[SOLVED] CS algorithm /* Reads a 128 kB file into static data and sorts the bytes in

/* Reads a 128 kB file into static data and sorts the bytes in
it, using counting sort, a single-pass algorithm.The sorted
data is written back to the same file in-place. */

#include
#include
#include tests/lib.h
#include tests/main.h

const char *test_name = child-sort;

unsigned char buf[128 * 1024];
size_t histogram[256];

int
main (int argc UNUSED, char *argv[])
{
int handle;
unsigned char *p;
size_t size;
size_t i;

quiet = true;

CHECK ((handle = open (argv[1])) > 1, open %s, argv[1]);

size = read (handle, buf, sizeof buf);
for (i = 0; i < size; i++)histogram[buf[i]]++;p = buf;for (i = 0; i < sizeof histogram / sizeof *histogram; i++) {size_t j = histogram[i];while (j– > 0)
*p++ = i;
}
seek (handle, 0);
write (handle, buf, size);
close (handle);

return 123;
}