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use anyhow::bail;
pub mod matroska;
pub mod read;
pub mod write;
#[derive(Debug, Clone)]
pub enum Master {
Start,
End,
}
pub trait ValueFromBuf: Sized {
fn from_buf(buf: &[u8]) -> anyhow::Result<Self>;
}
impl ValueFromBuf for u64 {
fn from_buf(buf: &[u8]) -> anyhow::Result<Self> {
if buf.len() > 8 {
bail!("u64 too big")
}
let mut val = 0u64;
for byte in buf {
val <<= 8;
val |= *byte as u64;
}
Ok(val)
}
}
impl ValueFromBuf for i64 {
fn from_buf(buf: &[u8]) -> anyhow::Result<Self> {
if buf.len() > 8 {
bail!("i64 too big")
}
Ok(if buf[0] > 127 {
if buf.len() == 8 {
i64::from_be_bytes(buf.try_into().unwrap())
} else {
-((1 << (buf.len() * 8)) - (u64::from_buf(buf)? as i64))
}
} else {
u64::from_buf(buf)? as i64
})
}
}
impl ValueFromBuf for f64 {
fn from_buf(buf: &[u8]) -> anyhow::Result<Self> {
Ok(if buf.len() == 4 {
f32::from_be_bytes(buf.try_into().unwrap()) as f64
} else if buf.len() == 8 {
f64::from_be_bytes(buf.try_into().unwrap())
} else {
bail!("float is not 4 or 8 bytes long");
})
}
}
impl ValueFromBuf for Vec<u8> {
fn from_buf(buf: &[u8]) -> anyhow::Result<Self> {
Ok(buf.to_vec())
}
}
impl ValueFromBuf for String {
fn from_buf(buf: &[u8]) -> anyhow::Result<Self> {
Ok(String::from_utf8(Vec::from(buf))?)
}
}
impl ValueFromBuf for Master {
/// this has an internal usage, where buf has len of 1, when an end should be constructed
fn from_buf(buf: &[u8]) -> anyhow::Result<Self> {
Ok(match buf.len() {
0 => Master::Start,
1 => Master::End,
_ => unreachable!(),
})
}
}
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