ConfigFile Class Reference

Class for loading configuration file information. More...

#include <configfile.h>

Collaboration diagram for ConfigFile:

List of all members.


Detailed Description

Class for loading configuration file information.

This class is used to load and configure drivers from a configuration text file. This file is divided into sections, with section having a set of key/value fields.

Example file format is as follows:

# This is a comment

# The keyword 'driver' begins a section
driver
(
  # This line is used to identify which driver to
  # instantiate
  name "mydriver"

  # This line lists the interfaces that the driver
  # will support
  provides ["position2d:0" "laser:0"]

  # This line lists the devices to which the driver
  # will subscribe
  requires ["ptz:0"]

  # An integer
  key1  0             
  # A string
  key2 "foo"          
  # A tuple of strings
  key3 ["foo" "bar"]  
  # A tuple of multiple types
  key4 ["foo" 3.14 42]
)

The most common use of this class is for a driver to extract configuration file options. All drivers are passed a ConfigFile pointer cf and an integer section in their contructor (see Driver::Driver). The driver code can use this information to retrieve key/value information that was given inside the appropriate driver() section in the configuration file. For example:

  int maximum_speed = cf->ReadInt(section, "max_speed", -1);
  if(maximum_speed == -1)
  {
    // Since the default value of -1 was assigned,
    // no "max_speed" key/value was given in the configuration
    // file.
  }

For each type Foo, there is a method ReadFoo() that looks for a key/value pair in the indicated section and with the type Foo. The last argument specifies a default value to return if the given key is not found. The default should either be a reasonable value or a recognizably invalid value (so that you can determine when the user did not specify a value).

Always use ReadLength for linear dimensions, positions, and time derivatives (velocities, accelerations, etc.) ; this method will return values in meters, regardless of what local units are being used in the configuration file. Similarly, always use ReadAngle for angular quanities; this method will always return values in radians.

Always use ReadFilename for filenames; this method will return absolute paths, appropriately converting any relative paths that are given in the configuration file. Non-absolute paths in the configuration file are assumed to be relative to the directory in which the configuration file itself resides.

Always use ReadColor for packed 24-bit color values.

Drivers that support multiple interfaces must use ReadDeviceAddr to find out which interfaces they have been asked to support (single-interface drivers specify their one interface in the Driver constructor). For example, to check whether the driver has been asked to support a position2d interface, and if so, to add that interface:

  player_devaddr_t position_addr;
  if(cf->ReadDeviceAddr(&position_addr, section, "provides",
                        PLAYER_POSITION2D_CODE, -1, NULL) == 0)
  {
    if(this->AddInterface(position_addr) != 0)
    {
      this->SetError(-1);
      return;
    }
  }

A driver can support more than interface of the same type. For example, the p2os driver supports 3 position2d interfaces: one for wheelmotors/odometry, one for compass, and one for gyro. In this case, the last argument to ReadDeviceAddr is used to differentiate them, according to key that was given in the "provides" line. For example, if in the configuration file we have:

driver
(
  name "mydriver"
  provides ["odometry:::position2d:0" "gyro:::position2d:1"]
)

then in the driver code we can do something like this:

  player_devaddr_t odom_addr, gyro_addr;

  // Do we create an odometry position interface?
  if(cf->ReadDeviceAddr(&odom_addr, section, "provides",
                        PLAYER_POSITION2D_CODE, -1, "odometry") == 0)
  {
    if(this->AddInterface(odom_addr) != 0)
    {
      this->SetError(-1);
      return;
    }
  }

  // Do we create a gyro position interface?
  if(cf->ReadDeviceAddr(&gyro_addr, section, "provides",
                        PLAYER_POSITION2D_CODE, -1, "gyro") == 0)
  {
    if(this->AddInterface(gyro_addr) != 0)
    {
      this->SetError(-1);
      return;
    }
  }

Drivers that subscribe to other devices use ReadDeviceAddr in the same way to retrieve information from the "requires" line of the configuration file.

Classes

struct  CMacro
struct  Field
struct  Section
struct  Token

Public Member Functions

 ConfigFile (uint32_t _default_host, uint32_t _default_robot)
 Standard constructor.
 ConfigFile (const char *_default_host, uint32_t _default_robot)
 Alternate constructor, to specify the host as a string.
 ConfigFile ()
 Alternate constructor, used when not loading from a file.
 ~ConfigFile ()
 Standard destructor.
bool Load (const char *filename)
 Load config from file.
void InsertFieldValue (int index, const char *name, const char *value)
 Add a (name,value) pair directly into the database, without reading from a file.
bool WarnUnused ()
 Check for unused fields and print warnings.
bool ReadBool (int section, const char *name, bool value)
 Read a boolean value (one of: yes, no, true, false, 1, 0)
const char * ReadString (int section, const char *name, const char *value)
 Read a string value.
int ReadInt (int section, const char *name, int value)
 Read an integer value.
double ReadFloat (int section, const char *name, double value)
 Read a floating point (double) value.
double ReadLength (int section, const char *name, double value)
 Read a length (includes unit conversion, if any).
double ReadAngle (int section, const char *name, double value)
 Read an angle (includes unit conversion).
uint32_t ReadColor (int section, const char *name, uint32_t value)
 Read a color (includes text to RGB conversion)
const char * ReadFilename (int section, const char *name, const char *value)
 Read a filename.
int GetTupleCount (int section, const char *name)
 Get the number of values in a tuple.
const char * ReadTupleString (int section, const char *name, int index, const char *value)
 Read a string from a tuple field.
int ReadTupleInt (int section, const char *name, int index, int value)
 Read an integer from a tuple field.
double ReadTupleFloat (int section, const char *name, int index, double value)
 Read a float (double) from a tuple field.
double ReadTupleLength (int section, const char *name, int index, double value)
 Read a length from a tuple (includes units conversion)
double ReadTupleAngle (int section, const char *name, int index, double value)
 Read an angle form a tuple (includes units conversion)
uint32_t ReadTupleColor (int section, const char *name, int index, uint32_t value)
 Read a color (includes text to RGB conversion)
int ReadDeviceAddr (player_devaddr_t *addr, int section, const char *name, int code, int index, const char *key)
 Read a device id.
bool ParseDriver (int section)
bool ParseInterface (int section)
bool ParseAllDrivers ()
bool ParseAllInterfaces ()
int GetSectionCount ()
 Get the number of sections.
const char * GetSectionType (int section)
 Get a section type name.
int LookupSection (const char *type)
 Lookup a section number by section type name.
int GetSectionParent (int section)
 Get a section's parent section.
void DumpTokens ()
 Dump the token list (for debugging).
void DumpSections ()
 Dump the section list for debugging.
void DumpFields ()
 Dump the field list for debugging.

Public Attributes

char * filename
 Name of the file we loaded.

Private Types

enum  {
  TokenComment, TokenWord, TokenNum, TokenString,
  TokenBool, TokenOpenSection, TokenCloseSection, TokenOpenTuple,
  TokenCloseTuple, TokenSpace, TokenEOL
}

Private Member Functions

void InitFields ()
bool Save (const char *filename)
void WriteBool (int section, const char *name, bool value)
void WriteBool_Compat (int section, const char *name, bool value)
void WriteString (int section, const char *name, const char *value)
void WriteInt (int section, const char *name, int value)
void WriteFloat (int section, const char *name, double value)
void WriteLength (int section, const char *name, double value)
void WriteTupleString (int section, const char *name, int index, const char *value)
void WriteTupleInt (int section, const char *name, int index, int value)
void WriteTupleFloat (int section, const char *name, int index, double value)
void WriteTupleLength (int section, const char *name, int index, double value)
void WriteTupleAngle (int section, const char *name, int index, double value)
bool LoadTokens (FILE *file, int include)
bool LoadTokenComment (FILE *file, int *line, int include)
bool LoadTokenWord (FILE *file, int *line, int include)
bool LoadTokenInclude (FILE *file, int *line, int include)
bool LoadTokenNum (FILE *file, int *line, int include)
bool LoadTokenString (FILE *file, int *line, int include)
bool LoadTokenSpace (FILE *file, int *line, int include)
bool SaveTokens (FILE *file)
void ClearTokens ()
bool AddToken (int type, const char *value, int include)
bool SetTokenValue (int index, const char *value)
const char * GetTokenValue (int index)
bool ParseTokens ()
bool ParseTokenInclude (int *index, int *line)
bool ParseTokenDefine (int *index, int *line)
bool ParseTokenPlugin (int *index, int *line)
bool ParseTokenWord (int section, int *index, int *line)
bool ParseTokenSection (int section, int *index, int *line)
bool ParseTokenField (int section, int *index, int *line)
bool ParseTokenTuple (int section, int field, int *index, int *line)
void ClearMacros ()
int AddMacro (const char *macroname, const char *sectionname, int line, int starttoken, int endtoken)
int LookupMacro (const char *macroname)
void DumpMacros ()
void ClearSections ()
int AddSection (int parent, const char *type)
void ClearFields ()
int AddField (int section, const char *name, int line)
void AddFieldValue (int field, int index, int value_token)
int GetField (int section, const char *name)
int GetFieldValueCount (int field)
const char * GetFieldValue (int field, int index, bool flag_used=true)
void SetFieldValue (int field, int index, const char *value)
uint32_t LookupColor (const char *name)

Private Attributes

int token_size
int token_count
Tokentokens
int macro_size
int macro_count
CMacromacros
int section_size
int section_count
Sectionsections
int field_size
int field_count
Fieldfields
uint32_t default_host
uint32_t default_robot
double unit_length
double unit_angle

Member Function Documentation

int ConfigFile::GetSectionParent ( int  section)

Get a section's parent section.

Returns:
Returns -1 if there is no parent.
int ConfigFile::GetTupleCount ( int  section,
const char *  name 
)

Get the number of values in a tuple.

Parameters:
sectionSection to read.
nameField name.
void ConfigFile::InitFields ( ) [private]

Intitialization helper

void ConfigFile::InsertFieldValue ( int  index,
const char *  name,
const char *  value 
)

Add a (name,value) pair directly into the database, without reading from a file.

The (name,value) goes into the "global" section. Can be called multiple times with different index to create a tuple field.

Parameters:
indexIndex of the value within the field (0 unless the field is a tuple)
nameName of the field
valueValue to be assigned
bool ConfigFile::Load ( const char *  filename)

Load config from file.

Parameters:
filenameName of file; can be relative or fully qualified path.
Returns:
Returns true on success.
int ConfigFile::LookupSection ( const char *  type)

Lookup a section number by section type name.

Returns:
Returns -1 if there is no section with this type.
double ConfigFile::ReadAngle ( int  section,
const char *  name,
double  value 
)

Read an angle (includes unit conversion).

In the configuration file, angles are specified in degrees; this method will convert them to radians.

Parameters:
sectionSection to read.
nameField name
valueDefault value if the field is not present in the file (radians).
Returns:
Returns the field value.

Referenced by mbasedriver::mbasedriver().

bool ConfigFile::ReadBool ( int  section,
const char *  name,
bool  value 
)

Read a boolean value (one of: yes, no, true, false, 1, 0)

Parameters:
sectionSection to read.
nameField name
valueDefault value if this field is not present in the file
Returns:
Returns the field value
uint32_t ConfigFile::ReadColor ( int  section,
const char *  name,
uint32_t  value 
)

Read a color (includes text to RGB conversion)

In the configuration file colors may be specified with sybolic names; e.g., "blue" and "red". This function will convert them to an RGB value using the X11 rgb.txt file.

Parameters:
sectionSection to read.
nameField name
valueDefault value if the field is not present in the file (RGB).
Returns:
Returns the field value.
int ConfigFile::ReadDeviceAddr ( player_devaddr_t addr,
int  section,
const char *  name,
int  code,
int  index,
const char *  key 
)

Read a device id.

Reads a device id from the named field of the given section. The returned id will match the given code, index and key values.

Parameters:
addraddress field to be filled in.
sectionFile section.
nameField name.
codeInterface type code (use 0 to match all interface types).
indexTuple index (use -1 to match all indices).
keyDevice key value (use NULL to match all key vales).
Returns:
Non-zero on error.

Referenced by mbasedriver::mbasedriver(), SegwayRMP400::SegwayRMP400(), and SphereDriver::SphereDriver().

const char* ConfigFile::ReadFilename ( int  section,
const char *  name,
const char *  value 
)

Read a filename.

Always returns an absolute path. If the filename is entered as a relative path, we prepend the config file's path to it.

Parameters:
sectionSection to read.
nameField name
valueDefault value if the field is not present in the file.
Returns:
Returns the field value.
double ConfigFile::ReadFloat ( int  section,
const char *  name,
double  value 
)

Read a floating point (double) value.

Parameters:
sectionSection to read.
nameField name
valueDefault value if the field is not present in the file.
Returns:
Returns the field value.
int ConfigFile::ReadInt ( int  section,
const char *  name,
int  value 
)

Read an integer value.

Parameters:
sectionSection to read.
nameField name
valueDefault value if the field is not present in the file.
Returns:
Returns the field value.

Referenced by mbasedriver::mbasedriver(), SegwayRMP400::SegwayRMP400(), and SphereDriver::SphereDriver().

double ConfigFile::ReadLength ( int  section,
const char *  name,
double  value 
)

Read a length (includes unit conversion, if any).

Parameters:
sectionSection to read.
nameField name
valueDefault value if the field is not present in the file.
Returns:
Returns the field value.

Referenced by mbasedriver::mbasedriver().

const char* ConfigFile::ReadString ( int  section,
const char *  name,
const char *  value 
)

Read a string value.

Parameters:
sectionSection to read.
nameField name
valueDefault value if the field is not present in the file.
Returns:
Returns the field value.

Referenced by mbasedriver::mbasedriver(), and SphereDriver::SphereDriver().

double ConfigFile::ReadTupleAngle ( int  section,
const char *  name,
int  index,
double  value 
)

Read an angle form a tuple (includes units conversion)

In the configuration file, angles are specified in degrees; this method will convert them to radians.

Parameters:
sectionSection to read.
nameField name
indexTuple index (zero-based)
valueDefault value if the field is not present in the file.
Returns:
Returns the tuple element value.
uint32_t ConfigFile::ReadTupleColor ( int  section,
const char *  name,
int  index,
uint32_t  value 
)

Read a color (includes text to RGB conversion)

In the configuration file colors may be specified with sybolic names; e.g., "blue" and "red". This function will convert them to an RGB value using the X11 rgb.txt file.

Parameters:
sectionSection to read.
nameField name
indexTuple index (zero-based)
valueDefault value if the field is not present in the file (RGB).
Returns:
Returns the field value.
double ConfigFile::ReadTupleFloat ( int  section,
const char *  name,
int  index,
double  value 
)

Read a float (double) from a tuple field.

Parameters:
sectionSection to read.
nameField name
indexTuple index (zero-based)
valueDefault value if the field is not present in the file.
Returns:
Returns the tuple element value.
int ConfigFile::ReadTupleInt ( int  section,
const char *  name,
int  index,
int  value 
)

Read an integer from a tuple field.

Parameters:
sectionSection to read.
nameField name
indexTuple index (zero-based)
valueDefault value if the field is not present in the file.
Returns:
Returns the tuple element value.

Referenced by SphereDriver::SphereDriver().

double ConfigFile::ReadTupleLength ( int  section,
const char *  name,
int  index,
double  value 
)

Read a length from a tuple (includes units conversion)

Parameters:
sectionSection to read.
nameField name
indexTuple index (zero-based)
valueDefault value if the field is not present in the file.
Returns:
Returns the tuple element value.
const char* ConfigFile::ReadTupleString ( int  section,
const char *  name,
int  index,
const char *  value 
)

Read a string from a tuple field.

Parameters:
sectionSection to read.
nameField name
indexTuple index (zero-based)
valueDefault value if the field is not present in the file.
Returns:
Returns the tuple element value.
bool ConfigFile::WarnUnused ( )

Check for unused fields and print warnings.

Returns:
Returns true if there are unused fields.

The documentation for this class was generated from the following file: