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use std::fmt;
#[derive(Clone, Copy, Debug)]
pub struct ChunkHeader {
offset: u64,
header_size: u16,
chunk_size: u32,
chunk_type: u16,
}
impl ChunkHeader {
pub fn new(offset: u64, header_size: u16, chunk_size: u32, chunk_type: u16) -> Self {
Self {
offset,
header_size,
chunk_size,
chunk_type,
}
}
pub fn get_offset(&self) -> u64 {
self.offset
}
pub fn get_header_size(&self) -> u16 {
self.header_size
}
pub fn get_data_offset(&self) -> u64 {
self.offset + u64::from(self.header_size)
}
pub fn get_chunk_end(&self) -> u64 {
self.offset + u64::from(self.chunk_size)
}
pub fn absolute(&self, relative: u64) -> u64 {
let absolute = self.offset + relative;
if absolute > self.get_chunk_end() {
panic!("Requested a relative value out of bounds");
}
absolute
}
pub fn get_token(&self) -> u16 {
self.chunk_type
}
}
impl fmt::Display for ChunkHeader {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(
f,
"(Token:{:X}; Start: {}; Data: {}; End {})",
self.chunk_type,
self.offset,
self.get_data_offset(),
self.get_chunk_end()
)
}
}
#[cfg(test)]
mod tests {
use super::ChunkHeader;
#[test]
pub fn it_returns_data_offset() {
let chunk = ChunkHeader::new(4000, 8, 16, 0);
assert_eq!(4008, chunk.get_data_offset());
}
#[test]
pub fn it_returns_chunk_end() {
let chunk = ChunkHeader::new(4000, 8, 16, 0);
assert_eq!(4016, chunk.get_chunk_end());
}
#[test]
#[should_panic]
pub fn it_panics_from_relative_out_of_bound() {
let chunk = ChunkHeader::new(4000, 8, 500, 0);
chunk.absolute(510);
}
#[test]
pub fn it_returns_absolute_offsets_from_relative_ones() {
let chunk = ChunkHeader::new(4000, 8, 500, 0);
let res = chunk.absolute(490);
assert_eq!(4490, res);
}
}