The Tcpdump Group git mirrors - tcpslice/blob - seek-tell.c

   1 /*
   2  * Copyright (c) 1993, 1994, 1995, 1996, 1997
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that: (1) source code distributions
   7  * retain the above copyright notice and this paragraph in its entirety, (2)
   8  * distributions including binary code include the above copyright notice and
   9  * this paragraph in its entirety in the documentation or other materials
  10  * provided with the distribution, and (3) all advertising materials mentioning
  11  * features or use of this software display the following acknowledgement:
  12  * ``This product includes software developed by the University of California,
  13  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
  14  * the University nor the names of its contributors may be used to endorse
  15  * or promote products derived from this software without specific prior
  16  * written permission.
  17  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
  18  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
  19  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  20  *
  21  * 64-bit-offset fseek and ftell.
  22  */
  23
  24 #include <config.h>
  25
  26 // For fseeko() and ftello().
  27 #if defined(__SUNPRO_C) && ! defined(__EXTENSIONS__)
  28 #define __EXTENSIONS__
  29 #endif
  30
  31 #include <stdio.h>
  32 #include <errno.h>
  33
  34 #include "tcpslice.h"
  35
  36 #if defined(HAVE_FSEEKO)
  37 /*
  38  * We have fseeko(), so we have ftello().
  39  * If we have large file support (files larger than 2^31-1 bytes),
  40  * fseeko() will let us seek to a current file position with more
  41  * than 32 bits and ftello() will give us a current file position
  42  * with more than 32 bits.
  43  */
  44 int
  45 fseek64(FILE *p, const int64_t offset, const int whence)
  46 {
  47         off_t off_t_offset;
  48
  49         /*
  50          * Make sure the offset fits.
  51          */
  52         off_t_offset = (off_t)offset;
  53         if (offset != off_t_offset) {
  54                 /*
  55                  * It doesn't.  Fail with EINVAL.
  56                  */
  57                 errno = EINVAL;
  58                 return (-1);
  59         }
  60         return (fseeko(p, off_t_offset, whence));
  61 }
  62
  63 int64_t
  64 ftell64(FILE *p)
  65 {
  66         return (ftello(p));
  67 }
  68 #elif defined(_MSC_VER)
  69 /*
  70  * We have Visual Studio; we support only 2005 and later, so we have
  71  * _fseeki64() and _ftelli64().
  72  */
  73 int
  74 fseek64(FILE *p, const int64_t offset, const int whence)
  75 {
  76         return (_fseeki64(p, offset, whence));
  77 }
  78
  79 int64_t
  80 ftell64(FILE *p)
  81 {
  82         return (_ftelli64(p));
  83 }
  84 #else
  85 /*
  86  * We don't have ftello() or _ftelli64(), so fall back on ftell().
  87  * Either long is 64 bits, in which case ftell() should suffice,
  88  * or this is probably an older 32-bit UN*X without large file
  89  * support, which means you'll probably get errors trying to
  90  * write files > 2^31-1, so it won't matter anyway.
  91  *
  92  * XXX - what about MinGW?
  93  */
  94 int
  95 fseek64(FILE *p, const int64_t offset, const int whence)
  96 {
  97         long long_offset;
  98
  99         /*
 100          * Make sure the offset fits.
 101          */
 102         long_offset = (long)offset;
 103         if (offset != long_offset) {
 104                 /*
 105                  * It doesn't.  Fail with EINVAL.
 106                  */
 107                 errno = EINVAL;
 108                 return (-1);
 109         }
 110         return (fseek(p, long_offset, whence));
 111 }
 112
 113 int64_t
 114 ftell64(FILE *p)
 115 {
 116         return (ftell(p));
 117 }
 118 #endif