Method: SectionStripper#updateEXTH121

Defined in:
lib/kindlestrip.rb

#updateEXTH121(srcs_secnum, srcs_cnt, mobiheader) ⇒ Object 



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# File 'lib/kindlestrip.rb', line 87

def updateEXTH121(srcs_secnum, srcs_cnt, mobiheader)
  mobi_length, = mobiheader[0x14...0x18].unpack("N")
  exth_flag, = mobiheader[0x80...0x84].unpack("N")
  exth = "NONE"
  begin
    if exth_flag & 0x40 != 0
      exth = mobiheader[16 + mobi_length .. -1]
      if exth.length >= 4 && exth[0, 4] == "EXTH"
        nitems, = exth[8...12].unpack("N")
        pos = 12
        nitems.times do
          type, size = exth[pos ... pos + 8].unpack("NN")
          #puts "#{type}, #{size}"
          if type == 121
            boundaryptr, = exth[pos + 8 ... pos + size].unpack("N")
            if srcs_secnum <= boundaryptr
              boundaryptr -= srcs_cnt
              prefix = mobiheader[0, 16 + mobi_length + pos + 8]
              suffix = mobiheader[16 + mobi_length + pos + 8 + 4 .. -1]
              nval = [boundaryptr].pack("N")
              mobiheader = prefix + nval + suffix
            end
          end
          pos += size
        end
      end
    end
  rescue
  end
  mobiheader
end