /// Returns the contents of the integer as big-endian bytes.
@@ -731,9 +733,11 @@ impl<'a> BigInt<'a> {
     /// as required by DER: minimally and if the high bit would be set in the
     /// first octet, a leading `\x00` should be prepended (to disambiguate from
     /// negative values).
-    pub fn new(data: &'a [u8]) -> Option<Self> {
-        validate_integer(data, true).ok()?;
-        Some(BigInt { data })
+    pub const fn new(data: &'a [u8]) -> Option<Self> {
+        match validate_integer(data, true) {
+            Ok(()) => Some(BigInt { data }),
+            Err(_) => None,
+        }
     }
 
     /// Returns the contents of the integer as big-endian bytes.
@@ -874,7 +878,7 @@ fn read_4_digits(data: &mut &[u8]) -> ParseResult<u16> {
         + u16::from(read_digit(data)?))
 }
 
-fn validate_date(year: u16, month: u8, day: u8) -> ParseResult<()> {
+const fn validate_date(year: u16, month: u8, day: u8) -> ParseResult<()> {
     if day < 1 {
         return Err(ParseError::new(ParseErrorKind::InvalidValue));
     }
@@ -934,26 +938,28 @@ pub struct DateTime {
 }
 
 impl DateTime {
-    pub fn new(
+    pub const fn new(
         year: u16,
         month: u8,
         day: u8,
         hour: u8,
         minute: u8,
         second: u8,
     ) -> ParseResult<DateTime> {
-        validate_date(year, month, day)?;
         if hour > 23 || minute > 59 || second > 59 {
             return Err(ParseError::new(ParseErrorKind::InvalidValue));
         }
-        Ok(DateTime {
-            year,
-            month,
-            day,
-            hour,
-            minute,
-            second,
-        })
+        match validate_date(year, month, day) {
+            Ok(()) => Ok(DateTime {
+                year,
+                month,
+                day,
+                hour,
+                minute,
+                second,
+            }),
+            Err(e) => Err(e),
+        }
     }
 
     /// The calendar year.