example_checksum.c File Reference

Example of librnr support for checksum algorithms. More...

#include <stdio.h>
#include <libgen.h>
#include <time.h>
#include <string.h>
#include "rnr/rnrconfig.h"
#include "rnr/log.h"
#include "rnr/new.h"
#include "rnr/opts.h"
#include "rnr/checksum.h"
#include "version.h"

Go to the source code of this file.

Functions
static int	init (int argc, char *argv[])
	Main initialization. More...
static void	starttimer (struct timespec *pstart)
	Start nano second timer. More...
static long	stoptimer (struct timespec *pstart)
	Stop nano second timer. More...
static void	profile (char *sText)
	Profile the various checksum algorithms. More...
int	main (int argc, char *argv[])
	Example main. More...

Variables
static char *	Argv0
	the command
static bool_t	OptsPrintPoem = false
	do [not] print poem
static OptsPgmInfo_T	PgmInfo
	Program information. More...
static OptsInfo_T	OptsInfo []
	Command line options information. More...
static char *	Jabberwocky
	Jabberwocky by Lewis Carroll.

Detailed Description

Example of librnr support for checksum algorithms.

LastChangedDate

2013-03-05 09:45:13 -0700 (Tue, 05 Mar 2013)

Rev

2729

Author

Robin Knight (robin.nosp@m..kni.nosp@m.ght@r.nosp@m.oadn.nosp@m.arrow.nosp@m.s.co.nosp@m.m)

Copyright

© 2013-2018. RoadNarrows LLC..
http://www.roadnarrows.com
All Rights Reserved

Definition in file example_checksum.c.

Function Documentation

static int init ( int  argc, char *  argv[]  )

static

Main initialization.

Parameters

argc	Command-line argument count.
argv	Command-line argument list.

Returns

Returns 1 on success, exits on failure.

Definition at line 104 of file example_checksum.c.

References Argv0, OptsGet(), and PkgInfo.

Referenced by main().

{
  // name of this process
  Argv0 = basename(argv[0]);

  // parse input options
  argv = OptsGet(Argv0, &PkgInfo, &PgmInfo, OptsInfo, true, &argc, argv);

  return 1;
}

int main	(	int	argc,
		char *	argv[]
	)

Example main.

Parameters

argc	Command-line argument count.
argv	Command-line argument list.

Exit Status:

Program exits with 0 success, > 0 on failure.

Definition at line 237 of file example_checksum.c.

References init(), Jabberwocky, new_strdup(), OptsPrintPoem, and profile().

{
  char   *sText;
  char    c;
  int     k;
  int     i;

  if( !init(argc, argv) )
  {
    return 2;
  }

  if( OptsPrintPoem )
  {
    printf("\n%s\n", Jabberwocky);
  }

  //
  // --- Profile 1
  //
  printf("Text:   Jabberwocky  -- Lewis Carroll\n");
  printf("Length: %zu bytes\n", strlen(Jabberwocky));

  profile(Jabberwocky);

  printf("\n");

  //
  // --- Profile 2
  //
  sText = new_strdup(Jabberwocky);

  c = sText[0];
  sText[0] = sText[1];
  sText[1] = c;

  printf("Text:   Jabberwocky, 1 byte swapped  -- Lewis Carroll\n");
  printf("Length: %zu bytes\n", strlen(sText));

  profile(sText);

  printf("\n");

  delete(sText);

  //
  // --- Profile 3
  //
  k = 25;

  sText = new(strlen(Jabberwocky) * (size_t)k + (size_t)1);

  for(i=0, *sText=0; i<k; ++i)
  {
    strcat(sText, Jabberwocky);
  }

  printf("Text:   Jabberwocky * %d  -- Lewis Carroll\n", k);
  printf("Length: %zu bytes\n", strlen(sText));

  profile(sText);

  printf("\n");

  delete(sText);

  return 0;
}

static void profile ( char *  sText )

static

Profile the various checksum algorithms.

Parameters

sText

Null-terminated text string.

Definition at line 199 of file example_checksum.c.

References generate_checksum16(), generate_checksum32(), generate_checksum8(), generate_crc32(), starttimer(), and stoptimer().

Referenced by main().

{
  struct timespec t;
  uint_t          chksum;
  long            nsec;

  printf("Algorithm               Result         nSecs\n");

  starttimer(&t);
  chksum = (uint_t)generate_checksum8((byte_t *)sText, strlen(sText));
  nsec = stoptimer(&t);
  printf(" 8-bit chksum  %10u 0x%08x  %6ld\n", chksum, chksum, nsec);

  starttimer(&t);
  chksum = (uint_t)generate_checksum16((byte_t *)sText, strlen(sText));
  nsec = stoptimer(&t);
  printf("16-bit chksum  %10u 0x%08x  %6ld\n", chksum, chksum, nsec);

  starttimer(&t);
  chksum = (uint_t)generate_checksum32((byte_t *)sText, strlen(sText));
  nsec = stoptimer(&t);
  printf("32-bit chksum  %10u 0x%08x  %6ld\n", chksum, chksum, nsec);

  starttimer(&t);
  chksum = (uint_t)generate_crc32((byte_t *)sText, strlen(sText));
  nsec = stoptimer(&t);
  printf("32-bit crc     %10u 0x%08x  %6ld\n", chksum, chksum, nsec);
}

static void starttimer ( struct timespec *  pstart )

static

Start nano second timer.

Parameters

[out]

pstart

Pointer to start timespec.

Definition at line 161 of file example_checksum.c.

Referenced by profile().

{
  clock_gettime(CLOCK_REALTIME, pstart);
}

static long stoptimer ( struct timespec *  pstart )

static

Stop nano second timer.

Parameters

[in]

pstart

Pointer to start timespec.

Returns

Elaspse time in nano seconds.

Definition at line 173 of file example_checksum.c.

Referenced by profile().

{
  struct timespec tstop;
  long            nsec;

  clock_gettime(CLOCK_REALTIME, &tstop);

  nsec = (tstop.tv_sec - pstart->tv_sec) * 1000000000;

  if( tstop.tv_nsec >= pstart->tv_nsec )
  {
    nsec += (tstop.tv_nsec - pstart->tv_nsec);
  }
  else
  {
    nsec += (1000000000 - pstart->tv_nsec + tstop.tv_nsec); 
  }

  return nsec;
}

Variable Documentation

OptsInfo_T OptsInfo[]

static

Initial value:

=
{
  
  {
    .long_opt     = "poem",
    .short_opt    = OPTS_NO_SHORT,
    .has_arg      = no_argument,
    .has_default  = true,
    .opt_addr     = &OptsPrintPoem,
    .fn_cvt       = OptsCvtArgBool,
    .fn_fmt       = OptsFmtBool,
    .arg_name     = NULL,
    .opt_desc     = "Do [not] print poem."
  },

  {NULL, }
}

Command line options information.

Definition at line 78 of file example_checksum.c.

OptsPgmInfo_T PgmInfo

static

Initial value:

=
{
  .synopsis = "Example of librnr checksum algorithms.",

  .long_desc = 
    "The %P command runs serveral checksum algorithms over a fixed body of "
    "text and prints the results to stdout."
}

Program information.

Definition at line 66 of file example_checksum.c.