n-Gram-Based Text Compression

Algorithm 1

Pseudocode of the compression phase.

  input: The source text file

  output: The encoded stream

() inputstring = read source text file

() count = number of grams in the inputstring

() while    do

()    st5 = get first five grams of the inputstring

()    index = find(st5, five_gram_dict)

()    if    then

()       force_four_gram_compression(st4)

()       outputstring += compress(index, 5)

()       delete first five grams of the inputstring

()     count −= 5

()  end

()  else

()     st4 += get first gram of the inputstring

()     delete first gram of the inputstring

()     count −= 1

()     if  number of grams of st4 = 4  then

()      four_gram_compression(st4)

()     end

()    end

() end

(21)  if    then

()   four_gram_compression(inputstring)

()  end