1 files changed, 83 insertions, 0 deletions
diff --git a/vendor/der/src/reader/pem.rs b/vendor/der/src/reader/pem.rs
new file mode 100644
index 000000000..01bb4f20e
--- /dev/null
+++ b/vendor/der/src/reader/pem.rs
@@ -0,0 +1,83 @@
+//! Streaming PEM reader.
+
+use super::Reader;
+use crate::{ErrorKind, Header, Length, Result};
+use pem_rfc7468::Decoder;
+
+/// `Reader` type which decodes PEM on-the-fly.
+#[cfg(feature = "pem")]
+#[cfg_attr(docsrs, doc(cfg(feature = "pem")))]
+#[derive(Clone)]
+pub struct PemReader<'i> {
+    /// Inner PEM decoder.
+    decoder: Decoder<'i>,
+
+    /// Input length (in bytes after Base64 decoding).
+    input_len: Length,
+
+    /// Position in the input buffer (in bytes after Base64 decoding).
+    position: Length,
+}
+
+#[cfg(feature = "pem")]
+#[cfg_attr(docsrs, doc(cfg(feature = "pem")))]
+impl<'i> PemReader<'i> {
+    /// Create a new PEM reader which decodes data on-the-fly.
+    ///
+    /// Uses the default 64-character line wrapping.
+    pub fn new(pem: &'i [u8]) -> Result<Self> {
+        let decoder = Decoder::new(pem)?;
+        let input_len = Length::try_from(decoder.remaining_len())?;
+
+        Ok(Self {
+            decoder,
+            input_len,
+            position: Length::ZERO,
+        })
+    }
+
+    /// Get the PEM label which will be used in the encapsulation boundaries
+    /// for this document.
+    pub fn type_label(&self) -> &'i str {
+        self.decoder.type_label()
+    }
+}
+
+#[cfg(feature = "pem")]
+#[cfg_attr(docsrs, doc(cfg(feature = "pem")))]
+impl<'i> Reader<'i> for PemReader<'i> {
+    fn input_len(&self) -> Length {
+        self.input_len
+    }
+
+    fn peek_byte(&self) -> Option<u8> {
+        // TODO(tarcieri): lookahead buffer
+        None
+    }
+
+    fn peek_header(&self) -> Result<Header> {
+        // TODO(tarcieri): lookahead buffer
+        Err(ErrorKind::Reader.into())
+    }
+
+    fn position(&self) -> Length {
+        self.position
+    }
+
+    fn read_slice(&mut self, _len: Length) -> Result<&'i [u8]> {
+        // Can't borrow from PEM because it requires decoding
+        Err(ErrorKind::Reader.into())
+    }
+
+    fn read_into<'o>(&mut self, buf: &'o mut [u8]) -> Result<&'o [u8]> {
+        let bytes = self.decoder.decode(buf)?;
+        self.position = (self.position + bytes.len())?;
+
+        debug_assert_eq!(
+            self.position,
+            (self.input_len - Length::try_from(self.decoder.remaining_len())?)?
+        );
+
+        Ok(bytes)
+    }
+}