Re: Binary recognition is to narrow.

[Hideki IWAMOTO]

Hi.

>         if (((float)strange)/size > 0.3f)

When an empty file is tested on old systems, SIGFPE may occur here.
The calculation of 0.0/0.0 should be avoided for portability.


On Wed, 18 Nov 2009 17:46:01 +0100 (CET), Erik Jonsson wrote...
> Hi all,
> 
> The function is_binary is a bit naive and therefore tags to much as binary
> content. It is quite common with names in the first 32 bytes and it's also
> common with strange characters in names. Strange as in char > 127.
> 
> I have rewritten the function a bit and think you probably should
> incorporate this fix or one of your own in a future release.
> 
> Here is my version...
> 
> static int
> is_binary(const char *path)
> {
>         int ip;
>         char buf[32];
>         int i, c, size;
>         int strange = 0;
> 
>         ip = open(path, O_RDONLY);
>         if (ip < 0)
>                 die("cannot open file '%s' in read mode.", path);
>         size = read(ip, buf, sizeof(buf));
>         close(ip);
>         if (size < 0)
>                 return 1;
>         if (size >= 7 && locatestring(buf, "!<arch>", MATCH_AT_FIRST))
>                 return 1;
>         for (i = 0; i < size; i++) {
>                 c = (unsigned char)buf[i];
>                 if (c <= 8)
>                         return 1;
>                 if (c >= 14 && c < 32)
>                         return 1;
>                 if (c > 128)
>                         strange++;
> 
>         }
>         if (((float)strange)/size > 0.3f)
>             return 1;
> 
>         return 0;
> }
> 
> 
> 
> 
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Hideki IWAMOTO  address@hidden