file/internat.c

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Portions Copyright (c) 1999 Apple Computer, Inc.  All Rights
   7  * Reserved.  This file contains Original Code and/or Modifications of
   8  * Original Code as defined in and that are subject to the Apple Public
   9  * Source License Version 1.1 (the "License").  You may not use this file
  10  * except in compliance with the License.  Please obtain a copy of the
  11  * License at http://www.apple.com/publicsource and read it before using
  12  * this file.
  13  *
  14  * The Original Code and all software distributed under the License are
  15  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  16  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  17  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE OR NON- INFRINGEMENT.  Please see the
  19  * License for the specific language governing rights and limitations
  20  * under the License.
  21  *
  22  * @APPLE_LICENSE_HEADER_END@
  23  */
  24 /*      $OpenBSD: internat.c,v 1.1 1997/02/09 23:58:26 millert Exp $    */
  25
  26 #include <string.h>
  27 #include <sys/types.h>
  28
  29 #include "file.h"
  30
  31 #define F 0
  32 #define T 1
  33
  34 /*
  35  * List of characters that look "reasonable" in international
  36  * language texts.  That's almost all characters :), except a
  37  * few in the control range of ASCII (all the known international
  38  * charactersets share the bottom half with ASCII).
  39  */
  40 static char maybe_internat[256] = {
  41         F, F, F, F, F, F, F, F, T, T, T, T, T, T, F, F,  /* 0x0X */
  42         F, F, F, F, F, F, F, F, F, F, F, T, F, F, F, F,  /* 0x1X */
  43         T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T,  /* 0x2X */
  44         T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T,  /* 0x3X */
  45         T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T,  /* 0x4X */
  46         T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T,  /* 0x5X */
  47         T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T,  /* 0x6X */
  48         T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, F,  /* 0x7X */
  49         T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T,  /* 0x8X */
  50         T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T,  /* 0x9X */
  51         T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T,  /* 0xaX */
  52         T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T,  /* 0xbX */
  53         T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T,  /* 0xcX */
  54         T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T,  /* 0xdX */
  55         T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T,  /* 0xeX */
  56         T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T   /* 0xfX */
  57 };
  58
  59 /* Maximal length of a line we consider "reasonable". */
  60 #define MAXLINELEN 300
  61
  62 int
  63 internatmagic(buf, nbytes)
  64         unsigned char *buf;
  65         int nbytes;
  66 {
  67         int i;
  68         unsigned char *cp;
  69
  70         nbytes--;
  71
  72         /* First, look whether there are "unreasonable" characters. */
  73         for (i = 0, cp = buf; i < nbytes; i++, cp++)
  74                 if (!maybe_internat[*cp])
  75                         return 0;
  76
  77         /*
  78          * Now, look whether the file consists of lines of
  79          * "reasonable" length.
  80          */
  81
  82         for (i = 0; i < nbytes;) {
  83                 cp = memchr(buf, '\n', nbytes - i);
  84                 if (cp == NULL) {
  85                         /* Don't fail if we hit the end of buffer. */
  86                         if (i + MAXLINELEN >= nbytes)
  87                                 break;
  88                         else
  89                                 return 0;
  90                 }
  91                 if (cp - buf > MAXLINELEN)
  92                         return 0;
  93                 i += (cp - buf + 1);
  94                 buf = cp + 1;
  95         }
  96         ckfputs("International language text", stdout);
  97         return 1;
  98 }