__init__.py

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import genmsg.msgs

try:
    from cStringIO import StringIO  # Python 2.x
except ImportError:
    from io import StringIO  # Python 3.x

MSG_TYPE_TO_CPP = {
    'byte': 'int8_t',
    'char': 'uint8_t',
    'bool': 'uint8_t',
    'uint8': 'uint8_t',
    'int8': 'int8_t',
    'uint16': 'uint16_t',
    'int16': 'int16_t',
    'uint32': 'uint32_t',
    'int32': 'int32_t',
    'uint64': 'uint64_t',
    'int64': 'int64_t',
    'float32': 'float',
    'float64': 'double',
    'string': 'std::basic_string<char, std::char_traits<char>, typename std::allocator_traits<ContainerAllocator>::template rebind_alloc<char>>',
    'time': 'ros::Time',
    'duration': 'ros::Duration',
}


# used
def msg_type_to_cpp(type_):
    """
    Convert a message type into the C++ declaration for that type.

    Example message types: uint32, std_msgs/String.
    Example C++ types: uint32_t, std_msgs::String_<ContainerAllocator>

    @param type_: The message type
    @type type_: str
    @return: The C++ declaration
    @rtype: str
    """
    (base_type, is_array, array_len) = genmsg.msgs.parse_type(type_)
    cpp_type = None
    if (genmsg.msgs.is_builtin(base_type)):
        cpp_type = MSG_TYPE_TO_CPP[base_type]
    elif (len(base_type.split('/')) == 1):
        if (genmsg.msgs.is_header_type(base_type)):
            cpp_type = ' ::std_msgs::Header_<ContainerAllocator> '
        else:
            cpp_type = '%s_<ContainerAllocator> ' % (base_type)
    else:
        pkg = base_type.split('/')[0]
        msg = base_type.split('/')[1]
        cpp_type = ' ::%s::%s_<ContainerAllocator> ' % (pkg, msg)

    if (is_array):
        if (array_len is None):
            return 'std::vector<%s, typename std::allocator_traits<ContainerAllocator>::template rebind_alloc<%s>>' % (cpp_type, cpp_type)
        else:
            return 'boost::array<%s, %s> ' % (cpp_type, array_len)
    else:
        return cpp_type


def _escape_string(s):
    s = s.replace('\\', '\\\\')
    s = s.replace('"', '\\"')
    return s


def escape_message_definition(definition):
    lines = definition.splitlines()
    if not lines:
        lines.append('')
    s = StringIO()
    for line in lines:
        line = _escape_string(line)
        # individual string literals cannot be too long; need to utilize string concatenation for long strings
        # https://docs.microsoft.com/en-us/cpp/c-language/maximum-string-length?view=vs-2017
        s.write('"%s\\n"\n' % (line))

    val = s.getvalue()
    s.close()
    return val


# used2
def cpp_message_declarations(name_prefix, msg):
    """
    Return the different possible C++ declarations for a message given the message itself.

    @param name_prefix: The C++ prefix to be prepended to the name, e.g. "std_msgs::"
    @type name_prefix: str
    @param msg: The message type
    @type msg: str
    @return: A tuple of 3 different names.  cpp_message_decelarations("std_msgs::", "String") returns the tuple
        ("std_msgs::String_", "std_msgs::String_<ContainerAllocator>", "std_msgs::String")
    @rtype: str
    """
    pkg, basetype = genmsg.names.package_resource_name(msg)
    cpp_name = ' ::%s%s' % (name_prefix, msg)
    if (pkg):
        cpp_name = ' ::%s::%s' % (pkg, basetype)
    return ('%s_' % (cpp_name), '%s_<ContainerAllocator> ' % (cpp_name), '%s' % (cpp_name))


# todo
def is_fixed_length(spec, msg_context, includepath):
    """
    Return whether or not the message is fixed-length.

    @param spec: The message spec
    @type spec: genmsg.msgs.MsgSpec
    @param package: The package of the
    @type package: str
    """
    types = []
    for field in spec.parsed_fields():
        if (field.is_array and field.array_len is None):
            return False

        if (field.base_type == 'string'):
            return False

        if (not field.is_builtin):
            types.append(field.base_type)

    types = set(types)
    for t in types:
        t = genmsg.msgs.resolve_type(t, spec.package)
        assert isinstance(includepath, dict)
        new_spec = genmsg.msg_loader.load_msg_by_type(msg_context, t, includepath)
        if (not is_fixed_length(new_spec, msg_context, includepath)):
            return False

    return True


# used2
def default_value(type_):
    """
    Return the value to initialize a message member with.

    0 for integer types, 0.0 for floating point, false for bool,
    empty string for everything else

    @param type_: The type
    @type type_: str
    """
    if type_ in [
        'byte', 'int8', 'int16', 'int32', 'int64',
        'char', 'uint8', 'uint16', 'uint32', 'uint64',
    ]:
        return '0'
    elif type_ in ['float32', 'float64']:
        return '0.0'
    elif type_ == 'bool':
        return 'false'

    return ''


# used2
def takes_allocator(type_):
    """
    Return whether or not a type can take an allocator in its constructor.

    False for all builtin types except string.
    True for all others.

    @param type_: The type
    @type: str
    """
    return type_ not in [
        'byte', 'int8', 'int16', 'int32', 'int64',
        'char', 'uint8', 'uint16', 'uint32', 'uint64',
        'float32', 'float64', 'bool', 'time', 'duration']


def escape_string(str_):
    str_ = str_.replace('\\', '\\\\')
    str_ = str_.replace('"', '\\"')
    return str_


# used
def generate_fixed_length_assigns(spec, container_gets_allocator, cpp_name_prefix):
    """
    Initialize any fixed-length arrays.

    @param s: The stream to write to
    @type s: stream
    @param spec: The message spec
    @type spec: genmsg.msgs.MsgSpec
    @param container_gets_allocator: Whether or not a container type (whether it's another message, a vector, array or string)
        should have the allocator passed to its constructor.  Assumes the allocator is named _alloc.
    @type container_gets_allocator: bool
    @param cpp_name_prefix: The C++ prefix to use when referring to the message, e.g. "std_msgs::"
    @type cpp_name_prefix: str
    """
    # Assign all fixed-length arrays their default values
    for field in spec.parsed_fields():
        if (not field.is_array or field.array_len is None):
            continue

        val = default_value(field.base_type)
        if (container_gets_allocator and takes_allocator(field.base_type)):
            # String is a special case, as it is the only builtin type that takes an allocator
            if (field.base_type == 'string'):
                string_cpp = msg_type_to_cpp('string')
                yield '    %s.assign(%s(_alloc));\n' % (field.name, string_cpp)
            else:
                (cpp_msg_unqualified, cpp_msg_with_alloc, _) = cpp_message_declarations(cpp_name_prefix, field.base_type)
                yield '    %s.assign(%s(_alloc));\n' % (field.name, cpp_msg_with_alloc)
        elif (len(val) > 0):
            yield '    %s.assign(%s);\n' % (field.name, val)


# used
def generate_initializer_list(spec, container_gets_allocator):
    """
    Write the initializer list for a constructor.

    @param s: The stream to write to
    @type s: stream
    @param spec: The message spec
    @type spec: genmsg.msgs.MsgSpec
    @param container_gets_allocator: Whether or not a container type (whether it's another message, a vector, array or string)
        should have the allocator passed to its constructor.  Assumes the allocator is named _alloc.
    @type container_gets_allocator: bool
    """
    op = ':'
    for field in spec.parsed_fields():
        val = default_value(field.base_type)
        use_alloc = takes_allocator(field.base_type)
        if (field.is_array):
            if (field.array_len is None and container_gets_allocator):
                yield '  %s %s(_alloc)' % (op, field.name)
            else:
                yield '  %s %s()' % (op, field.name)
        else:
            if (container_gets_allocator and use_alloc):
                yield '  %s %s(_alloc)' % (op, field.name)
            else:
                yield '  %s %s(%s)' % (op, field.name, val)
        op = ','