ngcw_junk.h File Reference

#include <stdbool.h>
#include <stdint.h>
#include "lfg.h"

Go to the source code of this file.

Data Structures
struct	NgcwJunkEntry
	In-memory junk map entry. More...

Macros
#define	AARUFORMAT_CONTEXT_DECLARED
#define	NGCW_JUNK_MAP_VERSION   1
	Current junk map serialization version.

Typedefs
typedef struct NgcwJunkEntry	NgcwJunkEntry
	In-memory junk map entry.

Functions
int32_t	ngcw_serialize_junk_map (const NgcwJunkEntry *entries, uint32_t count, uint8_t **out_data, uint32_t *out_len)
	Serialize a junk map for storage as a media tag.
int32_t	ngcw_deserialize_junk_map (const uint8_t *data, uint32_t data_len, NgcwJunkEntry **entries, uint32_t *count, uint16_t *seed_size)
	Deserialize a junk map from a media tag buffer.
int	ngcw_regenerate_junk_sector (const NgcwJunkEntry *entries, uint32_t entry_count, uint64_t disc_offset, uint8_t *output, uint32_t length)
	Regenerate a junk sector from the junk map.
void	ngcw_junk_lazy_init (aaruformat_context *ctx)
	Lazy initialization: load junk map from media tags.

Macro Definition Documentation

AARUFORMAT_CONTEXT_DECLARED

#define AARUFORMAT_CONTEXT_DECLARED

Definition at line 31 of file ngcw_junk.h.

NGCW_JUNK_MAP_VERSION

#define NGCW_JUNK_MAP_VERSION   1

Current junk map serialization version.

Definition at line 40 of file ngcw_junk.h.

Referenced by ngcw_deserialize_junk_map(), and ngcw_serialize_junk_map().

Typedef Documentation

NgcwJunkEntry

typedef struct NgcwJunkEntry NgcwJunkEntry

In-memory junk map entry.

Each entry describes a contiguous region of LFG-generated junk on disc.

Function Documentation

ngcw_deserialize_junk_map()

int32_t ngcw_deserialize_junk_map	(	const uint8_t *	data,
		uint32_t	data_len,
		NgcwJunkEntry **	entries,
		uint32_t *	count,
		uint16_t *	seed_size )

Deserialize a junk map from a media tag buffer.

Parameters

data	Serialized data buffer.
data_len	Length of the data buffer.
entries	Output: malloc'd array of NgcwJunkEntry (caller must free).
count	Output: number of entries.
seed_size	Output: seed size in uint32 words.

Returns

0 on success, negative error code on failure.

< Current junk map serialization version.

< Number of uint32 words needed to seed the LFG.

Definition at line 104 of file ngcw_junk.c.

References JUNK_MAP_HEADER_SIZE, NgcwJunkEntry::length, NGC_LFG_SEED_SIZE, ngcw_deserialize_junk_map(), NGCW_JUNK_MAP_VERSION, NgcwJunkEntry::offset, NgcwJunkEntry::partition_index, read_le16(), read_le32(), and read_le64().

Referenced by ngcw_deserialize_junk_map(), and ngcw_junk_lazy_init().

ngcw_junk_lazy_init()

void ngcw_junk_lazy_init

(

aaruformat_context *

ctx

)

Lazy initialization: load junk map from media tags.

Populates ctx->ngcw_junk_entries from the kMediaTagNgcwJunkMap media tag.

Parameters

ctx	AaruFormat context.

Definition at line 211 of file ngcw_junk.c.

References mediaTagEntry::data, JUNK_MAP_HEADER_SIZE, kMediaTagNgcwJunkMap, mediaTagEntry::length, aaruformat_context::mediaTags, ngcw_deserialize_junk_map(), aaruformat_context::ngcw_junk_entries, aaruformat_context::ngcw_junk_entry_count, ngcw_junk_lazy_init(), and aaruformat_context::ngcw_junk_seed_size.

Referenced by aaruf_read_sector(), and ngcw_junk_lazy_init().

ngcw_regenerate_junk_sector()

int ngcw_regenerate_junk_sector	(	const NgcwJunkEntry *	entries,
		uint32_t	entry_count,
		uint64_t	disc_offset,
		uint8_t *	output,
		uint32_t	length )

Regenerate a junk sector from the junk map.

Looks up the given disc byte offset in the junk map, initializes the LFG with the matching entry's seed, advances to the correct stream position, and generates the requested number of bytes.

Parameters

entries	Array of junk entries (sorted by offset).
entry_count	Number of entries.
disc_offset	Disc byte offset of the sector to regenerate.
output	Output buffer to fill.
length	Number of bytes to generate.

Returns

0 on success, -1 if the offset is not in the junk map.

< Number of uint32 words needed to seed the LFG.

Definition at line 154 of file ngcw_junk.c.

References NgcwJunkEntry::length, ngc_lfg_get_bytes(), NGC_LFG_SEED_SIZE, ngc_lfg_set_seed(), ngcw_regenerate_junk_sector(), and NgcwJunkEntry::offset.

Referenced by aaruf_read_sector(), and ngcw_regenerate_junk_sector().

ngcw_serialize_junk_map()

int32_t ngcw_serialize_junk_map	(	const NgcwJunkEntry *	entries,
		uint32_t	count,
		uint8_t **	out_data,
		uint32_t *	out_len )

Serialize a junk map for storage as a media tag.

Format (all little-endian): [2 bytes] version (uint16) [4 bytes] entry_count (uint32) [2 bytes] seed_size (uint16) — NGC_LFG_SEED_SIZE For each entry (86 bytes when seed_size=17): [8 bytes] offset (uint64) [8 bytes] length (uint64) [2 bytes] partition_index (uint16) [seed_size * 4 bytes] seed (raw bytes, big-endian uint32 words)

Parameters

entries	Array of junk entries.
count	Number of entries.
out_data	Output: malloc'd buffer (caller must free).
out_len	Output: length of the buffer.

Returns

0 on success, negative error code on failure.

< Number of uint32 words needed to seed the LFG.

< Current junk map serialization version.

< Number of uint32 words needed to seed the LFG.

< Number of uint32 words needed to seed the LFG.

Definition at line 75 of file ngcw_junk.c.

References JUNK_MAP_HEADER_SIZE, NGC_LFG_SEED_SIZE, NGCW_JUNK_MAP_VERSION, ngcw_serialize_junk_map(), write_le16(), write_le32(), and write_le64().

Referenced by ngcw_serialize_junk_map().