Serialize a value for use with PHP's deserialize() function. This function
    can serialize bytes, strings, integers, floats, booleans, None, lists,
    dicts and custom objects implementing __php__().

    Args:
        value: The value to serialize.

    Returns:
        bytes: The serialized form of `value` ready to be unserialized by PHP.

    Example:
        >>> from pwny import *
        >>> php_serialize([b'foo', u'bar', 42, 2.5, True, None, {'a': 'b'}])
        b'a:7:{i:0;s:3:"foo";i:1;s:3:"bar";i:2;i:42;i:3;d:2.5;i:4;b:1;i:5;N;i:6;a:1:{s:1:"a";s:1:"b";}}'

def php_serialize(value):
    """
    Serialize a value for use with PHP's deserialize() function. This function
    can serialize bytes, strings, integers, floats, booleans, None, lists,
    dicts and custom objects implementing __php__().

    Args:
        value: The value to serialize.

    Returns:
        bytes: The serialized form of `value` ready to be unserialized by PHP.

    Example:
        >>> from pwny import *
        >>> php_serialize([b'foo', u'bar', 42, 2.5, True, None, {'a': 'b'}])
        b'a:7:{i:0;s:3:"foo";i:1;s:3:"bar";i:2;i:42;i:3;d:2.5;i:4;b:1;i:5;N;i:6;a:1:{s:1:"a";s:1:"b";}}'
    """

    def serialize_array(items):
        content = b''.join(
            php_serialize(i) + php_serialize(v)
            for i, v in items
        )
        return 'a:{0}:'.format(len(value)).encode('utf8') + b'{' + content + b'}'

    def serialize_str(prefix, item):
        return prefix + b':' + str(item).encode('utf8') + b';'

    if isinstance(value, six.binary_type):
        return b's:' + str(len(value)).encode('utf8') + b':"' + value + b'";'
    elif isinstance(value, six.text_type):
        return php_serialize(value.encode('utf8'))
    elif isinstance(value, bool):
        return serialize_str(b'b', 1 if value else 0)
    elif isinstance(value, int):
        return serialize_str(b'i', value)
    elif isinstance(value, float):
        return serialize_str(b'd', value)
    elif value is None:
        return b'N;'
    elif isinstance(value, (list, tuple)):
        return serialize_array(enumerate(value))
    elif isinstance(value, dict):
        return serialize_array(six.iteritems(value))
    else:
        return value.__php__()