Reuse, not rework

License Awareness

Highly Reusable Software

By activity
Professions, Sciences, Humanities, Business, ...

User Interface
Text-based, GUI, Audio, Video, Keyboards, Mouse, Images,...

Text Strings
Conversions, tests, processing, manipulation,...

Integer, Floating point, Matrix, Statistics, Boolean, ...

Algorithms, Memory, Process control, Debugging, ...

Stored Data
Data storage, Integrity, Encryption, Compression, ...

Networks, protocols, Interprocess, Remote, Client Server, ...

Hard World
Timing, Calendar and Clock, Audio, Video, Printer, Controls...

File System
Management, Filtering, File & Directory access, Viewers, ...


librock_CRC32 - CRC-32 (CCITT standard algorithm) on memory block(s)
#License - #Source code - #Example Use -


#include <librock/procede.h>

        librock_uint32_t crc, /* Before first call set = ~0 */
        const void *Buffer,
        unsigned int cbBuffer


Routine calculates the CRC for a block of data using table lookup method. It accepts an original value for the crc, and returns the updated value. The caller must precondition the crc to all 1's before the first call, and invert the result after all blocks are complete.

Typical use is

#ifdef librock_TYPICAL_USE_CRC32
   #include <librock/target/types.c>

   librock_uint32_t crccomp = 0xffffffffL;

   char *buf = "this is a test";
   crccomp = librock_CRC32(crccomp,buf,strlen(buf));
   printf("%08lx\n", (crccomp ^ 0xFFFFFFFFL));


    // librock_PRIVATE BuildCRCTable()
    // librock_PRIVATE unsigned long CRCTable[256]
    // librock_PRIVATE char CRCTableBuilt


  Copyright 1998-2002 Forrest J. Cavalier III,
  Licensed under BSD-ish license, NO WARRANTY. Copies must retain this block.
  License text in <librock/license/librock.txt> librock_LIDESC_HC=12440211096131f5976d36be0cddca4cd9152e45

Source Code

./data/integrity/crc32.c (implementation, plus source of this manual page)

Tests and Supported Platform Types

This is a representative sample. Librock code is highly portable. For a particular platform not reported here, request paid support

librock_CRC32 passed tests in tcrc32 (Unix/Linux/BSD: 2002/08/08 sys=FreeBSD using gcc)
librock_CRC32 passed tests in tcrc32 (WIN32: 2002/08/08 sys=NT 4.0 using MSVC)

This software is part of Librock

Rapid reuse, without rework. Details
This page copyright (C) 2002-2003 Forrest J. Cavalier III, d-b-a Mib Software, Saylorsburg PA 18353, USA

Verbatim copying and distribution of this generated page is permitted in any medium provided that no changes are made.
(The source of this manual page may be covered by a more permissive license which allows modifications.)

Want to help? We welcome comments, patches. -- Need help? Request paid support.