README
¶
CDB golang implementation
cdb is a fast, reliable, simple package for creating and reading constant databases see docs for more details
Advantages
- Iterator support
- Thread safe for reading
- Lazily key, value reading using io.SectionReader
- Buffered disc write
Example
f, _ := os.Create("test.cdb")
defer f.Close()
handle := cdb.New()
data := []struct {
key, value string
}{
{"key1", "value1"},
{"key2", "value2"},
{"key3", "value3"},
{"key4", "value4"},
{"key5", "value5"},
{"key6", "value6"},
{"key7", "value7"},
}
writer, err := handle.GetWriter(f)
if err != nil {
t.Error(err)
}
for _, c := range data {
writer.Put([]byte(c.key), []byte(c.value))
}
writer.Close()
reader, _ := handle.GetReader(f)
for _, c := range data {
value, err := reader.Get([]byte(c.key))
}
Documentation
¶
Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
Types ¶
type CDB ¶
type CDB struct {
Hasher
}
CDB is an associative array: it maps strings (“keys”) to strings (“data”).
func (*CDB) GetWriter ¶
func (cdb *CDB) GetWriter(writer io.WriteSeeker) (Writer, error)
GetWriter returns new Writer object.
func (*CDB) SetHash ¶
SetHash tells cdb to use given hash function for calculations. Given hash will be used only for new instances of Reader, Writer, i.e.
h := cdb.New() h.GetWriter(f) ... do some work ( here we use default Hasher ) h.SetHash(fnv.Hash32) h.GetReader(f) - only new instances will be use fnv.Hash32
type Iterator ¶
type Iterator interface {
// Next moves iterator to the next record. Returns true on success otherwise false.
Next() (bool, error)
// Record returns record on which points given iterator.
Record() Record
// HasNext tells can iterator be moved to the next record.
HasNext() bool
}
Iterator provides API for walking through database's records. Do not share object between multiple goroutines.
type Reader ¶
type Reader interface {
// Get returns first value associated with given key or returns nil if there is no associations.
Get(key []byte) ([]byte, error)
// Has returns true if given key exists, otherwise returns false.
Has(key []byte) (bool, error)
// Iterator returns new Iterator object that points on first record.
Iterator() (Iterator, error)
// IteratorAt returns new Iterator object that points on first record associated with given key.
IteratorAt(key []byte) (Iterator, error)
// Size returns the size of the dataset
Size() int
}
Reader provides API for getting values by given keys. All methods are thread safe.
type Record ¶
type Record interface {
// Key returns io.Reader with given record's key and key size.
Key() (io.Reader, uint32)
// Value returns io.Reader with given record's value and value size.
Value() (io.Reader, uint32)
}
Record provides API for reading record key, value. Do not share object between multiple goroutines.
Source Files
Directories