CRC32 C or C implementation

Question

I m looking for an implementation of CRC32 in C or C   that is explicitly licensed as being no cost or public domain   The implementation here seems nice  but the only thing it says about the license is  source code   which isn t good enough   I d prefer non LGPL so I don t have to fool around with a DLL  my app is closed source    I saw the adler32 implementation in zlib  but I m checking small chunks of data  which adler is not good for

User · Answer

The SNIPPETS C Source Code Archive has a CRC32 implementation that is freely usable:

/* Copyright (C) 1986 Gary S. Brown.  You may use this program, or
   code or tables extracted from it, as desired without restriction.*/

(Unfortunately, c.snippets.org seems to have died. Fortunately, the Wayback Machine has it archived.)

In order to be able to compile the code, you'll need to add typedefs for BYTE as an unsigned 8-bit integer and DWORD as an unsigned 32-bit integer, along with the header files crc.h & sniptype.h.

The only critical item in the header is this macro (which could just as easily go in CRC_32.c itself:

#define UPDC32(octet, crc) (crc_32_tab[((crc) ^ (octet)) & 0xff] ^ ((crc) >> 8))

User · Answer

rurban s fork of SMHasher  the original SMHasher seems abandoned  has hardware CRC32 support  The changes were added before the initial commit  but try comparing the new CMakeLists txt and the old one  which doesn t mention SSE at all    The best option is probably Intel s zlib fork with PCLMULQDQ support described in this paper  This library also has the SSE 4 2 optimizations   If you don t need portability and you re on Linux  you can use the kernel s implementation  which is hardware accelerated if available   https   stackoverflow com a 11156040 309483

User · Answer

The mhash library works pretty good for me  It s fast enough  supports multiple types of hashing  crc32  MD5  SHA-1  HAVAL  RIPEMD128  RIPEMD160  TIGER  GOST  etc    To get CRC32 of a string you would do something like this    MHASH td   mhash init MHASH CRC32     if  td    MHASH FAILED  return -1     handle failure   mhash td  s  strlen s      unsigned int digest   0     crc32 will be stored here   mhash deinit td   amp digest        do endian swap here if desired

User · Answer

Use the Boost C   libraries   There is a CRC included there and the license is good

User · Answer

The SNIPPETS C Source Code Archive has a CRC32 implementation that is freely usable:

/* Copyright (C) 1986 Gary S. Brown.  You may use this program, or
   code or tables extracted from it, as desired without restriction.*/

(Unfortunately, c.snippets.org seems to have died. Fortunately, the Wayback Machine has it archived.)

In order to be able to compile the code, you'll need to add typedefs for BYTE as an unsigned 8-bit integer and DWORD as an unsigned 32-bit integer, along with the header files crc.h & sniptype.h.

The only critical item in the header is this macro (which could just as easily go in CRC_32.c itself:

#define UPDC32(octet, crc) (crc_32_tab[((crc) ^ (octet)) & 0xff] ^ ((crc) >> 8))

User · Answer

The crc code in zlib  http   zlib net   is among the fastest there is  and has a very liberal open source license   And you should not use adler-32 except for special applications where speed is more important than error detection performance

User · Answer

using zlib h  http   refspecs linuxbase org LSB 3 0 0 LSB-Core-generic LSB-Core-generic zlib-crc32-1 html     include  lt zlib h gt  unsigned long  crc   crc32 0L  Z NULL  0   crc   crc32 crc   const unsigned char  data address  data len

User · Answer

Use the Boost C   libraries   There is a CRC included there and the license is good

User · Answer

I am the author of the source code at the specified link  While the intention of the source code license is not clear  it will be later today   the code is in fact open and free for use in your free or commercial applications with no strings attached

User · Answer

I am the author of the source code at the specified link  While the intention of the source code license is not clear  it will be later today   the code is in fact open and free for use in your free or commercial applications with no strings attached

User · Answer

rurban s fork of SMHasher  the original SMHasher seems abandoned  has hardware CRC32 support  The changes were added before the initial commit  but try comparing the new CMakeLists txt and the old one  which doesn t mention SSE at all    The best option is probably Intel s zlib fork with PCLMULQDQ support described in this paper  This library also has the SSE 4 2 optimizations   If you don t need portability and you re on Linux  you can use the kernel s implementation  which is hardware accelerated if available   https   stackoverflow com a 11156040 309483

User · Answer

I am the author of the source code at the specified link  While the intention of the source code license is not clear  it will be later today   the code is in fact open and free for use in your free or commercial applications with no strings attached

User · Answer

Use the Boost C   libraries   There is a CRC included there and the license is good

User · Answer

I am the author of the source code at the specified link  While the intention of the source code license is not clear  it will be later today   the code is in fact open and free for use in your free or commercial applications with no strings attached

User · Answer

pycrc is a Python script that generates C CRC code  with options to select the CRC size  algorithm and model   It s released under the MIT licence   Is that acceptable for your purposes

User · Answer

The most simple and straightforward C C   implementation that I found is in a link at the bottom of this page   Web Page  http   www barrgroup com Embedded-Systems How-To CRC-Calculation-C-Code  Code Download Link  https   barrgroup com code crc zip  It is a simple standalone implementation with one  h and one  c file  There is support for CRC32  CRC16 and CRC CCITT thru the use of a define   Also  the code lets the user change parameter settings like the CRC polynomial  initial final XOR value  and reflection options if you so desire   The license is not explicitly defined ala LGPL or similar   However the site does say that they are placing the code in the public domain for any use   The actual code files also say this   Hope it helps

User · Answer

pycrc is a Python script that generates C CRC code  with options to select the CRC size  algorithm and model   It s released under the MIT licence   Is that acceptable for your purposes

User · Answer

The crc code in zlib  http   zlib net   is among the fastest there is  and has a very liberal open source license   And you should not use adler-32 except for special applications where speed is more important than error detection performance

User · Answer

The mhash library works pretty good for me  It s fast enough  supports multiple types of hashing  crc32  MD5  SHA-1  HAVAL  RIPEMD128  RIPEMD160  TIGER  GOST  etc    To get CRC32 of a string you would do something like this    MHASH td   mhash init MHASH CRC32     if  td    MHASH FAILED  return -1     handle failure   mhash td  s  strlen s      unsigned int digest   0     crc32 will be stored here   mhash deinit td   amp digest        do endian swap here if desired

User · Answer

The SNIPPETS C Source Code Archive has a CRC32 implementation that is freely usable:

/* Copyright (C) 1986 Gary S. Brown.  You may use this program, or
   code or tables extracted from it, as desired without restriction.*/

(Unfortunately, c.snippets.org seems to have died. Fortunately, the Wayback Machine has it archived.)

In order to be able to compile the code, you'll need to add typedefs for BYTE as an unsigned 8-bit integer and DWORD as an unsigned 32-bit integer, along with the header files crc.h & sniptype.h.

The only critical item in the header is this macro (which could just as easily go in CRC_32.c itself:

#define UPDC32(octet, crc) (crc_32_tab[((crc) ^ (octet)) & 0xff] ^ ((crc) >> 8))

User · Answer

The most simple and straightforward C C   implementation that I found is in a link at the bottom of this page   Web Page  http   www barrgroup com Embedded-Systems How-To CRC-Calculation-C-Code  Code Download Link  https   barrgroup com code crc zip  It is a simple standalone implementation with one  h and one  c file  There is support for CRC32  CRC16 and CRC CCITT thru the use of a define   Also  the code lets the user change parameter settings like the CRC polynomial  initial final XOR value  and reflection options if you so desire   The license is not explicitly defined ala LGPL or similar   However the site does say that they are placing the code in the public domain for any use   The actual code files also say this   Hope it helps

User · Answer

The SNIPPETS C Source Code Archive has a CRC32 implementation that is freely usable:

/* Copyright (C) 1986 Gary S. Brown.  You may use this program, or
   code or tables extracted from it, as desired without restriction.*/

(Unfortunately, c.snippets.org seems to have died. Fortunately, the Wayback Machine has it archived.)

In order to be able to compile the code, you'll need to add typedefs for BYTE as an unsigned 8-bit integer and DWORD as an unsigned 32-bit integer, along with the header files crc.h & sniptype.h.

The only critical item in the header is this macro (which could just as easily go in CRC_32.c itself:

#define UPDC32(octet, crc) (crc_32_tab[((crc) ^ (octet)) & 0xff] ^ ((crc) >> 8))

User · Answer

using zlib h  http   refspecs linuxbase org LSB 3 0 0 LSB-Core-generic LSB-Core-generic zlib-crc32-1 html     include  lt zlib h gt  unsigned long  crc   crc32 0L  Z NULL  0   crc   crc32 crc   const unsigned char  data address  data len

User · Answer

Use the Boost C   libraries   There is a CRC included there and the license is good

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