def _decompress(binary: bin) -> bin:
"""
This function decompresses a binary using the scheme defined in the first byte of the input
Args:
binary (bin): a compressed binary
Returns:
bin: decompressed binary
"""
# check the 1-byte header to check the compression scheme used
compress_scheme = binary[0]
# remove the 1-byte header from the input stream
binary = binary[1:]
# 1) Decompress or return the original stream
if compress_scheme == LZ4:
return lz4.frame.decompress(binary)
elif compress_scheme == ZSTD:
return zstd.decompress(binary)
elif compress_scheme == NO_COMPRESSION:
return binary
else:
raise CompressionNotFoundException("compression scheme not found for"
" compression code:" +
str(compress_scheme))
def _compress(decompressed_input_bin: bin) -> bin:
"""
This function compresses a binary using the function _apply_compress_scheme
if the input has been already compressed in some step, it will return it as it is
Args:
decompressed_input_bin (bin): binary to be compressed
Returns:
bin: a compressed binary
"""
compress_stream, compress_scheme = _apply_compress_scheme(decompressed_input_bin)
try:
z = scheme_to_bytes[compress_scheme] + compress_stream
return z
except KeyError:
raise CompressionNotFoundException(
f"Compression scheme not found for compression code: {str(compress_scheme)}"
)
def _decompress(compressed_input_bin: bin, compress_scheme=LZ4) -> bin:
"""
This function decompresses a binary using LZ4
Args:
compressed_input_bin (bin): a compressed binary
compress_scheme: the compression method to use
Returns:
bin: decompressed binary
"""
if compress_scheme == LZ4:
return lz4.frame.decompress(compressed_input_bin)
elif compress_scheme == ZSTD:
return zstd.decompress(compressed_input_bin)
else:
raise CompressionNotFoundException("compression scheme note found for"
" compression code:" +
str(compress_scheme))
