Re: {Spam?} writing binary files

Hi,

There's an even easier way if you have an array of ints.
Casting the array to a string will turn each element of the array into a
character:

> array(int) arr = ({ 4, 5, 9, 12, 255, 0, 8 });
> (string)arr;
(1) Result: "\4\5\t\f\377\0\b"

So just f->write((string)arr) would work.


The same thing also works in reverse:

> (array)"\4\5\t\f\377\0\b";
(3) Result: ({ /* 7 elements */
                4,
                5,
                9,
                12,
                255,
                0,
                8
            })


Most of the time I typically just operate on indexes in the string when
dealing with binary formats, like:

> string s = "abc";
> s[1] = 'd';
> s;
(7) Result: "adc"


Range operators are also incredibly helpful, and are applicable to both
strings and arrays (great for parsing binary formats):

> string s = "potato";
> s[2..];
(8) Result: "tato"
> s[2..3];
(9) Result: "ta"
> s[2..<1];
(10) Result: "tat"
> s[1..<2];


An important thing to note as well is that a character is not limited to
0-255, larger values are allowed to support unicode strings, or
'widestrings'.
Only thing to remember is that a widestring would need to be encoded
when writing to a file, for example using UTF-8.

> string a = "\u1234";
> a[0];
(17) Result: 4660
> string_to_utf8(a);
(18) Result: "\341\210\264"


Happy file writing :)

Best regards,
Pontus

On 05/02/2017 06:04 AM, larcky wrote:
> Hi thanks for reply!
> That example was perfect but also as you suggested...
> 
> int main()
> {
>     Stdio.File f = Stdio.File("foo.bin", "wct");
>     array(int) arr = ({ 4, 5, 9, 12, 255, 0, 8 });
>     *f->write( sprintf("%{%c%}", arr) );*
>     f->close();
>     return 0;
> } 
> 
> Pike=awesome
> 
> 
> 
> --
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>