All Classes Namespaces Files Functions Variables Typedefs Enumerations Enumerator Friends Macros Pages
pdftron::PDF::TextSearch Class Reference

#include <TextSearch.h>

Public Types

enum  TextSearchModes {
  e_reg_expression = 0x0001, e_case_sensitive = e_reg_expression << 1, e_whole_word = e_case_sensitive << 1, e_search_up = e_whole_word << 1,
  e_page_stop = e_search_up << 1, e_highlight = e_page_stop << 1, e_ambient_string = e_highlight << 1, e_raw_text_search = e_ambient_string << 1
typedef TRN_UInt32 Mode

Public Member Functions

 TextSearch ()
 ~TextSearch ()
bool Begin (PDFDoc &doc, const UString &pattern, Mode mode, int start_page=-1, int end_page=-1)
SearchResult Run ()
bool SetPattern (const UString &pattern)
Mode GetMode () const
void SetMode (Mode mode)
void SetRightToLeftLanguage (bool flag)
int GetCurrentPage () const
void SetOCGContext (OCG::Context *context)
void Destroy ()

Detailed Description

TextSearch searches through a PDF document for a user-given search pattern. The current implementation supports both verbatim search and the search using regular expressions, whose detailed syntax can be found at:

TextSearch also provides users with several useful search modes and extra information besides the found string that matches the pattern. TextSearch can either keep running until a matched string is found or be set to return periodically in order for the caller to perform any necessary updates (e.g., UI updates). It is also worth mentioning that the search modes can be changed on the fly while searching through a document.

Possible use case scenarios for TextSearch include:

  • Guide users of a PDF viewer (e.g. implemented by PDFViewCtrl) to places where they are intersted in;
  • Find interested PDF documents which contain certain patterns;
  • Extract interested information (e.g., credit card numbers) from a set of files;
  • Extract Highlight information (refer to the Highlights class for details) from files for external use.


  • Since hyphens ('-') are frequently used in PDF documents to concatenate the two broken pieces of a word at the end of a line, for example

    "TextSearch is powerful for finding patterns in PDF files; yes, it is really pow- erful."

    a search for "powerful" should return both instances. However, not all end-of-line hyphens are hyphens added to connect a broken word; some of them could be "real" hyphens. In addition, an input search pattern may also contain hyphens that complicate the situation. To tackle this problem, the following conventions are adopted:

    a)When in the verbatim search mode and the pattern contains no hyphen, a matching string is returned if it is exactly the same or it contains end-of-line or start-of-line hyphens. For example, as mentioned above, a search for "powerful" would return both instances. b)When in verbatim search mode and the pattern contains one or multiple hyphens, a matching string is returned only if the string matches the pattern exactly. For example, a search for "pow-erful" will only return the second instance, and a search for "power-ful" will return nothing. c)When searching using regular expressions, hyphens are not taken care implicitly. Users should take care of it themselves. For example, in order to find both the "powerful" instances, the input pattern can be "pow-{0,1}erful".

A sample use case (in C++):

* //... Initialize PDFNet ...
* PDFDoc doc(filein);
* doc.InitSecurityHandler();
* int page_num;
* char buf[32];
* UString result_str, ambient_string;
* Highlights hlts;
* TextSearch txt_search;
* UString pattern( "joHn sMiTh" );
* //PDFDoc doesn't allow simultaneous access from different threads. If this
* //document could be used from other threads (e.g., the rendering thread inside
* //PDFView/PDFViewCtrl, if used), it is good practice to lock it.
* //Notice: don't forget to call doc.Unlock() to avoid deadlock.
* doc.Lock();
* txt_search.Begin( doc, pattern, mode );
* while ( true )
* {
* SearchResult result = code = txt_search.Run(page_num, result_str, ambient_string, hlts );
* if ( code == TextSearch::e_found )
* {
* result_str.ConvertToAscii(buf, 32, true);
* cout << "found one instance: " << char_buf << endl;
* }
* else
* {
* break;
* }
* }
* //unlock the document to avoid deadlock.
* doc.UnLock();

For a full sample, please take a look at the TextSearch sample project.

Definition at line 173 of file TextSearch.h.

Member Typedef Documentation

typedef TRN_UInt32 pdftron::PDF::TextSearch::Mode

Typedef the search mode.

Definition at line 186 of file TextSearch.h.

Member Enumeration Documentation

Search modes that control how searching is conducted.


Definition at line 191 of file TextSearch.h.

Constructor & Destructor Documentation

pdftron::PDF::TextSearch::TextSearch ( )

Constructor and destructor.

pdftron::PDF::TextSearch::~TextSearch ( )

Member Function Documentation

bool pdftron::PDF::TextSearch::Begin ( PDFDoc doc,
const UString pattern,
Mode  mode,
int  start_page = -1,
int  end_page = -1 

Initialize for search process. This should be called before starting the actual search with method Run().

docthe PDF document to search in.
patternthe pattern to search for. When regular expression is used, it contains the expression, and in verbatim mode, it is the exact string to search for.
modethe mode of the search process.
start_pagethe start page of the page range to search in. The default value is -1 indicating the range starts from the first page.
end_pagethe end page of the page range to search in. The default value is -1 indicating the range ends at the last page.
true if the initialization has succeeded.
void pdftron::PDF::TextSearch::Destroy ( )

Frees the native memory of the object.

int pdftron::PDF::TextSearch::GetCurrentPage ( ) const

Retrieve the number of the current page that is searched in. If the returned value is -1, it indicates the search process has not been initialized (e.g., Begin() is not called yet); if the returned value is 0, it indicates the search process has finished, and if the returned value is positive, it is a valid page number.

the current page number.
Mode pdftron::PDF::TextSearch::GetMode ( ) const

Retrieve the current search mode.

the current search mode.
SearchResult pdftron::PDF::TextSearch::Run ( )

Search the document and returns upon the following circumstances: a)Reached the end of the document; b)Reached the end of a page (if set to return by specifying mode 'e_page_stop' ); c)Found an instance matching the search pattern.

Note that this method should be called in a loop in order to find all matching instances; in other words, the search is conducted in an incremental fashion.

void pdftron::PDF::TextSearch::SetMode ( Mode  mode)

Set the current search mode. For example, the following code turns on the regular expressions:

TextSearch ts; ... TextSearch::Mode mode = ts.GetMode(); mode |= TextSearch::e_reg_expression; ts.SetMode(mode); ...

modethe search mode to set.
void pdftron::PDF::TextSearch::SetOCGContext ( OCG::Context context)

Sets the Optional Content Group (OCG) context that should be used when processing the document. This function can be used to change the current OCG context. Optional content (such as PDF layers) will be selectively processed based on the states of optional content groups in the given context.

ctxOptional Content Group (OCG) context, or NULL if TextSearch should process all content on the page.
bool pdftron::PDF::TextSearch::SetPattern ( const UString pattern)

Set the current search pattern. Note that it is not necessary to call this method since the search pattern is already set when calling the Begin() method. This method is provided for users to change the search pattern while searching through a document.

patternthe search pattern to set.
true if the setting has succeeded.
void pdftron::PDF::TextSearch::SetRightToLeftLanguage ( bool  flag)

Tells TextSearch that language is from right to left.

flagSet to true if the language is right to left.

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