oxipng/src/deflate/miniz_stream.rs
2020-03-31 23:31:17 -04:00

71 lines
2.3 KiB
Rust

use crate::atomicmin::AtomicMin;
use crate::error::PngError;
use crate::PngResult;
use miniz_oxide::deflate::core::*;
pub(crate) fn compress_to_vec_oxipng(
input: &[u8],
level: u8,
window_bits: i32,
strategy: i32,
max_size: &AtomicMin,
deadline: &crate::Deadline,
) -> PngResult<Vec<u8>> {
// The comp flags function sets the zlib flag if the window_bits parameter is > 0.
let flags = create_comp_flags_from_zip_params(level.into(), window_bits, strategy);
let mut compressor = CompressorOxide::new(flags);
// if max size is known, then expect that much data (but no more than input.len())
let mut output = Vec::with_capacity(max_size.get().unwrap_or(input.len() / 2).min(input.len()));
// # Unsafe
// We trust compress to not read the uninitialized bytes.
unsafe {
let cap = output.capacity();
output.set_len(cap);
}
let mut in_pos = 0;
let mut out_pos = 0;
loop {
let (status, bytes_in, bytes_out) = compress(
&mut compressor,
&input[in_pos..],
&mut output[out_pos..],
TDEFLFlush::Finish,
);
out_pos += bytes_out;
in_pos += bytes_in;
match status {
TDEFLStatus::Done => {
output.truncate(out_pos);
break;
}
TDEFLStatus::Okay => {
if let Some(max) = max_size.get() {
if output.len() > max {
return Err(PngError::DeflatedDataTooLong(output.len()));
}
}
if deadline.passed() {
return Err(PngError::TimedOut);
}
// We need more space, so extend the vector.
if output.len().saturating_sub(out_pos) < 30 {
let current_len = output.len();
output.reserve(current_len);
// # Unsafe
// We trust compress to not read the uninitialized bytes.
unsafe {
let cap = output.capacity();
output.set_len(cap);
}
}
}
// Not supposed to happen unless there is a bug.
_ => panic!("Bug! Unexpectedly failed to compress!"),
}
}
Ok(output)
}