sunrpc/xdr_mem.c

   1 /* @(#)xdr_mem.c        2.1 88/07/29 4.0 RPCSRC */
   2 /*
   3  * Sun RPC is a product of Sun Microsystems, Inc. and is provided for
   4  * unrestricted use provided that this legend is included on all tape
   5  * media and as a part of the software program in whole or part.  Users
   6  * may copy or modify Sun RPC without charge, but are not authorized
   7  * to license or distribute it to anyone else except as part of a product or
   8  * program developed by the user.
   9  *
  10  * SUN RPC IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING THE
  11  * WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
  12  * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
  13  *
  14  * Sun RPC is provided with no support and without any obligation on the
  15  * part of Sun Microsystems, Inc. to assist in its use, correction,
  16  * modification or enhancement.
  17  *
  18  * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
  19  * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY SUN RPC
  20  * OR ANY PART THEREOF.
  21  *
  22  * In no event will Sun Microsystems, Inc. be liable for any lost revenue
  23  * or profits or other special, indirect and consequential damages, even if
  24  * Sun has been advised of the possibility of such damages.
  25  *
  26  * Sun Microsystems, Inc.
  27  * 2550 Garcia Avenue
  28  * Mountain View, California  94043
  29  */
  30 #if !defined(lint) && defined(SCCSIDS)
  31 static char sccsid[] = "@(#)xdr_mem.c 1.19 87/08/11 Copyr 1984 Sun Micro";
  32 #endif
  33
  34 /*
  35  * xdr_mem.h, XDR implementation using memory buffers.
  36  *
  37  * Copyright (C) 1984, Sun Microsystems, Inc.
  38  *
  39  * If you have some data to be interpreted as external data representation
  40  * or to be converted to external data representation in a memory buffer,
  41  * then this is the package for you.
  42  *
  43  */
  44
  45
  46 #include <string.h>
  47 #include <rpc/rpc.h>
  48
  49 static bool_t xdrmem_getlong (XDR *, long *);
  50 static bool_t xdrmem_putlong (XDR *, const long *);
  51 static bool_t xdrmem_getbytes (XDR *, caddr_t, u_int);
  52 static bool_t xdrmem_putbytes (XDR *, const char *, u_int);
  53 static u_int xdrmem_getpos (const XDR *);
  54 static bool_t xdrmem_setpos (XDR *, u_int);
  55 static long *xdrmem_inline (XDR *, int);
  56 static void xdrmem_destroy (XDR *);
  57
  58 static const struct xdr_ops xdrmem_ops =
  59 {
  60   xdrmem_getlong,
  61   xdrmem_putlong,
  62   xdrmem_getbytes,
  63   xdrmem_putbytes,
  64   xdrmem_getpos,
  65   xdrmem_setpos,
  66   xdrmem_inline,
  67   xdrmem_destroy
  68 };
  69
  70 /*
  71  * The procedure xdrmem_create initializes a stream descriptor for a
  72  * memory buffer.
  73  */
  74 void
  75 xdrmem_create (xdrs, addr, size, op)
  76      XDR *xdrs;
  77      const caddr_t addr;
  78      u_int size;
  79      enum xdr_op op;
  80 {
  81
  82   xdrs->x_op = op;
  83   /* We have to add the const since the `struct xdr_ops' in `struct XDR'
  84      is not `const'.  */
  85   xdrs->x_ops = (struct xdr_ops *) &xdrmem_ops;
  86   xdrs->x_private = xdrs->x_base = addr;
  87   xdrs->x_handy = size;
  88 }
  89
  90 /*
  91  * Nothing needs to be done for the memory case.  The argument is clearly
  92  * const.
  93  */
  94
  95 static void
  96 xdrmem_destroy (XDR *xdrs)
  97 {
  98 }
  99
 100 /*
 101  * Gets the next word from the memory referenced by xdrs and places it
 102  * in the long pointed to by lp.  It then increments the private word to
 103  * point at the next element.  Neither object pointed to is const
 104  */
 105 static bool_t
 106 xdrmem_getlong (xdrs, lp)
 107      XDR *xdrs;
 108      long *lp;
 109 {
 110
 111   if ((xdrs->x_handy -= 4) < 0)
 112     return FALSE;
 113   *lp = (int32_t) ntohl ((*((int32_t *) (xdrs->x_private))));
 114   xdrs->x_private += 4;
 115   return TRUE;
 116 }
 117
 118 /*
 119  * Puts the long pointed to by lp in the memory referenced by xdrs.  It
 120  * then increments the private word to point at the next element.  The
 121  * long pointed at is const
 122  */
 123 static bool_t
 124 xdrmem_putlong (xdrs, lp)
 125      XDR *xdrs;
 126      const long *lp;
 127 {
 128
 129   if ((xdrs->x_handy -= 4) < 0)
 130     return FALSE;
 131   *(int32_t *) xdrs->x_private = htonl (*lp);
 132   xdrs->x_private += 4;
 133   return TRUE;
 134 }
 135
 136 /*
 137  * Gets an unaligned number of bytes from the xdrs structure and writes them
 138  * to the address passed in addr.  Be very careful when calling this routine
 139  * as it could leave the xdrs pointing to an unaligned structure which is not
 140  * a good idea.  None of the things pointed to are const.
 141  */
 142 static bool_t
 143 xdrmem_getbytes (xdrs, addr, len)
 144      XDR *xdrs;
 145      caddr_t addr;
 146      u_int len;
 147 {
 148
 149   if ((xdrs->x_handy -= len) < 0)
 150     return FALSE;
 151   bcopy (xdrs->x_private, addr, len);
 152   xdrs->x_private += len;
 153   return TRUE;
 154 }
 155
 156 /*
 157  * The complementary function to the above.  The same warnings apply about
 158  * unaligned data.  The source address is const.
 159  */
 160 static bool_t
 161 xdrmem_putbytes (xdrs, addr, len)
 162      XDR *xdrs;
 163      const char *addr;
 164      u_int len;
 165 {
 166
 167   if ((xdrs->x_handy -= len) < 0)
 168     return FALSE;
 169   bcopy (addr, xdrs->x_private, len);
 170   xdrs->x_private += len;
 171   return TRUE;
 172 }
 173
 174 /*
 175  * Not sure what this one does.  But it clearly doesn't modify the contents
 176  * of xdrs.  **FIXME** does this not assume u_int == u_long?
 177  */
 178 static u_int
 179 xdrmem_getpos (xdrs)
 180      const XDR *xdrs;
 181 {
 182
 183   return (u_long) xdrs->x_private - (u_long) xdrs->x_base;
 184 }
 185
 186 /*
 187  * xdrs modified
 188  */
 189 static bool_t
 190 xdrmem_setpos (xdrs, pos)
 191      XDR *xdrs;
 192      u_int pos;
 193 {
 194   caddr_t newaddr = xdrs->x_base + pos;
 195   caddr_t lastaddr = xdrs->x_private + xdrs->x_handy;
 196
 197   if ((long) newaddr > (long) lastaddr)
 198     return FALSE;
 199   xdrs->x_private = newaddr;
 200   xdrs->x_handy = (long) lastaddr - (long) newaddr;
 201   return TRUE;
 202 }
 203
 204 /*
 205  * xdrs modified
 206  */
 207 static long *
 208 xdrmem_inline (xdrs, len)
 209      XDR *xdrs;
 210      int len;
 211 {
 212   long *buf = 0;
 213
 214   if (xdrs->x_handy >= len)
 215     {
 216       xdrs->x_handy -= len;
 217       buf = (long *) xdrs->x_private;
 218       xdrs->x_private += len;
 219     }
 220   return buf;
 221 }