README
¶
Arbitrary-precision CRC calculator in golang
Can calculate CRCs of any bit width (between CRC-1 and CRC-64) and can process input of any bit length. Automatically creates 256-entry accelerator tables for the used CRC algorithms. Provides presets for and has been tested against the 100+ CRC algorithms listed in Greg Cook's CRC catalogue.
import "github.com/pasztorpisti/go-crc"
func Example() {
// Using CRC-5/USB to calculate the CRC of a byte slice:
fmt.Printf("usb1: %#x\n", crc.CRC5USB.Calc([]byte("123456789")))
// Calculating the CRC when the data arrives in chunks:
c := crc.CRC5USB.NewCRC()
c.UpdateBits([]byte("12345"), 8*4+2)
// The previous call consumed four bytes and the two least significant bits
// of the last byte. '5' is 0b00110101 in binary so that update would have
// had the same effect with inputs like "1234\x01" and "1234\xfd".
// The call below provides the 6 most significant bits of the '5'.
c.UpdateBits([]byte{0b001101}, 6)
c.Update([]byte("6789"))
fmt.Printf("usb2: %#x\n", c.Final())
// Custom polynomial:
// 0xa2eb was picked from the CRC Polynomial Zoo:
// https://users.ece.cmu.edu/~koopman/crc/crc16.html
a, err := crc.NewAlgo[uint16](16, 0xa2eb, 0xffff, 0xffff, true, true)
if err != nil {
panic(err)
}
fmt.Printf("zoo/a2eb: %#x\n", a.Calc([]byte("123456789")))
// Output:
// usb1: 0x19
// usb2: 0x19
// zoo/a2eb: 0x4e4c
}
Here is the godoc that you probably don't need.
Documentation
¶
Overview ¶
Package crc is an arbitrary-precision CRC calculator that can calculate CRCs of any bit width (between CRC-1 and CRC-64) and can process input of any bit length (the end of the input data doesn't have to be on a byte boundary).
Whole bytes of the input data are processed with the help of a precalculated 256-element accelerator table. If the end of input isn't byte-aligned then the remaining (7 or fewer) bits are calculated into the CRC by a tableless bit-by-bit method.
This package provides presets for and has been tested against the 100+ CRC algorithms listed in Greg Cook's CRC catalogue: https://reveng.sourceforge.io/crc-catalogue/all.htm
Example ¶
This example demonstrates the use of the CRC-5/USB preset and a custom CRC-16 algorithm.
// Using CRC-5/USB to calculate the CRC of a byte slice:
fmt.Printf("usb1: %#x\n", crc.CRC5USB.Calc([]byte("123456789")))
// Calculating the CRC when the data arrives in chunks:
c := crc.CRC5USB.NewCRC()
c.UpdateBits([]byte("12345"), 8*4+2)
// The previous call consumed four bytes and the two least significant bits
// of the last byte. '5' is 0b00110101 in binary so that update would have
// had the same effect with inputs like "1234\x01" and "1234\xfd".
// The call below provides the 6 most significant bits of the '5'.
c.UpdateBits([]byte{0b001101}, 6)
c.Update([]byte("6789"))
fmt.Printf("usb2: %#x\n", c.Final())
// Custom polynomial:
// 0xa2eb was picked from the CRC Polynomial Zoo:
// https://users.ece.cmu.edu/~koopman/crc/crc16.html
a, err := crc.NewAlgo[uint16](16, 0xa2eb, 0xffff, 0xffff, true, true)
if err != nil {
panic(err)
}
fmt.Printf("zoo/a2eb: %#x\n", a.Calc([]byte("123456789")))
Output: usb1: 0x19 usb2: 0x19 zoo/a2eb: 0x4e4c
Index ¶
Examples ¶
Constants ¶
This section is empty.
Variables ¶
View Source
var ( CRC8 = CRC8SMBUS CRC16 = CRC16ARC CRC32 = CRC32ISOHDLC CRC64 = CRC64ECMA182 CRC32C = CRC32ISCSI CRC32D = CRC32BASE91D CRC32Q = CRC32AIXM A = CRC16ISOIEC144433A B = CRC16IBMSDLC X25 = CRC16IBMSDLC CRC16X25 = CRC16IBMSDLC XMODEM = CRC16XMODEM KERMIT = CRC16KERMIT CRC16CCITT = CRC16KERMIT CRC16CCITTFALSE = CRC16IBM3740 // commonly misidentified as CRC-16/CCITT CRC16AUGCCITT = CRC16SPIFUJITSU V41LSB = CRC16KERMIT V41MSB = CRC16XMODEM PKZIP = CRC32ISOHDLC V42 = CRC32ISOHDLC XZ = CRC32ISOHDLC POSIX = CRC32CKSUM CASTAGNOLI = CRC32ISCSI CRC3GSM = mustNewPreset[uint8](3, 0x3, 0x0, 0x7, false, false) // CRC-3/GSM CRC3ROHC = mustNewPreset[uint8](3, 0x3, 0x7, 0x0, true, true) // CRC-3/ROHC CRC4INTERLAKEN = mustNewPreset[uint8](4, 0x3, 0xf, 0xf, false, false) // CRC-4/INTERLAKEN CRC4G704 = mustNewPreset[uint8](4, 0x3, 0x0, 0x0, true, true) // CRC-4/G-704 Alias: CRC-4/ITU CRC5USB = mustNewPreset[uint8](5, 0x05, 0x1f, 0x1f, true, true) // CRC-5/USB CRC5EPCC1G2 = mustNewPreset[uint8](5, 0x09, 0x09, 0x00, false, false) // CRC-5/EPC-C1G2 Alias: CRC-5/EPC CRC5G704 = mustNewPreset[uint8](5, 0x15, 0x00, 0x00, true, true) // CRC-5/G-704 Alias: CRC-5/ITU CRC6G704 = mustNewPreset[uint8](6, 0x03, 0x00, 0x00, true, true) // CRC-6/G-704 Alias: CRC-6/ITU CRC6CDMA2000B = mustNewPreset[uint8](6, 0x07, 0x3f, 0x00, false, false) // CRC-6/CDMA2000-B CRC6DARC = mustNewPreset[uint8](6, 0x19, 0x00, 0x00, true, true) // CRC-6/DARC CRC6CDMA2000A = mustNewPreset[uint8](6, 0x27, 0x3f, 0x00, false, false) // CRC-6/CDMA2000-A CRC6GSM = mustNewPreset[uint8](6, 0x2f, 0x00, 0x3f, false, false) // CRC-6/GSM CRC7MMC = mustNewPreset[uint8](7, 0x09, 0x00, 0x00, false, false) // CRC-7/MMC Alias: CRC-7 CRC7UMTS = mustNewPreset[uint8](7, 0x45, 0x00, 0x00, false, false) // CRC-7/UMTS CRC7ROHC = mustNewPreset[uint8](7, 0x4f, 0x7f, 0x00, true, true) // CRC-7/ROHC CRC8SMBUS = mustNewPreset[uint8](8, 0x07, 0x00, 0x00, false, false) // CRC-8/SMBUS Alias: CRC-8 CRC8I4321 = mustNewPreset[uint8](8, 0x07, 0x00, 0x55, false, false) // CRC-8/I-432-1 CRC8ROHC = mustNewPreset[uint8](8, 0x07, 0xff, 0x00, true, true) // CRC-8/ROHC CRC8GSMA = mustNewPreset[uint8](8, 0x1d, 0x00, 0x00, false, false) // CRC-8/GSM-A CRC8MIFAREMAD = mustNewPreset[uint8](8, 0x1d, 0xc7, 0x00, false, false) // CRC-8/MIFARE-MAD CRC8ICODE = mustNewPreset[uint8](8, 0x1d, 0xfd, 0x00, false, false) // CRC-8/I-CODE CRC8HITAG = mustNewPreset[uint8](8, 0x1d, 0xff, 0x00, false, false) // CRC-8/HITAG CRC8SAEJ1850 = mustNewPreset[uint8](8, 0x1d, 0xff, 0xff, false, false) // CRC-8/SAE-J1850 CRC8TECH3250 = mustNewPreset[uint8](8, 0x1d, 0xff, 0x00, true, true) // CRC-8/TECH-3250 Alias: CRC-8/AES, CRC-8/EBU CRC8OPENSAFETY = mustNewPreset[uint8](8, 0x2f, 0x00, 0x00, false, false) // CRC-8/OPENSAFETY CRC8AUTOSAR = mustNewPreset[uint8](8, 0x2f, 0xff, 0xff, false, false) // CRC-8/AUTOSAR CRC8NRSC5 = mustNewPreset[uint8](8, 0x31, 0xff, 0x00, false, false) // CRC-8/NRSC-5 CRC8MAXIMDOW = mustNewPreset[uint8](8, 0x31, 0x00, 0x00, true, true) // CRC-8/MAXIM-DOW Alias: CRC-8/MAXIM, DOW-CRC CRC8DARC = mustNewPreset[uint8](8, 0x39, 0x00, 0x00, true, true) // CRC-8/DARC CRC8GSMB = mustNewPreset[uint8](8, 0x49, 0x00, 0xff, false, false) // CRC-8/GSM-B CRC8LTE = mustNewPreset[uint8](8, 0x9b, 0x00, 0x00, false, false) // CRC-8/LTE CRC8CDMA2000 = mustNewPreset[uint8](8, 0x9b, 0xff, 0x00, false, false) // CRC-8/CDMA2000 CRC8WCDMA = mustNewPreset[uint8](8, 0x9b, 0x00, 0x00, true, true) // CRC-8/WCDMA CRC8BLUETOOTH = mustNewPreset[uint8](8, 0xa7, 0x00, 0x00, true, true) // CRC-8/BLUETOOTH CRC8DVBS2 = mustNewPreset[uint8](8, 0xd5, 0x00, 0x00, false, false) // CRC-8/DVB-S2 CRC10GSM = mustNewPreset[uint16](10, 0x175, 0x000, 0x3ff, false, false) // CRC-10/GSM CRC10ATM = mustNewPreset[uint16](10, 0x233, 0x000, 0x000, false, false) // CRC-10/ATM Alias: CRC-10, CRC-10/I-610 CRC10CDMA2000 = mustNewPreset[uint16](10, 0x3d9, 0x3ff, 0x000, false, false) // CRC-10/CDMA2000 CRC11UMTS = mustNewPreset[uint16](11, 0x307, 0x000, 0x000, false, false) // CRC-11/UMTS CRC11FLEXRAY = mustNewPreset[uint16](11, 0x385, 0x01a, 0x000, false, false) // CRC-11/FLEXRAY CRC12DECT = mustNewPreset[uint16](12, 0x80f, 0x000, 0x000, false, false) // CRC-12/DECT Alias: X-CRC-12 CRC12UMTS = mustNewPreset[uint16](12, 0x80f, 0x000, 0x000, false, true) // CRC-12/UMTS Alias: CRC-12/3GPP CRC12GSM = mustNewPreset[uint16](12, 0xd31, 0x000, 0xfff, false, false) // CRC-12/GSM CRC12CDMA2000 = mustNewPreset[uint16](12, 0xf13, 0xfff, 0x000, false, false) // CRC-12/CDMA2000 CRC13BBC = mustNewPreset[uint16](13, 0x1cf5, 0x0000, 0x0000, false, false) // CRC-13/BBC CRC14DARC = mustNewPreset[uint16](14, 0x0805, 0x0000, 0x0000, true, true) // CRC-14/DARC CRC14GSM = mustNewPreset[uint16](14, 0x202d, 0x0000, 0x3fff, false, false) // CRC-14/GSM CRC15CAN = mustNewPreset[uint16](15, 0x4599, 0x0000, 0x0000, false, false) // CRC-15/CAN Alias: CRC-15 CRC15MPT1327 = mustNewPreset[uint16](15, 0x6815, 0x0000, 0x0001, false, false) // CRC-15/MPT1327 CRC16DECTX = mustNewPreset[uint16](16, 0x0589, 0x0000, 0x0000, false, false) // CRC-16/DECT-X Alias: X-CRC-16 CRC16DECTR = mustNewPreset[uint16](16, 0x0589, 0x0000, 0x0001, false, false) // CRC-16/DECT-R Alias: R-CRC-16 CRC16NRSC5 = mustNewPreset[uint16](16, 0x080b, 0xffff, 0x0000, true, true) // CRC-16/NRSC-5 CRC16XMODEM = mustNewPreset[uint16](16, 0x1021, 0x0000, 0x0000, false, false) // CRC-16/XMODEM Alias: CRC-16/ACORN, CRC-16/LTE, CRC-16/V-41-MSB, XMODEM, ZMODEM CRC16GSM = mustNewPreset[uint16](16, 0x1021, 0x0000, 0xffff, false, false) // CRC-16/GSM CRC16SPIFUJITSU = mustNewPreset[uint16](16, 0x1021, 0x1d0f, 0x0000, false, false) // CRC-16/SPI-FUJITSU Alias: CRC-16/AUG-CCITT CRC16IBM3740 = mustNewPreset[uint16](16, 0x1021, 0xffff, 0x0000, false, false) // CRC-16/IBM-3740 Alias: CRC-16/AUTOSAR, CRC-16/CCITT-FALSE CRC16GENIBUS = mustNewPreset[uint16](16, 0x1021, 0xffff, 0xffff, false, false) // CRC-16/GENIBUS Alias: CRC-16/DARC, CRC-16/EPC, CRC-16/EPC-C1G2, CRC-16/I-CODE CRC16KERMIT = mustNewPreset[uint16](16, 0x1021, 0x0000, 0x0000, true, true) // CRC-16/KERMIT Alias: CRC-16/BLUETOOTH, CRC-16/CCITT, CRC-16/CCITT-TRUE, CRC-16/V-41-LSB, CRC-CCITT, KERMIT CRC16TMS37157 = mustNewPreset[uint16](16, 0x1021, 0x89ec, 0x0000, true, true) // CRC-16/TMS37157 CRC16RIELLO = mustNewPreset[uint16](16, 0x1021, 0xb2aa, 0x0000, true, true) // CRC-16/RIELLO CRC16ISOIEC144433A = mustNewPreset[uint16](16, 0x1021, 0xc6c6, 0x0000, true, true) // CRC-16/ISO-IEC-14443-3-A Alias: CRC-A CRC16MCRF4XX = mustNewPreset[uint16](16, 0x1021, 0xffff, 0x0000, true, true) // CRC-16/MCRF4XX CRC16IBMSDLC = mustNewPreset[uint16](16, 0x1021, 0xffff, 0xffff, true, true) // CRC-16/IBM-SDLC Alias: CRC-16/ISO-HDLC, CRC-16/ISO-IEC-14443-3-B, CRC-16/X-25, CRC-B, X-25 CRC16PROFIBUS = mustNewPreset[uint16](16, 0x1dcf, 0xffff, 0xffff, false, false) // CRC-16/PROFIBUS Alias: CRC-16/IEC-61158-2 CRC16EN13757 = mustNewPreset[uint16](16, 0x3d65, 0x0000, 0xffff, false, false) // CRC-16/EN-13757 CRC16DNP = mustNewPreset[uint16](16, 0x3d65, 0x0000, 0xffff, true, true) // CRC-16/DNP CRC16OPENSAFETYA = mustNewPreset[uint16](16, 0x5935, 0x0000, 0x0000, false, false) // CRC-16/OPENSAFETY-A CRC16M17 = mustNewPreset[uint16](16, 0x5935, 0xffff, 0x0000, false, false) // CRC-16/M17 CRC16LJ1200 = mustNewPreset[uint16](16, 0x6f63, 0x0000, 0x0000, false, false) // CRC-16/LJ1200 CRC16OPENSAFETYB = mustNewPreset[uint16](16, 0x755b, 0x0000, 0x0000, false, false) // CRC-16/OPENSAFETY-B CRC16UMTS = mustNewPreset[uint16](16, 0x8005, 0x0000, 0x0000, false, false) // CRC-16/UMTS Alias: CRC-16/BUYPASS, CRC-16/VERIFONE CRC16DDS110 = mustNewPreset[uint16](16, 0x8005, 0x800d, 0x0000, false, false) // CRC-16/DDS-110 CRC16CMS = mustNewPreset[uint16](16, 0x8005, 0xffff, 0x0000, false, false) // CRC-16/CMS CRC16ARC = mustNewPreset[uint16](16, 0x8005, 0x0000, 0x0000, true, true) // CRC-16/ARC Alias: ARC, CRC-16, CRC-16/LHA, CRC-IBM CRC16MAXIMDOW = mustNewPreset[uint16](16, 0x8005, 0x0000, 0xffff, true, true) // CRC-16/MAXIM-DOW Alias: CRC-16/MAXIM CRC16MODBUS = mustNewPreset[uint16](16, 0x8005, 0xffff, 0x0000, true, true) // CRC-16/MODBUS Alias: MODBUS CRC16USB = mustNewPreset[uint16](16, 0x8005, 0xffff, 0xffff, true, true) // CRC-16/USB CRC16T10DIF = mustNewPreset[uint16](16, 0x8bb7, 0x0000, 0x0000, false, false) // CRC-16/T10-DIF CRC16TELEDISK = mustNewPreset[uint16](16, 0xa097, 0x0000, 0x0000, false, false) // CRC-16/TELEDISK CRC16CDMA2000 = mustNewPreset[uint16](16, 0xc867, 0xffff, 0x0000, false, false) // CRC-16/CDMA2000 CRC17CANFD = mustNewPreset[uint32](17, 0x1685b, 0x00000, 0x00000, false, false) // CRC-17/CAN-FD CRC21CANFD = mustNewPreset[uint32](21, 0x102899, 0x000000, 0x000000, false, false) // CRC-21/CAN-FD CRC24BLE = mustNewPreset[uint32](24, 0x00065b, 0x555555, 0x000000, true, true) // CRC-24/BLE CRC24INTERLAKEN = mustNewPreset[uint32](24, 0x328b63, 0xffffff, 0xffffff, false, false) // CRC-24/INTERLAKEN CRC24FLEXRAYB = mustNewPreset[uint32](24, 0x5d6dcb, 0xabcdef, 0x000000, false, false) // CRC-24/FLEXRAY-B CRC24FLEXRAYA = mustNewPreset[uint32](24, 0x5d6dcb, 0xfedcba, 0x000000, false, false) // CRC-24/FLEXRAY-A CRC24LTEB = mustNewPreset[uint32](24, 0x800063, 0x000000, 0x000000, false, false) // CRC-24/LTE-B CRC24OS9 = mustNewPreset[uint32](24, 0x800063, 0xffffff, 0xffffff, false, false) // CRC-24/OS-9 CRC24LTEA = mustNewPreset[uint32](24, 0x864cfb, 0x000000, 0x000000, false, false) // CRC-24/LTE-A CRC24OPENPGP = mustNewPreset[uint32](24, 0x864cfb, 0xb704ce, 0x000000, false, false) // CRC-24/OPENPGP Alias: CRC-24 CRC30CDMA = mustNewPreset[uint32](30, 0x2030b9c7, 0x3fffffff, 0x3fffffff, false, false) // CRC-30/CDMA CRC31PHILIPS = mustNewPreset[uint32](31, 0x04c11db7, 0x7fffffff, 0x7fffffff, false, false) // CRC-31/PHILIPS CRC32XFER = mustNewPreset[uint32](32, 0x000000af, 0x00000000, 0x00000000, false, false) // CRC-32/XFER CRC32CKSUM = mustNewPreset[uint32](32, 0x04c11db7, 0x00000000, 0xffffffff, false, false) // CRC-32/CKSUM Alias: CKSUM, CRC-32/POSIX CRC32MPEG2 = mustNewPreset[uint32](32, 0x04c11db7, 0xffffffff, 0x00000000, false, false) // CRC-32/MPEG-2 CRC32BZIP2 = mustNewPreset[uint32](32, 0x04c11db7, 0xffffffff, 0xffffffff, false, false) // CRC-32/BZIP2 Alias: CRC-32/AAL5, CRC-32/DECT-B, B-CRC-32 CRC32JAMCRC = mustNewPreset[uint32](32, 0x04c11db7, 0xffffffff, 0x00000000, true, true) // CRC-32/JAMCRC Alias: JAMCRC CRC32ISOHDLC = mustNewPreset[uint32](32, 0x04c11db7, 0xffffffff, 0xffffffff, true, true) // CRC-32/ISO-HDLC Alias: CRC-32, CRC-32/ADCCP, CRC-32/V-42, CRC-32/XZ, PKZIP CRC32ISCSI = mustNewPreset[uint32](32, 0x1edc6f41, 0xffffffff, 0xffffffff, true, true) // CRC-32/ISCSI Alias: CRC-32/BASE91-C, CRC-32/CASTAGNOLI, CRC-32/INTERLAKEN, CRC-32C CRC32MEF = mustNewPreset[uint32](32, 0x741b8cd7, 0xffffffff, 0x00000000, true, true) // CRC-32/MEF Note: this algorithm uses Koopman's polynomial CRC32CDROMEDC = mustNewPreset[uint32](32, 0x8001801b, 0x00000000, 0x00000000, true, true) // CRC-32/CD-ROM-EDC CRC32AIXM = mustNewPreset[uint32](32, 0x814141ab, 0x00000000, 0x00000000, false, false) // CRC-32/AIXM Alias: CRC-32Q CRC32BASE91D = mustNewPreset[uint32](32, 0xa833982b, 0xffffffff, 0xffffffff, true, true) // CRC-32/BASE91-D Alias: CRC-32D CRC32AUTOSAR = mustNewPreset[uint32](32, 0xf4acfb13, 0xffffffff, 0xffffffff, true, true) // CRC-32/AUTOSAR CRC40GSM = mustNewPreset[uint64](40, 0x0004820009, 0x0000000000, 0xffffffffff, false, false) // CRC-40/GSM CRC64GOISO = mustNewPreset[uint64](64, 0x000000000000001b, 0xffffffffffffffff, 0xffffffffffffffff, true, true) // CRC-64/GO-ISO CRC64MS = mustNewPreset[uint64](64, 0x259c84cba6426349, 0xffffffffffffffff, 0x0000000000000000, true, true) // CRC-64/MS CRC64ECMA182 = mustNewPreset[uint64](64, 0x42f0e1eba9ea3693, 0x0000000000000000, 0x0000000000000000, false, false) // CRC-64/ECMA-182 Alias: CRC-64 CRC64WE = mustNewPreset[uint64](64, 0x42f0e1eba9ea3693, 0xffffffffffffffff, 0xffffffffffffffff, false, false) // CRC-64/WE CRC64XZ = mustNewPreset[uint64](64, 0x42f0e1eba9ea3693, 0xffffffffffffffff, 0xffffffffffffffff, true, true) // CRC-64/XZ Alias: CRC-64/GO-ECMA CRC64REDIS = mustNewPreset[uint64](64, 0xad93d23594c935a9, 0x0000000000000000, 0x0000000000000000, true, true) // CRC-64/REDIS )
These presets provide quick access to well documented CRC algorithms. Use their NewCRC and Calc methods to perform CRC calculations.
Functions ¶
This section is empty.
Types ¶
type Algo ¶
type Algo[T UInt] interface { NewCRC() CRC[T] // Calculate the CRC of chunked data Calc(data []byte) T // Calculate the CRC of a single chunk of data CalcBits(data []byte, bitLen int) T // Calculate the CRC of a single chunk of data }
Algo is a parametrized CRC algorithm. It can be shared and reused by goroutines to save on the resources spent on creating the related accelerator table.
func NewAlgo ¶
NewAlgo creates a parametrized CRC algorithm instance - this involves the calculation of an accelerator table with 256 entries of type T. Ideally you create and share one Algo instance per CRC algorithm during the lifespan of the process. Width can be between 1...64 (inclusive) - it mustn't exceed the bit width of T. Poly and init are always in (unreflected) MSB-first format.
type CRC ¶
type CRC[T UInt] interface { Update(data []byte) UpdateBits(data []byte, bitLen int) Final() T // Final returns the final CRC value Residue() T // Residue returns the final CRC value without the xorout step }
A CRC instance is a lightweight "throw-away" object that can calculate the CRC of your chunked data with zero or more Update() calls.
type Preset ¶
Preset is a proxy to a wrapped Algo instance that is created only when a method of the Preset is called. Unused presets never create Algo instances so their tables aren't allocated and calculated.
The methods of a Preset instance use synchronization to create the Algo instance in a goroutine-safe way. The synchronization overhead is insignificant if the program doesn't call the Preset methods very often. If it becomes significant it can be avoided by using the underlying Algo instance directly after querying it with the Preset.Algo method. The methods of the CRC instances returned by Preset.NewCRC aren't affected by the previously mentioned synchronization.
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