codon/stdlib/os/path.codon

# Copyright (C) 2022 Exaloop Inc. <https://exaloop.io>

def splitext(p: str) -> Tuple[str, str]:
    """
    Split the extension from a pathname.
    Extension is everything from the last dot to the end, ignoring
    leading dots.  Returns "(root, ext)"; ext may be empty."""
    sep = "/"
    extsep = "."

    sepIndex = p.rfind(sep)
    dotIndex = p.rfind(extsep)
    if dotIndex > sepIndex:
        # skip all leading dots
        filenameIndex = sepIndex + 1
        while filenameIndex < dotIndex:
            if p[filenameIndex : filenameIndex + 1] != extsep:
                return p[:dotIndex], p[dotIndex:]
            filenameIndex += 1
    return p, p[:0]