#ident "$Id$"
#include "dbufio.h"
#include <stdio.h>
#include <fcntl.h>
#include <toku_assert.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>

enum { N  = 5 };
enum { M = 10 };
static void test1 (size_t chars_per_file, size_t bytes_per_read) {
    int fds[N];
    char fnames[N][100];
    size_t n_read[N];
    int still_live[N];
    int n_live=N;
    for (int i=0; i<N; i++) {
	snprintf(fnames[i], 100, "dbufio-test-file%d.data", i);
	unlink(fnames[i]);
	fds[i] = open(fnames[i], O_CREAT|O_RDWR, S_IRWXU);
	//printf("fds[%d]=%d is %s\n", i, fds[i], fnames[i]);
	assert(fds[i]>=0);
	n_read[i]=0;
	still_live[i]=i;
	for (size_t j=0; j<chars_per_file; j++) {
	    unsigned char c = (i+j)%256;
	    int r = toku_os_write(fds[i], &c, 1);
	    if (r!=0) printf("fds[%d]=%d r=%d errno=%d (%s)\n", i, fds[i], r, errno, strerror(errno));
	    assert(r==0);
	}
	{
	    int r = lseek(fds[i], 0, SEEK_SET);
	    assert(r==0);
	}
	
    }
    DBUFIO_FILESET bfs;
    {
	int r = create_dbufio_fileset(&bfs, N, fds, M);
	assert(r==0);
    }
    while (n_live>0) {
	int indirectnum = random()%n_live;
	int filenum = still_live[indirectnum];
	char buf[bytes_per_read];
	size_t n_read_here=0;
	int r = dbufio_fileset_read(bfs, filenum, buf, bytes_per_read, &n_read_here);
	//printf("read(%d) -> %d (%ld) (old n_read=%ld)\n", filenum, r, n_read_here, n_read[filenum]);
	if (r==0) {
	    // did read something
	    assert(n_read_here==bytes_per_read);
	    n_read[filenum]+=n_read_here;
	    //printf(" new n_read=%ld\n", n_read[filenum]);
	    assert(n_read[filenum]<=chars_per_file);
	} else {
	    assert(r==EOF);
	    assert(n_read[filenum]==chars_per_file);
	    still_live[indirectnum] = still_live[n_live-1];
	    n_live--;
	}
    }
    {
	int r = destroy_dbufio_fileset(bfs);
	assert(r==0);
    }
    for (int i=0; i<N; i++) {
	{
	    int r = unlink(fnames[i]);
	    assert(r==0);
	}
	{
	    int r = close(fds[i]);
	    assert(r==0);
	}
	assert(n_read[i]==chars_per_file);
    }
}

				  

int main (int argc __attribute__((__unused__)), char *argv[]__attribute__((__unused__))) {
//    test1(0, 1);
//    test1(1, 1);
//    test1(15, 1);
//    test1(100, 1);
    test1(30, 3); // 3 and M are relatively prime.  But 3 divides the file size.
    return 0;
}