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use libz_sys;
use miniz_sys;
use libc::c_int;
use std::cmp::max;

/// Decompress a data stream using the DEFLATE algorithm
pub fn inflate(data: &[u8]) -> Result<Vec<u8>, String> {
    let mut input = data.to_owned();
    let mut stream = super::libz_stream::Stream::new_decompress();
    let mut output = Vec::with_capacity(data.len());
    loop {
        match stream.decompress_vec(input.as_mut(), output.as_mut()) {
            libz_sys::Z_OK => output.reserve(data.len()),
            libz_sys::Z_STREAM_END => break,
            c => return Err(format!("Error code on decompress: {}", c)),
        }
    }
    output.shrink_to_fit();

    Ok(output)
}

/// Compress a data stream using the zlib implementation of the DEFLATE algorithm
pub fn deflate(data: &[u8], zc: u8, zm: u8, zs: u8, zw: u8) -> Result<Vec<u8>, String> {
    let mut input = data.to_owned();
    // Compressed input should be smaller than decompressed, so allocate less than data.len()
    // However, it needs a minimum capacity in order to handle very small images
    let mut output = Vec::with_capacity(max(1024, data.len() / 20));
    if zs == 0 || zs == 1 {
        // Miniz performs 1-2 orders of magnitude better for strategies 0 and 1
        let mut stream = super::miniz_stream::Stream::new_compress(zc as c_int,
                                                                   zw as c_int,
                                                                   zm as c_int,
                                                                   zs as c_int);
        loop {
            match stream.compress_vec(input.as_mut(), output.as_mut()) {
                miniz_sys::MZ_OK => output.reserve(max(1024, data.len() / 20)),
                miniz_sys::MZ_STREAM_END => break,
                c => return Err(format!("Error code on compress: {}", c)),
            }
        }
    } else {
        // libz performs an order of magnitude better for strategies 2 and 3
        let mut stream = super::libz_stream::Stream::new_compress(zc as c_int,
                                                                  zw as c_int,
                                                                  zm as c_int,
                                                                  zs as c_int);
        loop {
            match stream.compress_vec(input.as_mut(), output.as_mut()) {
                libz_sys::Z_OK => output.reserve(max(1024, data.len() / 20)),
                libz_sys::Z_STREAM_END => break,
                c => return Err(format!("Error code on compress: {}", c)),
            }
        }
    }

    output.shrink_to_fit();

    Ok(output)
}