write more code

1 files changed, 21 insertions, 0 deletions

diff --git a/matroska/src/size.rs b/matroska/src/size.rs
new file mode 100644
index 0000000..e774f0a
--- /dev/null
+++ b/matroska/src/size.rs
@@ -0,0 +1,21 @@
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum EbmlSize {
+    Exact(usize),
+    Unknown,
+}
+impl EbmlSize {
+    pub fn from_vint((value, len): (u64, usize)) -> EbmlSize {
+        if value == ((1 << (7 * len)) - 1) {
+            Self::Unknown
+        } else {
+            Self::Exact(value as usize)
+        }
+    }
+    pub fn some(self) -> Option<usize> {
+        match self {
+            EbmlSize::Exact(s) => Some(s),
+            EbmlSize::Unknown => None,
+        }
+    }
+}