1 files changed, 121 insertions, 0 deletions
diff --git a/third_party/rust/deflate/src/lzvalue.rs b/third_party/rust/deflate/src/lzvalue.rs
new file mode 100644
index 0000000000..acbbde8b20
--- /dev/null
+++ b/third_party/rust/deflate/src/lzvalue.rs
@@ -0,0 +1,121 @@
+use huffman_table::{MAX_DISTANCE, MIN_MATCH};
+#[cfg(test)]
+use huffman_table::MAX_MATCH;
+
+#[derive(Copy, Clone, Eq, PartialEq, Debug)]
+pub struct StoredLength {
+    length: u8,
+}
+
+impl StoredLength {
+    #[cfg(test)]
+    pub fn from_actual_length(length: u16) -> StoredLength {
+        assert!(length <= MAX_MATCH && length >= MIN_MATCH);
+        StoredLength {
+            length: (length - MIN_MATCH) as u8,
+        }
+    }
+
+    pub fn new(stored_length: u8) -> StoredLength {
+        StoredLength {
+            length: stored_length,
+        }
+    }
+
+    pub fn stored_length(&self) -> u8 {
+        self.length
+    }
+
+    #[cfg(test)]
+    pub fn actual_length(&self) -> u16 {
+        u16::from(self.length) + MIN_MATCH
+    }
+}
+
+#[derive(Copy, Clone, Eq, PartialEq, Debug)]
+pub enum LZType {
+    Literal(u8),
+    StoredLengthDistance(StoredLength, u16),
+}
+
+#[derive(Copy, Clone, Eq, PartialEq, Debug)]
+pub struct LZValue {
+    litlen: u8,
+    distance: u16,
+}
+
+impl LZValue {
+    #[inline]
+    pub fn literal(value: u8) -> LZValue {
+        LZValue {
+            litlen: value,
+            distance: 0,
+        }
+    }
+
+    #[inline]
+    pub fn length_distance(length: u16, distance: u16) -> LZValue {
+        debug_assert!(distance > 0 && distance <= MAX_DISTANCE);
+        let stored_length = (length - MIN_MATCH) as u8;
+        LZValue {
+            litlen: stored_length,
+            distance: distance,
+        }
+    }
+
+    #[inline]
+    pub fn value(&self) -> LZType {
+        if self.distance != 0 {
+            LZType::StoredLengthDistance(StoredLength::new(self.litlen), self.distance)
+        } else {
+            LZType::Literal(self.litlen)
+        }
+    }
+}
+
+#[cfg(test)]
+pub fn lit(l: u8) -> LZValue {
+    LZValue::literal(l)
+}
+
+#[cfg(test)]
+pub fn ld(l: u16, d: u16) -> LZValue {
+    LZValue::length_distance(l, d)
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    use huffman_table::{MIN_MATCH, MIN_DISTANCE, MAX_MATCH, MAX_DISTANCE};
+    #[test]
+    fn lzvalue() {
+        for i in 0..255 as usize + 1 {
+            let v = LZValue::literal(i as u8);
+            if let LZType::Literal(n) = v.value() {
+                assert_eq!(n as usize, i);
+            } else {
+                panic!();
+            }
+        }
+
+        for i in MIN_MATCH..MAX_MATCH + 1 {
+            let v = LZValue::length_distance(i, 5);
+            if let LZType::StoredLengthDistance(l, _) = v.value() {
+                assert_eq!(l.actual_length(), i);
+            } else {
+                panic!();
+            }
+        }
+
+        for i in MIN_DISTANCE..MAX_DISTANCE + 1 {
+            let v = LZValue::length_distance(5, i);
+
+            if let LZType::StoredLengthDistance(_, d) = v.value() {
+                assert_eq!(d, i);
+            } else {
+                panic!("Failed to get distance {}", i);
+            }
+        }
+
+    }
+}