Foxit PDF SDK

Public Member Functions | Static Public Attributes | List of all members
FSDK.PDFNumberTree Class Reference

## Public Member Functions
| constructor (document, type)
| Constructor, with parameters. More...
| GetObj (number)
| Get the value (as PDF object) of a specified key integer. More...
| GetType ()
| Get the type of current number tree. More...
| HasNumber (number)
| Check if the specified key integer exists in current number tree. More...
| IsEmpty ()
| Check whether current object is empty or not. More...
| RemoveAllObjs ()
| Remove all key integers from current number tree, along with theirs value (as PDF object). More...
| RemoveObj (number)
| Remove a key integer from current number tree, along with its value (as PDF object). More...
| SetObj (number, pdf_object)
| Set the value (as PDF object) of a specified key integer. If the key integer does not exist, it will be added to current number tree with the value. More...

## Static Public Attributes
static | e_PageLabels
| Enumeration for number tree type. More...

## Detailed Description

Number tree is a kind of common data structure in PDF. A number tree is similar to a number tree, except that keys in a number tree are integers instead of strings and are sorted in ascending numerical order. Number tree has following characteristics:

- key integers in a number tree are sorted in ascending numerical order and each key integer in the same number tree is unique;
- values associated with the key integers may be objects of any type, depending on the purpose of the number tree;
- number tree can represent an arbitrarily large collection of key-value pairs, which can be looked up efficiently without requiring the entire data structure to be read from the PDF file.

Class FSDK.PDFNumberTree is used to be associated with an existing number tree with specified type or create one. It offers functions to get key-value pairs in the number tree, and set/add/remove any key-value pair. Currently, class FSDK.PDFNumberTree can be associated with following number tree defined in PDF document:

- Page labels number tree (with type FSDK.PDFNumberTree.e_PageLabels), which defines the page labeling for the document. The keys in this tree are page indexes; the corresponding values are page label dictionaries (Please refer to <PDF Renferece 1.7> P594 Section 8.3.1, "Page Labels"). Each page index denotes the first page in a labeling range to which the specified page label dictionary applies. The tree must include a value for page index 0.

## Member Function Documentation

## ◆ constructor()

FSDK.PDFNumberTree.constructor | ( | document | ,
|  | type |
| ) |  |

Constructor, with parameters.

If there exists number tree with specified type in the PDF document, this function is just to construct a PDF number tree object to be associated with the number tree. If there is no such number tree in PDF document, the constructed PDF number tree object can be used to create such number tree in PDF document and add items to the number tree.

Parameters

  [in] | document | A valid PDF document object.
  [in] | type | The type of the number tree. Please refer to values starting from FSDK.PDFNumberTree.e_PageLabels and this should be one of these values.

## ◆ GetObj()

FSDK.PDFNumberTree.GetObj | ( | number |  | ) |

Get the value (as PDF object) of a specified key integer.

Parameters

  [in] | number | An integer as the key.

Returns
  A FSDK.PDFObject object. The type of returned PDF object depends on the purpose of current number tree. Please refer to comment of class FSDK.PDFNumberTree for more details. If not found, this function will return null.

## ◆ GetType()

FSDK.PDFNumberTree.GetType | ( |  | ) |

Get the type of current number tree.

Returns
  Type of current number tree. Please refer to values starting from FSDK.PDFNumberTree.e_PageLabels and this would be one of these values.

## ◆ HasNumber()

FSDK.PDFNumberTree.HasNumber | ( | number |  | ) |

Check if the specified key integer exists in current number tree.

Parameters

  [in] | number | An integer that represents the key to be checked.

Returns
  true means the specified integer exists in current number tree, and false means the specified integer does not exist in current number tree.

## ◆ IsEmpty()

FSDK.PDFNumberTree.IsEmpty | ( |  | ) |

Check whether current object is empty or not.

When the current object is empty, that means current object is useless.

Returns
  true means current object is empty, while false means not.

## ◆ RemoveAllObjs()

FSDK.PDFNumberTree.RemoveAllObjs | ( |  | ) |

Remove all key integers from current number tree, along with theirs value (as PDF object).

Returns
  true means success, while false means failure.

## ◆ RemoveObj()

FSDK.PDFNumberTree.RemoveObj | ( | number |  | ) |

Remove a key integer from current number tree, along with its value (as PDF object).

If the input key integer does not exist in current number tree, this function will return true directly.

Parameters

  [in] | number | An integer as the key to be removed.

Returns
  true means success, while false means failure.

## ◆ SetObj()

FSDK.PDFNumberTree.SetObj | ( | number | ,
|  | pdf_object |
| ) |  |

Set the value (as PDF object) of a specified key integer. If the key integer does not exist, it will be added to current number tree with the value.

Parameters

  [in] | number | An integer as the key.
  [in] | pdf_object | A PDF object to be set as the key's value. It should not be null. The type of this PDF object should match current number tree; otherwise, the input PDF object is invalid. Please refer to comment of class FSDK.PDFNumberTree for more details. User should not release this PDF object after this function succeeds.

Returns
  true means success, while false means failure.

## Member Data Documentation

## ◆ e_PageLabels

FSDK.PDFNumberTree.e_PageLabels
| static

Enumeration for number tree type.

Values of this enumeration should be used alone."PageLabels" number tree.