decompress.h File Reference

Wraps the bios decompress functionality into something a bit easier to use. More...

#include <nds/bios.h>
#include <nds/ndstypes.h>

Enumerations
enum	DecompressType {   LZ77 ,   LZ77Vram ,   HUFF ,   RLE ,   RLEVram }
	The types of decompression available. More...

Functions
void	decompress (const void *data, void *dst, DecompressType type)
	Decompresses data using the suported type.
void	decompressStream (const void *data, void *dst, DecompressType type, getByteCallback readCB, getHeaderCallback getHeaderCB)
	Decompresses data using the suported type.
void	decompressStreamStruct (const void *data, void *dst, DecompressType type, void *param, TDecompressionStream *ds)
	Decompresses data using the suported type.

Detailed Description

Wraps the bios decompress functionality into something a bit easier to use.

Enumeration Type Documentation

DecompressType

enum DecompressType

The types of decompression available.

VRAM only accepts 16-bit and 32-bit writes. If the CPU tries to write in 8-bit units, the write is ignored. Due to how the BIOS decompresses data, some of the options of this enum are safe to be used in VRAM, and others aren't.

Enumerator
LZ77	LZ77 decompression.
LZ77Vram	LZ77 decompression (VRAM can be used as destination).
HUFF	Huffman decompression (VRAM can be used as destination).
RLE	Run Length Encoding decompression.
RLEVram	Run Length Encoding decompression (VRAM can be used as detination).

Function Documentation

decompress()

void decompress	(	const void *	data,
		void *	dst,
		DecompressType	type
	)

Decompresses data using the suported type.

When 'type' is HUFF, this function will allocate 512 bytes in the stack as a temporary buffer.

Parameters

dst	Destination to decompress to.
data	Data to decompress.
type	Type of data to decompress.

decompressStream()

void decompressStream	(	const void *	data,
		void *	dst,
		DecompressType	type,
		getByteCallback	readCB,
		getHeaderCallback	getHeaderCB
	)

Decompresses data using the suported type.

Only LZ77Vram, HUFF and RLEVram support streaming, but HUFF isn't supported by this function at all, use decompressStreamStruct() instead.

Parameters

dst	Destination to decompress to.
data	Data to decompress.
type	Type of data to decompress.
readCB	A callback to read the next byte of data.
getHeaderCB	A callback to read the 32 byte header.

decompressStreamStruct()

void decompressStreamStruct	(	const void *	data,
		void *	dst,
		DecompressType	type,
		void *	param,
		TDecompressionStream *	ds
	)

Decompresses data using the suported type.

Only LZ77Vram, HUFF and RLEVram support streaming.

For HUFF, make sure to pass a 512 byte buffer in 'param' to be used as a temporary buffer by the decompression code.

Parameters

dst	Destination to decompress to.
data	Data to decompress.
type	Type of data to decompress.
param	A value to be passed to getHeaderCallback(), or a temporary buffer for HUFF.
ds	A struct with callbacks to be used by the decompression routine.