asdf

README

go-asdf

Advanced Scientific Data Format reader library in pure Go.

The blocks are eagerly read and uncompressed. The tree is mapped with gabs.

Usage

import "github.com/src-d/go-asdf"

fmt.Println(asdf.OpenFile("path/to/file.asdf", nil).Tree)

Contributions

...are welcome, see CONTRIBUTING and code of conduct.

License

Apache 2.0, see LICENSE.

Documentation

Index

• Constants
• func Grep(reader io.Reader, needle []byte) (int, error)
• type Block
  • func ReadBlock(reader io.Reader) (*Block, error)
  • func (block *Block) Uncompress() error
• type CompressionKind
• type File
  • func Open(reader io.ReadSeeker, progress ProgressCallback) (*File, error)
  • func OpenFile(fileName string, progress ProgressCallback) (*File, error)
• type ProgressCallback

Constants

const (
	// CompressionNone corresponds to no compression.
	CompressionNone CompressionKind = iota
	// CompressionZLIB corresponds to zlib compression: balanced compression/decompression performance, moderate compression ratio.
	CompressionZLIB CompressionKind = iota
	// CompressionBZIP2 corresponds to bzip2 compression: slow compression/decompression, good compression ratio.
	CompressionBZIP2 CompressionKind = iota
	// CompressionLZ4 corresponds to lz4 compression: very fast compression/decompression, poor compression ratio for complex data, moderate/good for ordered.
	CompressionLZ4 CompressionKind = iota

	// FlagStreamed denotes a streamed block. Not used anywhere yet.
	FlagStreamed uint32 = 1
)

Functions

func Grep

func Grep(reader io.Reader, needle []byte) (int, error)

Grep does the same as the UNIX `grep -m1` command: search for the first occurrence of the specified byte sequence in a byte stream. -1 is returned if there is no match.

Types

type Block

type Block struct {
	// Data is the block's payload.
	Data []byte
	// Flags is the block's flags. The 1.x standard does not define any flags except `FlagStreamed`.
	Flags uint32
	// Compression is the block's compression type: none, zlib, bzip2 or lz4.
	Compression CompressionKind
	// contains filtered or unexported fields
}

Block corresponds to an ASDF block.

func ReadBlock

func ReadBlock(reader io.Reader) (*Block, error)

ReadBlock loads another block from the specified reader. That block may be compressed, call `Uncompress()` to obtain the original Data.

func (*Block) Uncompress

func (block *Block) Uncompress() error

Uncompress switches the block's compression to "none", uncompressing `Data` in-place as needed and checking the checksum.

type CompressionKind

type CompressionKind int

CompressionKind indicates the block compression type: none, zlib, bzip2 or lz4.

type File

type File struct {
	core.Document
	// FormatVersion corresponds to the contents of #ASDF header comment.
	FormatVersion semver.Version
	// FormatVersion corresponds to the contents of #ASDF_STANDARD header comment.
	StandardVersion semver.Version
}

File is the top level, ASDF file type.

func Open

func Open(reader io.ReadSeeker, progress ProgressCallback) (*File, error)

Open reads ASDF from a seekable reader.

func OpenFile

func OpenFile(fileName string, progress ProgressCallback) (*File, error)

OpenFile reads ASDF from the file system.

type ProgressCallback

type ProgressCallback func(done, total int)

ProgressCallback allows tracking the file loading progress. Both done *and* total will grow dynamically.