refactor parse impl

1 files changed, 27 insertions, 0 deletions

diff --git a/src/util.rs b/src/util.rs
index 809287f..48ab55e 100644
--- a/src/util.rs
+++ b/src/util.rs
@@ -13,3 +13,30 @@ macro_rules! parse_match {
         };
     };
 }
+
+#[macro_export]
+macro_rules! match_variant {
+    ( $values:expr, $x:path, $field:expr ) => {
+        match &$values[$field] {
+            $x(x) => { Ok(x.clone()) },
+            _ => { Err("") }
+        }.unwrap();
+    }
+}
+
+pub fn prepend_byte_len(buf: &mut Vec<u8>) {
+    use std::convert::TryInto;
+    let len: i32 = buf.len().try_into().unwrap();
+    let ulen: &[u8] = &len.to_be_bytes();
+    buf.insert(0, ulen[3]);
+    buf.insert(0, ulen[2]);
+    buf.insert(0, ulen[1]);
+    buf.insert(0, ulen[0]);
+}
+
+pub fn insert_bytes(pos: usize, buf: &mut Vec<u8>, input: &mut [u8]) {
+    input.reverse();
+    for i in input {
+        buf.insert(pos, *i)
+    }
+}