format

Author: HITGIF

rtp/src/codecs/av1/leb128.rs

@@ -0,0 +1,64 @@
+use bytes::{BufMut, Bytes, BytesMut};
+
+pub fn encode_leb128(mut val: u32) -> u32 {
+    let mut b = 0;
+    loop {
+        b |= val & 0b_0111_1111;
+        val >>= 7;
+        if val != 0 {
+            b |= 0b_1000_0000;
+            b <<= 8;
+        } else {
+            return b;
+        }
+    }
+}
+
+pub fn decode_leb128(mut val: u32) -> u32 {
+    let mut b = 0;
+    loop {
+        b |= val & 0b_0111_1111;
+        val >>= 8;
+        if val == 0 {
+            return b;
+        }
+        b <<= 7;
+    }
+}
+
+pub fn read_leb128(bytes: &Bytes) -> (u32, usize) {
+    let mut encoded = 0;
+    for i in 0..bytes.len() {
+        encoded |= bytes[i] as u32;
+        if bytes[i] & 0b_1000_0000 == 0 {
+            return (decode_leb128(encoded), i + 1);
+        }
+        encoded <<= 8;
+    }
+    (0, 0)
+}
+
+pub fn leb128_size(value: u32) -> usize {
+    let mut size = 0;
+    let mut value = value;
+    while value >= 0b_1000_0000 {
+        size += 1;
+        value >>= 7;
+    }
+    size + 1
+}
+
+pub trait BytesMutExt {
+    fn put_leb128(&mut self, n: u32);
+}
+
+impl BytesMutExt for BytesMut {
+    fn put_leb128(&mut self, n: u32) {
+        let encoded = encode_leb128(n);
+        let leb128_size = leb128_size(n);
+        for i in (0..leb128_size).rev() {
+            let byte = (encoded >> (i * 8)) as u8;
+            self.put_u8(byte)
+        }
+    }
+}