TrajectoryReader module

Module contents

template<typename TrajectoryT>
class TrajectoryReader : public tracktable::GenericReader<TrajectoryT>

Read trajectories from files.

This reader wraps the following pipeline:

• Read lines from a text file

• Skip any lines that begin with a designated comment character (‘#’ by default)

• Tokenize each line using specified delimiters (whitespace by default)

• Create a trajectory (user-specified type) from each tokenized line

• Return the resulting points via a C++ iterator

You will use set_input() to supply an input stream, set_comment_character() to configure which lines to skip, set_field_delimiter() to specify how to turn lines into fields.

Public Functions

inline TrajectoryReader()

Instantiate TrajectoryReader using a default configuration

Default reader configuration

If you are reading BasePoints, this sets coordinates 0 to d-1 (D is the point’s dimension) using columns 0 to d-1.

If you are reading TrajectoryPoints, column 0 is the object ID, column 1 is the timestamp, and columns 2 through D+1 (inclusive) are the coordinates.

These are the default settings. You can override any or all of them after you instantiate the reader.

inline TrajectoryReader(std::istream &infile)

Instantiate a TrajectoryReader using a std::istream and default configuration

Default reader configuration

If you are reading BasePoints, this sets coordinates 0 to d-1 (D is the point’s dimension) using columns 0 to d-1.

If you are reading TrajectoryPoints, column 0 is the object ID, column 1 is the timestamp, and columns 2 through D+1 (inclusive) are the coordinates.

These are the default settings. You can override any or all of them after you instantiate the reader.

Parameters:

infile – [in] Stream to read input from

inline TrajectoryReader(TrajectoryReader const &other)

Copy contructor, create a reader with a copy of another

Parameters:

other – [in] TrajectoryReader to copy from

inline virtual ~TrajectoryReader()

Destructor.

inline TrajectoryReader &operator=(TrajectoryReader const &other)

Assign a TrajectoryReader to the value of another.

Parameters:

other – [in] TrajectoryReader to assign value of

Returns:

Reader with the new assigned value

inline bool operator==(TrajectoryReader const &other) const

Check whether one reader is equal to another by comparing all the properties.

Two readers are equal if all of their properties are equal.

Parameters:

other – [in] TrajectoryReader for comparison

Returns:

Boolean indicating equivalency

inline bool operator!=(TrajectoryReader const &other) const

Check whether two TrajectoryReaders are unequal.

Parameters:

other – [in] TrajectoryReader for comparison

Returns:

Boolean indicating equivalency

inline void set_default_configuration()

Default reader configuration

If you are reading BasePoints, this sets coordinates 0 to d-1 (D is the point’s dimension) using columns 0 to d-1.

If you are reading TrajectoryPoints, column 0 is the object ID, column 1 is the timestamp, and columns 2 through D+1 (inclusive) are the coordinates.

These are the default settings. You can override any or all of them after you instantiate the reader.

inline void set_comment_character(string_type const &comment)

Specify comment character for skipping lines

A line is a comment if and only if its first non-whitespace character is the comment character (‘#’ by default). We will skip such lines entirely. We do not handle inline or trailing comments: a line will either be included in its entirety or skipped completely.

Parameters:

comment – [in] Single character

inline string_type comment_character() const

Retrieve current value of comment character.

This function invalidates any outstanding iterators.

Returns:

Current value of comment character

inline void set_null_value(string_type const &_null_value)

Specify string value to be interpreted as null

Parameters:

_null_value – [in] String to interpret as null

inline string_type null_value() const

Get string value for nulls

Returns:

Current string that will be interpreted as null

inline void set_input(std::istream &_input)

Supply input stream from delimited text source.

We read our input from C++ std::istreams. The stream you supply will be traversed exactly once.

Parameters:

_input – [in] Stream from which we will read points

inline std::istream &input() const

Retrieve the current input stream.

Bug:

We currently have no way to indicate whether the stream is valid.

Returns:

Stream being used for input.

inline void set_warnings_enabled(bool onoff)

Enable/disable warnings during parsing.

We may run into type mismatches and bad casts while we’re parsing headers and data. This flag determines whether or not warnings will be printed.

Parameters:

onoff – [in] Warnings are on / off

inline bool warnings_enabled() const

Check whether warnings are enable

Returns:

Whether or not warnings are on

inline void set_field_delimiter(string_type const &delimiters)

Set one or more characters as field delimiters.

Each character in the argument to this function will be treated as a potential field delimiter. If you supply ",|" as your delimiter then both the comma and the exclamation point will be used to tokenize field.

This function invalidates any outstanding iterators.

Parameters:

delimiters – [in] String containing all desired delimiter characters

inline string_type field_delimiter() const

Retrieve the current set of delimiter characters.

Returns:

String containing all delimiters

inline void set_timestamp_format(string_type const &format)

Set the format of the timestamp

Parameters:

format – [in] String containing the format of the time stamp

inline string_type timestamp_format() const

Retrieve the format of the timestamp

Returns:

The timestamp format

Private Types

typedef TrajectoryT trajectory_type

typedef trajectory_type::point_type point_type

typedef tracktable::LineReader line_reader_type

typedef tracktable::SkipCommentsReader<line_reader_type::iterator> skip_comments_reader_type

typedef tracktable::StringTokenizingReader<skip_comments_reader_type::iterator> string_tokenizer_type

typedef boost::shared_ptr<trajectory_type> trajectory_shared_ptr_type

typedef string_vector_type::const_iterator token_iter_type

typedef std::pair<token_iter_type, token_iter_type> token_range_type

typedef std::vector<token_range_type> token_range_vector_type

typedef PointFromTokensReader<point_type, token_range_vector_type::iterator> point_reader_type

Private Functions

inline virtual trajectory_shared_ptr_type next_item()

Increment the iterator the next item to be read in

Returns:

The next item

inline trajectory_shared_ptr_type parse_trajectory(string_vector_type const &tokens)

Parse the read in trajectory

Parameters:

tokens – Tokens that are read in and parsed

inline void populate_trajectory_points(token_iter_type token_begin, token_iter_type token_end, std::size_t num_points, trajectory_shared_ptr_type trajectory)

Populate the trajectorie’s points

Parameters:

• token_begin – [in] Start of tokens read in

• token_end – [in] End of tokens read in

• num_points – [in] Num of points expected to be in trajectory

• trajectory – [in] Trajectory to populate

inline void populate_trajectory_points_from_token_ranges(token_range_vector_type::iterator input_range_begin, token_range_vector_type::iterator input_range_end, trajectory_shared_ptr_type trajectory)

Populate the trajectories points from token ranges

Parameters:

• input_range_begin – [in] Start of range to read in

• input_range_end – [in] End of range to read in

• trajectory – [in] Trajectory to populate

Private Members

line_reader_type LineReader

point_reader_type PointReader

skip_comments_reader_type SkipCommentsReader

string_tokenizer_type StringTokenizer

string_type TimestampFormat

string_tokenizer_type::iterator TokenizedInputBegin

string_tokenizer_type::iterator TokenizedInputEnd

bool WarningsEnabled

int TrajectoriesRead

rw::detail::TrajectoryHeader ParseTrajectoryHeader