# cDisplayString Class Reference
[Utility classes]

`#include <cdispstr.h>`

List of all members.

## Detailed Description

Class for storage and easy manipulation of display strings.

Display strings are used to control the graphical presentation of network elements when a GUI execution environment is used (Tkenv).

A display string consist of several named tags, where each tag may have several arguments (parameters). The syntax: "tag1=value1,val2,val3;tag2=val4,val5".

This class facilitates tasks such as adding new tags, adding arguments to existing tags, removing tags or replacing arguments. The internal storage method allows very fast operation; it will generally be faster than direct string manipulation.

The object doesn't try to interpret the display string in any way, nor does it know the meaning of the different tags; it merely parses the string as data elements separated by semicolons, equal signs and commas.

An example:

       cDisplayString dispstr("a=1,2;p=alpha,,3");
       dispstr.insertTag("x");
       dispstr.setTagArg("x",0,"joe");
       dispstr.setTagArg("x",2,"jim");
       dispstr.setTagArg("p",0,"beta");
       ev << dispstr.getString();  // result: "x=joe,,jim;a=1,2;p=beta,,3"

Limitation: a tag may have at most 16 arguments.

## Public Member Functions

| cDisplayString ()
| cDisplayString (const char *dispstr)
| cDisplayString (const cDisplayString &ds)
| ~cDisplayString ()
cDisplayString & | operator= (const cDisplayString &ds)
cDisplayString & | operator= (const char *s)
| operator const char * () const
const char * | getString () const
bool | parse (const char *displaystr)
bool | existsTag (const char *tagname) const
int | getNumArgs (const char *tagname) const
const char * | getTagArg (const char *tagname, int index) const
bool | setTagArg (const char *tagname, int index, const char *value)
bool | setTagArg (const char *tagname, int index, long value)
bool | removeTag (const char *tagname)
int | getNumTags () const
const char * | getTagName (int tagindex) const
int | getNumArgs (int tagindex) const
const char * | getTagArg (int tagindex, int index) const
bool | setTagArg (int tagindex, int index, const char *value)
int | insertTag (const char *tagname, int atindex=0)
bool | removeTag (int tagindex)

## Constructor & Destructor Documentation

cDisplayString::cDisplayString | ( |  | ) |

| Constructor.

cDisplayString::cDisplayString | ( | const char * | dispstr | ) |

| Constructor.

cDisplayString::cDisplayString | ( | const cDisplayString & | ds | ) |

| Copy constructor.

cDisplayString::~cDisplayString | ( |  | ) |

| Destructor.

## Member Function Documentation

bool cDisplayString::existsTag | ( | const char * | tagname | ) | const

| Returns true if the stored display string contains the given tag.

int cDisplayString::getNumArgs | ( | int | tagindex | ) | const

| Returns the number of arguments a tag actually has in the display string. The count includes empty arguments too. For example, for the "x=8,,15,2;y=2" display string getNumArgs("x") returns 4, and getNumArgs("y") returns 1. If the display string doesn't contain the given tag, 0 is returned.

int cDisplayString::getNumArgs | ( | const char * | tagname | ) | const

| Returns the number of arguments a tag actually has in the display string. The count includes empty arguments too. For example, for the "x=8,,15,2;y=2" display string getNumArgs("x") returns 4, and getNumArgs("y") returns 1. If the display string doesn't contain the given tag, 0 is returned.

int cDisplayString::getNumTags | ( |  | ) | const

| Returns the number of tags in the display string. Tags are indexed starting from 0.

const char* cDisplayString::getString | ( |  | ) | const

| Returns the display string.

const char* cDisplayString::getTagArg | ( | int | tagindex,
|  | int | index
| ) | const

| Returns pointer to the indexth argument of the given tag. If the tag doesn't exist or the index is out of range, NULL is returned.

const char* cDisplayString::getTagArg | ( | const char * | tagname,
|  | int | index
| ) | const

| Returns pointer to the indexth argument of the given tag. If the tag doesn't exist or the index is out of range, empty string ("") is returned.

const char* cDisplayString::getTagName | ( | int | tagindex | ) | const

| Returns the name of the tag given with its index. If the tag index is out of range, NULL is returned.

int cDisplayString::insertTag | ( | const char * | tagname,
|  | int | atindex = `0`
| ) |

| Inserts a tag into the display string, optionally at the given index. If no index is given, the tag is inserted at the beginning of the string. Return value is the index of the tag. If the display string already contains a tag with the given tagname, nothing is changed and the index of the existing tag is returned.

cDisplayString::operator const char * | ( |  | ) | const`[inline]`

| Conversion to string.

cDisplayString& cDisplayString::operator= | ( | const char * | s | ) | `[inline]`

| Conversion from string.

cDisplayString& cDisplayString::operator= | ( | const cDisplayString & | ds | ) | `[inline]`

| Assignment operator.

bool cDisplayString::parse | ( | const char * | displaystr | ) |

| Sets the display string to the given value. The return value is false if there was an error parsing the string.

bool cDisplayString::removeTag | ( | int | tagindex | ) |

| Removes the given tag with all its arguments from the display string. The result is true if the tag was actually deleted (it existed before), false otherwise.

bool cDisplayString::removeTag | ( | const char * | tagname | ) |

| Removes the given tag with all its arguments from the display string. The result is true if the tag was actually deleted (it existed before), false otherwise.

bool cDisplayString::setTagArg | ( | int | tagindex,
|  | int | index,
|  | const char * | value
| ) |

| Sets an argument for the given tag. The value may be NULL pointer. If index points beyond the last argument, the list of arguments will be extended by inserting intervening empty arguments if necessary. The result is true if the operation was successful. False is returned if the given tag doesn't exist, or index is invalid (negative or greater than the maximum numer of arguments, currently 16).

bool cDisplayString::setTagArg | ( | const char * | tagname,
|  | int | index,
|  | long | value
| ) |

| Convenience function to set a tag argument to a numeric value. Converts 'value' to string, then calls setTagArg(const char *, int, const char *).

bool cDisplayString::setTagArg | ( | const char * | tagname,
|  | int | index,
|  | const char * | value
| ) |

| Sets an argument for the given tag. The value may be NULL pointer. If index points beyond the last argument, the list of arguments will be extended by inserting intervening empty arguments if necessary. The result is true if the operation was successful. False is returned if the given tag doesn't exist, or index is invalid (negative or greater than the maximum numer of arguments, currently 16).

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

- cdispstr.h