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coherent

/* Test program for malloc errors are
 * Error 1 area wrong after initialization
 * Error 2 area wrong after realloc shrink
 * Error 3 area wrong after realloc expand
 * First number after error is what byte was expected
 * Second number is what byte was found
 * Third number is where
 * Fourth number is size of area being looked at
 */

#define XSIZ 113
#include <stdio.h>

extern char *malloc();
extern char *realloc();
extern void  free();
extern unsigned rand();

static unsigned mct, mfail, rct, rfail, ect, count;

static struct mloc {
	char *area;
	unsigned siz;
} locs[XSIZ];

unsigned
vsiz()
{
	unsigned i;

	i = rand() >> 4;
	return(i ? i : 10);
}
		
mkval(siz, loc)
unsigned siz;
char *loc;
{
	char fil=siz;

	for(;siz>0; siz--)
		*loc++=fil;
}

ckval(point, fill, siz, loc)
unsigned point, fill, siz;
char *loc;
{
	char fil=fill, chx, *xloc=loc;
	unsigned  xsiz=siz;

	for(;siz>0; siz--) {
		if((chx=*loc++) != fil) {
		   printf("Error: %d %x %x %d %d\n", 
			   point, fil, chx, xsiz-siz, xsiz);
		   ect++;
		   return(1);
		}
	}
	return(0);
}

churn(loc)
struct mloc *loc;
{
	unsigned nsiz;
	char *savp;

	if(loc->area == NULL) {	/* build an area */
		mct++;
		if(NULL != (loc->area=malloc(loc->siz=vsiz())))
			mkval(loc->siz, loc->area);
		else
			mfail++;
		return;
	}
	ckval(1, loc->siz, loc->siz, loc->area);
	if(rand() & (1<<10)) {	/* free or realloc */
		free(loc->area);
		loc->area=NULL;
		count--;	/* frees don't count */
	} else {
		rct++;
		if(NULL != (savp=realloc(loc->area, nsiz=vsiz()))) {
			loc->area=savp;
			ckval(2+(loc->siz<nsiz), /* 2=contract 3=expand */
				 loc->siz,	 /* filler byte */
				 loc->siz<nsiz ? loc->siz : nsiz, /* size */
				 loc->area);	 /* area */
			mkval(loc->siz=nsiz, loc->area);
		}
		else
			rfail++;
	}
}

main(argc, argv) int argc; char *argv[];
{
	if (argc > 1)
		srand(atoi(argv[1]));

	for(count=0; count < XSIZ; count++)
		locs[count].area = NULL;

	for(count=0; count<500; count++) {
		churn(&locs[rand() % XSIZ]);
		if(!memok())
			printf("memok %d\n", count);
	}

	printf("%4d mallocs     %4d failed\n", mct, mfail);
	printf("%4d reallocs    %4d failed\n", rct, rfail);
	printf("%d errors reported\n", ect);
}

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