sio

package
Version: v0.28.4 Latest Latest
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Published: Dec 9, 2020 License: BSD-3-Clause Imports: 11 Imported by: 0

README

sio

GoDoc

sio is a pure Go implementation of SIO (Serial I/O).

Installation

$ go get go-hep.org/x/hep/sio

Documentation

The documentation is browsable at godoc.org: https://godoc.org/go-hep.org/x/hep/sio

Example

package main

import (
	"fmt"
	"io"

	"go-hep.org/x/hep/sio"
)

type LCRunHeader struct {
	RunNbr   int32
	Detector string
	Descr    string
	SubDets  []string
}

func main() {
	fname := "c_sim.slcio"
	fmt.Printf(">>> opening [%s]\n", fname)

	f, err := sio.Open(fname)
	if err != nil {
		panic(err)
	}
	defer f.Close()

	var runhdr LCRunHeader
	runhdr.RunNbr = 42
	rec := f.Record("LCRunHeader")
	rec.SetUnpack(true)
	rec.Connect("RunHeader", &runhdr)

	fmt.Printf("::: [%s]\n", f.Name())
	fmt.Printf("::: [%s]\n", f.FileName())
	for {
		fmt.Printf("-----------------------------------------------\n")
		var rec *sio.Record

		rec, err = f.ReadRecord()
		fmt.Printf("***\n")
		if err != nil {
			if err == io.EOF {
				break
			}
			panic(err)
		}
		if rec == nil {
			fmt.Printf("** no record!\n")
			break
		}

		fmt.Printf(">> record: %s\n", rec.Name())
		if rec.Name() == "LCRunHeader" {
			fmt.Printf("runnbr: %d\n", runhdr.RunNbr)
			fmt.Printf("det:    %q\n", runhdr.Detector)
			dets := "["
			for i, det := range runhdr.SubDets {
				dets += fmt.Sprintf("%q", det)
				if i+1 != len(runhdr.SubDets) {
					dets += ", "
				}
			}
			dets += "]"
			fmt.Printf("dets:   %s\n", dets)
		}
	}
}

TODO

  • implement read/write pointers
  • implement buffered i/o
  • handle big files (ie: file offsets as int64)

Bibliography

Documentation

Overview

Package sio implements a record-oriented persistency mechanism.

Index

Constants

This section is empty.

Variables

View Source
var (
	ErrStreamNoRecMarker   = errors.New("sio: no record marker found")
	ErrRecordNoBlockMarker = errors.New("sio: no block marker found")
	ErrBlockConnected      = errors.New("sio: block already connected")

	// ErrBlockShortRead means that the deserialization of a SIO block
	// read too few bytes with regard to what was written out in the
	// Block header length.
	ErrBlockShortRead = errors.New("sio: read too few bytes")
)

Functions

This section is empty.

Types

type Block

type Block interface {
	Codec
	Versioner

	Name() string
}

Block is the interface implemented by an object that can be stored to (and loaded from) an SIO stream.

type Codec

type Codec interface {
	Marshaler
	Unmarshaler
}

Code is the interface implemented by an object that can unmarshal and marshal itself from and to a binary, sio-compatible, form.

type Decoder

type Decoder struct {
	// contains filtered or unexported fields
}

Decoder decodes SIO streams. Decoder provides a nice API to deal with errors that may occur during decoding.

func NewDecoder

func NewDecoder(r Reader) *Decoder

NewDecoder creates a new Decoder reading from the provided sio.Reader.

func (*Decoder) Decode

func (dec *Decoder) Decode(ptr interface{})

Decode reads the next value from the input sio stream and stores it in the data, an empty interface value wrapping a pointer to a concrete value.

func (*Decoder) Err

func (dec *Decoder) Err() error

Err returns the first encountered error while decoding, if any.

func (*Decoder) Pointer

func (dec *Decoder) Pointer(ptr interface{})

Pointer marks a (pointer to a) pointer, assigning it a unique identifier, so links between values (inside a given SIO record) can be rebuilt.

func (*Decoder) Tag

func (dec *Decoder) Tag(ptr interface{})

Tag tags a pointer, assigning it a unique identifier, so links between values (inside a given SIO record) can be rebuilt.

type Encoder

type Encoder struct {
	// contains filtered or unexported fields
}

Encoder encodes values into a SIO stream. Encoder provides a nice API to deal with errors that may occur during encoding.

func NewEncoder

func NewEncoder(w Writer) *Encoder

NewEncoder creates a new Encoder writing to the provided sio.Writer.

func (*Encoder) Encode

func (enc *Encoder) Encode(data interface{})

Encode writes the next value to the output sio stream.

func (*Encoder) Err

func (dec *Encoder) Err() error

Err returns the first encountered error while decoding, if any.

func (*Encoder) Pointer

func (enc *Encoder) Pointer(ptr interface{})

Pointer marks a (pointer to a) pointer, assigning it a unique identifier, so links between values (inside a given SIO record) can be stored.

func (*Encoder) Tag

func (enc *Encoder) Tag(ptr interface{})

Tag tags a pointer, assigning it a unique identifier, so links between values (inside a given sio record) can be stored.

type Linker

type Linker interface {
	LinkSio(v uint32) error
}

Linker is the interface implemented by an object that needs to recompute (internal) pointers, after the sio layer had performed pointer tagging/chasing relocation.

type Marshaler

type Marshaler interface {
	MarshalSio(w Writer) error
}

Marshaler is the interface implemented by an object that can marshal itself into a binary, sio-compatible, form.

type Operation

type Operation int
const (
	OpRead Operation = iota
	OpWrite
)

type Reader

type Reader interface {
	io.Reader

	Versioner
	Tag(ptr interface{}) error
	Pointer(ptr interface{}) error
}

Reader is the interface that wraps the basic io.Reader interface and adds SIO pointer tagging capabilities.

type Record

type Record struct {
	// contains filtered or unexported fields
}

Record manages blocks of data

func (*Record) Compress

func (rec *Record) Compress() bool

Compress returns the compression flag

func (*Record) Connect

func (rec *Record) Connect(name string, ptr interface{}) error

Connect connects a Block to this Record (for reading or writing)

func (*Record) Disconnect

func (rec *Record) Disconnect()

Disconnect disconnects all blocks previously connected to this Record (for reading or writing.)

func (*Record) Name

func (rec *Record) Name() string

Name returns the name of this record

func (*Record) Options

func (rec *Record) Options() uint32

Options returns the options of this record.

func (*Record) SetCompress

func (rec *Record) SetCompress(compress bool)

SetCompress sets or resets the compression flag

func (*Record) SetUnpack

func (rec *Record) SetUnpack(unpack bool)

SetUnpack sets whether to unpack incoming records

func (*Record) Unpack

func (rec *Record) Unpack() bool

Unpack returns whether to unpack incoming records

type Stream

type Stream struct {
	// contains filtered or unexported fields
}

Stream manages operations of a single RIO stream.

func Create

func Create(fname string) (*Stream, error)

Create opens and connects a RIO stream to a file for writing

func Open

func Open(fname string) (*Stream, error)

Open opens and connects a RIO stream to a file for reading

func (*Stream) Close

func (stream *Stream) Close() error

Close closes a stream and the underlying file

func (*Stream) CurPos

func (stream *Stream) CurPos() int64

CurPos returns the current position in the file

-1 if error

func (*Stream) DelRecord

func (stream *Stream) DelRecord(n string)

DelRecord removes the Record with name n from this Stream. DelRecord is a no-op if such a Record was not known to the Stream.

func (*Stream) Fd

func (stream *Stream) Fd() uintptr

Fd returns the integer Unix file descriptor referencing the underlying open file.

func (*Stream) FileName

func (stream *Stream) FileName() string

FileName returns the name of the file connected to that stream

func (*Stream) HasRecord

func (stream *Stream) HasRecord(n string) bool

HasRecord returns whether a Record with name n has been added to this Stream

func (*Stream) Mode

func (stream *Stream) Mode() (os.FileMode, error)

Mode returns the stream mode (as os.FileMode)

func (*Stream) Name

func (stream *Stream) Name() string

Name returns the stream name

func (*Stream) ReadRecord

func (stream *Stream) ReadRecord() (*Record, error)

ReadRecord reads the next record

func (*Stream) Record

func (stream *Stream) Record(name string) *Record

Record adds a Record to the list of records to read/write or returns the Record with that name.

func (*Stream) Records

func (stream *Stream) Records() []*Record

Records returns the list of Records currently attached to this Stream.

func (*Stream) Seek

func (stream *Stream) Seek(offset int64, whence int) (int64, error)

Seek sets the offset for the next Read or Write on the stream to offset, interpreted according to whence: 0 means relative to the origin of the file, 1 means relative to the current offset, and 2 means relative to the end. It returns the new offset and an error, if any.

func (*Stream) SetCompressionLevel

func (stream *Stream) SetCompressionLevel(lvl int)

SetCompressionLevel sets the (zlib) compression level

func (*Stream) Stat

func (stream *Stream) Stat() (os.FileInfo, error)

Stat returns the FileInfo structure describing underlying file. If there is an error, it will be of type *os.PathError.

func (*Stream) Sync

func (stream *Stream) Sync() error

Sync commits the current contents of the stream to stable storage.

func (*Stream) WriteRecord

func (stream *Stream) WriteRecord(record *Record) error

type Unmarshaler

type Unmarshaler interface {
	UnmarshalSio(r Reader) error
}

Unmarshaler is the interface implemented by an object that can unmarshal a binary, sio-compatible, representation of itself.

type Versioner

type Versioner interface {
	VersionSio() uint32
}

Versioner is the interface implemented by an object that tells which version of SIO serialization/deserialization it supports.

type Writer

type Writer interface {
	io.Writer

	Versioner
	Tag(ptr interface{}) error
	Pointer(ptr interface{}) error
}

Writer is the interface that wraps the basic io.Writer interface and adds SIO pointer tagging capabilities.

Directories

Path Synopsis
cmd

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