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Merged
postmodern merged 1 commit into from
Jul 13, 2023
Merged

Unified Digest::CRC#update #41

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12 changes: 3 additions & 9 deletions README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -115,7 +115,9 @@ require 'digest/crc32'
module Digest
class CRC3000 < CRC32

WIDTH = 4
WIDTH = 32

REFLECT_INPUT = true

INIT_CRC = 0xffffffff

Expand All @@ -124,14 +126,6 @@ module Digest
TABLE = [
# ....
].freeze

def update(data)
data.each_byte do |b|
@crc = (((@crc >> 8) & 0x00ffffff) ^ @table[(@crc ^ b) & 0xff])
end

return self
end
end
end
```
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63 changes: 57 additions & 6 deletions lib/digest/crc.rb
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Expand Up @@ -17,6 +17,9 @@ class CRC < Digest::Class
# The bit width of the CRC checksum
WIDTH = 0

# Define true or false whether the input direction is bit reversed or not of the CRC checksum
REFLECT_INPUT = nil

# Default place holder CRC table
TABLE = [].freeze

Expand Down Expand Up @@ -60,10 +63,11 @@ def self.pack(crc)
# Initializes the CRC checksum.
#
def initialize
@init_crc = self.class.const_get(:INIT_CRC)
@xor_mask = self.class.const_get(:XOR_MASK)
@width = self.class.const_get(:WIDTH)
@table = self.class.const_get(:TABLE)
@init_crc = self.class.const_get(:INIT_CRC)
@xor_mask = self.class.const_get(:XOR_MASK)
@width = self.class.const_get(:WIDTH)
@reflect_input = self.class.const_get(:REFLECT_INPUT)
@table = self.class.const_get(:TABLE)

reset
end
Expand Down Expand Up @@ -93,10 +97,57 @@ def digest_length
# @param [String] data
# The data to update the CRC checksum with.
#
# @abstract
# @raise [NotImplementedError]
# If WIDTH, TABLE, or REFLECT_INPUT constants are not set properly.
#
def update(data)
raise(NotImplementedError,"#{self.class}##{__method__} not implemented")
unless @width >= 1
raise(NotImplementedError, "incompleted #{self.class} as CRC (expected WIDTH to be 1 or more)")
end

if @table.empty?
raise(NotImplementedError, "incompleted #{self.class} as CRC (expected TABLE to be not empty)")
end

if @reflect_input.nil?
raise(NotImplementedError, "incompleted #{self.class} as CRC (expected REFLECT_INPUT to be not nil)")
end

table = @table
crc = @crc

if @reflect_input
if @width > 8
data.each_byte do |b|
crc = table[b ^ (0xff & crc)] ^ (crc >> 8)
end
else
data.each_byte do |b|
# Omit (crc >> 8) since bits upper than the lower 8 bits are always 0
crc = table[b ^ (0xff & crc)]
end
end
else
if @width > 8
higher_bit_off = @width - 8
remain_mask = ~(-1 << higher_bit_off)

data.each_byte do |b|
crc = table[b ^ (0xff & (crc >> higher_bit_off))] ^ ((remain_mask & crc) << 8)
end
else
padding = 8 - @width

data.each_byte do |b|
# Omit (crc << 8) since bits lower than the upper 8 bits are always 0
crc = table[b ^ (0xff & (crc << padding))]
end
end
end

@crc = crc

self
end

#
Expand Down
16 changes: 2 additions & 14 deletions lib/digest/crc15.rb
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Expand Up @@ -10,6 +10,8 @@ class CRC15 < CRC

WIDTH = 15

REFLECT_INPUT = false

# Generated by `./pycrc.py --algorithm=table-driven --model=crc-16 --generate=c`
TABLE = [
0x0000, 0x4599, 0x4eab, 0x0b32, 0x58cf, 0x1d56, 0x1664, 0x53fd, 0x7407, 0x319e, 0x3aac, 0x7f35, 0x2cc8, 0x6951, 0x6263, 0x27fa,
Expand All @@ -30,20 +32,6 @@ class CRC15 < CRC
0x276f, 0x62f6, 0x69c4, 0x2c5d, 0x7fa0, 0x3a39, 0x310b, 0x7492, 0x5368, 0x16f1, 0x1dc3, 0x585a, 0x0ba7, 0x4e3e, 0x450c, 0x0095
].freeze

#
# Updates the CRC15 checksum.
#
# @param [String] data
# The data to update the checksum with.
#
def update(data)
data.each_byte do |b|
@crc = (@table[((@crc >> 7) ^ b) & 0xff] ^ (@crc << 8)) & 0x7fff
end

return self
end

end
end

Expand Down
16 changes: 2 additions & 14 deletions lib/digest/crc16.rb
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Expand Up @@ -8,6 +8,8 @@ class CRC16 < CRC

WIDTH = 16

REFLECT_INPUT = true

INIT_CRC = 0x0000

# Generated by `./pycrc.py --algorithm=table-driven --model=crc-16`
Expand Down Expand Up @@ -46,20 +48,6 @@ class CRC16 < CRC
0x8201, 0x42c0, 0x4380, 0x8341, 0x4100, 0x81c1, 0x8081, 0x4040
].freeze

#
# Updates the CRC16 checksum.
#
# @param [String] data
# The data to update the checksum with.
#
def update(data)
data.each_byte do |b|
@crc = ((@table[(@crc ^ b) & 0xff] ^ (@crc >> 8)) & 0xffff)
end

return self
end

end
end

Expand Down
16 changes: 2 additions & 14 deletions lib/digest/crc16_ccitt.rb
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Expand Up @@ -6,6 +6,8 @@ module Digest
#
class CRC16CCITT < CRC16

REFLECT_INPUT = false

INIT_CRC = 0xffff

# Generated by `./pycrc.py --algorithm=table-driven --model=crc-16-ccitt --generate=c`
Expand Down Expand Up @@ -44,20 +46,6 @@ class CRC16CCITT < CRC16
0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0
].freeze

#
# Updates the CRC16 CCITT checksum.
#
# @param [String] data
# The data to update the checksum with.
#
def update(data)
data.each_byte do |b|
@crc = ((@table[((@crc >> 8) ^ b) & 0xff] ^ (@crc << 8)) & 0xffff)
end

return self
end

end
end

Expand Down
16 changes: 2 additions & 14 deletions lib/digest/crc16_dnp.rb
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Expand Up @@ -6,6 +6,8 @@ module Digest
#
class CRC16DNP < CRC16

REFLECT_INPUT = true

INIT_CRC = 0

TABLE = [
Expand Down Expand Up @@ -43,20 +45,6 @@ class CRC16DNP < CRC16
0x91af, 0xa7f1, 0xfd13, 0xcb4d, 0x48d7, 0x7e89, 0x246b, 0x1235
].freeze

#
# Updates the CRC16 DNP checksum.
#
# @param [String] data
# The data to update the checksum with.
#
def update(data)
data.each_byte do |b|
@crc = ((@crc >> 8) ^ @table[(@crc ^ b) & 0xff])
end

return self
end

def finish
self.class.pack(~@crc)
end
Expand Down
16 changes: 2 additions & 14 deletions lib/digest/crc16_genibus.rb
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Expand Up @@ -8,6 +8,8 @@ module Digest
#
class CRC16Genibus < CRC16

REFLECT_INPUT = false

INIT_XOR = 0xffff

INIT_CRC = 0x0000 ^ INIT_XOR
Expand Down Expand Up @@ -50,20 +52,6 @@ class CRC16Genibus < CRC16
0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0
].freeze

#
# Updates the CRC16 Genibus checksum.
#
# @param [String] data
# The data to update the checksum with.
#
def update(data)
data.each_byte do |b|
@crc = (@table[((@crc >> 8) ^ b) & 0xff] ^ (@crc << 8)) & 0xffff
end

return self
end

end
end

Expand Down
16 changes: 2 additions & 14 deletions lib/digest/crc16_kermit.rb
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Expand Up @@ -8,6 +8,8 @@ module Digest
#
class CRC16Kermit < CRC16

REFLECT_INPUT = true

# Generated by `./pycrc.py --algorithm=table-driven --model=kermit --generate=c`
TABLE = [
0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf,
Expand Down Expand Up @@ -44,20 +46,6 @@ class CRC16Kermit < CRC16
0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78
].freeze

#
# Updates the CRC16 Kermit checksum.
#
# @param [String] data
# The data to update the checksum with.
#
def update(data)
data.each_byte do |b|
@crc = (@table[(@crc ^ b) & 0xff] ^ (@crc >> 8)) & 0xffff
end

return self
end

end
end

Expand Down
4 changes: 3 additions & 1 deletion lib/digest/crc16_x_25.rb
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Expand Up @@ -6,6 +6,8 @@ module Digest
#
class CRC16X25 < CRC16

REFLECT_INPUT = true

INIT_XOR = 0xffff

INIT_CRC = 0x0 ^ INIT_XOR
Expand Down Expand Up @@ -47,7 +49,7 @@ class CRC16X25 < CRC16
0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330,
0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78
].freeze

end
end

Expand Down
16 changes: 2 additions & 14 deletions lib/digest/crc16_xmodem.rb
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Expand Up @@ -6,6 +6,8 @@ module Digest
#
class CRC16XModem < CRC16

REFLECT_INPUT = false

# Generated by `./pycrc.py --algorithm=table-driven --model=xmodem --generate=c`
TABLE = [
0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7,
Expand Down Expand Up @@ -42,20 +44,6 @@ class CRC16XModem < CRC16
0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0
].freeze

#
# Updates the CRC16 XModem checksum.
#
# @param [String] data
# The data to update the checksum with.
#
def update(data)
data.each_byte do |b|
@crc = ((@table[((@crc >> 8) ^ b) & 0xff] ^ (@crc << 8)) & 0xffff)
end

return self
end

end
end

Expand Down
16 changes: 2 additions & 14 deletions lib/digest/crc16_zmodem.rb
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Expand Up @@ -6,6 +6,8 @@ module Digest
#
class CRC16ZModem < CRC16

REFLECT_INPUT = false

# Generated by `./pycrc.py --algorithm=table-driven --model=zmodem --generate=c`
TABLE = [
0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7,
Expand Down Expand Up @@ -42,20 +44,6 @@ class CRC16ZModem < CRC16
0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0
].freeze

#
# Updates the CRC16 checksum.
#
# @param [String] data
# The data to update the checksum with.
#
def update(data)
data.each_byte do |b|
@crc = ((@table[((@crc >> 8) ^ b) & 0xff] ^ (@crc << 8)) & 0xffff)
end

return self
end

end
end

Expand Down
16 changes: 2 additions & 14 deletions lib/digest/crc24.rb
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Expand Up @@ -8,6 +8,8 @@ class CRC24 < CRC

WIDTH = 24

REFLECT_INPUT = false

INIT_CRC = 0xb704ce

# Generated by `./pycrc.py --algorithm=table-drive --model=crc24 --generate=c`
Expand Down Expand Up @@ -46,20 +48,6 @@ class CRC24 < CRC
0x42fa2f, 0xc4b6d4, 0xc82f22, 0x4e63d9, 0xd11cce, 0x575035, 0x5bc9c3, 0xdd8538
].freeze

#
# Updates the CRC24 checksum.
#
# @param [String] data
# The data to update the checksum with.
#
def update(data)
data.each_byte do |b|
@crc = ((@table[((@crc >> 16) ^ b) & 0xff] ^ (@crc << 8)) & 0xffffff)
end

return self
end

end
end

Expand Down
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