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 Go to latest Published: Oct 4, 2022 License: Apache-2.0 Imports: 20 Imported by: 0

Documentation

Index

Constants

This section is empty.

Variables

View Source 
var (
	// ErrEOF indicates an end of file when trying to read from a memory mapped file
	// and encountering the end of slice.
	ErrEOF = errors.New("ErrEOF: End of file")

	// ErrCommitAfterFinish indicates that write batch commit was called after
	// finish
	ErrCommitAfterFinish = errors.New("Batch commit not permitted after finish")
)
View Source 
var (

	// CastagnoliCrcTable is a CRC32 polynomial table
	CastagnoliCrcTable = crc32.MakeTable(crc32.Castagnoli)
)

Functions

func BloomBitsPerKey 

func BloomBitsPerKey(fp float64) int

BloomBitsPerKey returns the bits per key required by bloomfilter based on the false positive rate.

func BytesToU16 

func BytesToU16(b []byte) uint16

BytesToU16 converts the given byte slice to uint16

func BytesToU32 

func BytesToU32(b []byte) uint32

BytesToU32 converts the given byte slice to uint32

func BytesToU32Slice 

func BytesToU32Slice(b []byte) []uint32

BytesToU32Slice converts the given byte slice to uint32 slice

func BytesToU64 

func BytesToU64(b []byte) uint64

BytesToU64 converts the given byte slice to uint64

func BytesToU64Slice 

func BytesToU64Slice(b []byte) []uint64

BytesToU64Slice converts the given byte slice to uint64 slice

func CompareKeys 

func CompareKeys(key1, key2 []byte) int

CompareKeys checks the key without timestamp and checks the timestamp if keyNoTs is same. a<timestamp> would be sorted higher than aa<timestamp> if we use bytes.compare All keys should have timestamp.

func Copy 

func Copy(a []byte) []byte

Copy copies a byte slice and returns the copied slice.

func CreateSyncedFile 

func CreateSyncedFile(filename string, sync bool) (*os.File, error)

CreateSyncedFile creates a new file (using O_EXCL), errors if it already existed.

func FixedDuration 

func FixedDuration(d time.Duration) string

FixedDuration returns a string representation of the given duration with the hours, minutes, and seconds.

func GenerateIV 

func GenerateIV() ([]byte, error)

GenerateIV generates IV.

func Hash 

func Hash(b []byte) uint32

hash implements a hashing algorithm similar to the Murmur hash.

func IBytesToString 

func IBytesToString(size uint64, precision int) string

IBytesToString converts size in bytes to human readable format. The code is taken from humanize library and changed to provide value upto custom decimal precision. IBytesToString(12312412, 1) -> 11.7 MiB

func KeyWithTs 

func KeyWithTs(key []byte, ts uint64) []byte

KeyWithTs generates a new key by appending ts to key.

func OpenExistingFile 

func OpenExistingFile(filename string, flags Flags) (*os.File, error)

OpenExistingFile opens an existing file, errors if it doesn't exist.

func OpenSyncedFile 

func OpenSyncedFile(filename string, sync bool) (*os.File, error)

OpenSyncedFile creates the file if one doesn't exist.

func OpenTruncFile 

func OpenTruncFile(filename string, sync bool) (*os.File, error)

OpenTruncFile opens the file with O_RDWR | O_CREATE | O_TRUNC

func ParseKey 

func ParseKey(key []byte) []byte

ParseKey parses the actual key from the key bytes.

func ParseTs 

func ParseTs(key []byte) uint64

ParseTs parses the timestamp from the key bytes.

func SafeCopy 

func SafeCopy(a, src []byte) []byte

SafeCopy does append(a[:0], src...).

func SameKey 

func SameKey(src, dst []byte) bool

SameKey checks for key equality ignoring the version timestamp suffix.

func SetKeyTs 

func SetKeyTs(key []byte, ts uint64)

func U16ToBytes 

func U16ToBytes(v uint16) []byte

U16ToBytes converts the given Uint16 to bytes

func U32SliceToBytes 

func U32SliceToBytes(u32s []uint32) []byte

U32SliceToBytes converts the given Uint32 slice to byte slice

func U32ToBytes 

func U32ToBytes(v uint32) []byte

U32ToBytes converts the given Uint32 to bytes

func U64SliceToBytes 

func U64SliceToBytes(u64s []uint64) []byte

U64SliceToBytes converts the given Uint64 slice to byte slice

func U64ToBytes 

func U64ToBytes(v uint64) []byte

U64ToBytes converts the given Uint64 to bytes

func XORBlock 

func XORBlock(dst, src, key, iv []byte) error

XORBlock encrypts the given data with AES and XOR's with IV. Can be used for both encryption and decryption. IV is of AES block size.

func XORBlockAllocate 

func XORBlockAllocate(src, key, iv []byte) ([]byte, error)

func XORBlockStream 

func XORBlockStream(w io.Writer, src, key, iv []byte) error

Types

type Filter 

type Filter []byte

Filter is an encoded set of []byte keys.

func NewFilter 

func NewFilter(keys []uint32, bitsPerKey int) Filter

NewFilter returns a new Bloom filter that encodes a set of []byte keys with the given number of bits per key, approximately.

A good bitsPerKey value is 10, which yields a filter with ~ 1% false positive rate.

func (Filter) MayContain 

func (f Filter) MayContain(h uint32) bool

MayContain returns whether the filter may contain given key. False positives are possible, where it returns true for keys not in the original set.

func (Filter) MayContainKey 

func (f Filter) MayContainKey(k []byte) bool

type Flags 

type Flags int
const (
	// Sync indicates that O_DSYNC should be set on the underlying file,
	// ensuring that data writes do not return until the data is flushed
	// to disk.
	Sync Flags = 1 << iota
	// ReadOnly opens the underlying file on a read-only basis.
	ReadOnly
)

type PageBuffer 

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

PageBuffer consists of many pages. A page is a wrapper over []byte. PageBuffer can act as a replacement of bytes.Buffer. Instead of having single underlying buffer, it has multiple underlying buffers. Hence it avoids any copy during relocation(as happens in bytes.Buffer). PageBuffer allocates memory in pages. Once a page is full, it will allocate page with double the size of previous page. Its function are not thread safe.

func NewPageBuffer 

func NewPageBuffer(pageSize int) *PageBuffer

NewPageBuffer returns a new PageBuffer with first page having size pageSize.

func (*PageBuffer) Bytes 

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

Bytes returns whole Buffer data as single []byte.

func (*PageBuffer) Len 

func (b *PageBuffer) Len() int

Len returns length of PageBuffer.

func (*PageBuffer) NewReaderAt 

func (b *PageBuffer) NewReaderAt(offset int) *PageBufferReader

NewReaderAt returns a reader which starts reading from offset in page buffer.

func (*PageBuffer) Truncate 

func (b *PageBuffer) Truncate(n int)

Truncate truncates PageBuffer to length n.

func (*PageBuffer) Write 

func (b *PageBuffer) Write(data []byte) (int, error)

Write writes data to PageBuffer b. It returns number of bytes written and any error encountered.

func (*PageBuffer) WriteByte 

func (b *PageBuffer) WriteByte(data byte) error

WriteByte writes data byte to PageBuffer and returns any encountered error.

func (*PageBuffer) WriteTo 

func (b *PageBuffer) WriteTo(w io.Writer) (int64, error)

WriteTo writes whole buffer to w. It returns number of bytes written and any error encountered.

type PageBufferReader 

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

PageBufferReader is a reader for PageBuffer.

func (*PageBufferReader) Read 

func (r *PageBufferReader) Read(p []byte) (int, error)

Read reads upto len(p) bytes. It returns number of bytes read and any error encountered.

type RateMonitor 

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

func NewRateMonitor 

func NewRateMonitor(numSamples int) *RateMonitor

func (*RateMonitor) Capture 

func (rm *RateMonitor) Capture(sent uint64)

Capture captures the current number of sent bytes. This number should be monotonically increasing.

func (*RateMonitor) Rate 

func (rm *RateMonitor) Rate() uint64

Rate returns the average rate of transmission smoothed out by the number of samples.

type Slice 

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

Slice holds a reusable buf, will reallocate if you request a larger size than ever before. One problem is with n distinct sizes in random order it'll reallocate log(n) times.

func (*Slice) Resize 

func (s *Slice) Resize(sz int) []byte

Resize reuses the Slice's buffer (or makes a new one) and returns a slice in that buffer of length sz.

type Throttle 

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

Throttle allows a limited number of workers to run at a time. It also provides a mechanism to check for errors encountered by workers and wait for them to finish.

func NewThrottle 

func NewThrottle(max int) *Throttle

NewThrottle creates a new throttle with a max number of workers.

func (*Throttle) Do 

func (t *Throttle) Do() error

Do should be called by workers before they start working. It blocks if there are already maximum number of workers working. If it detects an error from previously Done workers, it would return it.

func (*Throttle) Done 

func (t *Throttle) Done(err error)

Done should be called by workers when they finish working. They can also pass the error status of work done.

func (*Throttle) Finish 

func (t *Throttle) Finish() error

Finish waits until all workers have finished working. It would return any error passed by Done. If Finish is called multiple time, it will wait for workers to finish only once(first time). From next calls, it will return same error as found on first call.

type WaterMark 

type WaterMark struct {
	Name string
	// contains filtered or unexported fields
}

WaterMark is used to keep track of the minimum un-finished index. Typically, an index k becomes finished or "done" according to a WaterMark once Done(k) has been called

  1. as many times as Begin(k) has, AND
  2. a positive number of times.

An index may also become "done" by calling SetDoneUntil at a time such that it is not inter-mingled with Begin/Done calls.

Since doneUntil and lastIndex addresses are passed to sync/atomic packages, we ensure that they are 64-bit aligned by putting them at the beginning of the structure.

func (*WaterMark) Begin 

func (w *WaterMark) Begin(index uint64)

Begin sets the last index to the given value.

func (*WaterMark) BeginMany 

func (w *WaterMark) BeginMany(indices []uint64)

BeginMany works like Begin but accepts multiple indices.

func (*WaterMark) Done 

func (w *WaterMark) Done(index uint64)

Done sets a single index as done.

func (*WaterMark) DoneMany 

func (w *WaterMark) DoneMany(indices []uint64)

DoneMany works like Done but accepts multiple indices.

func (*WaterMark) DoneUntil 

func (w *WaterMark) DoneUntil() uint64

DoneUntil returns the maximum index that has the property that all indices less than or equal to it are done.

func (*WaterMark) Init 

func (w *WaterMark) Init(closer *z.Closer)

Init initializes a WaterMark struct. MUST be called before using it.

func (*WaterMark) LastIndex 

func (w *WaterMark) LastIndex() uint64

LastIndex returns the last index for which Begin has been called.

func (*WaterMark) SetDoneUntil 

func (w *WaterMark) SetDoneUntil(val uint64)

SetDoneUntil sets the maximum index that has the property that all indices less than or equal to it are done.

func (*WaterMark) WaitForMark 

func (w *WaterMark) WaitForMark(ctx context.Context, index uint64) error

WaitForMark waits until the given index is marked as done.

Source Files

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