From 2b4e522b12a7eb87e91cd1cdc56064ee429a5212 Mon Sep 17 00:00:00 2001
From: Ben Bridle <bridle.benjamin@gmail.com>
Date: Tue, 11 Feb 2025 14:00:20 +1300
Subject: Initial commit

---
 src/parsers/packed_binary_literal.rs | 80 ++++++++++++++++++++++++++++++++++++
 1 file changed, 80 insertions(+)
 create mode 100644 src/parsers/packed_binary_literal.rs

(limited to 'src/parsers/packed_binary_literal.rs')

diff --git a/src/parsers/packed_binary_literal.rs b/src/parsers/packed_binary_literal.rs
new file mode 100644
index 0000000..9704fc4
--- /dev/null
+++ b/src/parsers/packed_binary_literal.rs
@@ -0,0 +1,80 @@
+use crate::*;
+
+
+pub fn parse_packed_binary_literal(string: &str, parent: &Tokeniser) -> PackedBinaryLiteral  {
+    use PackedBinaryLiteralParseError as ParseError;
+    use PackedBinaryLiteralParseErrorVariant as ParseErrorVar;
+
+    let mut value = 0;
+    let mut bits = 0;
+    let mut name = '\0';
+    let mut fields: Vec<BitField> = Vec::new();
+    let mut errors: Vec<ParseError> = Vec::new();
+
+    macro_rules! push_field {
+        ($source:expr) => {
+            if fields.iter().any(|f| f.name == name) {
+                let variant = ParseErrorVar::DuplicateFieldName(name);
+                errors.push(ParseError { source: $source, variant });
+            } else {
+                fields.push(BitField { name, source: $source, bits, shift: 0 });
+            }
+        };
+    }
+
+    let mut t = Tokeniser::new_child(string, parent);
+    t.position.to_next_char();  // skip opening hash character
+
+    while let Some(c) = t.eat_char() {
+        // Ignore underscores.
+        if c == '_' {
+            t.prev_position = t.prev_prev_position;
+            continue;
+        }
+
+        // Add a bit to the value;
+        value <<= 1;
+        for field in &mut fields {
+            field.shift += 1;
+        }
+
+        // Extend the current field.
+        if c == name {
+            bits += 1;
+            continue;
+        }
+
+        // Commit the current field.
+        if bits > 0 {
+            push_field!(t.mark_prev_end_position());
+            bits = 0;
+            name = '\0';
+        }
+
+        // Parse bit literals.
+        if c == '0' {
+            continue;
+        }
+        if c == '1' {
+            value |= 1;
+            continue;
+        }
+
+        t.mark_prev_start_position();
+        if c.is_alphabetic() {
+            name = c;
+            bits = 1;
+            continue;
+        } else {
+            let source = t.mark_end_position();
+            errors.push(ParseError { source, variant: ParseErrorVar::InvalidCharacter(c) });
+        }
+    }
+
+    // Commit the final field.
+    if bits > 0 {
+        push_field!(t.mark_end_position());
+    }
+
+    PackedBinaryLiteral { value, fields, errors }
+}
-- 
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