Rollcage 2 IMG

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Choose archive extension:

IMG + IDX

• Format Type : Archive
  
• Endian Order : Little Endian
  

Format Specifications

// IDX FILE

// for each file

uint32 {4}   - File Offset

uint32 {4}   - Compressed File Length

uint32 {4}   - Decompressed File Length

uint32 {4}   - Unused

// IMG FILE

// for each file

char {4}     - File Header (GT20)

uint32 {4}   - Decompressed File Length

uint32 {4}   - Unused (Same as the Unknown ID field in the IDX File)

uint32 {4}   - Length of additional Information

char {X}     - Additional Information

byte {X}     - Compressed Data

Compressed Data:

uint32 {4}   - 'ControlBits'

char {X}     - Compressed Data

uint32 {4}   - 'ControlBits'

char {X}     - Compressed Data

..

The ControlBits say how to decompress the data.

Whether the Bit is 0 and the next Byte is not compressed,

or the Bit is 1 and the next Byte(s) is/are compressed.

If the next Byte(s) is/are compressed, the next ControlBit say how its compressed.

The Next Bit is 0:

The decompressor reads the next Byte from the Data.

This Byte AND FFFFFF00 say the decompressor how much bytes to go back.

From that position the decompressor copies 2 bytes to the end of the already decompressed Data.

If the next ControlBit is 1 the decompressor copies 2 additional Bytes.

If the next ControlBit is 1 the decompressor copies 1 additional Byte.

The Next Bit is 1:

MultiEx BMS

Not written yet

Notes and Comments

• The *.IDX file contains the directory, the *.IMG file contains the data
  

Supported Programs

• Game Extractor