import re

def parse_semver(s):
    if not isinstance(s, str):
        return None
    pattern = re.compile(
        r'^(0|[1-9]\d*)\.(0|[1-9]\d*)\.(0|[1-9]\d*)'
        r'(?:-((?:0|[1-9]\d*|\d*[a-zA-Z-][0-9a-zA-Z-]*)'
        r'(?:\.(?:0|[1-9]\d*|\d*[a-zA-Z-][0-9a-zA-Z-]*))*))?'
        r'(?:\+([0-9a-zA-Z-]+(?:\.[0-9a-zA-Z-]+)*))?$'
    )
    m = pattern.match(s)
    if not m:
        return None
    major, minor, patch, prerelease, build = m.groups()
    return {
        "major": int(major),
        "minor": int(minor),
        "patch": int(patch),
        "prerelease": prerelease,
        "build": build,
    }