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Fix infinite loop and pointer update bug in decompress_bmi2 #231

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Merged
404Setup merged 1 commit into from
Feb 18, 2026
Merged

Fix infinite loop and pointer update bug in decompress_bmi2 #231

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2 changes: 1 addition & 1 deletion src/decompress/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -467,7 +467,7 @@ impl Decompressor {
DecompressResult::Success
}

fn decompress_huffman_block(
pub(crate) fn decompress_huffman_block(
&mut self,
input: &[u8],
in_idx: &mut usize,
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27 changes: 26 additions & 1 deletion src/decompress/x86.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -267,6 +267,7 @@ pub unsafe fn decompress_bmi2(
}

loop {
let mut eob_found = false;
unsafe {
let in_ptr_start = input.as_ptr();
let in_ptr_end = in_ptr_start.add(in_len);
Expand All @@ -292,6 +293,7 @@ pub unsafe fn decompress_bmi2(
if entry & HUFFDEC_END_OF_BLOCK != 0 {
bitbuf >>= entry as u8;
bitsleft -= entry & 0xFF;
eob_found = true;
break;
}
if entry & HUFFDEC_SUBTABLE_POINTER != 0 {
Expand Down Expand Up @@ -323,6 +325,9 @@ pub unsafe fn decompress_bmi2(

let saved_bitbuf = bitbuf;
let total_bits = entry & 0xFF;
if bitsleft < total_bits {
break;
}
bitbuf >>= total_bits;
bitsleft -= total_bits;

Expand Down Expand Up @@ -1733,10 +1738,30 @@ pub unsafe fn decompress_bmi2(
copied += 1;
}
}
out_idx += length;
out_next = out_next.add(length);
}
}
in_idx = in_next.offset_from(in_ptr_start) as usize;
out_idx = out_next.offset_from(out_ptr_start) as usize;
}

if eob_found {
break;
}

d.bitbuf = bitbuf;
d.bitsleft = bitsleft;
d.state = crate::decompress::DecompressorState::BlockBody;

let res = d.decompress_huffman_block(input, &mut in_idx, output, &mut out_idx);

bitbuf = d.bitbuf;
bitsleft = d.bitsleft;

if res != DecompressResult::Success {
return (res, in_idx, out_idx);
}
break;
}
}
_ => return (DecompressResult::BadData, 0, 0),
Expand Down
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