// Linux stand-in for the one call filius-ipad makes into Apple's Compression
// framework: COMPRESSION_ZLIB is raw DEFLATE (RFC 1951), decoded here by zlib.
import CZlib

public struct compression_algorithm: Equatable { let rawValue: Int32 }
public let COMPRESSION_ZLIB = compression_algorithm(rawValue: 0x205)

public func compression_decode_buffer(
    _ dst: UnsafeMutablePointer<UInt8>, _ dstSize: Int,
    _ src: UnsafePointer<UInt8>, _ srcSize: Int,
    _ scratch: UnsafeMutableRawPointer?, _ algorithm: compression_algorithm
) -> Int {
    var stream = z_stream()
    guard inflateInit2_(&stream, -15, ZLIB_VERSION, Int32(MemoryLayout<z_stream>.size)) == Z_OK else { return 0 }
    defer { inflateEnd(&stream) }
    stream.next_in = UnsafeMutablePointer(mutating: src)
    stream.avail_in = uInt(srcSize)
    stream.next_out = dst
    stream.avail_out = uInt(dstSize)
    let status = inflate(&stream, Z_FINISH)
    guard status == Z_STREAM_END || status == Z_OK || status == Z_BUF_ERROR else { return 0 }
    return Int(stream.total_out)
}