65 lines
1.5 KiB
Rust
65 lines
1.5 KiB
Rust
use crate::error::Error;
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#[derive(Debug)]
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pub struct PesHeader {
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pub version: [u8; 4],
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pub pec_offset: u32,
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}
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pub fn parse_header(data: &[u8]) -> Result<PesHeader, Error> {
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if data.len() < 12 {
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return Err(Error::TooShort {
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expected: 12,
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actual: data.len(),
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});
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}
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let magic = &data[0..4];
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if magic != b"#PES" {
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let mut m = [0u8; 4];
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m.copy_from_slice(magic);
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return Err(Error::InvalidPesMagic(m));
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}
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let mut version = [0u8; 4];
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version.copy_from_slice(&data[4..8]);
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let pec_offset = u32::from_le_bytes([data[8], data[9], data[10], data[11]]);
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Ok(PesHeader {
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version,
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pec_offset,
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})
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn parse_valid_header() {
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let mut data = vec![0u8; 20];
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data[0..4].copy_from_slice(b"#PES");
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data[4..8].copy_from_slice(b"0001");
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data[8..12].copy_from_slice(&16u32.to_le_bytes());
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let header = parse_header(&data).unwrap();
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assert_eq!(&header.version, b"0001");
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assert_eq!(header.pec_offset, 16);
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}
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#[test]
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fn reject_invalid_magic() {
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let data = b"NOTPES0001\x10\x00\x00\x00";
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let err = parse_header(data).unwrap_err();
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assert!(matches!(err, Error::InvalidPesMagic(_)));
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}
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#[test]
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fn reject_too_short() {
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let data = b"#PES00";
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let err = parse_header(data).unwrap_err();
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assert!(matches!(err, Error::TooShort { .. }));
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}
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}
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