README
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TAR Index
A TAR index file describes the layout of a TAR archive file. It contains metadata about each file entry in the archive:
- Header Position: The byte offset where the file's TAR header begins
- Header Blocks: The number of 512-byte blocks occupied by the TAR header
- File Size: The total number of bytes in the file content
Binary Format
To minimize file size, the index uses a compact binary format with the following structure:
| Field | Size | Description |
|---|---|---|
| Header Position | 8 bytes | Byte offset to the TAR header |
| Header Blocks | 2 bytes | Number of 512-byte blocks for the header |
| File Size | 6 bytes | Total file size in bytes |
All values are stored in big-endian byte order.
Example
For a file with:
- Header at byte position 1024
- Header spanning 1 block (512 bytes)
- File size of 2048 bytes
The index entry would be: 00 00 00 00 00 00 04 00 00 01 00 00 00 00 08 00
Documentation
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Index ¶
Constants ¶
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Variables ¶
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Functions ¶
Types ¶
type FileMetadata ¶
FileMetadata contains the metadata for a file in the index. Start is the offset of the file in the tar archive. HeaderBlocks is the number of blocks in the header of the file (each block is 512 bytes). Size is the size of the file in bytes.
type Index ¶
type Index struct {
Bytes []byte
// contains filtered or unexported fields
}
func OpenTarIndex ¶
OpenTarIndex opens a tar index file and returns an Index object. name is the path to the index file. Returns nil and an error if the file cannot be opened.
func (*Index) GetFileMetadata ¶
func (i *Index) GetFileMetadata(index uint64) (FileMetadata, error)
GetFileMetadata returns the metadata for a file in the index. index is the index of the file in the index. Returns the metadata for the file.
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