def delta_decode(binary_string):
length, encoded_bits = unary.decode(binary_string)
limit_offset = (length + 1) + length # encoding of the value itself, then 'value' number of bits to read
first_part, next_part = binary_string[:limit_offset], binary_string[limit_offset:] # we can now extract the first encoded binary
bits_to_decode = getvaluefrombinarystring(first_part) - 1
value = (1 << bits_to_decode) + getvaluefrombinarystring(next_part[:bits_to_decode])
consumed_bits = (length + 1) + length + bits_to_decode
return value, consumed_bits
def delta_decode(binary_string):
length, encoded_bits = unary.decode(binary_string)
limit_offset = (length + 1) + length # encoding of the value itself, then 'value' number of bits to read
first_part, next_part = binary_string[:limit_offset], binary_string[limit_offset:] # we can now extract the first encoded binary
bits_to_decode = getvaluefrombinarystring(first_part) - 1
value = (1 << bits_to_decode) + getvaluefrombinarystring(next_part[:bits_to_decode])
consumed_bits = (length + 1) + length + bits_to_decode
return value, consumed_bits
def omega_decode(binary_string, digits_to_read=1, consumed_bits=0):
if binary_string[0] == "0":
return digits_to_read, consumed_bits + 1
else:
bits = binary_string[:digits_to_read + 1]
next_part = binary_string[digits_to_read + 1:]
digits_to_read_next = getvaluefrombinarystring(bits)
return omega_decode(next_part, digits_to_read_next, consumed_bits + digits_to_read + 1)
def omega_decode(binary_string, digits_to_read=1, consumed_bits=0):
if binary_string[0] == "0":
return digits_to_read, consumed_bits + 1
else:
bits = binary_string[:digits_to_read + 1]
next_part = binary_string[digits_to_read + 1:]
digits_to_read_next = getvaluefrombinarystring(bits)
return omega_decode(next_part, digits_to_read_next, consumed_bits + digits_to_read + 1)
def gamma_decode(binary_string):
"""reads a gamma encoded value from the binary string, return the value and the number of consumed bits"""
# assert binary_string[0] == "0"
length, encoded_bits = unary.decode(binary_string)
offset = length + 1
remaining_bits = binary_string[offset: offset + length]
read_value = (1 << length ) + getvaluefrombinarystring(remaining_bits)
consumed_bits = length * 2 + 1
return read_value, consumed_bits
def gamma_decode(binary_string):
"""reads a gamma encoded value from the binary string, return the value and the number of consumed bits"""
# assert binary_string[0] == "0"
length, encoded_bits = unary.decode(binary_string)
offset = length + 1
remaining_bits = binary_string[offset:offset + length]
read_value = (1 << length) + getvaluefrombinarystring(remaining_bits)
consumed_bits = length * 2 + 1
return read_value, consumed_bits
def generate_root(polynom):
exponents = get_exponents(polynom)
# assert polynom == sorted(polynom, reverse=True)
width = max(exponents) # polynom[0]
# the number whose all bits of an exponent are sets, except the highest one
all_bits = or_all(1 << i for i in exponents)
highest_bit = 1 << width
polynomial_constant = all_bits ^ highest_bit
constant_bitstring = getpadbinstr(polynomial_constant, width)
reverse_bitstring = constant_bitstring[::-1]
reverse_constant = getvaluefrombinarystring(reverse_bitstring)
return polynomial_constant, reverse_constant, width
def generate_root(polynom):
exponents = get_exponents(polynom)
# assert polynom == sorted(polynom, reverse=True)
width = max(exponents) # polynom[0]
# the number whose all bits of an exponent are sets, except the highest one
all_bits = or_all(1 << i for i in exponents)
highest_bit = 1 << width
polynomial_constant = all_bits ^ highest_bit
constant_bitstring = getpadbinstr(polynomial_constant, width)
reverse_bitstring = constant_bitstring[::-1]
reverse_constant = getvaluefrombinarystring(reverse_bitstring)
return polynomial_constant, reverse_constant, width
def change_base(block, block_length, source_base, source_size, target_base, target_size):
"""takes block as a block_length-bit long binary stream.
reads it as entries of source_base, on source_size bits,
resplit bits as target_base chars, which are stored on target_size"""
# let's get a binary representation of our block, in our source base
bits_string = ""
for char in list(block):
bits_string += getpadbinstr(source_base.index(char), source_size)
# then split that representation in target_size bits long blocks
split_bits = (bits_string[i : i + target_size] for i in range(0, block_length, target_size))
# get the according values,
encoded_values = (getvaluefrombinarystring(i) for i in split_bits)
# and the corresponding entries from our target base
output_chars = [target_base[i] for i in encoded_values]
output_block = "".join(output_chars)
return output_block
def change_base(block, block_length, source_base, source_size, target_base,
target_size):
"""takes block as a block_length-bit long binary stream.
reads it as entries of source_base, on source_size bits,
resplit bits as target_base chars, which are stored on target_size"""
#let's get a binary representation of our block, in our source base
bits_string = ""
for char in list(block):
bits_string += getpadbinstr(source_base.index(char), source_size)
#then split that representation in target_size bits long blocks
split_bits = (bits_string[i:i + target_size]
for i in range(0, block_length, target_size))
#get the according values,
encoded_values = (getvaluefrombinarystring(i) for i in split_bits)
#and the corresponding entries from our target base
output_chars = [target_base[i] for i in encoded_values]
output_block = "".join(output_chars)
return output_block
assert char_range("A", "Z") == "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
#gcd
#returns the greatest common divisor of both parameters
assert gcd(6, 8) == 2
#lcm
#returns the least common multiplier of both parameters
assert lcm(6, 9) == 18
assert lcm(6, 8) == 24
assert getbinlen(0) == 1
assert getbinlen(1) == 1
assert getbinlen(3) == 2
assert getvaluefrombinarystring("1000") == 8
assert getvaluefrombinarystring("001000") == 8
assert getpadbinstr(8, 8) == "00001000"
assert getunkbinstr(0, 0, 8) == "000000000"
assert getunkbinstr(1, 0, 8) == "000000001"
assert getunkbinstr(2, 1, 8) == "00000001x"
assert getunkbinstr(237, 3, 8) == "011101xxx"
assert gethexstr("\x00") == "00"
assert gethexstr("\x00\x01") == "00 01"
assert gethexstr("abcd") == "61 62 63 64"
assert int2lebin(1, 2) == '\x01\x00'
assert int2lebin(65535, 2) == "\xff\xff"
assert char_range("A", "Z") == "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
#gcd
#returns the greatest common divisor of both parameters
assert gcd(6, 8) == 2
#lcm
#returns the least common multiplier of both parameters
assert lcm(6, 9) == 18
assert lcm(6, 8) == 24
assert getbinlen(0) == 1
assert getbinlen(1) == 1
assert getbinlen(3) == 2
assert getvaluefrombinarystring("1000") == 8
assert getvaluefrombinarystring("001000") == 8
assert getpadbinstr(8, 8) == "00001000"
assert getunkbinstr(0, 0, 8) == "000000000"
assert getunkbinstr(1, 0, 8) == "000000001"
assert getunkbinstr(2, 1, 8) == "00000001x"
assert getunkbinstr(237, 3, 8) == "011101xxx"
assert gethexstr("\x00") == "00"
assert gethexstr("\x00\x01") == "00 01"
assert gethexstr("abcd") == "61 62 63 64"
assert int2lebin(1, 2) == '\x01\x00'
assert int2lebin(65535, 2) == "\xff\xff"