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/*=============================================================================
testrandom
===============================================================================
Test for the random number generator type by generating 5 values with rand()
and comparing them against values in a table.
Currently only recognizes ISO glibc rand().
Options:
-q : quiet mode
-v : verbose mode : Use to generate values for new table
This is a self-contained program which does not require any libnetpbm
functions.
=============================================================================*/
#include <stdio.h>
#include <stdlib.h>
/* Exit values */
#define EXIT_ERROR 1
#define EXIT_UNKNOWN 80
#define ISO_GLIBC 81
/* 82-90: reserved */
typedef enum {QUIET=0, NORMAL=1, VERBOSE=2} VerbosityLevel;
/* On some Sun systems RAND_MAX is not defined */
#ifndef RAND_MAX
#define RAND_MAX 0
#endif
#define SEED 3791
static struct {
int const type;
/* Exit value for this rand() function */
int const randMax;
/* Usually 0x7fffffff, sometimes 0x7fff */
/* Other values are possible; 0 means undefined */
unsigned int const res[5];
/* Sample values returned from our tests */
const char * const name;
/* Name for this rand() function */
} rTable[2] = {
{ ISO_GLIBC, /* glibc rand() */
0x7fffffff, /* 31 bits */
{ 217313873, 969144303, 1757357552, 1096307597, 818311031 },
"ISO C glibc rand() or equivalent" },
/* Insert additional entries here */
{ 0, /* terminating code */
0,
{0, 0, 0, 0, 0}, NULL /* unknown type */}
};
static void
parseCommandLine(int const argc,
const char * const argv[],
VerbosityLevel * const verbosityP) {
*verbosityP = NORMAL; /* Initial value */
if (argc == 2) {
if (argv[1][0] == '-' && argv[1][2] == '\0') {
switch ( argv[1][1] ) {
case 'v' : *verbosityP = VERBOSE; break;
case 'q' : *verbosityP = QUIET ; break;
default : fprintf (stderr,
"Error: Unrecognized argument: %s\n", argv[1]);
exit (EXIT_ERROR);
}
}
}
if (argc > 2 ) {
fprintf (stderr, "Error: Too many arguments.\n");
exit (EXIT_ERROR);
}
}
int
main(int const argc, const char * const argv[]) {
unsigned int i;
unsigned int res[5];
VerbosityLevel verbosity;
parseCommandLine(argc, argv, &verbosity);
if (verbosity == VERBOSE) {
if (RAND_MAX > 0)
fprintf(stderr, "RAND_MAX = 0x%x (%d)\n", RAND_MAX, RAND_MAX);
else
fprintf(stderr, "RAND_MAX is undefined\n");
}
/* Set seed for pseudo-random number generator */
if (verbosity == VERBOSE)
fprintf(stderr, "Generating samples. Seed=%u\n", SEED);
srand(SEED);
/* Generate five samples and store in array res[] */
for (i = 0; i < 5; ++i) {
res[i] = rand();
if (verbosity == VERBOSE)
fprintf (stderr, "%d\n",res[i]);
}
/* Look for a match in table */
for (i = 0; rTable[i].type != 0; ++i) {
if (rTable[i].randMax == RAND_MAX && rTable[i].res[0] == res[0] &&
rTable[i].res[1] == res[1] && rTable[i].res[2] == res[2] &&
rTable[i].res[3] == res[3] && rTable[i].res[4] == res[4]) {
if (verbosity != QUIET)
fprintf(stderr,
"Random number generator is %s.\n", rTable[i].name);
exit(rTable[i].type);
}
}
/* No matches */
if (verbosity != QUIET)
fprintf(stderr, "Random number generator is of unknown type.\n");
exit(EXIT_UNKNOWN);
}
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