/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 1997, 1998, 1999
 *	Sleepycat Software.  All rights reserved.
 */

#include "db_config.h"

#ifndef lint
static const char sccsid[] = "@(#)os_rw.c	11.2 (Sleepycat) 9/20/99";
#endif /* not lint */

#ifndef NO_SYSTEM_INCLUDES
#include <sys/types.h>

#ifndef _MSC_VER /* _WIN32 */
#include <unistd.h>
#endif
#endif

#include "db_int.h"
#include "os_jump.h"

/*
 * CDB___os_io --
 *	Do an I/O.
 *
 * PUBLIC: int CDB___os_io __P((DB_IO *, int, ssize_t *));
 */
int
CDB___os_io(db_iop, op, niop)
	DB_IO *db_iop;
	int op;
	ssize_t *niop;
{
	int ret;

    /* HACK to debug where the O_BINARY mode of the file gets fouled up */
    /*
    printf("\n[CDB___os_io]");
    printf("DB_IO_READ:[%d], DB_IO_WRITE:[%d]\n", (DB_IO_READ==op?1:0), (DB_IO_WRITE==op?1:0));
    printf("[CDB___os_io]");
#ifdef HAVE_PREAD
    printf("using pread/pwrite\n");
#else
    printf("using CDB___os_read & CDB___os_write\n");
#endif
    printf("[CDB___os_io]");
    printf("FD=[%d], BYTES=[%d], PAGESIZE=[%d]\n", db_iop->fhp->fd, db_iop->bytes,db_iop->pagesize);
    */
    
#ifdef HAVE_PREAD
	switch (op) {
	case DB_IO_READ:
		if (CDB___db_jump.j_read != NULL)
			goto slow;
		*niop = pread(db_iop->fhp->fd, db_iop->buf,
		    db_iop->bytes, (off_t)db_iop->pgno * db_iop->pagesize);
		break;
	case DB_IO_WRITE:
		if (CDB___db_jump.j_write != NULL)
			goto slow;
		*niop = pwrite(db_iop->fhp->fd, db_iop->buf,
		    db_iop->bytes, (off_t)db_iop->pgno * db_iop->pagesize);
		break;
	}
	if (*niop == (ssize_t)db_iop->bytes)
		return (0);
slow:
#endif
	MUTEX_THREAD_LOCK(db_iop->mutexp);

	if ((ret = CDB___os_seek(db_iop->fhp,
	    db_iop->pagesize, db_iop->pgno, 0, 0, DB_OS_SEEK_SET)) != 0)
		goto err;
	switch (op) {
	case DB_IO_READ:
		ret =
		    CDB___os_read(db_iop->fhp, db_iop->buf, db_iop->bytes, niop);
		break;
	case DB_IO_WRITE:
		ret =
		    CDB___os_write(db_iop->fhp, db_iop->buf, db_iop->bytes, niop);
		break;
	}

err:	MUTEX_THREAD_UNLOCK(db_iop->mutexp);

	return (ret);

}

/*
 * CDB___os_read --
 *	Read from a file handle.
 *
 * PUBLIC: int CDB___os_read __P((DB_FH *, void *, size_t, ssize_t *));
 */
int
CDB___os_read(fhp, addr, len, nrp)
	DB_FH *fhp;
	void *addr;
	size_t len;
	ssize_t *nrp;
{
	size_t offset;
	ssize_t nr;
	u_int8_t *taddr;


    /* HACK to debug where the O_BINARY mode of the file gets fouled up */
    /*
	printf("\n[CDB___os_read] fhp->fd=[%d], len=[%d]\n", fhp->fd, len);
	printf("[CDB___os_read] CDB___db_jump.j_read==NULL ?[%d]\n",
			( CDB___db_jump.j_read == NULL ?1:0) );	
	printf("[CDB___os_read] lseek(fhp->fd, 0, SEEK_CUR)=[%d]\n", lseek(fhp->fd, 0, SEEK_CUR));
	printf("[CDB___os_read] current mode=[%#x]\n", setmode(fhp->fd, 0x8000));
    */
	
	for (taddr = addr,
	    offset = 0; offset < len; taddr += nr, offset += nr) {
		if ((nr = CDB___db_jump.j_read != NULL ?
		    CDB___db_jump.j_read(fhp->fd, taddr, len - offset) :
		    read(fhp->fd, taddr, len - offset)) < 0)
			return (CDB___os_get_errno());
		if (nr == 0)
			break;
	}
	*nrp = taddr - (u_int8_t *)addr;
	return (0);
}

/*
 * CDB___os_write --
 *	Write to a file handle.
 *
 * PUBLIC: int CDB___os_write __P((DB_FH *, void *, size_t, ssize_t *));
 */
int
CDB___os_write(fhp, addr, len, nwp)
	DB_FH *fhp;
	void *addr;
	size_t len;
	ssize_t *nwp;
{
	size_t offset;
	ssize_t nw;
	u_int8_t *taddr;

    /* HACK to debug where the O_BINARY mode of the file gets fouled up */
    /*
	printf("\n[CDB___os_write] fhp->fd=[%d], len=[%d]\n", fhp->fd, len);
	printf("[CDB___os_write] CDB___db_jump.j_write==NULL ?[%d]\n",
			( CDB___db_jump.j_write == NULL ?1:0) );	
	printf("[CDB___os_write] lseek(fhp->fd, 0, SEEK_CUR)=[%d]\n", lseek(fhp->fd, 0, SEEK_CUR));
	printf("[CDB___os_write] current mode=[%#x]\n", setmode(fhp->fd, 0x8000));
    */
    
	for (taddr = addr,
	    offset = 0; offset < len; taddr += nw, offset += nw) 
    {
		if ((nw = CDB___db_jump.j_write != NULL ?
		    CDB___db_jump.j_write(fhp->fd, taddr, len - offset) :
		    write(fhp->fd, taddr, len - offset)) < 0)
			return (CDB___os_get_errno());

        /* HACK to debug where the O_BINARY mode of the file gets fouled up */
        /* printf("** %d bytes written, wanted to write %d\n", nw, len-offset); */
    }
	*nwp = len;
    
    /* HACK to debug where the O_BINARY mode of the file gets fouled up */
	/* printf("[AFTER CDB___os_write] lseek(fhp->fd, 0, SEEK_CUR)=[%d]\n", lseek(fhp->fd, 0, SEEK_CUR)); */
	
    return (0);
}