def main(args):
# Handle command line arguments
if len(args) != 2:
sys.exit("Usage: python huffman-compress.py InputFile OutputFile")
inputfile = args[0]
outputfile = args[1]
# Read input file once to compute symbol frequencies.
# The resulting generated code is optimal for static Huffman coding and also canonical.
freqs = get_frequencies(inputfile)
freqs.increment(256) # EOF symbol gets a frequency of 1
code = freqs.build_code_tree()
canoncode = huffmancoding.CanonicalCode(tree=code, symbollimit=257)
# Replace code tree with canonical one. For each symbol,
# the code value may change but the code length stays the same.
code = canoncode.to_code_tree()
# Read input file again, compress with Huffman coding, and write output file
inp = open(inputfile, "rb")
bitout = huffmancoding.BitOutputStream(open(outputfile, "wb"))
try:
write_code_len_table(bitout, canoncode)
compress(code, inp, bitout)
finally:
bitout.close()
inp.close()
def main(args):
# Coleta argumentos de linha de comando.
if len(args) != 2:
sys.exit(
"Usage: python huffman-compress.py ArquivoEntrada ArquivoSaida")
inputfile = args[0]
outputfile = args[1]
# Le arquivo de entrada para processar a frequencia dos simbolos
freqs = get_frequencies(inputfile)
freqs.increment(256) # simbolo EOF recebe frequencia 1.
code = freqs.build_code_tree()
canoncode = huffmancoding.CanonicalCode(tree=code, symbollimit=257)
code = canoncode.to_code_tree()
# le arquivo novamente, comprime e escreve no arquivo saida.
inp = open(inputfile, "rb")
bitout = huffmancoding.BitOutputStream(open(outputfile, "wb"))
try:
write_code_len_table(bitout, canoncode)
compress(code, inp, bitout)
finally:
bitout.close()
inp.close()
def compressor(input_files, output_file):
# Read input file once to compute symbol frequencies.
# The resulting generated code is optimal for static Huffman coding and also canonical.
freqs = huffmancoding.FrequencyTable([0] * 257)
files_count = len(input_files)
for files in input_files:
get_frequencies(files, freqs)
freqs.increment(256) # EOF symbol
code = freqs.build_code_tree()
canoncode = huffmancoding.CanonicalCode(
tree=code, symbollimit=freqs.get_symbol_limit())
# Replace code tree with canonical one. For each symbol,
# the code value may change but the code length stays the same.
code = canoncode.to_code_tree()
# Read input file again, compress with Huffman coding, and write output file
with contextlib.closing(
huffmancoding.BitOutputStream(open(output_file + ".mhs",
"wb"))) as bitout:
inp = [open(filename, 'rb') for filename in input_files]
files_name = [os.path.basename(f.name) for f in inp]
write_code_len_table(bitout, canoncode, files_name)
compress(code, inp, bitout, files_count)
for file in inp:
file.close()
def read_code_len_table(bitin): codelengths = [] for i in range(257): # Le valores em big endian, 8 bits val = 0 for j in range(8): val = (val << 1) | bitin.read_no_eof() codelengths.append(val) return huffmancoding.CanonicalCode(codelengths=codelengths)
def read_code_len_table(bitin): def read_int(n): result = 0 for _ in range(n): result = (result << 1) | bitin.read_no_eof() # Big endian return result codelengths = [read_int(8) for _ in range(257)] return huffmancoding.CanonicalCode(codelengths=codelengths)
def read_code_len_table(bitin): codelengths = [] for i in range(257): # For this file format, we read 8 bits in big endian val = 0 for j in range(8): val = (val << 1) | bitin.read_no_eof() codelengths.append(val) return huffmancoding.CanonicalCode(codelengths=codelengths)
def huffman_compress(code_freq, quant_code, codeword_refer, output_file):
code_freq.append(1)
freq = huffmancoding.FrequencyTable(code_freq)
code_tree = freq.build_code_tree()
# Replace code tree with canonical one. For each symbol, the code value may change but the code length stays the same.
canonical_code = huffmancoding.CanonicalCode(tree=code_tree, symbollimit=freq.get_symbol_limit())
code_tree = canonical_code.to_code_tree()
codes = code_tree.codes
# f0 = open(codeword_refer, "w")
# for c in codes:
# f0.write(f'{c} \n')
# f0.close()
with contextlib.closing(huffmancoding.BitOutputStream(open(output_file, "wb"))) as bit_out:
write_code_len_table(bit_out, canonical_code)
compress(code_tree, quant_code, bit_out)
