c0

A Python implementation of C0DATA — structured data built on ASCII C0 control codes.

This is not a reimplementation: it's a thin, fast binding over the c0 C core (a CPython extension, no third-party dependencies), so the scan-heavy work runs as native C while the Python layer provides an idiomatic API. The read path is zero-copy — accessors return memoryview slices into the input buffer.

Usage

import c0

# Write
buf = c0.build(lambda b: (
    b.group("users", ["name", "amount"]),
    b.record("Alice", "100"),
    b.record("Bob", "200"),
))

# Read (zero-copy: fields are memoryviews into buf)
t = c0.Table(buf)
for rec in t:
    name, amount = rec.fields            # list[memoryview]
    rec.value(0)                         # bytes, DLE-escapes decoded

# Compact form is canonical — hashable for content addressing
assert c0.canonical(buf)

# Documents, streams, pretty
doc = c0.Document(buf)
log = c0.StreamReader(open("claims.c0", "rb").read())   # .torn, .committed, blocks
print(c0.pretty_format(buf))                            # Unicode Control Pictures

Install / build

The C core and the shared conformance vectors are git submodules:

git submodule update --init        # pulls in c0-c (the header) and c0-spec
pip install .                      # builds the extension

Requires a C compiler and the Python development headers.

Status

Binds the c0-c core: tokenizer, table/record and document/group readers (zero-copy), canonical helpers, ETB stream mode, and pretty (pretty_format/pretty_parse). The builder is pure Python (byte-identical to the C builder). Passes the shared conformance vectors from c0-spec.

Converters (CSV / JSON / C0DIFF) are not yet wrapped.

Test

python -m unittest discover -s tests

License

MIT