ari mcstatusface

src/leb128.rs

@@ -0,0 +1,38 @@
+const CONTINUE_BIT: u8 = 0x80;
+
+pub struct LEB128;
+
+impl LEB128 {
+    pub fn write_leb128(buffer: &mut Vec<u8>, mut value: u64) -> usize {
+        let mut size: usize = 0;
+        loop {
+            let mut byte: u8 = (value & (std::u8::MAX as u64)).try_into().unwrap();
+            value >>= 7;
+            if value != 0 {
+                byte |= CONTINUE_BIT;
+            }
+
+            buffer.push(byte);
+            size += 1;
+
+            if value == 0 {
+                return size;
+            }
+        }
+    }
+
+    pub fn read_leb128(buffer: &[u8]) -> (u32, usize) {
+        let mut result: u32 = 0;
+        let mut shift: usize = 0;
+        let mut offset: usize = 0;
+        loop {
+            let byte: u8 = buffer[offset];
+            result |= ((byte & (std::i8::MAX as u8)) as u32) << (shift as u32);
+            offset += 1;
+            if byte & CONTINUE_BIT == 0 || offset == 4 {
+                return (result, offset);
+            }
+            shift += 7;
+        }
+    }
+}