Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 241 insertions, 0 deletions

diff --git a/third_party/rust/base64/src/alphabet.rs b/third_party/rust/base64/src/alphabet.rs
new file mode 100644
index 0000000000..7cd1b57073
--- /dev/null
+++ b/third_party/rust/base64/src/alphabet.rs
@@ -0,0 +1,241 @@
+//! Provides [Alphabet] and constants for alphabets commonly used in the wild.
+
+use crate::PAD_BYTE;
+use core::fmt;
+#[cfg(any(feature = "std", test))]
+use std::error;
+
+const ALPHABET_SIZE: usize = 64;
+
+/// An alphabet defines the 64 ASCII characters (symbols) used for base64.
+///
+/// Common alphabets are provided as constants, and custom alphabets
+/// can be made via `from_str` or the `TryFrom<str>` implementation.
+///
+/// ```
+/// let custom = base64::alphabet::Alphabet::new("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/").unwrap();
+///
+/// let engine = base64::engine::GeneralPurpose::new(
+///     &custom,
+///     base64::engine::general_purpose::PAD);
+/// ```
+#[derive(Clone, Debug, Eq, PartialEq)]
+pub struct Alphabet {
+    pub(crate) symbols: [u8; ALPHABET_SIZE],
+}
+
+impl Alphabet {
+    /// Performs no checks so that it can be const.
+    /// Used only for known-valid strings.
+    const fn from_str_unchecked(alphabet: &str) -> Self {
+        let mut symbols = [0_u8; ALPHABET_SIZE];
+        let source_bytes = alphabet.as_bytes();
+
+        // a way to copy that's allowed in const fn
+        let mut index = 0;
+        while index < ALPHABET_SIZE {
+            symbols[index] = source_bytes[index];
+            index += 1;
+        }
+
+        Self { symbols }
+    }
+
+    /// Create an `Alphabet` from a string of 64 unique printable ASCII bytes.
+    ///
+    /// The `=` byte is not allowed as it is used for padding.
+    pub const fn new(alphabet: &str) -> Result<Self, ParseAlphabetError> {
+        let bytes = alphabet.as_bytes();
+        if bytes.len() != ALPHABET_SIZE {
+            return Err(ParseAlphabetError::InvalidLength);
+        }
+
+        {
+            let mut index = 0;
+            while index < ALPHABET_SIZE {
+                let byte = bytes[index];
+
+                // must be ascii printable. 127 (DEL) is commonly considered printable
+                // for some reason but clearly unsuitable for base64.
+                if !(byte >= 32_u8 && byte <= 126_u8) {
+                    return Err(ParseAlphabetError::UnprintableByte(byte));
+                }
+                // = is assumed to be padding, so cannot be used as a symbol
+                if byte == PAD_BYTE {
+                    return Err(ParseAlphabetError::ReservedByte(byte));
+                }
+
+                // Check for duplicates while staying within what const allows.
+                // It's n^2, but only over 64 hot bytes, and only once, so it's likely in the single digit
+                // microsecond range.
+
+                let mut probe_index = 0;
+                while probe_index < ALPHABET_SIZE {
+                    if probe_index == index {
+                        probe_index += 1;
+                        continue;
+                    }
+
+                    let probe_byte = bytes[probe_index];
+
+                    if byte == probe_byte {
+                        return Err(ParseAlphabetError::DuplicatedByte(byte));
+                    }
+
+                    probe_index += 1;
+                }
+
+                index += 1;
+            }
+        }
+
+        Ok(Self::from_str_unchecked(alphabet))
+    }
+}
+
+impl TryFrom<&str> for Alphabet {
+    type Error = ParseAlphabetError;
+
+    fn try_from(value: &str) -> Result<Self, Self::Error> {
+        Self::new(value)
+    }
+}
+
+/// Possible errors when constructing an [Alphabet] from a `str`.
+#[derive(Debug, Eq, PartialEq)]
+pub enum ParseAlphabetError {
+    /// Alphabets must be 64 ASCII bytes
+    InvalidLength,
+    /// All bytes must be unique
+    DuplicatedByte(u8),
+    /// All bytes must be printable (in the range `[32, 126]`).
+    UnprintableByte(u8),
+    /// `=` cannot be used
+    ReservedByte(u8),
+}
+
+impl fmt::Display for ParseAlphabetError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Self::InvalidLength => write!(f, "Invalid length - must be 64 bytes"),
+            Self::DuplicatedByte(b) => write!(f, "Duplicated byte: {:#04x}", b),
+            Self::UnprintableByte(b) => write!(f, "Unprintable byte: {:#04x}", b),
+            Self::ReservedByte(b) => write!(f, "Reserved byte: {:#04x}", b),
+        }
+    }
+}
+
+#[cfg(any(feature = "std", test))]
+impl error::Error for ParseAlphabetError {}
+
+/// The standard alphabet (uses `+` and `/`).
+///
+/// See [RFC 3548](https://tools.ietf.org/html/rfc3548#section-3).
+pub const STANDARD: Alphabet = Alphabet::from_str_unchecked(
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/",
+);
+
+/// The URL safe alphabet (uses `-` and `_`).
+///
+/// See [RFC 3548](https://tools.ietf.org/html/rfc3548#section-4).
+pub const URL_SAFE: Alphabet = Alphabet::from_str_unchecked(
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_",
+);
+
+/// The `crypt(3)` alphabet (uses `.` and `/` as the first two values).
+///
+/// Not standardized, but folk wisdom on the net asserts that this alphabet is what crypt uses.
+pub const CRYPT: Alphabet = Alphabet::from_str_unchecked(
+    "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz",
+);
+
+/// The bcrypt alphabet.
+pub const BCRYPT: Alphabet = Alphabet::from_str_unchecked(
+    "./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789",
+);
+
+/// The alphabet used in IMAP-modified UTF-7 (uses `+` and `,`).
+///
+/// See [RFC 3501](https://tools.ietf.org/html/rfc3501#section-5.1.3)
+pub const IMAP_MUTF7: Alphabet = Alphabet::from_str_unchecked(
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+,",
+);
+
+/// The alphabet used in BinHex 4.0 files.
+///
+/// See [BinHex 4.0 Definition](http://files.stairways.com/other/binhex-40-specs-info.txt)
+pub const BIN_HEX: Alphabet = Alphabet::from_str_unchecked(
+    "!\"#$%&'()*+,-0123456789@ABCDEFGHIJKLMNPQRSTUVXYZ[`abcdehijklmpqr",
+);
+
+#[cfg(test)]
+mod tests {
+    use crate::alphabet::*;
+    use std::convert::TryFrom as _;
+
+    #[test]
+    fn detects_duplicate_start() {
+        assert_eq!(
+            ParseAlphabetError::DuplicatedByte(b'A'),
+            Alphabet::new("AACDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/")
+                .unwrap_err()
+        );
+    }
+
+    #[test]
+    fn detects_duplicate_end() {
+        assert_eq!(
+            ParseAlphabetError::DuplicatedByte(b'/'),
+            Alphabet::new("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789//")
+                .unwrap_err()
+        );
+    }
+
+    #[test]
+    fn detects_duplicate_middle() {
+        assert_eq!(
+            ParseAlphabetError::DuplicatedByte(b'Z'),
+            Alphabet::new("ABCDEFGHIJKLMNOPQRSTUVWXYZZbcdefghijklmnopqrstuvwxyz0123456789+/")
+                .unwrap_err()
+        );
+    }
+
+    #[test]
+    fn detects_length() {
+        assert_eq!(
+            ParseAlphabetError::InvalidLength,
+            Alphabet::new(
+                "xxxxxxxxxABCDEFGHIJKLMNOPQRSTUVWXYZZbcdefghijklmnopqrstuvwxyz0123456789+/",
+            )
+            .unwrap_err()
+        );
+    }
+
+    #[test]
+    fn detects_padding() {
+        assert_eq!(
+            ParseAlphabetError::ReservedByte(b'='),
+            Alphabet::new("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+=")
+                .unwrap_err()
+        );
+    }
+
+    #[test]
+    fn detects_unprintable() {
+        // form feed
+        assert_eq!(
+            ParseAlphabetError::UnprintableByte(0xc),
+            Alphabet::new("\x0cBCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/")
+                .unwrap_err()
+        );
+    }
+
+    #[test]
+    fn same_as_unchecked() {
+        assert_eq!(
+            STANDARD,
+            Alphabet::try_from("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/")
+                .unwrap()
+        );
+    }
+}