ddt.h File Reference

On-disk headers for Deduplication Data Tables (DDT) versions 1 and 2. More...

#include <stdint.h>

Go to the source code of this file.

Data Structures
struct	DdtHeader
	Header preceding a version 1 (flat) deduplication table body. More...
struct	DdtHeader2
	Header preceding a version 2 hierarchical deduplication table. More...

Typedefs
typedef struct DdtHeader	DdtHeader
typedef struct DdtHeader2	DdtHeader2

Detailed Description

On-disk headers for Deduplication Data Tables (DDT) versions 1 and 2.

A DDT maps logical sector indices (LBAs within an image's logical address space) to (block, sector) pairs plus a base file offset, enabling content de-duplication inside the container. Two generations exist:

• DdtHeader ("version 1") flat table.
• DdtHeader2 ("version 2") hierarchical, multi-level subtables for scalability.

All integers are little-endian. Structures are packed (1-byte alignment). When porting to a big-endian architecture callers must perform byte swapping. Do not rely on compiler-introduced padding.

Compression of the table body (entries array) follows the same conventions as data blocks: first decompress according to the compression enum, then validate CRC64 for uncompressed contents.

Related enumerations:

• BlockType::DeDuplicationTable / BlockType::DeDuplicationTable2
• CompressionType
• DataType
• DdtSizeType (for DdtHeader2::sizeType)

Definition in file ddt.h.

Typedef Documentation

DdtHeader

typedef struct DdtHeader DdtHeader

DdtHeader2

typedef struct DdtHeader2 DdtHeader2