Exemple #1
0
def analyze(filename, printCode=False, writeDot=False):
    with open(filename, 'rb') as fi:
        s = fi.read()

    freq = Counter(s)
    tree = huffTree(freq)
    if writeDot:
        write_dot(tree, 'tree.dot', is_binary(s))
    code = huffCode(tree)
    if printCode:
        print_code(freq, code)
Exemple #2
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def analyze(filename, printCode=False, writeDot=False):
    with open(filename, 'rb') as fi:
        s = fi.read()

    freq = Counter(s)
    tree = huffTree(freq)
    if writeDot:
        write_dot(tree, 'tree.dot', is_binary(s))
    code = huffCode(tree)
    if printCode:
        print_code(freq, code)
Exemple #3
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def encode(filename):
    with open(filename, 'rb') as fi:
        s = fi.read()

    code = huffCode(huffTree(Counter(s)))
    with open(filename + '.huff', 'wb') as fo:
        for c in sorted(code):
            fo.write(('%02x %s\n' % (c if is_py3k else ord(c),
                                     code[c].to01())).encode())
        a = bitarray(endian='little')
        a.encode(code, s)
        # write unused bits
        fo.write(b'unused %s\n' % str(a.buffer_info()[3]).encode())
        a.tofile(fo)
    print('%d / %d' % (len(a), 8 * len(s)))
    print('Ratio =%6.2f%%' % (100.0 * a.buffer_info()[1] / len(s)))
Exemple #4
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def encode(filename):
    with open(filename, 'rb') as fi:
        s = fi.read()

    code = huffCode(huffTree(Counter(s)))
    with open(filename + '.huff', 'wb') as fo:
        for c in sorted(code):
            fo.write(('%02x %s\n' %
                      (c if is_py3k else ord(c), code[c].to01())).encode())
        a = bitarray(endian='little')
        a.encode(code, s)
        # write unused bits
        fo.write(b'unused %s\n' % str(a.buffer_info()[3]).encode())
        a.tofile(fo)
    print('%d / %d' % (len(a), 8 * len(s)))
    print('Ratio =%6.2f%%' % (100.0 * a.buffer_info()[1] / len(s)))
def main():
    txt = 1000 * open('README').read()

    t0 = time()
    freq = Counter(txt)
    print('count:     %9.6f sec' % (time() - t0))

    t0 = time()
    tree = huffTree(freq)
    print('tree:      %9.6f sec' % (time() - t0))

    write_dot(tree, 'tree.dot')
    code = huffCode(tree)
    # create tree from code (no frequencies)
    write_dot(make_tree(code), 'tree_raw.dot')

    a = bitarray()

    t0 = time()
    a.encode(code, txt)
    print('C encode:  %9.6f sec' % (time() - t0))

    # Time the decode function above
    t0 = time()
    res = decode(tree, a)
    Py_time = time() - t0
    assert ''.join(res) == txt
    print('Py decode: %9.6f sec' % Py_time)

    # Time the decode method which is implemented in C
    t0 = time()
    res = a.decode(code)
    assert ''.join(res) == txt
    C_time = time() - t0
    print('C decode:  %9.6f sec' % C_time)

    print('Ratio: %f' % (Py_time / C_time))
Exemple #6
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def main():
    txt = open('README').read()
    code = huffCode(freq_string(txt))

    sample = 2000 * txt

    a = bitarray()
    a.encode(code, sample)

    # Time the decode function above
    start_time = time.time()
    res = decode(code, a)
    Py_time = time.time() - start_time
    assert ''.join(res) == sample
    print('Py_time: %.6f sec' % Py_time)

    # Time the decode method which is implemented in C
    start_time = time.time()
    res = a.decode(code)
    C_time = time.time() - start_time
    assert ''.join(res) == sample
    print('C_time: %.6f sec' % C_time)

    print('Ratio: %f' % (Py_time / C_time))
Exemple #7
0
def main():
    txt = open('README').read()
    code = huffCode(freq_string(txt))

    sample = 2000 * txt

    a = bitarray()
    a.encode(code, sample)

    # Time the decode function above
    start_time = time.time()
    res = decode(code, a)
    Py_time = time.time() - start_time
    assert ''.join(res) == sample
    print('Py_time: %.6f sec' % Py_time)

    # Time the decode method which is implemented in C
    start_time = time.time()
    res = a.decode(code)
    C_time = time.time() - start_time
    assert ''.join(res) == sample
    print('C_time: %.6f sec' % C_time)

    print('Ratio: %f' % (Py_time / C_time))
Exemple #8
0
    res = []
    it = iter(bitsequence)
    while True:
        r = traverse(it, tree)
        if r is False:
            break
        else:
            if r == []:
                raise ValueError("prefix code does not match data")
            res.append(r)

    return res


txt = open('README').read()
code = huffCode(freq_string(txt))

sample = 1000*txt

a = bitarray()
a.encode(code, sample)

# Time the decode function above
start_time = time.time()
res = decode(code, a)
Py_time = time.time() - start_time
assert ''.join(res) == sample
print('Py_time: %.6f sec' % Py_time)

# Time the decode method which is implemented in C
start_time = time.time()
Exemple #9
0
    res = []
    it = iter(bitsequence)
    while True:
        r = traverse(it, tree)
        if r is False:
            break
        else:
            if r == []:
                raise ValueError("prefix code does not match data")
            res.append(r)

    return res


txt = open('README').read()
code = huffCode(freq_string(txt))

sample = 1000 * txt

a = bitarray()
a.encode(code, sample)

# Time the decode function above
start_time = time.time()
res = decode(code, a)
Py_time = time.time() - start_time
assert ''.join(res) == sample
print('Py_time: %.6f sec' % Py_time)

# Time the decode method which is implemented in C
start_time = time.time()