ioutil

package
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 Go to latest Published: Sep 30, 2024 License: MIT Imports: 11 Imported by: 0

Documentation

Overview

Package ioutil contains various I/O helpers.

Segmented files

SegmentedReader and SegmentedWriter define a file format that allows a single file to be partitioned into multiple independent sections. Each section has a header that specifies the size and type of the section and the offset of the next section. Thus the sections form a kind of linked list within the file.

Each section consists of a 64 byte header followed by data. The data can have any length, but the space on disk (in the file) will be padded to the nearest multiple of 64 to ensure the headers are aligned on 64-byte boundaries. When a section is opened for writing, if it is not the first section, its offset is recorded in the previous section's header. When a section writer is closed, the length of data written is recorded in the section's header and the file's offset is advanced to the next 64-byte boundary.

Section headers are structured as follows:

  • Type - 2 bytes
  • (reserved) - 6 bytes
  • Size - 8 bytes
  • Next section offset - 8 bytes
  • (reserved) - 40 bytes

Index

Constants

This section is empty.

Variables

This section is empty.

Functions

func AppendToSegmented added in v1.4.0 

func AppendToSegmented[V enumGet, U enumSet[V]](f io.ReadWriteSeeker) (*SegmentedWriter[V, U], []*Segment[V, U], error)

func NewSectionReader 

func NewSectionReader(rd SectionReader, start, end int64) (*io.SectionReader, error)

Types

type Buffer 

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

Buffer is an io.ReadWriteSeeker and io.ReaderAt backed by a byte array.

func NewBuffer 

func NewBuffer(b []byte) *Buffer

func (*Buffer) Bytes 

func (b *Buffer) Bytes() []byte

func (*Buffer) Read 

func (b *Buffer) Read(v []byte) (int, error)

func (*Buffer) ReadAt 

func (b *Buffer) ReadAt(v []byte, off int64) (int, error)

func (*Buffer) Seek 

func (b *Buffer) Seek(offset int64, whence int) (int64, error)

func (*Buffer) Write 

func (b *Buffer) Write(v []byte) (int, error)

type Discard added in v1.2.10 

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

Discard is an io.WriteSeeker that discards all data written to it.

func (*Discard) Seek added in v1.2.10 

func (d *Discard) Seek(offset int64, whence int) (int64, error)

func (*Discard) Write added in v1.2.10 

func (d *Discard) Write(p []byte) (n int, err error)

type MappedFile added in v1.4.0 

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

func OpenMappedFile added in v1.4.0 

func OpenMappedFile(name string, flags int, perm fs.FileMode) (_ *MappedFile, err error)

func (*MappedFile) Acquire added in v1.4.0 

func (f *MappedFile) Acquire() *MappedFileRange

func (*MappedFile) AcquireRange added in v1.4.0 

func (f *MappedFile) AcquireRange(start, end int64) *MappedFileRange

func (*MappedFile) Close added in v1.4.0 

func (f *MappedFile) Close() error

func (*MappedFile) Name added in v1.4.0 

func (f *MappedFile) Name() string

type MappedFileRange added in v1.4.0 

type MappedFileRange struct {
	Offset int64
	End    int64
	// contains filtered or unexported fields
}

func (*MappedFileRange) AcquireRange added in v1.4.0 

func (f *MappedFileRange) AcquireRange(start, end int64) *MappedFileRange

func (*MappedFileRange) Len added in v1.4.0 

func (f *MappedFileRange) Len() int

func (*MappedFileRange) Raw added in v1.4.0 

func (f *MappedFileRange) Raw() []byte

func (*MappedFileRange) Read added in v1.4.0 

func (f *MappedFileRange) Read(b []byte) (int, error)

func (*MappedFileRange) ReadAt added in v1.4.0 

func (f *MappedFileRange) ReadAt(b []byte, offset int64) (int, error)

func (*MappedFileRange) ReadByte added in v1.4.0 

func (f *MappedFileRange) ReadByte() (byte, error)

func (*MappedFileRange) Release added in v1.4.0 

func (f *MappedFileRange) Release()

func (*MappedFileRange) Seek added in v1.4.0 

func (f *MappedFileRange) Seek(offset int64, whence int) (int64, error)

func (*MappedFileRange) SetRange added in v1.4.0 

func (f *MappedFileRange) SetRange(start, end int64)

func (*MappedFileRange) Truncate added in v1.4.0 

func (f *MappedFileRange) Truncate(size int64) error

func (*MappedFileRange) UnreadByte added in v1.4.0 

func (f *MappedFileRange) UnreadByte() error

func (*MappedFileRange) Write added in v1.4.0 

func (f *MappedFileRange) Write(b []byte) (int, error)

func (*MappedFileRange) WriteAt added in v1.4.0 

func (f *MappedFileRange) WriteAt(b []byte, offset int64) (int, error)

type SectionReader 

type SectionReader interface {
	io.Reader
	io.ReaderAt
	io.Seeker
}

type SectionWriter 

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

func NewSectionWriter 

func NewSectionWriter(wr io.WriteSeeker, start, end int64) (*SectionWriter, error)

func (*SectionWriter) Seek 

func (s *SectionWriter) Seek(offset int64, whence int) (int64, error)

func (*SectionWriter) Write 

func (s *SectionWriter) Write(p []byte) (n int, err error)

type Segment 

type Segment[V enumGet, U enumSet[V]] struct {
	// contains filtered or unexported fields
}

Segment is a segment of a file.

func (*Segment[V, U]) Offset 

func (s *Segment[V, U]) Offset() int64

Offset returns the segment's offset.

func (*Segment[V, U]) Open 

func (s *Segment[V, U]) Open() (SectionReader, error)

Open opens the segment for reading.

func (*Segment[V, U]) Size 

func (s *Segment[V, U]) Size() int64

Size returns the segment's size.

func (*Segment[V, U]) Type 

func (s *Segment[V, U]) Type() V

Type returns the segment's type.

type SegmentWriter 

type SegmentWriter[V enumGet, U enumSet[V]] struct {
	// contains filtered or unexported fields
}

A SegmentWriter writes a section of a segmented file.

func (*SegmentWriter[V, U]) Close 

func (w *SegmentWriter[V, U]) Close() error

Close closes the segment and finalizes its header.

func (*SegmentWriter[V, U]) Seek 

func (w *SegmentWriter[V, U]) Seek(offset int64, whence int) (int64, error)

Seek seeks to an offset.

func (*SegmentWriter[V, U]) Type 

func (s *SegmentWriter[V, U]) Type() V

Type returns the segment's type.

func (*SegmentWriter[V, U]) Write 

func (w *SegmentWriter[V, U]) Write(p []byte) (n int, err error)

Write writes bytes.

type SegmentedReader 

type SegmentedReader[V enumGet, U enumSet[V]] struct {
	// contains filtered or unexported fields
}

SegmentedReader reads a segmented file.

func NewSegmentedReader 

func NewSegmentedReader[V enumGet, U enumSet[V]](file SectionReader) *SegmentedReader[V, U]

NewSegmentedReader returns a new segmented reader for the file.

func (*SegmentedReader[V, U]) Next 

func (r *SegmentedReader[V, U]) Next() (*Segment[V, U], error)

Next finds the segment.

type SegmentedWriter 

type SegmentedWriter[V enumGet, U enumSet[V]] struct {
	// contains filtered or unexported fields
}

SegmentedWriter writes a segmented file.

func NewSegmentedWriter 

func NewSegmentedWriter[V enumGet, U enumSet[V]](w io.WriteSeeker) *SegmentedWriter[V, U]

NewSegmentedWriter returns a new segmented writer.

func (*SegmentedWriter[V, U]) Open 

func (w *SegmentedWriter[V, U]) Open(typ V) (*SegmentWriter[V, U], error)

Open opens a segment.

Source Files

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