Created
May 5, 2021 04:59
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DataFile buffered io file wrapper for handling, reading, and writing binary data
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package db | |
import ( | |
"bufio" | |
"encoding/binary" | |
"io" | |
"os" | |
"path/filepath" | |
"unsafe" | |
) | |
const blockSZ = 16 | |
type DataFile struct { | |
file *os.File | |
rw *bufio.ReadWriter | |
} | |
func OpenDataFile(path string) (*DataFile, error) { | |
file, err := openFile(path) | |
if err != nil { | |
return nil, err | |
} | |
r := bufio.NewReaderSize(file, blockSZ) | |
w := bufio.NewWriterSize(file, blockSZ) | |
return &DataFile{ | |
file: file, | |
rw: bufio.NewReadWriter(r, w), | |
}, nil | |
} | |
func (df *DataFile) Stat() (os.FileInfo, error) { | |
return df.file.Stat() | |
} | |
func (df *DataFile) Read(b []byte) (int, error) { | |
return df.rw.Read(b) | |
} | |
func (df *DataFile) ReadByte() (byte, error) { | |
return df.rw.ReadByte() | |
} | |
func (df *DataFile) ReadBytes() ([]byte, error) { | |
n, err := df.ReadUvarint() | |
if err != nil { | |
return nil, err | |
} | |
b := make([]byte, n) | |
if _, err := io.ReadFull(df.rw, b); err != nil { | |
return nil, err | |
} | |
return b, nil | |
} | |
func (df *DataFile) ReadString() (string, error) { | |
b, err := df.ReadBytes() | |
if err != nil { | |
return "", err | |
} | |
return *(*string)(unsafe.Pointer(&b)), nil | |
} | |
func (df *DataFile) ReadUint16() (uint16, error) { | |
var buf [2]byte | |
if _, err := io.ReadFull(df.rw, buf[:]); err != nil { | |
return 0, err | |
} | |
return binary.LittleEndian.Uint16(buf[:]), nil | |
} | |
func (df *DataFile) ReadUint32() (uint32, error) { | |
var buf [4]byte | |
if _, err := io.ReadFull(df.rw, buf[:]); err != nil { | |
return 0, err | |
} | |
return binary.LittleEndian.Uint32(buf[:]), nil | |
} | |
func (df *DataFile) ReadUint64() (uint64, error) { | |
var buf [8]byte | |
if _, err := io.ReadFull(df.rw, buf[:]); err != nil { | |
return 0, err | |
} | |
return binary.LittleEndian.Uint64(buf[:]), nil | |
} | |
func (df *DataFile) ReadUvarint() (uint64, error) { | |
return binary.ReadUvarint(df.rw) | |
} | |
func (df *DataFile) ReaderBuffered() int { | |
return df.rw.Reader.Buffered() | |
} | |
func (df *DataFile) ReaderSize() int { | |
return df.rw.Reader.Size() | |
} | |
func (df *DataFile) UnreadByte() error { | |
return df.rw.UnreadByte() | |
} | |
func (df *DataFile) Write(b []byte) (int, error) { | |
return df.rw.Write(b) | |
} | |
func (df *DataFile) WriteByte(b byte) error { | |
return df.rw.WriteByte(b) | |
} | |
func (df *DataFile) WriteBytes(b []byte) error { | |
return df.WriteString(*(*string)(unsafe.Pointer(&b))) | |
} | |
func (df *DataFile) WriteString(s string) error { | |
if err := df.WriteUvarint(uint64(len(s))); err != nil { | |
return err | |
} | |
_, err := df.rw.WriteString(s) | |
return err | |
} | |
func (df *DataFile) WriteUint16(x uint16) error { | |
var buf [2]byte | |
binary.LittleEndian.PutUint16(buf[:], x) | |
_, err := df.rw.Write(buf[:]) | |
return err | |
} | |
func (df *DataFile) WriteUint32(x uint32) error { | |
var buf [4]byte | |
binary.LittleEndian.PutUint32(buf[:], x) | |
_, err := df.rw.Write(buf[:]) | |
return err | |
} | |
func (df *DataFile) WriteUint64(x uint64) error { | |
var buf [8]byte | |
binary.LittleEndian.PutUint64(buf[:], x) | |
_, err := df.rw.Write(buf[:]) | |
return err | |
} | |
func (df *DataFile) WriteUvarint(x uint64) error { | |
var buf [10]byte | |
n := binary.PutUvarint(buf[:], x) | |
_, err := df.rw.Write(buf[:n]) | |
return err | |
} | |
func (df *DataFile) Available() int { | |
return df.rw.Available() | |
} | |
func (df *DataFile) WriterBuffered() int { | |
return df.rw.Writer.Buffered() | |
} | |
func (df *DataFile) WriterSize() int { | |
return df.rw.Writer.Size() | |
} | |
func (df *DataFile) Peek(n int) ([]byte, error) { | |
return df.rw.Peek(n) | |
} | |
func (df *DataFile) Discard(n int) (int, error) { | |
return df.rw.Discard(n) | |
} | |
func (df *DataFile) Flush() error { | |
return df.rw.Flush() | |
} | |
func (df *DataFile) Sync() error { | |
err := df.rw.Flush() | |
if err != nil { | |
return err | |
} | |
return df.file.Sync() | |
} | |
func (df *DataFile) Truncate(size int64) error { | |
err := df.rw.Flush() | |
if err != nil { | |
return err | |
} | |
err = df.file.Sync() | |
if err != nil { | |
return err | |
} | |
df.rw = nil | |
err = df.file.Truncate(size) | |
if err != nil { | |
return err | |
} | |
r := bufio.NewReaderSize(df.file, blockSZ) | |
w := bufio.NewWriterSize(df.file, blockSZ) | |
df.rw = bufio.NewReadWriter(r, w) | |
return nil | |
} | |
func (df *DataFile) Close() error { | |
err := df.rw.Flush() | |
if err != nil { | |
return err | |
} | |
err = df.file.Sync() | |
if err != nil { | |
return err | |
} | |
err = df.file.Close() | |
if err != nil { | |
return err | |
} | |
return nil | |
} | |
func openFile(path string) (*os.File, error) { | |
var fd *os.File | |
var err error | |
if _, err = os.Stat(path); os.IsNotExist(err) { | |
dir, file := filepath.Split(path) | |
err = os.MkdirAll(dir, os.ModeDir) | |
if err != nil { | |
return nil, err | |
} | |
fd, err = os.Create(dir + file) | |
if err != nil { | |
return nil, err | |
} | |
err = fd.Close() | |
if err != nil { | |
return fd, err | |
} | |
} | |
fd, err = os.OpenFile(path, os.O_RDWR|os.O_APPEND, os.ModeSticky) | |
if err != nil { | |
return nil, err | |
} | |
return fd, nil | |
} |
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