/* -*- mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*- */
// vim: ft=cpp:expandtab:ts=8:sw=4:softtabstop=4:
#ident "$Id$"
#ident "Copyright (c) 2007-2012 Tokutek Inc.  All rights reserved."
#ident "The technology is licensed by the Massachusetts Institute of Technology, Rutgers State University of New Jersey, and the Research Foundation of State University of New York at Stony Brook under United States of America Serial No. 11/760379 and to the patents and/or patent applications resulting from it."
#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, false);
	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;
}
