Re: [go-nuts] How does one convert fixed array to a string (tersely)?

I'll do
data := new(Data)
binary.Read(someBuf, binary.BigEndian, &data)

On Monday, September 10, 2012 11:10:30 PM UTC-4, Jake Brukhman wrote:

Context:

I have a struct that will be filled in from binary data. I know field
"str" is going to be a 4-byte string when I read it in.

type Data struct {
one int32
two int32
str [4]byte
}

I'll do

data := new(Data)
binary.Read(someBuf, binary.BigEndian, &data)

and will want to interpret "str" as a string -- but what's the best way to
do the conversion and/or reading in in this case?

Thanks,
Jake

On Monday, September 10, 2012 11:10:30 PM UTC-4, Jake Brukhman wrote:

Context:

I have a struct that will be filled in from binary data. I know field
"str" is going to be a 4-byte string when I read it in.

type Data struct {
one int32
two int32
str [4]byte
}

I'll do

data := new(Data)
binary.Read(someBuf, binary.BigEndian, &data)

and will want to interpret "str" as a string -- but what's the best way to
do the conversion and/or reading in in this case?

Thanks,
Jake

On Tuesday, September 11, 2012 9:07:41 AM UTC-4, Jake Brukhman wrote:

Hi Jordan!

Yes, you are right, I should have just passed in "data", not "&data".

You can simulate the expected input with a buffer or file (e.g. io.Reader)
that contains two int32's and a four character ASCII string:

int32(100), int32(101), "HOLA"

The output would be a Data struct populated with the analogous bytes of
the above.

Jake



On Sep 11, 2012, at 12:01 AM, jorelli <jordan...@gmail.com <javascript:>>
wrote:

I'll do

it's assumed what you mean is:

var data Data
binary.Read(someBuf, binary.BigEndian, &data)

otherwise you just passed **Data into binary.Read instead of *Data

could you perhaps plop in some sample input with the expected output? I'd
like to help, but I don't know how to simulate the input offhand.

something like in the example:

b := []byte{0x18, 0x2d, 0x44, 0x54, 0xfb, 0x21, 0x09, 0x40}

would be killer.

otherwise if it's just six bytes:

var data [6]byte
binary.Read(someBuf, binary.BigEndian, &data)

one := int32(data[0])
two := int32(data[1])
str := string(data[2:])

I'm not sure if that actually works, I'm just curious to learn about
binary handling.

On Tuesday, September 11, 2012 11:05:45 AM UTC-4, jorelli wrote:

ah, ok. Well, a [4]string is an array of four strings, not an array
describing a string of four characters. That would be [4]rune, but almost
nothing takes array inputs because an array's size is a part of its type
([4]rune and [5]rune are distinct types); you're going to be left working
with slices length checks to ensure consistency since [4]rune will be an
almost-certainly meaningless input to any function.

Passing a rune slice into binary.Read and then converting it to a string
works.

Anywho, I found a very ugly solution that my gut tells me must be subtly
wrong in some way, specifically when handling strings of the wrong size or
encoding:

http://play.golang.org/p/bzGRmm7cbf

It's assumed that you are not the ultimate source of the data. If you
are, you can save yourself some headache by using the gob package.