def test_encode_decode(self):
s = b'0123456789' * 12 + b'01234'
expected_rs_code = (
b'\x1a\xd0\xc75-\x08\xde\x9a\xdc\x9a\x17_\xa2\xf6\x15\x8b\x0e\xb2\xd4\xbb\x19\xe6:\x88\x1b\xee\x92\xd7N\xab'
)
inbuff = BytesIO(s * 2)
outbuff = BytesIO()
with reed_solomon_stream(inbuff) as reed_read, reed_solomon_stream(
outbuff, mode='write') as reed_write:
b = reed_read.read(125)
self.assertEqual(s + expected_rs_code, b)
reed_write.write(b)
outbuff.seek(0)
self.assertEqual(s, outbuff.read())
def _get_decoder_stream(outfile, ecc, fountain):
# set up the outstream: image -> reedsolomon -> fountain -> zstd_decompress -> raw bytes
f = open(outfile, 'wb')
if fountain:
import zstandard as zstd
from cimbar.fountain.fountain_decoder_stream import fountain_decoder_stream
decompressor = zstd.ZstdDecompressor().stream_writer(f)
f = fountain_decoder_stream(decompressor, _fountain_chunk_size(ecc))
on_rss_failure = b'' if fountain else None
return reed_solomon_stream(f, ecc, mode='write', on_failure=on_rss_failure) if ecc else f
def setUpClass(cls):
cls.inputs_dir = TemporaryDirectory()
cls.src_file = path.join(cls.inputs_dir.name, 'infile.txt')
random_data = bytearray(random.getrandbits(8) for _ in range(4000))
src_data = random_data * 4
with open(cls.src_file, 'wb') as f:
f.write(src_data)
cls.encoded_file = path.join(cls.inputs_dir.name, 'encoded.png')
encode(cls.src_file, cls.encoded_file, dark=True)
cls.decode_clean = path.join(cls.inputs_dir.name,
'decode-no-ecc-clean.txt')
with reed_solomon_stream(cls.src_file,
30) as rss, open(cls.decode_clean, 'wb') as f:
f.write(rss.read(7500))
def _get_encoder_stream(src, ecc, fountain, compression_level=6):
# various checks to set up the instream.
# the hierarchy is raw bytes -> zstd -> fountain -> reedsolomon -> image
f = open(src, 'rb')
if fountain:
import zstandard as zstd
from cimbar.fountain.fountain_encoder_stream import fountain_encoder_stream
reader = zstd.ZstdCompressor(level=compression_level).stream_reader(f)
f = fountain_encoder_stream(reader, _fountain_chunk_size(ecc))
estream = reed_solomon_stream(f, ecc) if ecc else f
read_size = _fountain_chunk_size(ecc) if fountain else 16384
read_count = (f.len // read_size) * 2 if fountain else 1
params = {
'read_size': read_size,
'read_count': read_count,
}
return estream, params