codec_optimized.go

package bmdb

import (
	"errors"
)

var errShortBuffer = errors.New("short buffer for decode")

// DecodeIntoEntry decodes bytes produced by Entry.Encode into the provided Entry.
// It reuses backing arrays for Key and Value to minimize allocations.
func DecodeIntoEntry(b []byte, e *Entry) error {
	if e == nil {
		return errors.New("nil entry")
	}

	// Parse header/meta once and get header length
	headerLen, err := e.ParseMeta(b)
	if err != nil {
		return err
	}

	// Ensure payload length is sufficient
	payloadStart := int(headerLen)
	keyEnd := payloadStart + int(e.Meta.KeySize)
	valEnd := keyEnd + int(e.Meta.ValueSize)

	if len(b) < valEnd {
		return errShortBuffer
	}

	e.Key = append(e.Key[:0], b[payloadStart:keyEnd]...)
	e.Value = append(e.Value[:0], b[keyEnd:valEnd]...)

	return nil
}