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/* $Id: alloca.c,v 1.1 2007/07/01 06:16:40 dmix Exp $ */
#include <alloca.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#define elemof(v) (sizeof(v) / sizeof((v)[0]))
/* A few of alloca() calls in the one function. */
void test_few_alloca (void)
{
unsigned char *p[10];
int i, n;
/* Allocate and fill each block with sizes: 1 .. elemof(p) */
for (n = 1; n < (int)elemof(p); n++) {
p[n-1] = alloca (n);
memset (p[n-1], n, n);
}
/* Check that there is no overlapping. */
for (n = 1; n < (int)elemof(p); n++) {
for (i = 0; i < n; i++)
if (p[n-1][i] != n)
exit (__LINE__);
}
}
/* Variable size array and alloca() together. */
void test_with_var_array (int n)
{
unsigned char s[n];
unsigned char *p;
int i;
/* Fill variable size array. */
memset (s, 1, n);
/* Allocate and fill the second array. */
p = alloca (n);
memset (p, 2, n);
/* Refill the first array. */
for (i = 0; i < n; i++) s[i] += 1;
/* Check both. */
if (memcmp (s, p, n))
exit (__LINE__);
}
/* Increment the each element of buf[].
The second argument is the number of elements. */
void inc_array (unsigned char *buf, ...)
{
va_list ap;
int n, i;
va_start (ap, buf);
n = va_arg (ap, int);
va_end (ap);
for (i = 0; i < n; i++) buf[i] += 1;
}
/* Check the compatibility with call of function, where arguments are
allocated in the stack. */
void test_with_var_args (int n)
{
unsigned char *p;
int i;
/* Allocate and fill. */
p = alloca (n);
memset (p, 1, n);
/* Args are placed in stack. */
inc_array (p, n);
/* Check the result. */
for (i = 0; i < n; i++) {
if (p[i] != 2)
exit (__LINE__);
}
}
int main ()
{
test_few_alloca ();
test_with_var_array (10);
test_with_var_args (20);
return 0;
}
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