forked from vitessio/vitess
/
binarymd5.go
74 lines (64 loc) · 1.65 KB
/
binarymd5.go
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package vindexes
import (
"bytes"
"crypto/md5"
"fmt"
)
// BinaryMD5 is a vindex that hashes binary bits to a keyspace id.
type BinaryMD5 struct {
name string
}
// NewBinaryMD5 creates a new BinaryMD5.
func NewBinaryMD5(name string, _ map[string]string) (Vindex, error) {
return &BinaryMD5{name: name}, nil
}
// String returns the name of the vindex.
func (vind *BinaryMD5) String() string {
return vind.name
}
// Cost returns the cost as 1.
func (vind *BinaryMD5) Cost() int {
return 1
}
// Verify returns true if ids maps to ksids.
func (vind *BinaryMD5) Verify(_ VCursor, ids []interface{}, ksids [][]byte) (bool, error) {
if len(ids) != len(ksids) {
return false, fmt.Errorf("BinaryMD5_hash.Verify: length of ids %v doesn't match length of ksids %v", len(ids), len(ksids))
}
for rowNum := range ids {
data, err := binHashKey(ids[rowNum])
if err != nil {
return false, fmt.Errorf("BinaryMD5_hash.Verify: %v", err)
}
if bytes.Compare(data, ksids[rowNum]) != 0 {
return false, nil
}
}
return true, nil
}
// Map returns the corresponding keyspace id values for the given ids.
func (vind *BinaryMD5) Map(_ VCursor, ids []interface{}) ([][]byte, error) {
out := make([][]byte, 0, len(ids))
for _, id := range ids {
data, err := binHashKey(id)
if err != nil {
return nil, fmt.Errorf("BinaryMd5.Map :%v", err)
}
out = append(out, data)
}
return out, nil
}
func binHashKey(key interface{}) ([]byte, error) {
source, err := getBytes(key)
if err != nil {
return nil, err
}
return binHash(source), nil
}
func binHash(source []byte) []byte {
sum := md5.Sum(source)
return sum[:]
}
func init() {
Register("binary_md5", NewBinaryMD5)
}