NSA
Used in the following games:
- Monster Girl Quest
- みずいろ
- 月姫
Structure
| Header | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Size | Content | Description | ||||||||||||
| 2Bytes | Number of files | |||||||||||||
| 4Bytes | Index Size | |||||||||||||
| Index | ||||||||||||||
| Size | Content | Description | ||||||||||||
| (Length)+1Byte | File name | Terminated with 0x00 | ||||||||||||
| 1Bytes | Compress Switch | 00=false 01=true | ||||||||||||
| 4Bytes | Offset | |||||||||||||
| 4Bytes | Compressed Size | |||||||||||||
| 4Bytes | Uncompressed Size | |||||||||||||
Note: All numbers are big endian. Why big endian on a little endian system? Go ask the developer. >.<
Research
| First 5 Index Entries for 'arc.nsa' of みずいろ | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Index Size | Filename | Offset | Filesize1 | Filesize2 | ||||||||||
| 22bytes | b\00.jpg | 0 | 155636 | 155636 | ||||||||||
| 23bytes | b\001.jpg | 155636 | 140467 | 140467 | ||||||||||
| 22bytes | b\01.jpg | 296103 | 169994 | 169994 | ||||||||||
| 22bytes | b\01.jpg | 466097 | 136249 | 136249 | ||||||||||
| 22bytes | b\05.jpg | 602346 | 150570 | 150570 | ||||||||||
Two file sizes suggest the archive supports compression. However in this case, it does not appear to be used due to same size for both filesize values. Compression method is unknown. Would be nice if it was zlib since I have experience implementing that.