validate canons without yatest_common

1 files changed, 89 insertions, 0 deletions

diff --git a/library/go/blockcodecs/codecs.go b/library/go/blockcodecs/codecs.go
new file mode 100644
index 00000000000..b45bda6d616
--- /dev/null
+++ b/library/go/blockcodecs/codecs.go
@@ -0,0 +1,89 @@
+package blockcodecs
+
+import (
+	"encoding/binary"
+	"fmt"
+	"sync"
+
+	"go.uber.org/atomic"
+)
+
+type CodecID uint16
+
+type Codec interface {
+	ID() CodecID
+	Name() string
+
+	DecodedLen(in []byte) (int, error)
+	Encode(dst, src []byte) ([]byte, error)
+	Decode(dst, src []byte) ([]byte, error)
+}
+
+var (
+	codecsByID   sync.Map
+	codecsByName sync.Map
+)
+
+// Register new codec.
+//
+// NOTE: update FindCodecByName description, after adding new codecs.
+func Register(c Codec) {
+	if _, duplicate := codecsByID.LoadOrStore(c.ID(), c); duplicate {
+		panic(fmt.Sprintf("codec with id %d is already registered", c.ID()))
+	}
+
+	RegisterAlias(c.Name(), c)
+}
+
+func RegisterAlias(name string, c Codec) {
+	if _, duplicate := codecsByName.LoadOrStore(name, c); duplicate {
+		panic(fmt.Sprintf("codec with name %s is already registered", c.Name()))
+	}
+}
+
+func ListCodecs() []Codec {
+	var c []Codec
+	codecsByID.Range(func(key, value interface{}) bool {
+		c = append(c, value.(Codec))
+		return true
+	})
+	return c
+}
+
+func FindCodec(id CodecID) Codec {
+	c, ok := codecsByID.Load(id)
+	if ok {
+		return c.(Codec)
+	} else {
+		return nil
+	}
+}
+
+// FindCodecByName returns codec by name.
+//
+// Possible names:
+//
+//	null
+//	snappy
+//	zstd08_{level} - level is integer 1, 3 or 7.
+//	zstd_{level} - level is integer 1, 3 or 7.
+func FindCodecByName(name string) Codec {
+	c, ok := codecsByName.Load(name)
+	if ok {
+		return c.(Codec)
+	} else {
+		return nil
+	}
+}
+
+var (
+	maxDecompressedBlockSize = atomic.NewInt32(16 << 20) // 16 MB
+)
+
+func DecodedLen(in []byte) (int, error) {
+	if len(in) < 8 {
+		return 0, fmt.Errorf("short block: %d < 8", len(in))
+	}
+
+	return int(binary.LittleEndian.Uint64(in[:8])), nil
+}