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random_r.c
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Sun, Aug 4, 16:19

random_r.c
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/*<html><pre> -<a href="index_r.htm#TOC"
>-------------------------------</a><a name="TOP">-</a>
random_r.c and utilities
Park & Miller's minimimal standard random number generator
argc/argv conversion
Used by rbox. Do not use 'qh'
*/
#include "libqhull_r.h"
#include "random_r.h"
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#ifdef _MSC_VER /* Microsoft Visual C++ -- warning level 4 */
#pragma warning( disable : 4706) /* assignment within conditional function */
#pragma warning( disable : 4996) /* function was declared deprecated(strcpy, localtime, etc.) */
#endif
/*-<a href="qh-globa_r.htm#TOC"
>-------------------------------</a><a name="argv_to_command">-</a>
qh_argv_to_command(argc, argv, command, max_size )
build command from argc/argv
max_size is at least
returns:
a space-delimited string of options (just as typed)
returns false if max_size is too short
notes:
silently removes
makes option string easy to input and output
matches qh_argv_to_command_size()
argc may be 0
*/
int qh_argv_to_command(int argc, char *argv[], char* command, int max_size) {
int i, remaining;
char *s;
*command= '\0'; /* max_size > 0 */
if (argc) {
if ((s= strrchr( argv[0], '\\')) /* get filename w/o .exe extension */
|| (s= strrchr( argv[0], '/')))
s++;
else
s= argv[0];
if ((int)strlen(s) < max_size) /* WARN64 */
strcpy(command, s);
else
goto error_argv;
if ((s= strstr(command, ".EXE"))
|| (s= strstr(command, ".exe")))
*s= '\0';
}
for (i=1; i < argc; i++) {
s= argv[i];
remaining= max_size - (int)strlen(command) - (int)strlen(s) - 2; /* WARN64 */
if (!*s || strchr(s, ' ')) {
char *t= command + strlen(command);
remaining -= 2;
if (remaining < 0) {
goto error_argv;
}
*t++= ' ';
*t++= '"';
while (*s) {
if (*s == '"') {
if (--remaining < 0)
goto error_argv;
*t++= '\\';
}
*t++= *s++;
}
*t++= '"';
*t= '\0';
}else if (remaining < 0) {
goto error_argv;
}else
strcat(command, " ");
strcat(command, s);
}
return 1;
error_argv:
return 0;
} /* argv_to_command */
/*-<a href="qh-globa_r.htm#TOC"
>-------------------------------</a><a name="argv_to_command_size">-</a>
qh_argv_to_command_size(argc, argv )
return size to allocate for qh_argv_to_command()
notes:
argc may be 0
actual size is usually shorter
*/
int qh_argv_to_command_size(int argc, char *argv[]) {
unsigned int count= 1; /* null-terminator if argc==0 */
int i;
char *s;
for (i=0; i<argc; i++){
count += (int)strlen(argv[i]) + 1; /* WARN64 */
if (i>0 && strchr(argv[i], ' ')) {
count += 2; /* quote delimiters */
for (s=argv[i]; *s; s++) {
if (*s == '"') {
count++;
}
}
}
}
return count;
} /* argv_to_command_size */
/*-<a href="qh-geom_r.htm#TOC"
>-------------------------------</a><a name="rand">-</a>
qh_rand()
qh_srand(qh, seed )
generate pseudo-random number between 1 and 2^31 -2
notes:
For qhull and rbox, called from qh_RANDOMint(),etc. [user.h]
From Park & Miller's minimal standard random number generator
Communications of the ACM, 31:1192-1201, 1988.
Does not use 0 or 2^31 -1
this is silently enforced by qh_srand()
Can make 'Rn' much faster by moving qh_rand to qh_distplane
*/
/* Global variables and constants */
#define qh_rand_a 16807
#define qh_rand_m 2147483647
#define qh_rand_q 127773 /* m div a */
#define qh_rand_r 2836 /* m mod a */
int qh_rand(qhT *qh) {
int lo, hi, test;
int seed = qh->last_random;
hi = seed / qh_rand_q; /* seed div q */
lo = seed % qh_rand_q; /* seed mod q */
test = qh_rand_a * lo - qh_rand_r * hi;
if (test > 0)
seed= test;
else
seed= test + qh_rand_m;
qh->last_random= seed;
/* seed = seed < qh_RANDOMmax/2 ? 0 : qh_RANDOMmax; for testing */
/* seed = qh_RANDOMmax; for testing */
return seed;
} /* rand */
void qh_srand(qhT *qh, int seed) {
if (seed < 1)
qh->last_random= 1;
else if (seed >= qh_rand_m)
qh->last_random= qh_rand_m - 1;
else
qh->last_random= seed;
} /* qh_srand */
/*-<a href="qh-geom_r.htm#TOC"
>-------------------------------</a><a name="randomfactor">-</a>
qh_randomfactor(qh, scale, offset )
return a random factor r * scale + offset
notes:
qh.RANDOMa/b are defined in global_r.c
qh_RANDOMint requires 'qh'
*/
realT qh_randomfactor(qhT *qh, realT scale, realT offset) {
realT randr;
randr= qh_RANDOMint;
return randr * scale + offset;
} /* randomfactor */
/*-<a href="qh-geom_r.htm#TOC"
>-------------------------------</a><a name="randommatrix">-</a>
qh_randommatrix(qh, buffer, dim, rows )
generate a random dim X dim matrix in range [-1,1]
assumes buffer is [dim+1, dim]
returns:
sets buffer to random numbers
sets rows to rows of buffer
sets row[dim] as scratch row
notes:
qh_RANDOMint requires 'qh'
*/
void qh_randommatrix(qhT *qh, realT *buffer, int dim, realT **rows) {
int i, k;
realT **rowi, *coord, realr;
coord= buffer;
rowi= rows;
for (i=0; i < dim; i++) {
*(rowi++)= coord;
for (k=0; k < dim; k++) {
realr= qh_RANDOMint;
*(coord++)= 2.0 * realr/(qh_RANDOMmax+1) - 1.0;
}
}
*rowi= coord;
} /* randommatrix */
/*-<a href="qh-globa_r.htm#TOC"
>-------------------------------</a><a name="strtol">-</a>
qh_strtol( s, endp) qh_strtod( s, endp)
internal versions of strtol() and strtod()
does not skip trailing spaces
notes:
some implementations of strtol()/strtod() skip trailing spaces
*/
double qh_strtod(const char *s, char **endp) {
double result;
result= strtod(s, endp);
if (s < (*endp) && (*endp)[-1] == ' ')
(*endp)--;
return result;
} /* strtod */
int qh_strtol(const char *s, char **endp) {
int result;
result= (int) strtol(s, endp, 10); /* WARN64 */
if (s< (*endp) && (*endp)[-1] == ' ')
(*endp)--;
return result;
} /* strtol */

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