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iterator.go

iterator.go - Overview​

This file defines the ValueStruct and Iterator interface, along with related helper functions for encoding and decoding ValueStruct instances.

Detailed Documentation​

ValueStruct​

type ValueStruct struct {
	Meta      byte
	UserMeta  byte
	ExpiresAt uint64
	Value     []byte

	Version uint64 // This field is not serialized. Only for internal usage.
}
  • Purpose: Represents the value and metadata associated with a key. Includes internal metadata.
    • Meta: Internal metadata.
    • UserMeta: User-defined metadata.
    • ExpiresAt: Unix timestamp indicating when the value expires.
    • Value: The actual value (byte array).
    • Version: Internal versioning field (not serialized).

sizeVarint​

func sizeVarint(x uint64) (n int)
  • Purpose: Calculates the number of bytes required to represent a uint64 value when encoded as a varint.
    • Parameters:
      • x: The uint64 value.
    • Returns: The number of bytes required for varint encoding.

ValueStruct.EncodedSize​

func (v *ValueStruct) EncodedSize() uint32
  • Purpose: Calculates the size in bytes required to encode the ValueStruct.
    • Returns: The encoded size of the ValueStruct as a uint32.

ValueStruct.Decode​

func (v *ValueStruct) Decode(b []byte)
  • Purpose: Decodes a byte slice into the ValueStruct. The length of the slice is used to determine the length of the Value field.
    • Parameters:
      • b: The byte slice to decode.

ValueStruct.Encode​

func (v *ValueStruct) Encode(b []byte) uint32
  • Purpose: Encodes the ValueStruct into a byte slice. Expects the slice to be large enough to hold the encoded data (at least v.EncodedSize() bytes).
    • Parameters:
      • b: The byte slice to encode into.
    • Returns: The number of bytes written to the slice.

ValueStruct.EncodeTo​

func (v *ValueStruct) EncodeTo(buf *bytes.Buffer)
  • Purpose: Encodes the ValueStruct into a bytes.Buffer. Avoids creating byte arrays per key-value pair.
    • Parameters:
      • buf: The bytes.Buffer to encode into.

Iterator​

type Iterator interface {
	Next()
	Rewind()
	Seek(key []byte)
	Key() []byte
	Value() ValueStruct
	Valid() bool
	Close() error
}
  • Purpose: Defines a basic iterator interface for key-value pairs.
    • Next(): Moves the iterator to the next key-value pair.
    • Rewind(): Resets the iterator to the beginning.
    • Seek(key []byte): Moves the iterator to the first key-value pair with a key equal to or greater than the provided key.
    • Key(): Returns the current key.
    • Value(): Returns the current ValueStruct.
    • Valid(): Indicates if the iterator is currently pointing to a valid key-value pair.
    • Close(): Closes the iterator and releases any associated resources.

Getting Started Relevance​