usr/src/lib/libast/common/sfio/sfgetm.c

   1 /***********************************************************************
   2 *                                                                      *
   3 *               This software is part of the ast package               *
   4 *          Copyright (c) 1985-2010 AT&T Intellectual Property          *
   5 *                      and is licensed under the                       *
   6 *                  Common Public License, Version 1.0                  *
   7 *                    by AT&T Intellectual Property                     *
   8 *                                                                      *
   9 *                A copy of the License is available at                 *
  10 *            http://www.opensource.org/licenses/cpl1.0.txt             *
  11 *         (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9)         *
  12 *                                                                      *
  13 *              Information and Software Systems Research               *
  14 *                            AT&T Research                             *
  15 *                           Florham Park NJ                            *
  16 *                                                                      *
  17 *                 Glenn Fowler <gsf@research.att.com>                  *
  18 *                  David Korn <dgk@research.att.com>                   *
  19 *                   Phong Vo <kpv@research.att.com>                    *
  20 *                                                                      *
  21 ***********************************************************************/
  22 #include        "sfhdr.h"
  23
  24 /*      Read an unsigned long value coded portably for a given range.
  25 **
  26 **      Written by Kiem-Phong Vo
  27 */
  28
  29 #if __STD_C
  30 Sfulong_t sfgetm(Sfio_t* f, Sfulong_t m)
  31 #else
  32 Sfulong_t sfgetm(f, m)
  33 Sfio_t*         f;
  34 Sfulong_t       m;
  35 #endif
  36 {
  37         Sfulong_t       v;
  38         reg uchar       *s, *ends, c;
  39         reg int         p;
  40         SFMTXDECL(f);
  41
  42         SFMTXENTER(f, (Sfulong_t)(-1));
  43
  44         if(f->mode != SF_READ && _sfmode(f,SF_READ,0) < 0)
  45                 SFMTXRETURN(f, (Sfulong_t)(-1));
  46
  47         SFLOCK(f,0);
  48
  49         for(v = 0;; )
  50         {       if(SFRPEEK(f,s,p) <= 0)
  51                 {       f->flags |= SF_ERROR;
  52                         v = (Sfulong_t)(-1);
  53                         goto done;
  54                 }
  55                 for(ends = s+p; s < ends;)
  56                 {       c = *s++;
  57                         v = (v << SF_BBITS) | SFBVALUE(c);
  58                         if((m >>= SF_BBITS) <= 0)
  59                         {       f->next = s;
  60                                 goto done;
  61                         }
  62                 }
  63                 f->next = s;
  64         }
  65 done:
  66         SFOPEN(f,0);
  67         SFMTXRETURN(f, v);
  68 }