I would be amazed if there isn't a way of getting the raw underlying bytes
from the IP address, rather than the text (ASCII). The address
111.111.111.111 is literally the 4 bytes with decimal values 111, 111, 111
and 111. No ASCII required.
On Wed, 18 Jul 2018, 10:28 sanjana gupta, <sanjana.gupta...@gmail.com>
wrote:
> Hey Marc,
>
> I am sorry if I am repeating my words. Please enlighten me on this thing :
>
> "bytes" requires me to give a std::string (c++) value as input. The
> problem with string for me is that a usual 4-byte ipv4 address like
> 111.111.111.111 becomes 15-bytes string "111.111.111.111"
>
> Having said that, I feel discouraged to use bytes over uint32 (or int type
> for that matter) as it already increases the *size of the data to be
> encoded*. As a result, we can say that :
> size of (encoded message using "bytes" type) > size of (encoded message
> using "int" type)
>
> Is my understanding correct? Thanks!
>
>
> On Wednesday, July 18, 2018 at 2:40:01 PM UTC+5:30, Marc Gravell wrote:
>>
>> At that point I'd probably use "repeated bytes", then. It'll cost you an
>> extra byte on v4 addresses, but it is simple.
>>
>> On Wed, 18 Jul 2018, 09:36 sanjana gupta, <sanjana....@gmail.com> wrote:
>>
>>> Thanks Marc for your reply! By mistake I wrote 8-bytes for ipv4. I have
>>> corrected it as 4-bytes in my question. Thanks for that :)
>>>
>>> One thing I want to ask you is that can I use "oneof" if my field
>>> "localEndpoint" is repeated?
>>> I mean to say that my one "profile" message can have any among :
>>> -> 2 ipv4 addresses
>>> -> OR 2 ipv6 addresses
>>> -> OR 1 ipv4 + 1 ipv6 addresses
>>> in the field "localEndpoint".
>>>
>>> So in that case, is "oneof" usage correct? I think that a "oneof" cannot
>>> be repeated. Please correct me if I am wrong.
>>>
>>> On Wednesday, July 18, 2018 at 12:54:39 PM UTC+5:30, Marc Gravell wrote:
>>>>
>>>> You should be able to encode ipv4 in 4 bytes, making fixed32 ideal,
>>>> since you can avoid the length prefix. For ipv6, you're going to need 16
>>>> bytes, so "bytes" is probably your best bet, since it will only require a
>>>> single header. You can then create a union of those:
>>>>
>>>> oneof ip_addr {
>>>> fixed32 v4 = 1;
>>>> bytes v6 = 2;
>>>> }
>>>>
>>>> That seems pretty optimal to me.
>>>>
>>>> Marc
>>>>
>>>> On Wed, 18 Jul 2018, 08:16 sanjana gupta, <sanjana....@gmail.com>
>>>> wrote:
>>>>
>>>>> I read that protobuf has a type called "*bytes*" which can store
>>>>> arbitrary number of bytes and is the equivalent of "C++ string".
>>>>>
>>>>> The reason why I don't prefer to use "bytes" is that it expects input
>>>>> as a C++ string i.e., boost IP will need to be converted to a string.
>>>>>
>>>>>
>>>>> Now my concern lies here : I want to perform serialize and send the
>>>>> encoded protobuf message over TCP socket. I want to ensure that the
>>>>> *encoded
>>>>> message size is as small as possible*.
>>>>>
>>>>>
>>>>> Currently, I am using the below .proto file :
>>>>>
>>>>> syntax = "proto2";
>>>>>
>>>>> message profile
>>>>>
>>>>> {
>>>>>
>>>>> repeated *uint32* localEndpoint = 1;
>>>>>
>>>>> repeated *uint32* remoteEndpoint = 2;
>>>>>
>>>>> }
>>>>>
>>>>>
>>>>> In order to save boost IP in the protobuf message, I am first
>>>>> converting boost IP into byte-format array by using
>>>>> "boost::asio::ip::address_v4::to_bytes()". So for a v4 IP, resultant array
>>>>> size is 8. Then I am converting 1st 4 bytes from the resultant byte-array
>>>>> into one uint32_t number and then storing in "localEndpoint" field of the
>>>>> protobuf message. Likewise, I repeat for the next 4 bytes. I am taking 4
>>>>> bytes at a time so as to utilize full 32 bits of the uint32.
>>>>>
>>>>>
>>>>> Hence for a v4 address, 2 occurrence of "localEndpoint" field is used.
>>>>> Similarly, for a v6 address, 4 occurrence of "localEndpoint" field is
>>>>> used.
>>>>>
>>>>>
>>>>> Please allow me to highlight that if I had used "bytes" here, my input
>>>>> string itself would have been of size 15 bytes for a v4 ip like
>>>>> 111.111.111.111
>>>>>
>>>>>
>>>>> Using uint32 instead of "bytes" does save me some encoded-data-size
>>>>> but I am looking for a more efficient protobuf type requiring lesser
>>>>> number
>>>>> of bytes.
>>>>>
>>>>>
>>>>> Sorry for a long description but I wanted to explain my query in
>>>>> details. Please help me.. Thanks a lot in advance :)
>>>>>
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