# Message-Utils
Here you can find all the libraries related to the message structure for transmitting [`FarmToad-IoT-Messages`](#message-structure)
## Swift-MessageUtils
It's a library in swift to serialize and deserialize a 
message. However, it has been only carefully tested for
**Serialization** of the message and **Deserialization**
without signature checks.

## Typescript-MessageUtils
It's a Typescript library (Compatible with JavaScript too) that aims 
to offer only the **Deserialization** along a **Signature Check**. 

However, here it is not offered any type of **Serialization** feature 
as deemed unnecessary during the development of the project. 

# Message Structure
Messages were left with a broad margin for versions, signatures, and 
fields, to ensure a high degree of flexibility in the project.

Here it is described the message structure for each 
`FarmToad-IoT-Messages`.

## Index
- [`Main Corpus`](#main-corpus)
- [`Fields`](#fields)

## Main corpus
```
+-+ 64 - bits---+----------------+-------------+----------------+-----------------------+
|0| Version 7   | Message Type 8 | Dev Type 8  | RESERVED 8     | Sign Type 32          |
+-+-------------+----------------+-------------+----------------+-----------------------+
| Timestamp 64                                                                          |
+---------------------------------------------------------------------------------------+
| DevID 128 bits                                                                        |
|                                                                                       |
+---------------------------------------------------------------------------------------+
| Location 192 bits                                                                     |
|                                                                                       |
|                                                                                       |
+---------------------------------------------------------------------------------------+
\                                                                                       /
 | Fields -----------------------------------------------------------------------------|
/                                                                                       \
+---------------------------------------------------------------------------------------+
| 0 Padding 64 - n                                                                      |
+---------------------------------------------------------------------------------------+
| Signature - arbitrary number of bit                                                   |
|                                                                                       |
|                                                                                       |
|                                                                                       |
|                                                                                       |
|                                                                                       |
|                                                                                       |
|                                                                                       |
+---------------------------------------------------------------------------------------+
```

## Fields
each field can be at most 8 * 2^32 bits of length:
- 34359738368 bits
- 4294967296 Bytes


```
+-- 64 - bits--------------------------+----------------------------------------+
|  Key-Length 32                       | Value-Length 32                        |
+--------------------------------------+----------------------------------------+
\   Key                                                                         /
 |-----------------------------------------------------------------------------|
/   Value                                                                       \
+-------------------------------------------------------------------------------+
```

## Key
**MUST** be a `String`

## Value
It's up to the Application to decide whether the value is 
a string or another type of datum