# nile

nile is a binary diffing tool

## Algoritm

nile uses a block based LCS algoritm to generate deltas

## Format

The format:
```
0    MAGIC     7 8 COMPRESSION 15
16           MD5-OLD           31
32           MD5-NEW           47
48         DIFFERENCES        ...
```

* ```MAGIC```: static string ```NILE1.0 ```
* ```COMPRESSION```: stack of compression algorithms
* ```MD5-OLD```: md5sum of the old uncompressed file
* ```MD5-NEW```: md5sum of the new uncompressed file
* ```DATA```: a list of differences described below

### Difference

* all numbers are network byte order

```
0     SKIP     3 4  OLDLENGTH   7
8  NEWLENGTH  11 12  NEWDATA  ...
```

* ```SKIP```: skip X bytes till next difference
* ```OLDLENGTH```: length of difference in old data
* ```NEWLENGTH```: length of difference in new data
* ```NEWDATA```: new data with length descripbed in ```NEWLENGTH```