nerosow/linegetter

Fast line reader for big files written in and for Go.

linegetter

Package containing methods for fast random access reads from huge files, typically log files.

Interfaces

LineGetter

LineGetter implements random access to lines from io.ReadSeeker object. Lines are separated with ASCII line feed character, 0x0A in hex.

type LineGetter struct {...}

Functions

NewLineGetter

NewLineGetter returns a new LineGetter. Upon creation of LineGetter, the whole ReadSeeker is scanned. If the io.ReadSeeker is nil, nil is returned.

func NewLineGetter(rs io.ReadSeeker) *LineGetter {...}

GetLineCount

GetLineCount returns the number of lines available in the LineGetter.

func (lg *LineGetter) GetLineCount() int64 {...}

GetLine

GetLine returns the n-th line from the LineGetter.

• If the line number is out of range, ErrInvalidArgument is returned.
• If some error happens during reading, the error is returned and the resulting string does not contain the full expected length.
• If the line length exceeds MaxLineLength, ErrLineTruncated is returned and the resulting string is truncated to MaxLineLength size.

func (lg *LineGetter) GetLine(ln int64) (string, error) {...}

Errors

var (
    ErrInvalidArgument = errors.New("invalid argument")
    ErrLineTruncated   = errors.New("line truncated")
)

Constants

const (
    read_chunk_sz int64 = 16383 // 0x3FFF
    MaxLineLength int64 = read_chunk_sz
)