implementing my own ebml library

5 files changed, 125 insertions, 0 deletions

diff --git a/remuxer/src/format/ebml/matroska.rs b/remuxer/src/format/ebml/matroska.rs
new file mode 100644
index 0000000..50aa783
--- /dev/null
+++ b/remuxer/src/format/ebml/matroska.rs
@@ -0,0 +1,39 @@
+pub enum TagType {
+    Master,
+    UnsignedInt,
+    Integer,
+    Utf8,
+    Binary,
+    Float,
+}
+
+macro_rules! define_ebml {
+    ($master:ident { $($name:ident: $kind:ty = $id:literal),* }) => {
+        pub enum $master {
+            $($name($kind)),*
+        }
+        impl $master {
+            
+        }
+    };
+}
+
+// 0x1a45dfa3
+define_ebml! {
+    Ebml {
+        EbmlVersion: u64 = 0x4286,
+        EbmlReadVersion: u64 = 0x42f7,
+        EbmlMaxIdLength: u64 = 0x42f2,
+        EbmlMaxSizeLength: u64 = 0x42f3,
+        DocType: String = 0x4282,
+        DocTypeVersion: u64 = 0x4287,
+        DocTypeReadVersion: u64 = 0x4285,
+        DocTypeExtension: DocTypeExtension = 0x4281
+    }
+}
+define_ebml! {
+    DocTypeExtension {
+        Name: String = 0x4283,
+        Version:  u64 = 0x4284
+    }
+}
diff --git a/remuxer/src/format/ebml/mod.rs b/remuxer/src/format/ebml/mod.rs
new file mode 100644
index 0000000..d8a703a
--- /dev/null
+++ b/remuxer/src/format/ebml/mod.rs
@@ -0,0 +1,3 @@
+pub mod read;
+pub mod write;
+pub mod matroska;
diff --git a/remuxer/src/format/ebml/read.rs b/remuxer/src/format/ebml/read.rs
new file mode 100644
index 0000000..06ccf2f
--- /dev/null
+++ b/remuxer/src/format/ebml/read.rs
@@ -0,0 +1,44 @@
+use std::io::{Read, Seek};
+
+use anyhow::Result;
+
+pub struct EbmlReader<T> {
+    inner: T,
+    position: usize,
+}
+
+impl<T: Read + Seek> EbmlReader<T> {
+    pub fn new(inner: T) -> Self {
+        Self { inner, position: 0 }
+    }
+
+    pub fn read_byte(&mut self) -> Result<u8> {
+        let mut b = [0u8];
+        self.inner.read_exact(&mut b)?;
+        Ok(b[0])
+    }
+    pub fn read_vint(&mut self) -> Result<(u64, u64)> {
+        let s = self.read_byte()? as u64;
+        let len = s.leading_zeros() + 1;
+        let mut value = s;
+        value -= 1 << (8 - len);
+        for _ in 0..(len - 1) {
+            value <<= 8;
+            value += self.read_byte()? as u64;
+        }
+        Ok((value, len.into()))
+    }
+
+    pub fn read_tag_id(&mut self) -> Result<u64> {
+        let (value, len) = self.read_vint()?;
+        Ok(value + (1 << (7 * len)))
+    }
+
+    pub fn read_tag(&mut self) -> Result<()> {
+        let id = self.read_tag_id()?;
+
+        Ok(())
+
+    }
+}
+
diff --git a/remuxer/src/format/ebml/write.rs b/remuxer/src/format/ebml/write.rs
new file mode 100644
index 0000000..1dee225
--- /dev/null
+++ b/remuxer/src/format/ebml/write.rs
@@ -0,0 +1,38 @@
+use anyhow::{bail, Result};
+use std::io::Write;
+
+pub struct EbmlWriter<T> {
+    inner: T,
+    position: usize,
+}
+
+impl<T: Write> EbmlWriter<T> {
+    pub fn new(inner: T, position: usize) -> Self {
+        Self { inner, position }
+    }
+
+    pub fn write(&mut self, data: &[u8]) -> Result<()> {
+        self.inner.write_all(data)?;
+        self.position += data.len();
+        Ok(())
+    }
+
+    pub fn write_vint(&mut self, i: u64) -> Result<()> {
+        if i > (1 << 56) - 1 {
+            bail!("vint does not fit");
+        }
+        let mut len = 1;
+        while len <= 8 {
+            if i < (1 << ((7 * len) - 1)) {
+                break;
+            }
+            len += 1;
+        }
+        let mut bytes = i.to_be_bytes();
+        bytes[0] |= 1 << (8 - len);
+        self.write(&bytes)
+    }
+
+}
+
+
diff --git a/remuxer/src/format/mod.rs b/remuxer/src/format/mod.rs
new file mode 100644
index 0000000..faec908
--- /dev/null
+++ b/remuxer/src/format/mod.rs
@@ -0,0 +1 @@
+pub mod ebml;