diff options
Diffstat (limited to 'vendor/github.com/syndtr/goleveldb/leveldb/key.go')
-rw-r--r-- | vendor/github.com/syndtr/goleveldb/leveldb/key.go | 143 |
1 files changed, 143 insertions, 0 deletions
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/key.go b/vendor/github.com/syndtr/goleveldb/leveldb/key.go new file mode 100644 index 000000000..ad8f51ec8 --- /dev/null +++ b/vendor/github.com/syndtr/goleveldb/leveldb/key.go @@ -0,0 +1,143 @@ +// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com> +// All rights reserved. +// +// Use of this source code is governed by a BSD-style license that can be +// found in the LICENSE file. + +package leveldb + +import ( + "encoding/binary" + "fmt" + + "github.com/syndtr/goleveldb/leveldb/errors" + "github.com/syndtr/goleveldb/leveldb/storage" +) + +// ErrInternalKeyCorrupted records internal key corruption. +type ErrInternalKeyCorrupted struct { + Ikey []byte + Reason string +} + +func (e *ErrInternalKeyCorrupted) Error() string { + return fmt.Sprintf("leveldb: internal key %q corrupted: %s", e.Ikey, e.Reason) +} + +func newErrInternalKeyCorrupted(ikey []byte, reason string) error { + return errors.NewErrCorrupted(storage.FileDesc{}, &ErrInternalKeyCorrupted{append([]byte{}, ikey...), reason}) +} + +type keyType uint + +func (kt keyType) String() string { + switch kt { + case keyTypeDel: + return "d" + case keyTypeVal: + return "v" + } + return fmt.Sprintf("<invalid:%#x>", uint(kt)) +} + +// Value types encoded as the last component of internal keys. +// Don't modify; this value are saved to disk. +const ( + keyTypeDel = keyType(0) + keyTypeVal = keyType(1) +) + +// keyTypeSeek defines the keyType that should be passed when constructing an +// internal key for seeking to a particular sequence number (since we +// sort sequence numbers in decreasing order and the value type is +// embedded as the low 8 bits in the sequence number in internal keys, +// we need to use the highest-numbered ValueType, not the lowest). +const keyTypeSeek = keyTypeVal + +const ( + // Maximum value possible for sequence number; the 8-bits are + // used by value type, so its can packed together in single + // 64-bit integer. + keyMaxSeq = (uint64(1) << 56) - 1 + // Maximum value possible for packed sequence number and type. + keyMaxNum = (keyMaxSeq << 8) | uint64(keyTypeSeek) +) + +// Maximum number encoded in bytes. +var keyMaxNumBytes = make([]byte, 8) + +func init() { + binary.LittleEndian.PutUint64(keyMaxNumBytes, keyMaxNum) +} + +type internalKey []byte + +func makeInternalKey(dst, ukey []byte, seq uint64, kt keyType) internalKey { + if seq > keyMaxSeq { + panic("leveldb: invalid sequence number") + } else if kt > keyTypeVal { + panic("leveldb: invalid type") + } + + dst = ensureBuffer(dst, len(ukey)+8) + copy(dst, ukey) + binary.LittleEndian.PutUint64(dst[len(ukey):], (seq<<8)|uint64(kt)) + return internalKey(dst) +} + +func parseInternalKey(ik []byte) (ukey []byte, seq uint64, kt keyType, err error) { + if len(ik) < 8 { + return nil, 0, 0, newErrInternalKeyCorrupted(ik, "invalid length") + } + num := binary.LittleEndian.Uint64(ik[len(ik)-8:]) + seq, kt = uint64(num>>8), keyType(num&0xff) + if kt > keyTypeVal { + return nil, 0, 0, newErrInternalKeyCorrupted(ik, "invalid type") + } + ukey = ik[:len(ik)-8] + return +} + +func validInternalKey(ik []byte) bool { + _, _, _, err := parseInternalKey(ik) + return err == nil +} + +func (ik internalKey) assert() { + if ik == nil { + panic("leveldb: nil internalKey") + } + if len(ik) < 8 { + panic(fmt.Sprintf("leveldb: internal key %q, len=%d: invalid length", []byte(ik), len(ik))) + } +} + +func (ik internalKey) ukey() []byte { + ik.assert() + return ik[:len(ik)-8] +} + +func (ik internalKey) num() uint64 { + ik.assert() + return binary.LittleEndian.Uint64(ik[len(ik)-8:]) +} + +func (ik internalKey) parseNum() (seq uint64, kt keyType) { + num := ik.num() + seq, kt = uint64(num>>8), keyType(num&0xff) + if kt > keyTypeVal { + panic(fmt.Sprintf("leveldb: internal key %q, len=%d: invalid type %#x", []byte(ik), len(ik), kt)) + } + return +} + +func (ik internalKey) String() string { + if ik == nil { + return "<nil>" + } + + if ukey, seq, kt, err := parseInternalKey(ik); err == nil { + return fmt.Sprintf("%s,%s%d", shorten(string(ukey)), kt, seq) + } + return fmt.Sprintf("<invalid:%#x>", []byte(ik)) +} |