def create_data(version, error_correction, data_list):
buffer = BitBuffer()
for data in data_list:
buffer.put(data.mode, 4)
buffer.put(len(data), length_in_bits(data.mode, version))
data.write(buffer)
# Calculate the maximum number of bits for the given version.
rs_blocks = base.rs_blocks(version, error_correction)
bit_limit = 0
for block in rs_blocks:
bit_limit += block.data_count * 8
if len(buffer) > bit_limit:
raise exceptions.DataOverflowError(
"Code length overflow. Data size (%s) > size available (%s)" %
(len(buffer), bit_limit))
# Terminate the bits (add up to four 0s).
for i in range(min(bit_limit - len(buffer), 4)):
buffer.put_bit(False)
# Delimit the string into 8-bit words, padding with 0s if necessary.
delimit = len(buffer) % 8
if delimit:
for i in range(8 - delimit):
buffer.put_bit(False)
# Add special alternating padding bitstrings until buffer if full.
bytes_to_fill = (bit_limit - len(buffer)) // 8
for i in range(bytes_to_fill):
buffer.put(PAD0 if i % 2 == 0 else PAD1, 8)
return create_bytes(buffer, rs_blocks)
def create_data(version, error_correction, data_list, colors, control_colors=None, copy_colors_to_ec=False):
if None == control_colors:
control_colors = defaultdict(lambda :True)
last_color = colors[-1]
bit_buf = BitBuffer()
for data in data_list:
bit_buf.put(data.mode, 4, colors[0])
bit_buf.put(len(data), length_in_bits(data.mode, version), colors[0])
data.write_to_buffer(bit_buf, colors[:len(data)])
colors = colors[len(data):]
# Calculate the maximum number of bits for the given version.
rs_blocks = base.rs_blocks(version, error_correction)
bit_limit = 0
for block in rs_blocks:
bit_limit += block.data_count * 8
if len(bit_buf) > bit_limit:
raise exceptions.DataOverflowError(
"Code length overflow. Data size (%s) > size available (%s)" %
(len(bit_buf), bit_limit))
# Terminate the bits (add up to four 0s).
for i in range(min(bit_limit - len(bit_buf), 4)):
bit_buf.put_bit(False, last_color)
# Delimit the string into 8-bit words, padding with 0s if necessary.
delimit = len(bit_buf) % 8
if delimit:
bit_buf.put(0, 8 - delimit, control_colors['padding'])
# Add special alternating padding bitstrings until bit_buf is full.
bytes_to_fill = (bit_limit - len(bit_buf)) // 8
for i in range(bytes_to_fill):
if i % 2 == 0:
bit_buf.put(PAD0, 8, control_colors['padding'])
else:
bit_buf.put(PAD1, 8, control_colors['padding'])
data_and_error_correction = generate_error_correction(bit_buf, rs_blocks, control_colors, copy_colors_to_ec)
encoded_data = combain_data_and_error_correction(data_and_error_correction)
return encoded_data
def create_data(version, error_correction, data_list):
rs_blocks = base.rs_blocks(version, error_correction)
buffer = BitBuffer()
for data in data_list:
buffer.put(data.mode, 4)
buffer.put(len(data), length_in_bits(data.mode, version))
data.write(buffer)
# calc num max data.
total_data_count = 0
for block in rs_blocks:
total_data_count += block.data_count
if len(buffer) > total_data_count * 8:
raise exceptions.DataOverflowError("Code length overflow. Data size "
"(%s) > size available (%s)" %
(len(buffer), total_data_count * 8))
# end code
if len(buffer) + 4 <= total_data_count * 8:
buffer.put(0, 4)
# padding
while len(buffer) % 8:
buffer.put_bit(False)
# padding
while True:
if len(buffer) >= total_data_count * 8:
break
buffer.put(PAD0, 8)
if len(buffer) >= total_data_count * 8:
break
buffer.put(PAD1, 8)
return create_bytes(buffer, rs_blocks)
def create_data(version, error_correction, data_list):
rs_blocks = base.rs_blocks(version, error_correction)
buffer = BitBuffer()
for data in data_list:
buffer.put(data.mode, 4)
buffer.put(len(data),
length_in_bits(data.mode, version))
data.write(buffer)
# calc num max data.
total_data_count = 0
for block in rs_blocks:
total_data_count += block.data_count
if len(buffer) > total_data_count * 8:
raise exceptions.DataOverflowError("Code length overflow. Data size "
"(%s) > size available (%s)" % (len(buffer), total_data_count * 8))
# end code
if len(buffer) + 4 <= total_data_count * 8:
buffer.put(0, 4)
# padding
while len(buffer) % 8:
buffer.put_bit(False)
# padding
while True:
if len(buffer) >= total_data_count * 8:
break
buffer.put(PAD0, 8)
if len(buffer) >= total_data_count * 8:
break
buffer.put(PAD1, 8)
return create_bytes(buffer, rs_blocks)
(1 << 10) | (1 << 8) | (1 << 5) | (1 << 4) | (1 << 2) | (1 << 1) |
(1 << 0))
G18 = (
(1 << 12) | (1 << 11) | (1 << 10) | (1 << 9) | (1 << 8) | (1 << 5) |
(1 << 2) | (1 << 0))
G15_MASK = (1 << 14) | (1 << 12) | (1 << 10) | (1 << 4) | (1 << 1)
PAD0 = 0xEC
PAD1 = 0x11
MAX_VERSION = 40
# Precompute bit count limits, indexed by error correction level and code size
_data_count = lambda block: block.data_count
BIT_LIMIT_TABLE = [
[0] + [8*sum(map(_data_count, base.rs_blocks(version, error_correction)))
for version in xrange(1, MAX_VERSION+1)]
for error_correction in xrange(4)
]
def BCH_type_info(data):
d = data << 10
while BCH_digit(d) - BCH_digit(G15) >= 0:
d ^= (G15 << (BCH_digit(d) - BCH_digit(G15)))
return ((data << 10) | d) ^ G15_MASK
def BCH_type_number(data):
d = data << 12
G15 = (
(1 << 10) | (1 << 8) | (1 << 5) | (1 << 4) | (1 << 2) | (1 << 1) |
(1 << 0))
G18 = (
(1 << 12) | (1 << 11) | (1 << 10) | (1 << 9) | (1 << 8) | (1 << 5) |
(1 << 2) | (1 << 0))
G15_MASK = (1 << 14) | (1 << 12) | (1 << 10) | (1 << 4) | (1 << 1)
PAD0 = 0xEC
PAD1 = 0x11
# Precompute bit count limits, indexed by error correction level and code size
_data_count = lambda block: block.data_count
BIT_LIMIT_TABLE = [
[0] + [8*sum(map(_data_count, base.rs_blocks(version, error_correction)))
for version in xrange(1, 41)]
for error_correction in xrange(4)
]
def BCH_type_info(data):
d = data << 10
while BCH_digit(d) - BCH_digit(G15) >= 0:
d ^= (G15 << (BCH_digit(d) - BCH_digit(G15)))
return ((data << 10) | d) ^ G15_MASK
def BCH_type_number(data):
d = data << 12
