Module: PCRE2::Lib

Extended by:
FFI::Library
Defined in:
lib/pcre2/lib.rb

Constant Summary collapse

RETURN_CODE_NO_ERROR = 
100
PCRE2_SIZE = 
typedef :size_t,   :PCRE2_SIZE
PCRE2_SPTR = 
typedef :pointer,  :PCRE2_SPTR
PCRE2_UCHAR8 = 
typedef :uint8_t,  :PCRE2_UCHAR8
PCRE2_UCHAR16 = 
typedef :uint16_t, :PCRE2_UCHAR16
PCRE2_UCHAR32 = 
typedef :uint32_t, :PCRE2_UCHAR32
PCRE2_UCHAR =

For 8-bit PCRE

typedef :PCRE2_UCHAR8, :PCRE2_UCHAR

Class Method Summary collapse

Class Method Details

.compile_pattern(pattern, options = []) ⇒ Object

Some utility functions to help make the above more palatable



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# File 'lib/pcre2/lib.rb', line 62

def self.compile_pattern(pattern, options = [])
  pattern_string_ptr = FFI::MemoryPointer.from_string(pattern)
  error_code_ptr     = FFI::MemoryPointer.new(:int, 1)
  error_offset_ptr   = FFI::MemoryPointer.new(PCRE2_SIZE, 1)
  options            = options.flatten.inject(0) { |memo, option| memo | option }

  pattern_ptr = PCRE2::Lib.pcre2_compile_8(pattern_string_ptr, pattern.size, options, error_code_ptr, error_offset_ptr, nil)

  if pattern_ptr.null?
    error_code = error_code_ptr.read_int
    error_offset = error_offset_ptr.read(PCRE2_SIZE)

    raise PCRE2::Error.from_error_code(error_code, "while compiling pattern #{pattern} @ #{error_offset}")
  end

  FFI::AutoPointer.new(pattern_ptr, PCRE2::Lib.method(:pcre2_code_free_8))
end

.create_match_data_for_pattern(pattern_ptr) ⇒ Object 



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# File 'lib/pcre2/lib.rb', line 80

def self.create_match_data_for_pattern(pattern_ptr)
  match_data_ptr = PCRE2::Lib.pcre2_match_data_create_from_pattern_8(pattern_ptr, nil)
  FFI::AutoPointer.new(match_data_ptr, PCRE2::Lib.method(:pcre2_match_data_free_8))
end

.get_error_message(error_code) ⇒ Object 



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# File 'lib/pcre2/lib.rb', line 43

def self.get_error_message(error_code)
  if error_code.kind_of?(FFI::MemoryPointer)
    error_code = error_code.read_int
  end

  buffer = FFI::MemoryPointer.new(PCRE2_UCHAR, 120)
  result = pcre2_get_error_message_8(error_code, buffer, buffer.size)

  case result
  when PCRE2::PCRE2_ERROR_BADDATA
    "Error number #{error_code} unknown"
  when PCRE2::PCRE2_ERROR_NOMEMORY
    raise PCRE2::Error, "Buffer of #{buffer.size} is not large enough to contain message"
  else
    buffer.read_string
  end
end

.get_ovector_pairs(match_data_ptr, pair_count) ⇒ Object 



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# File 'lib/pcre2/lib.rb', line 118

def self.get_ovector_pairs(match_data_ptr, pair_count)
  if pair_count.nil?
    pair_count = PCRE2::Lib.pcre2_get_ovector_count_8(match_data_ptr)
  end

  ovector_ptr = PCRE2::Lib.pcre2_get_ovector_pointer_8(match_data_ptr)
  type_size = FFI.type_size(:size_t)

  pair_count.times.map do |i|
    [
      ovector_ptr.get(:size_t, i*2 * type_size),
      ovector_ptr.get(:size_t, (i*2+1) * type_size)
    ]
  end
end

.match(pattern_ptr, body, position: 0, match_data_ptr: nil) ⇒ Object 



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# File 'lib/pcre2/lib.rb', line 85

def self.match(pattern_ptr, body, position: 0, match_data_ptr: nil)
  position ||= 0
  match_data_ptr ||= create_match_data_for_pattern(pattern_ptr)

  body_ptr = FFI::MemoryPointer.from_string(body)

  return_code =
    PCRE2::Lib.pcre2_match_8(
      pattern_ptr,
      body_ptr,
      body_ptr.size,
      position,
      0,
      match_data_ptr,
      nil
    )

  case return_code
  when 0
    raise PCRE2::Error, "Not enough memory in MatchData to store all captures"
  when PCRE2::PCRE2_ERROR_NOMATCH
    result_count = 0
  else
    if return_code < 0
      raise PCRE2::Error.from_error_code(return_code)
    else
      result_count = return_code
    end
  end

  [result_count, match_data_ptr]
end

.named_captures(pattern_ptr) ⇒ Object 



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# File 'lib/pcre2/lib.rb', line 134

def self.named_captures(pattern_ptr)
  named_captures_count = FFI::MemoryPointer.new(:uint32_t, 1)
  name_entry_size      = FFI::MemoryPointer.new(:uint32_t, 1)
  name_table_ptr       = FFI::MemoryPointer.new(:pointer, 1)

  if PCRE2::Lib.pcre2_pattern_info_8(pattern_ptr, PCRE2::PCRE2_INFO_NAMECOUNT, named_captures_count) != 0
    raise "Something went wrong"
  end

  if PCRE2::Lib.pcre2_pattern_info_8(pattern_ptr, PCRE2::PCRE2_INFO_NAMEENTRYSIZE, name_entry_size) != 0
    raise "Something went wrong"
  end

  if PCRE2::Lib.pcre2_pattern_info_8(pattern_ptr, PCRE2::PCRE2_INFO_NAMETABLE, name_table_ptr) != 0
    raise "Something went wrong"
  end

  named_captures_count = named_captures_count.read_uint32
  name_entry_size      = name_entry_size.read_uint32
  name_table_ptr       = name_table_ptr.read_pointer

  names_and_positions =
    named_captures_count.times.map do |i|
      ovector_position = (name_table_ptr.get_int8(0) << 8) + name_table_ptr.get_int8(1)
      match_name = (name_table_ptr+2).read_string_to_null

      name_table_ptr += name_entry_size

      [match_name, ovector_position]
    end

  # Convert an array of [name, position] into a Hash of name => [position (, position, ...)], with possible duplicate names
  names_and_positions.each_with_object(Hash.new {[]} ) { |(name, position), hash| hash[name] <<= position }
end