/*
 * XDR implementation on POSIX file interface, with buffering
 *
 * Copyright (C) 1992, University Corp for Atmospheric Research
 *
 * This set of routines implements a XDR on a POSIX file descriptor.
 * XDR_ENCODE serializes onto the descriptor, XDR_DECODE de-serializes
 * from the descriptor. As in stdio, we buffer i/o. This XDR is most
 * useful when the descriptor actually represents a file. It
 * corrects some performance problems with xdrstdio_getpos() and
 * xdrstdio_getpos() in the xdr_stdio implementation.
 *
 * -glenn
 */
/* $Id: xdrposix.c,v 1.27 2003/12/10 21:15:14 epourmal Exp $ */

/*
 * 32-bit integer on the host architecture (on the CRAY, this is actually 64
 * bits; however, a pointer to this type is still passed to the XDR functions
 * x_getlong() and x_putlong(), so, on that platform, it doesn't matter if
 * the following isn't 32-bits):
 */
#ifdef CRAY
#   undef  NETLONG
#   define NETLONG  long
#endif
#ifndef NETLONG
#   define NETLONG  long
#endif
typedef NETLONG     netlong;
#undef  NETLONG

#ifdef vms
#   include <unixio.h>
#   include <file.h>
#else
#   if defined MSDOS || defined WINNT || defined WIN32
#       include <io.h>
#   else
#       if defined (__MWERKS__)
#            include <unistd.h>
#       else
#           if !(defined(macintosh) || defined (SYMANTEC_C))
#               include <unistd.h>
#           endif
#       endif
#   endif
#   include <fcntl.h>
#endif

#if defined(macintosh) || defined (SYMANTEC_C)
#include <types.h>
#else
#include <sys/types.h>
#endif

#include <string.h>
#include "local_nc.h" /* prototypes for NCadvis, nc_error */
		      /* also obtains <stdio.h>, <rpc/types.h>, &
		       * <rpc/xdr.h> */
#include "netcdf.h" /* NC_ */
#include "mfhdf.h"

#if !(defined DOS_FS || defined(macintosh) || defined (SYMANTEC_C))
#   if defined VMS
        typedef u_long ncpos_t;  /* size of u_long is 32 for DECC AXP */
#   else 
        typedef u_int ncpos_t ;  /* all unicies */
#   endif
#else
#  if defined DOS_FS
      typedef off_t ncpos_t ;
#  elif defined __APPLE__
      typedef u_int ncpos_t;
#  else /* macintosh */
      typedef u_long ncpos_t ;
#  endif /* macintosh */
#endif

typedef struct {
    int fd;         /* the file descriptor */   
    int mode;       /* file access mode, O_RDONLY, etc */
    int isdirty ;
    off_t page ;
    int nread ;     /* number of bytes succesfully read */
    int nwrote ;    /* number of bytes last write */
    int cnt ;       /* number of valid bytes in buffer */
    unsigned char *ptr;         /* next byte */
#ifndef CRAY
#ifdef DOS_FS
#ifdef QAK
#define BIOBUFSIZ   4096
#else
#define BIOBUFSIZ   512
#endif
#else
#define BIOBUFSIZ   8192
#endif
#else
#define BIOBUFSIZ   196608 /* stat.st_oblksize */
#endif
    unsigned char base[BIOBUFSIZ];      /* the data buffer */
} biobuf;


static void
free_biobuf(abuf)
biobuf *abuf;
{
    if(abuf == NULL)
        return;
    HDfree((VOIDP)abuf) ;
}


static biobuf *
new_biobuf(fd, fmode)
int fd;
int fmode;
{
    biobuf *biop ;

    biop = (biobuf *)HDmalloc(sizeof(biobuf)) ;
    if(biop == NULL)
        return NULL ;
    biop->fd = fd ;

    biop->mode = fmode ;

    biop->isdirty = 0 ;
    biop->page = 0 ;
    biop->nread = 0 ;
    biop->nwrote = 0 ;
    biop->cnt = 0 ;
    memset(biop->base, 0, ((size_t)(BIOBUFSIZ))) ;
    biop->ptr = biop->base ;

    return biop ;
}


static int
rdbuf(biop)
biobuf *biop;
{
    memset(biop->base, 0, ((size_t)(BIOBUFSIZ))) ;

    if(biop->mode & O_WRONLY)
    {
        biop->cnt = 0 ;
    }
    else
    {
        if(biop->nwrote != BIOBUFSIZ)
        {
            /* last write wasn't a full block, adjust position ahead */
            if(lseek(biop->fd, biop->page * BIOBUFSIZ, SEEK_SET) == ((off_t)-1))
                return -1 ;
        }
        biop->nread = biop->cnt = read(biop->fd, (VOIDP)biop->base, BIOBUFSIZ) ;
    }
    biop->ptr = biop->base ;
    return biop->cnt ;
}


static int
wrbuf(biop)
biobuf *biop;
{

    if(!((biop->mode & O_WRONLY) || (biop->mode & O_RDWR))
        || biop->cnt == 0) 
    {
        biop->nwrote = 0 ;
    }
    else
    {
        if(biop->nread != 0)
        {
            /* if we read something, we have to adjust position back */
            if(lseek(biop->fd, biop->page * BIOBUFSIZ, SEEK_SET) == ((off_t)-1))
                return -1 ;
        }
        biop->nwrote = write(biop->fd, (VOIDP)biop->base, biop->cnt) ;
    }
    biop->isdirty = 0 ;

    return biop->nwrote ;
}

static int
nextbuf(biop)
biobuf *biop;
{
    if(biop->isdirty)
    {
        if(wrbuf(biop) < 0)
            return -1 ;
    }

    biop->page++ ;

    /* read it in */
    if(rdbuf(biop) < 0 )
        return -1 ;

    return biop->cnt ;
}


#define CNT(p) ((p)->ptr - (p)->base)
/* # of unread bytes in buffer */
#define REM(p) ((p)->cnt - CNT(p)) 
/* available space for write in buffer */
#define BREM(p) (BIOBUFSIZ - CNT(p))

static int
bioread(biop, ptr, nbytes)
biobuf *biop;
unsigned char *ptr;
int nbytes;
{
    int ngot = 0 ;
    size_t rem ; 

    if(nbytes == 0)
        return 0 ;  

    while(nbytes > (rem = REM(biop)))
    {
        if(rem > 0)
        {
            (void) memcpy(ptr, biop->ptr, rem) ;
            ptr += rem ;
            nbytes -= rem ;
            ngot += rem ;
        }
        if(nextbuf(biop) <= 0)
            return ngot ;
    }
    /* we know nbytes <= REM at this point */
    (void) memcpy(ptr, biop->ptr, (size_t)nbytes) ;
    biop->ptr += nbytes ;
    ngot += nbytes ;
    return ngot ;
}


static int
biowrite(biop, ptr, nbytes)
biobuf *biop;
unsigned char *ptr;
int nbytes;
{
    size_t rem ;
    int nwrote = 0 ;
    int cnt ;

    if(!((biop->mode & O_WRONLY) || (biop->mode & O_RDWR)))
        return -1 ;

    while(nbytes > (rem = BREM(biop)))
    {
        if(rem > 0)
        {
            (void) memcpy(biop->ptr, ptr, rem) ;
            biop->isdirty = !0 ;
            biop->cnt = BIOBUFSIZ ;
            ptr += rem ;
            nbytes -= rem ;
            nwrote += rem ;
        }
        if(nextbuf(biop) < 0)
            return nwrote ;
    }
    /* we know nbytes <= BREM at this point */
    (void) memcpy(biop->ptr, ptr, (size_t)nbytes) ;
    biop->isdirty = !0 ;
    biop->ptr += nbytes ;
    if((cnt = CNT(biop)) > biop->cnt)
        biop->cnt = cnt ;
    nwrote += nbytes ;

    return nwrote ;
}


static bool_t   xdrposix_getlong();
static bool_t   xdrposix_putlong();
#if (_MIPS_SZLONG == 64) || (defined __sun && defined _LP64) || defined AIX5L64 || defined __x86_64__
static bool_t   xdrposix_getint();
static bool_t   xdrposix_putint();
#endif
static bool_t   xdrposix_getbytes();
static bool_t   xdrposix_putbytes();
static ncpos_t  xdrposix_getpos();
static bool_t   xdrposix_setpos();
#ifdef CRAY
static inline_t *   xdrposix_inline();
#else
#if (_MIPS_SZLONG == 64)
static long *    xdrposix_inline();
#else
#if (defined __sun && defined _LP64)
static rpc_inline_t *    xdrposix_inline();
#else
#if (defined __x86_64__ )
static int32_t *    xdrposix_inline();
#else
#if (defined __alpha )
static int *    xdrposix_inline();
#else
static netlong *    xdrposix_inline(); 
#endif
#endif
#endif
#endif
#endif
static void xdrposix_destroy();

/*
 * Ops vector for posix type XDR
 */
static struct xdr_ops   xdrposix_ops = {
    xdrposix_getlong,   /* deserialize a 32-bit int */
    xdrposix_putlong,   /* serialize a 32-bit int */
#if (_MIPS_SZLONG == 64)
    /* IRIX64 has 64 bits long and 32 bits int. */
    /* It defines two extra entries for get/put int. */
    xdrposix_getint,   /* deserialize a 32-bit int */
    xdrposix_putint,   /* serialize a 32-bit int */
#endif
    xdrposix_getbytes,  /* deserialize counted bytes */
    xdrposix_putbytes,  /* serialize counted bytes */
    xdrposix_getpos,    /* get offset in the stream */
    xdrposix_setpos,    /* set offset in the stream */
    xdrposix_inline,    /* prime stream for inline macros */
#if (defined __sun && defined _LP64) || defined __x86_64__
    xdrposix_destroy,   /* destroy stream */
#ifndef __x86_64__
    NULL,               /* no xdr_control function defined */
#endif
    /* Solaris 64-bit (arch=v9) has 64 bits long and 32 bits int. */
    /* It defines the two extra entries for get/put int. here */
    xdrposix_getint,   /* deserialize a 32-bit int */
    xdrposix_putint    /* serialize a 32-bit int */
#else
#ifdef AIX5L64
    xdrposix_destroy,
    NULL,
    NULL,
    xdrposix_getint,
    xdrposix_putint
#else /*AIX5L64 */
    xdrposix_destroy    /* destroy stream */
#endif /*AIX5L64 */
#endif
};


/*
 * Fake an XDR initialization for HDF files
 */
void
hdf_xdrfile_create(xdrs, ncop)
     XDR *xdrs;
     int ncop;
{
    biobuf *biop = new_biobuf(-1, 0) ;
    
    if(ncop & NC_CREAT)
        xdrs->x_op = XDR_ENCODE;
    else
        xdrs->x_op = XDR_DECODE;
        
    xdrs->x_ops = &xdrposix_ops;
    xdrs->x_private = (caddr_t) biop;
    
} /* hdf_xdrfile_create */


/*
 * Initialize a posix xdr stream.
 * Sets the xdr stream handle xdrs for use on the file descriptor fd.
 * Operation flag is set to op.
 */
static int
xdrposix_create(xdrs, fd, fmode, op)
    XDR *xdrs;
    int fd;
    int fmode;
    enum xdr_op op;
{

    biobuf *biop = new_biobuf(fd, fmode) ;
#ifdef XDRDEBUG
fprintf(stderr,"xdrposix_create(): xdrs=%p, fd=%d, fmode=%d, op=%d\n",xdrs,fd,fmode,(int)op);
fprintf(stderr,"xdrposix_create(): after new_biobuf(), biop=%p\n",biop);
#endif
    xdrs->x_op = op;
    xdrs->x_ops = &xdrposix_ops;
    xdrs->x_private = (caddr_t) biop ;
    /* unused */
    xdrs->x_handy = 0;
    xdrs->x_base = 0;
    if(biop == NULL)
        return -1 ;
    
    /* if write only, or just created (empty), done */
    if((biop->mode & O_WRONLY)
            || (biop->mode & O_CREAT))
        return 0 ;

#ifdef XDRDEBUG
fprintf(stderr,"xdrposix_create(): before rdbuf()\n");
#endif
    /* else, read the first bufferful */
    return( rdbuf(biop) ) ;
}

/*
 * "sync" a posix xdr stream.
 */
static int
xdrposix_sync(xdrs)
    XDR *xdrs;
{
    biobuf *biop = (biobuf *)xdrs->x_private ;
    if(biop->isdirty)
    {
        /* flush */
        if(wrbuf(biop) < 0)
            return -1 ;
    }

    biop->nwrote = 0 ; /* force seek in rdbuf */

    /* read it in */
    if(rdbuf(biop) < 0 )
        return -1 ;

    return biop->cnt ;
}


/*
 * Destroy a posix xdr stream.
 * Cleans up the xdr stream handle xdrs previously set up by xdrposix_create.
 */
static void
xdrposix_destroy(xdrs)
    XDR *xdrs;
{
    /* flush */
    biobuf *biop = (biobuf *)xdrs->x_private ;
    if(biop->isdirty)
    {
        (void) wrbuf(biop) ;
    }
    if(biop->fd != -1) 
            (void) close(biop->fd) ;
    free_biobuf(biop);
}

static bool_t
xdrposix_getlong(xdrs, lp)
    XDR *xdrs;
#if (defined __alpha) 
    int *lp;
#else
    long *lp;
#endif
{
    unsigned char *up = (unsigned char *)lp ;
#if (defined CRAY || defined AIX5L64)   
    *lp = 0 ;
    up += (sizeof(long) - 4) ;
#endif
    if(bioread((biobuf *)xdrs->x_private, up, 4) < 4)
        return (FALSE);
#ifdef SWAP
    *lp =  ntohl(*lp);
#endif
    return (TRUE);
}

static bool_t
xdrposix_putlong(xdrs, lp)
    XDR *xdrs;
#if (defined __alpha) 
    int *lp;
#else
    long *lp;
#endif
{

    unsigned char *up = (unsigned char *)lp ;
#ifdef SWAP
    netlong mycopy = htonl(*lp);
    up = (unsigned char *)&mycopy;
#endif
#if (defined CRAY || defined AIX5L64 )
    up += (sizeof(long) - 4) ;
#endif

    if (biowrite((biobuf *)xdrs->x_private, up, 4) < 4)
        return (FALSE);
    return (TRUE);
}

static bool_t
xdrposix_getbytes(xdrs, addr, len)
    XDR *xdrs;
    caddr_t addr;
#if (defined __alpha)
    int len;
#else
    u_int len;
#endif
{

    if ((len != 0)
            && (bioread((biobuf *)xdrs->x_private, (unsigned char *)addr, (int)len) != len))
        return (FALSE);
    return (TRUE);
}

static bool_t
xdrposix_putbytes(xdrs, addr, len)
    XDR *xdrs;
    caddr_t addr;
#if (defined __alpha)
    int len;
#else
    u_int len;
#endif
{

    if ((len != 0)
            && (biowrite((biobuf *)xdrs->x_private, (unsigned char *)addr, (int)len) != len))
        return (FALSE);
    return (TRUE);
}

static ncpos_t
xdrposix_getpos(xdrs)
    XDR *xdrs;
{

    biobuf *biop = (biobuf *)xdrs->x_private ;
    return (BIOBUFSIZ * biop->page + CNT(biop));
}

static bool_t
xdrposix_setpos(xdrs, pos) 
    XDR *xdrs;
    ncpos_t pos;
{ 
    biobuf *biop = (biobuf *)xdrs->x_private ;
    off_t page ;
    int index ;
    int nread ;
    page = pos / BIOBUFSIZ ;
    index = pos % BIOBUFSIZ ;
    if(page != biop->page)
    {
        if(biop->isdirty)
        {
            if( wrbuf(biop) < 0)
                return FALSE ;
        }
        if(page != biop->page +1)
            biop->nwrote = 0 ; /* force seek in rdbuf */

        biop->page = page ;
    
        nread = rdbuf(biop) ;
        if(nread < 0
                || ((biop->mode & O_RDONLY) && nread < index))
            return FALSE ;
    }
    biop->ptr = biop->base + index ;
    return TRUE ;
}

/*ARGSUSED*/
#ifdef CRAY
static inline_t *
#else
#if (_MIPS_SZLONG == 64)
static long *
#else
#if (defined __sun && defined _LP64)
static rpc_inline_t *
#else
#if (defined  __alpha)
static int* 
#else
#if (defined  __x86_64__)
static int32_t * 
#else
static netlong * 
#endif
#endif
#endif
#endif
#endif
xdrposix_inline(xdrs, len)
    XDR *xdrs;
#if (defined  __alpha)
int 
#else
    u_int
#endif
          len;

{

    /*
     * Must do some work to implement this: must insure
     * enough data in the underlying posix buffer,
     * that the buffer is aligned so that we can indirect through a
     * netlong *, and stuff this pointer in xdrs->x_buf.
     */
    return (NULL);
}

#if (_MIPS_SZLONG == 64) || (defined __sun && defined _LP64) || defined AIX5L64  || defined __x86_64__

static bool_t
xdrposix_getint(xdrs, lp)
    XDR *xdrs;
    int *lp;
{
    unsigned char *up = (unsigned char *)lp ;
#ifdef CRAY
    *lp = 0 ;
    up += (sizeof(long) - 4) ;
#endif
    if(bioread((biobuf *)xdrs->x_private, up, 4) < 4)
        return (FALSE);
#ifdef SWAP
    *lp = ntohl(*lp);
#endif
    return (TRUE);
}

static bool_t
xdrposix_putint(xdrs, lp)
    XDR *xdrs;
    int *lp;
{

    unsigned char *up = (unsigned char *)lp ;
#ifdef SWAP
    netlong mycopy = htonl(*lp);
    up = (unsigned char *)&mycopy;
#endif
#ifdef CRAY
    up += (sizeof(long) - 4) ;
#endif

    if (biowrite((biobuf *)xdrs->x_private, up, 4) < 4)
        return (FALSE);
    return (TRUE);
}
#endif /* end of xdrposix_put(get)int */

int
NCxdrfile_sync(xdrs)
XDR *xdrs ;
{
    return xdrposix_sync(xdrs) ;
}

int
NCxdrfile_create(xdrs, path, ncmode)
XDR *xdrs ;
const char *path ;
int ncmode ;
{
    int fmode ;
    int  fd ;
    enum xdr_op op ;

#ifdef XDRDEBUG
fprintf(stderr,"NCxdrfile_create(): XDR=%p, path=%s, ncmode=%d\n",xdrs,path,ncmode);
#endif
    switch(ncmode & 0x0f) {
    case NC_NOCLOBBER :
        fmode = O_RDWR | O_CREAT | O_EXCL ;
        break ;
    case NC_CLOBBER :
        fmode = O_RDWR | O_CREAT | O_TRUNC ;
        break ;
    case NC_WRITE :
        fmode = O_RDWR ;
        break ;
    case NC_NOWRITE :
        fmode = O_RDONLY ;
        break ;
    default:
        NCadvise(NC_EINVAL, "Bad flag %0x", ncmode & 0x0f) ;
        return(-1) ;
    }
#ifdef CRAY
    fmode |= O_RAW ;
#endif
#ifdef DOS_FS
    /*
     * set default mode to binary to suppress the expansion of
     * 0x0f into CRLF
     */
    if(_fmode != O_BINARY)
        _fmode = O_BINARY ;
#endif
#if defined(macintosh) || defined (SYMANTEC_C)
    fd = open(path, fmode);
#else /* !macintosh  */
    fd = open(path, fmode, 0666) ;
#endif /* !macintosh */
#ifdef XDRDEBUG
fprintf(stderr,"NCxdrfile_create(): fmode=%d, fd=%d\n",fmode,fd);
#endif
    if( fd == -1 )
    {
        nc_serror("filename \"%s\"", path) ;
        return(-1) ;
    } /* else */

    if( ncmode & NC_CREAT )
    {
        op = XDR_ENCODE ;
    } else {
        op = XDR_DECODE ;
    }
    
#ifdef XDRDEBUG
fprintf(stderr,"NCxdrfile_create(): before xdrposix_create()\n");
#endif
    if(xdrposix_create(xdrs, fd, fmode, op) < 0)
        return -1 ;
    /* else */
#ifdef XDRDEBUG
fprintf(stderr,"NCxdrfile_create(): after xdrposix_create()\n");
#endif
    return fd ;
}