Method: Spreadsheet::Excel::Reader#read_formula

Defined in:
lib/spreadsheet/excel/reader.rb

#read_formula(worksheet, addr, work) ⇒ Object 



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# File 'lib/spreadsheet/excel/reader.rb', line 352

def read_formula worksheet, addr, work
  # Offset  Size  Contents
  #      0     2  Index to row
  #      2     2  Index to column
  #      4     2  Index to XF record (➜ 6.115)
  #      6     8  Result of the formula. See below for details.
  #     14     2  Option flags:
  #               Bit  Mask    Contents
  #                 0  0x0001  1 = Recalculate always
  #                 1  0x0002  1 = Calculate on open
  #                 3  0x0008  1 = Part of a shared formula
  #     16     4  Not used
  #     20  var.  Formula data (RPN token array, ➜ 4)
  #               Offset  Size  Contents
  #                    0     2  Size of the following formula data (sz)
  #                    2    sz  Formula data (RPN token array)
  #               [2+sz]  var.  (optional) Additional data for specific tokens
  #                             (➜ 4.1.6, for example tArray token, ➜ 4.8.7)
  #
  # Result of the Formula
  # Dependent on the type of value the formula returns, the result field has
  # the following format:
  #
  # Result is a numeric value:
  # Offset  Size  Contents
  #      0     8  IEEE 754 floating-point value (64-bit double precision)
  #
  # Result is a string (the string follows in a STRING record, ➜ 6.98):
  # Offset  Size  Contents
  #      0     1  0x00 (identifier for a string value)
  #      1     5  Not used
  #      6     2  0xffff
  # Note: In BIFF8 the string must not be empty. For empty cells there is a
  # special identifier defined (see below).
  #
  # Result is a Boolean value:
  # Offset  Size  Contents
  #      0     1  0x01 (identifier for a Boolean value)
  #      1     1  Not used
  #      2     1  0 = FALSE, 1 = TRUE
  #      3     3  Not used
  #      6     2  0xffff
  #
  # Result is an error value:
  # Offset  Size  Contents
  #      0     1  0x02 (identifier for an error value)
  #      1     1  Not used
  #      2     1  Error code (➜ 3.7)
  #      3     3  Not used
  #      6     2  0xffff
  #
  # Result is an empty cell (BIFF8), for example an empty string:
  # Offset  Size  Contents
  #      0     1  0x03 (identifier for an empty cell)
  #      1     5  Not used
  #      6     2  0xffff
  row, column, xf, rtype, rval, rcheck, opts = work.unpack "v3CxCx3v2"
  formula = Formula.new
  formula.shared = (opts & 0x08) > 0
  formula.data = work[20..]
  if rcheck != 0xffff || rtype > 3
    value, = work.unpack "x6E"
    unless value
      # on architectures where sizeof(double) > 8
      value, = work.unpack "x6e"
    end
    formula.value = value
  elsif rtype == 0
    pos, op, _len, work = get_next_chunk
    if op == :sharedfmla
      ## TODO: formula-support in 0.8.0
      pos, op, _len, work = get_next_chunk
    end
    if op == :string
      formula.value = client read_string(work, 2), @workbook.encoding
    else
      warn "String Value expected after Formula, but got #{op}"
      formula.value = Error.new 0x2a
      @pos = pos
    end
  elsif rtype == 1
    formula.value = rval > 0
  elsif rtype == 2
    formula.value = Error.new rval
  else
    # leave the Formula value blank
  end
  set_cell worksheet, row, column, xf, formula
end