1 files changed, 44 insertions, 0 deletions
diff --git a/third_party/rust/sfv/src/utils.rs b/third_party/rust/sfv/src/utils.rs
new file mode 100644
index 0000000000..7eb79340ba
--- /dev/null
+++ b/third_party/rust/sfv/src/utils.rs
@@ -0,0 +1,44 @@
+use data_encoding::{Encoding, Specification};
+use std::iter::Peekable;
+use std::str::Chars;
+
+pub(crate) fn base64() -> Result<Encoding, &'static str> {
+    let mut spec = Specification::new();
+    spec.check_trailing_bits = false;
+    spec.symbols
+        .push_str("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/");
+    spec.padding = None;
+    spec.ignore = "=".to_owned();
+    spec.encoding()
+        .map_err(|_err| "invalid base64 specification")
+}
+
+pub(crate) fn is_tchar(c: char) -> bool {
+    // See tchar values list in https://tools.ietf.org/html/rfc7230#section-3.2.6
+    let tchars = "!#$%&'*+-.^_`|~";
+    tchars.contains(c) || c.is_ascii_alphanumeric()
+}
+
+pub(crate) fn is_allowed_b64_content(c: char) -> bool {
+    c.is_ascii_alphanumeric() || c == '+' || c == '=' || c == '/'
+}
+
+pub(crate) fn consume_ows_chars(input_chars: &mut Peekable<Chars>) {
+    while let Some(c) = input_chars.peek() {
+        if c == &' ' || c == &'\t' {
+            input_chars.next();
+        } else {
+            break;
+        }
+    }
+}
+
+pub(crate) fn consume_sp_chars(input_chars: &mut Peekable<Chars>) {
+    while let Some(c) = input_chars.peek() {
+        if c == &' ' {
+            input_chars.next();
+        } else {
+            break;
+        }
+    }
+}