xdr_stdio.c

它通过提供glibc兼容使得应用程序移植到较小的c 库时相当得容易. 它能够应用到带虚拟存储的Linux和uClinux上.在大多数带MMU部件的平台上为使它更加紧凑,它也能够编译成共享库.uClib

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 * 2550 Garcia Avenue
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 */

/*
 * xdr_stdio.c, XDR implementation on standard i/o file.
 *
 * Copyright (C) 1984, Sun Microsystems, Inc.
 *
 * This set of routines implements a XDR on a stdio stream.
 * XDR_ENCODE serializes onto the stream, XDR_DECODE de-serializes
 * from the stream.
 */

#include <rpc/types.h>
#include <stdio.h>
#include <rpc/xdr.h>

#ifdef USE_IN_LIBIO
# include <libio/iolibio.h>
# define fflush(s) _IO_fflush (s)
# define fread(p, m, n, s) _IO_fread (p, m, n, s)
# define ftell(s) _IO_ftell (s)
# define fwrite(p, m, n, s) _IO_fwrite (p, m, n, s)
#endif

static bool_t xdrstdio_getlong (XDR *, long *);
static bool_t xdrstdio_putlong (XDR *, const long *);
static bool_t xdrstdio_getbytes (XDR *, caddr_t, u_int);
static bool_t xdrstdio_putbytes (XDR *, const char *, u_int);
static u_int xdrstdio_getpos (const XDR *);
static bool_t xdrstdio_setpos (XDR *, u_int);
static int32_t *xdrstdio_inline (XDR *, int);
static void xdrstdio_destroy (XDR *);
static bool_t xdrstdio_getint32 (XDR *, int32_t *);
static bool_t xdrstdio_putint32 (XDR *, const int32_t *);

/*
 * Ops vector for stdio type XDR
 */
static const struct xdr_ops xdrstdio_ops =
{
  xdrstdio_getlong,		/* deserialize a long int */
  xdrstdio_putlong,		/* serialize a long int */
  xdrstdio_getbytes,		/* deserialize counted bytes */
  xdrstdio_putbytes,		/* serialize counted bytes */
  xdrstdio_getpos,		/* get offset in the stream */
  xdrstdio_setpos,		/* set offset in the stream */
  xdrstdio_inline,		/* prime stream for inline macros */
  xdrstdio_destroy,		/* destroy stream */
  xdrstdio_getint32,		/* deserialize a int */
  xdrstdio_putint32		/* serialize a int */
};

/*
 * Initialize a stdio xdr stream.
 * Sets the xdr stream handle xdrs for use on the stream file.
 * Operation flag is set to op.
 */
void
xdrstdio_create (XDR *xdrs, FILE *file, enum xdr_op op)
{
  xdrs->x_op = op;
  /* We have to add the const since the `struct xdr_ops' in `struct XDR'
     is not `const'.  */
  xdrs->x_ops = (struct xdr_ops *) &xdrstdio_ops;
  xdrs->x_private = (caddr_t) file;
  xdrs->x_handy = 0;
  xdrs->x_base = 0;
}

/*
 * Destroy a stdio xdr stream.
 * Cleans up the xdr stream handle xdrs previously set up by xdrstdio_create.
 */
static void
xdrstdio_destroy (XDR *xdrs)
{
  (void) fflush ((FILE *) xdrs->x_private);
  /* xx should we close the file ?? */
};

static bool_t
xdrstdio_getlong (XDR *xdrs, long *lp)
{
  int32_t mycopy;

  if (fread ((caddr_t) & mycopy, 4, 1, (FILE *) xdrs->x_private) != 1)
    return FALSE;
  *lp = (int32_t) ntohl (mycopy);
  return TRUE;
}

static bool_t
xdrstdio_putlong (XDR *xdrs, const long *lp)
{
  long mycopy = htonl (*lp);
  lp = &mycopy;
  if (fwrite ((caddr_t) lp, 4, 1, (FILE *) xdrs->x_private) != 1)
    return FALSE;
  return TRUE;
}

static bool_t
xdrstdio_getbytes (XDR *xdrs, const caddr_t addr, u_int len)
{
  if ((len != 0) && (fread (addr, (int) len, 1,
			    (FILE *) xdrs->x_private) != 1))
    return FALSE;
  return TRUE;
}

static bool_t
xdrstdio_putbytes (XDR *xdrs, const char *addr, u_int len)
{
  if ((len != 0) && (fwrite (addr, (int) len, 1,
			     (FILE *) xdrs->x_private) != 1))
    return FALSE;
  return TRUE;
}

static u_int
xdrstdio_getpos (const XDR *xdrs)
{
  return (u_int) ftell ((FILE *) xdrs->x_private);
}

static bool_t
xdrstdio_setpos (XDR *xdrs, u_int pos)
{
  return fseek ((FILE *) xdrs->x_private, (long) pos, 0) < 0 ? FALSE : TRUE;
}

static int32_t *
xdrstdio_inline (XDR *xdrs, int len)
{
  /*
   * Must do some work to implement this: must insure
   * enough data in the underlying stdio buffer,
   * that the buffer is aligned so that we can indirect through a
   * long *, and stuff this pointer in xdrs->x_buf.  Doing
   * a fread or fwrite to a scratch buffer would defeat
   * most of the gains to be had here and require storage
   * management on this buffer, so we don't do this.
   */
  return NULL;
}

static bool_t
xdrstdio_getint32 (XDR *xdrs, int32_t *ip)
{
  int32_t mycopy;

  if (fread ((caddr_t) &mycopy, 4, 1, (FILE *) xdrs->x_private) != 1)
    return FALSE;
  *ip = ntohl (mycopy);
  return TRUE;
}

static bool_t
xdrstdio_putint32 (XDR *xdrs, const int32_t *ip)
{
  int32_t mycopy = htonl (*ip);

  ip = &mycopy;
  if (fwrite ((caddr_t) ip, 4, 1, (FILE *) xdrs->x_private) != 1)
    return FALSE;
  return TRUE;
}