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Add read_be_u16 and tidy parse_next_chunk

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Andrew 2025-01-14 19:06:19 +13:00 committed by Alejandro González
parent 6c7ab5d79f
commit 60911977f6
1 changed files with 18 additions and 20 deletions
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38
src/headers.rs
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@ -134,7 +134,7 @@ fn parse_jumbf_box(data: &[u8]) -> Option<(&[u8], &[u8])> {
return None;
}
let (len, rest) = data.split_at(4);
let len = u32::from_be_bytes(len.try_into().unwrap()) as usize;
let len = read_be_u32(len) as usize;
if len < 8 || len > data.len() {
return None;
}
@ -153,32 +153,25 @@ pub fn parse_next_chunk<'a>(
.get(*byte_offset..*byte_offset + 4)
.ok_or(PngError::TruncatedData)?,
);
if byte_data.len() < *byte_offset + 12 + length as usize {
return Err(PngError::TruncatedData);
}
*byte_offset += 4;
let chunk_start = *byte_offset;
let chunk_name = byte_data
.get(chunk_start..chunk_start + 4)
.ok_or(PngError::TruncatedData)?;
let chunk_name = &byte_data[chunk_start..chunk_start + 4];
if chunk_name == b"IEND" {
// End of data
return Ok(None);
}
*byte_offset += 4;
let data = byte_data
.get(*byte_offset..*byte_offset + length as usize)
.ok_or(PngError::TruncatedData)?;
let data = &byte_data[*byte_offset..*byte_offset + length as usize];
*byte_offset += length as usize;
let crc = read_be_u32(
byte_data
.get(*byte_offset..*byte_offset + 4)
.ok_or(PngError::TruncatedData)?,
);
let crc = read_be_u32(&byte_data[*byte_offset..*byte_offset + 4]);
*byte_offset += 4;
let chunk_bytes = byte_data
.get(chunk_start..chunk_start + 4 + length as usize)
.ok_or(PngError::TruncatedData)?;
let chunk_bytes = &byte_data[chunk_start..chunk_start + 4 + length as usize];
if !fix_errors && crc32(chunk_bytes) != crc {
return Err(PngError::new(&format!(
"CRC Mismatch in {} chunk; May be recoverable by using --fix",
@ -202,13 +195,13 @@ pub fn parse_ihdr_chunk(
0 => ColorType::Grayscale {
transparent_shade: trns_data
.filter(|t| t.len() >= 2)
.map(|t| u16::from_be_bytes([t[0], t[1]])),
.map(|t| read_be_u16(&t[0..2])),
},
2 => ColorType::RGB {
transparent_color: trns_data.filter(|t| t.len() >= 6).map(|t| RGB16 {
r: u16::from_be_bytes([t[0], t[1]]),
g: u16::from_be_bytes([t[2], t[3]]),
b: u16::from_be_bytes([t[4], t[5]]),
r: read_be_u16(&t[0..2]),
g: read_be_u16(&t[2..4]),
b: read_be_u16(&t[4..6]),
}),
},
3 => ColorType::Indexed {
@ -245,7 +238,12 @@ fn palette_to_rgba(
}
#[inline]
fn read_be_u32(bytes: &[u8]) -> u32 {
pub fn read_be_u16(bytes: &[u8]) -> u16 {
u16::from_be_bytes(bytes.try_into().unwrap())
}
#[inline]
pub fn read_be_u32(bytes: &[u8]) -> u32 {
u32::from_be_bytes(bytes.try_into().unwrap())
}