usr/src/lib/libast/common/stdio/fgets.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 #pragma prototyped
  23
  24 #include "stdhdr.h"
  25
  26 extern char*
  27 _stdgets(Sfio_t* f, char* us, int n, int isgets)
  28 {
  29         int             p;
  30         unsigned char*  is;
  31         unsigned char*  ps;
  32
  33         if(n <= 0 || !us || (f->mode != SF_READ && _sfmode(f,SF_READ,0) < 0))
  34                 return NIL(char*);
  35
  36         SFLOCK(f,0);
  37
  38         n -= 1;
  39         is = (uchar*)us;
  40
  41         while(n)
  42         {       /* peek the read buffer for data */
  43                 if((p = f->endb - (ps = f->next)) <= 0 )
  44                 {       f->getr = '\n';
  45                         f->mode |= SF_RC;
  46                         if(SFRPEEK(f,ps,p) <= 0)
  47                                 break;
  48                 }
  49
  50                 if(p > n)
  51                         p = n;
  52
  53 #if _lib_memccpy
  54                 if((ps = (uchar*)memccpy((char*)is,(char*)ps,'\n',p)) != NIL(uchar*))
  55                         p = ps-is;
  56                 is += p;
  57                 ps  = f->next+p;
  58 #else
  59                 if(!(f->flags&(SF_BOTH|SF_MALLOC)))
  60                 {       while(p-- && (*is++ = *ps++) != '\n')
  61                                 ;
  62                         p = ps-f->next;
  63                 }
  64                 else
  65                 {       reg int c = ps[p-1];
  66                         if(c != '\n')
  67                                 ps[p-1] = '\n';
  68                         while((*is++ = *ps++) != '\n')
  69                                 ;
  70                         if(c != '\n')
  71                         {       f->next[p-1] = c;
  72                                 if((ps-f->next) >= p)
  73                                         is[-1] = c;
  74                         }
  75                 }
  76 #endif
  77
  78                 /* gobble up read data and continue */
  79                 f->next = ps;
  80                 if(is[-1] == '\n')
  81                         break;
  82                 else if(n > 0)
  83                         n -= p;
  84         }
  85
  86         if((_Sfi = is - ((uchar*)us)) <= 0)
  87                 us = NIL(char*);
  88         else if(isgets && is[-1] == '\n')
  89         {       is[-1] = '\0';
  90                 _Sfi -= 1;
  91         }
  92         else    *is = '\0';
  93
  94         SFOPEN(f,0);
  95         return us;
  96 }
  97
  98 char*
  99 fgets(char* s, int n, Sfio_t* f)
 100 {
 101         STDIO_PTR(f, "fgets", char*, (char*, int, Sfio_t*), (s, n, f))
 102
 103         return _stdgets(f, s, n, 0);
 104 }
 105
 106 char*
 107 gets(char* s)
 108 {
 109         return _stdgets(sfstdin, s, BUFSIZ, 1);
 110 }