libPasPCRE2

libPasPCRE2 is delphi and object pascal bindings for Perl-compatible Regular Expressions library (PCRE2). Library is a set of functions that implement regular expression pattern matching using the same syntax and semantics as Perl 5.

Table of contents

• Requierements
• Installation
• Usage
• Testing
• Bindings
  • Usage example

Requirements

• Embarcadero (R) Rad Studio
• Free Pascal Compiler
• Lazarus IDE (optional)

Library is tested for

• Embarcadero (R) Delphi 10.3 on Windows 7 Service Pack 1 (Version 6.1, Build 7601, 64-bit Edition)
• FreePascal Compiler (3.2.0) and Lazarus IDE (2.0.10) on Ubuntu Linux 5.8.0-33-generic x86_64

Installation

Get the sources and add the source directory to the project search path. For FPC add the source directory to the fpc.cfg file.

Usage

Clone the repository git clone https://github.com/isemenkov/libpaspcre2.

Add the unit you want to use to the uses clause.

Testing

A testing framework consists of the following ingredients:

1. Test runner project located in unit-tests directory.
2. Test cases (DUnit for Delphi and FPCUnit for FPC based) for all containers classes.

Bindings

libpaspcre2.pas file contains the PCRE2 translated headers to use this library in pascal programs. You can find C API documentation at www.pcre.org website.

Usage example

uses
  libpaspcre2, utils.api.cstring;
  
var
  re : pcre2_code_8;
  rc : Integer;
  pattern, subject : PCRE2_SPTR8;
  error_buffer : string[255];
  subject_length : Int64;
  error_number : Integer;
  error_offset : PCRE2_SIZE;
  ovector : PPCRE2_SIZE;
  match_data : ppcre2_match_data_8;
  substring : string;
begin
  pattern := PCRE2_SPTR8(API.CString.Create('(?:\D|^)(5[1-5][0-9]{2}(?:\ |\-|)[0-9]{4}'+
    '(?:\ |\-|)[0-9]{4}(?:\ |\-|)[0-9]{4})(?:\D|$)').ToPAnsiChar);
  subject := PCRE2_SPTR8(API.CString.Create('5111 2222 3333 4444').ToPAnsiChar);
  subject_length := API.CString.Create('5111 2222 3333 4444').Length;
  
  re := pcre2_compile_8(pattern, PCRE2_ZERO_TERMINATED, 0, @error_number, @error_offset, nil);
  if re = nil then
  begin
    pcre2_get_error_message_8(error_number, PPCRE2_UCHAR8(@error_buffer[0]), 256);
    Fail(Format('PCRE2 compilation failed at offset %d: %s', [error_offset, error_buffer]));
  end;
  
  match_data := pcre2_match_data_create_from_pattern_8(re, nil);
  rc := pcre2_match_8(re, subject, subject_length, 0, 0, match_data, nil);
  if rc < 0 then
  begin
    case rc of
    PCRE2_ERROR_NOMATCH :
      begin
        pcre2_match_data_free_8(match_data);
        pcre2_code_free_8(re);
        Fail('No match');
      end;
    end;
  end;
  {
  ovector := pcre2_get_ovector_pointer_8(match_data);
  
  if ovector^ > (ovector + 1)^ then
    Fail('Error');
    
  substring := Copy(PChar(subject), ovector^, (ovector + 1)^ - ovector^);
  
  pcre2_match_data_free_8(match_data);
  pcre2_code_free_8(re);
  }
end;