Golang encoding.DecodeBytesAscending函数代码示例

// Addr returns the address for the key, used to lookup the range containing
// the key. In the normal case, this is simply the key's value. However, for
// local keys, such as transaction records, range-spanning binary tree node
// pointers, the address is the inner encoded key, with the local key prefix
// and the suffix and optional detail removed. This address unwrapping is
// performed repeatedly in the case of doubly-local keys. In this way, local
// keys address to the same range as non-local keys, but are stored separately
// so that they don't collide with user-space or global system keys.
//
// However, not all local keys are addressable in the global map. Only range
// local keys incorporating a range key (start key or transaction key) are
// addressable (e.g. range metadata and txn records). Range local keys
// incorporating the Range ID are not (e.g. abort cache entries, and range
// stats).
func Addr(k roachpb.Key) (roachpb.RKey, error) {
	if !bytes.HasPrefix(k, localPrefix) {
		return roachpb.RKey(k), nil
	}

	for {
		if bytes.HasPrefix(k, localStorePrefix) {
			return nil, errors.Errorf("store-local key %q is not addressable", k)
		}
		if bytes.HasPrefix(k, LocalRangeIDPrefix) {
			return nil, errors.Errorf("local range ID key %q is not addressable", k)
		}
		if !bytes.HasPrefix(k, LocalRangePrefix) {
			return nil, errors.Errorf("local key %q malformed; should contain prefix %q",
				k, LocalRangePrefix)
		}
		k = k[len(LocalRangePrefix):]
		var err error
		// Decode the encoded key, throw away the suffix and detail.
		if _, k, err = encoding.DecodeBytesAscending(k, nil); err != nil {
			return nil, err
		}
		if !bytes.HasPrefix(k, localPrefix) {
			break
		}
	}
	return roachpb.RKey(k), nil
}

// DecodeDataKey decodes a time series key into its components.
func DecodeDataKey(key roachpb.Key) (string, string, Resolution, int64, error) {
	// Detect and remove prefix.
	remainder := key
	if !bytes.HasPrefix(remainder, keyDataPrefix) {
		return "", "", 0, 0, util.Errorf("malformed time series data key %v: improper prefix", key)
	}
	remainder = remainder[len(keyDataPrefix):]

	// Decode series name.
	remainder, name, err := encoding.DecodeBytesAscending(remainder, nil)
	if err != nil {
		return "", "", 0, 0, err
	}
	// Decode resolution.
	remainder, resolutionInt, err := encoding.DecodeVarintAscending(remainder)
	if err != nil {
		return "", "", 0, 0, err
	}
	resolution := Resolution(resolutionInt)
	// Decode timestamp.
	remainder, timeslot, err := encoding.DecodeVarintAscending(remainder)
	if err != nil {
		return "", "", 0, 0, err
	}
	timestamp := timeslot * resolution.KeyDuration()
	// The remaining bytes are the source.
	source := remainder

	return string(name), string(source), resolution, timestamp, nil
}

func sequenceCacheKeyPrint(key roachpb.Key) string {
	b, id, err := encoding.DecodeBytesAscending([]byte(key), nil)
	if err != nil {
		return fmt.Sprintf("/%q/err:%v", key, err)
	}

	txnID, err := uuid.FromBytes(id)
	if err != nil {
		return fmt.Sprintf("/%q/err:%v", key, err)
	}

	if len(b) == 0 {
		return fmt.Sprintf("/%q", txnID)
	}

	b, epoch, err := encoding.DecodeUint32Descending(b)
	if err != nil {
		return fmt.Sprintf("/%q/err:%v", txnID, err)
	}

	_, seq, err := encoding.DecodeUint32Descending(b)
	if err != nil {
		return fmt.Sprintf("/%q/epoch:%d/err:%v", txnID, epoch, err)
	}

	return fmt.Sprintf("/%q/epoch:%d/seq:%d", txnID, epoch, seq)
}

// DecodeAbortCacheKey decodes the provided abort cache entry,
// returning the transaction ID.
func DecodeAbortCacheKey(key roachpb.Key, dest []byte) (*uuid.UUID, error) {
	// TODO(tschottdorf): redundant check.
	if !bytes.HasPrefix(key, LocalRangeIDPrefix) {
		return nil, util.Errorf("key %s does not have %s prefix", key, LocalRangeIDPrefix)
	}
	// Cut the prefix, the Range ID, and the infix specifier.
	b := key[len(LocalRangeIDPrefix):]
	b, _, err := encoding.DecodeUvarintAscending(b)
	if err != nil {
		return nil, err
	}
	b = b[1:]
	if !bytes.HasPrefix(b, LocalAbortCacheSuffix) {
		return nil, util.Errorf("key %s does not contain the abort cache suffix %s",
			key, LocalAbortCacheSuffix)
	}
	// Cut the abort cache suffix.
	b = b[len(LocalAbortCacheSuffix):]
	// Decode the id.
	b, idBytes, err := encoding.DecodeBytesAscending(b, dest)
	if err != nil {
		return nil, err
	}
	if len(b) > 0 {
		return nil, util.Errorf("key %q has leftover bytes after decode: %s; indicates corrupt key", key, b)
	}
	txnID, err := uuid.FromBytes(idBytes)
	return txnID, err
}

func abortCacheKeyPrint(key roachpb.Key) string {
	_, id, err := encoding.DecodeBytesAscending([]byte(key), nil)
	if err != nil {
		return fmt.Sprintf("/%q/err:%v", key, err)
	}

	txnID, err := uuid.FromBytes(id)
	if err != nil {
		return fmt.Sprintf("/%q/err:%v", key, err)
	}

	return fmt.Sprintf("/%q", txnID)
}

// DecodeRangeKey decodes the range key into range start key,
// suffix and optional detail (may be nil).
func DecodeRangeKey(key roachpb.Key) (startKey, suffix, detail roachpb.Key, err error) {
	if !bytes.HasPrefix(key, LocalRangePrefix) {
		return nil, nil, nil, errors.Errorf("key %q does not have %q prefix",
			key, LocalRangePrefix)
	}
	// Cut the prefix and the Range ID.
	b := key[len(LocalRangePrefix):]
	b, startKey, err = encoding.DecodeBytesAscending(b, nil)
	if err != nil {
		return nil, nil, nil, err
	}
	if len(b) < localSuffixLength {
		return nil, nil, nil, errors.Errorf("key %q does not have suffix of length %d",
			key, localSuffixLength)
	}
	// Cut the suffix.
	suffix = b[:localSuffixLength]
	detail = b[localSuffixLength:]
	return
}

// DecodeAbortCacheKey decodes the provided abort cache entry,
// returning the transaction ID.
func DecodeAbortCacheKey(key roachpb.Key, dest []byte) (*uuid.UUID, error) {
	_, _, suffix, detail, err := DecodeRangeIDKey(key)
	if err != nil {
		return nil, err
	}
	if !bytes.Equal(suffix, LocalAbortCacheSuffix) {
		return nil, errors.Errorf("key %s does not contain the abort cache suffix %s",
			key, LocalAbortCacheSuffix)
	}
	// Decode the id.
	detail, idBytes, err := encoding.DecodeBytesAscending(detail, dest)
	if err != nil {
		return nil, err
	}
	if len(detail) > 0 {
		return nil, errors.Errorf("key %q has leftover bytes after decode: %s; indicates corrupt key", key, detail)
	}
	txnID, err := uuid.FromBytes(idBytes)
	return txnID, err
}

// Addr returns the address for the key, used to lookup the range containing
// the key. In the normal case, this is simply the key's value. However, for
// local keys, such as transaction records, range-spanning binary tree node
// pointers, the address is the trailing suffix of the key, with the local key
// prefix removed. In this way, local keys address to the same range as
// non-local keys, but are stored separately so that they don't collide with
// user-space or global system keys.
//
// However, not all local keys are addressable in the global map. Only range
// local keys incorporating a range key (start key or transaction key) are
// addressable (e.g. range metadata and txn records). Range local keys
// incorporating the Range ID are not (e.g. sequence cache entries, and range
// stats).
//
// TODO(pmattis): Should KeyAddress return an error when the key is malformed?
func Addr(k roachpb.Key) roachpb.RKey {
	if k == nil {
		return nil
	}

	if !bytes.HasPrefix(k, localPrefix) {
		return roachpb.RKey(k)
	}
	if bytes.HasPrefix(k, LocalRangePrefix) {
		k = k[len(LocalRangePrefix):]
		_, k, err := encoding.DecodeBytesAscending(k, nil)
		if err != nil {
			panic(err)
		}
		return roachpb.RKey(k)
	}
	log.Fatalf("local key %q malformed; should contain prefix %q",
		k, LocalRangePrefix)
	return nil
}

func decodeSequenceCacheKey(key roachpb.Key, dest []byte) (*uuid.UUID, uint32, uint32, error) {
	// TODO(tschottdorf): redundant check.
	if !bytes.HasPrefix(key, keys.LocalRangeIDPrefix) {
		return nil, 0, 0, util.Errorf("key %s does not have %s prefix", key, keys.LocalRangeIDPrefix)
	}
	// Cut the prefix and the Range ID.
	b := key[len(keys.LocalRangeIDPrefix):]
	b, _, err := encoding.DecodeUvarintAscending(b)
	if err != nil {
		return nil, 0, 0, err
	}
	if !bytes.HasPrefix(b, keys.LocalSequenceCacheSuffix) {
		return nil, 0, 0, util.Errorf("key %s does not contain the sequence cache suffix %s",
			key, keys.LocalSequenceCacheSuffix)
	}
	// Cut the sequence cache suffix.
	b = b[len(keys.LocalSequenceCacheSuffix):]
	// Decode the id.
	b, idBytes, err := encoding.DecodeBytesAscending(b, dest)
	if err != nil {
		return nil, 0, 0, err
	}
	// Decode the epoch.
	b, epoch, err := encoding.DecodeUint32Descending(b)
	if err != nil {
		return nil, 0, 0, err
	}
	// Decode the sequence number.
	b, seq, err := encoding.DecodeUint32Descending(b)
	if err != nil {
		return nil, 0, 0, err
	}
	if len(b) > 0 {
		return nil, 0, 0, util.Errorf("key %q has leftover bytes after decode: %s; indicates corrupt key",
			key, b)
	}
	txnID, err := uuid.FromBytes(idBytes)
	return txnID, epoch, seq, err
}

// decodeDataKeySuffix decodes a time series key into its components.
func decodeDataKeySuffix(key roachpb.Key) (string, string, Resolution, int64, error) {
	// Decode series name.
	remainder, name, err := encoding.DecodeBytesAscending(key, nil)
	if err != nil {
		return "", "", 0, 0, err
	}
	// Decode resolution.
	remainder, resolutionInt, err := encoding.DecodeVarintAscending(remainder)
	if err != nil {
		return "", "", 0, 0, err
	}
	resolution := Resolution(resolutionInt)
	// Decode timestamp.
	remainder, timeslot, err := encoding.DecodeVarintAscending(remainder)
	if err != nil {
		return "", "", 0, 0, err
	}
	timestamp := timeslot * resolution.KeyDuration()
	// The remaining bytes are the source.
	source := remainder

	return string(name), string(source), resolution, timestamp, nil
}

// DecodeTableKey decodes a table key/value.
func DecodeTableKey(
	a *DatumAlloc, valType parser.Datum, key []byte, dir encoding.Direction,
) (parser.Datum, []byte, error) {
	if (dir != encoding.Ascending) && (dir != encoding.Descending) {
		return nil, nil, util.Errorf("invalid direction: %d", dir)
	}
	var isNull bool
	if key, isNull = encoding.DecodeIfNull(key); isNull {
		return parser.DNull, key, nil
	}
	var rkey []byte
	var err error
	switch valType.(type) {
	case *parser.DBool:
		var i int64
		if dir == encoding.Ascending {
			rkey, i, err = encoding.DecodeVarintAscending(key)
		} else {
			rkey, i, err = encoding.DecodeVarintDescending(key)
		}
		// No need to chunk allocate DBool as MakeDBool returns either
		// parser.DBoolTrue or parser.DBoolFalse.
		return parser.MakeDBool(parser.DBool(i != 0)), rkey, err
	case *parser.DInt:
		var i int64
		if dir == encoding.Ascending {
			rkey, i, err = encoding.DecodeVarintAscending(key)
		} else {
			rkey, i, err = encoding.DecodeVarintDescending(key)
		}
		return a.NewDInt(parser.DInt(i)), rkey, err
	case *parser.DFloat:
		var f float64
		if dir == encoding.Ascending {
			rkey, f, err = encoding.DecodeFloatAscending(key)
		} else {
			rkey, f, err = encoding.DecodeFloatDescending(key)
		}
		return a.NewDFloat(parser.DFloat(f)), rkey, err
	case *parser.DDecimal:
		var d *inf.Dec
		if dir == encoding.Ascending {
			rkey, d, err = encoding.DecodeDecimalAscending(key, nil)
		} else {
			rkey, d, err = encoding.DecodeDecimalDescending(key, nil)
		}
		dd := a.NewDDecimal(parser.DDecimal{})
		dd.Set(d)
		return dd, rkey, err
	case *parser.DString:
		var r string
		if dir == encoding.Ascending {
			rkey, r, err = encoding.DecodeUnsafeStringAscending(key, nil)
		} else {
			rkey, r, err = encoding.DecodeUnsafeStringDescending(key, nil)
		}
		return a.NewDString(parser.DString(r)), rkey, err
	case *parser.DBytes:
		var r []byte
		if dir == encoding.Ascending {
			rkey, r, err = encoding.DecodeBytesAscending(key, nil)
		} else {
			rkey, r, err = encoding.DecodeBytesDescending(key, nil)
		}
		return a.NewDBytes(parser.DBytes(r)), rkey, err
	case *parser.DDate:
		var t int64
		if dir == encoding.Ascending {
			rkey, t, err = encoding.DecodeVarintAscending(key)
		} else {
			rkey, t, err = encoding.DecodeVarintDescending(key)
		}
		return a.NewDDate(parser.DDate(t)), rkey, err
	case *parser.DTimestamp:
		var t time.Time
		if dir == encoding.Ascending {
			rkey, t, err = encoding.DecodeTimeAscending(key)
		} else {
			rkey, t, err = encoding.DecodeTimeDescending(key)
		}
		return a.NewDTimestamp(parser.DTimestamp{Time: t}), rkey, err
	case *parser.DTimestampTZ:
		var t time.Time
		if dir == encoding.Ascending {
			rkey, t, err = encoding.DecodeTimeAscending(key)
		} else {
			rkey, t, err = encoding.DecodeTimeDescending(key)
		}
		return a.NewDTimestampTZ(parser.DTimestampTZ{Time: t}), rkey, err
	case *parser.DInterval:
		var d duration.Duration
		if dir == encoding.Ascending {
			rkey, d, err = encoding.DecodeDurationAscending(key)
		} else {
			rkey, d, err = encoding.DecodeDurationDescending(key)
		}
		return a.NewDInterval(parser.DInterval{Duration: d}), rkey, err
	default:
		return nil, nil, util.Errorf("TODO(pmattis): decoded index key: %s", valType.Type())
//.........这里部分代码省略.........

func decodeTableKey(valType parser.Datum, key []byte, dir encoding.Direction) (
	parser.Datum, []byte, error) {
	if (dir != encoding.Ascending) && (dir != encoding.Descending) {
		return nil, nil, util.Errorf("invalid direction: %d", dir)
	}
	var isNull bool
	if key, isNull = encoding.DecodeIfNull(key); isNull {
		return parser.DNull, key, nil
	}
	var rkey []byte
	var err error
	switch valType.(type) {
	case parser.DBool:
		var i int64
		if dir == encoding.Ascending {
			rkey, i, err = encoding.DecodeVarintAscending(key)
		} else {
			rkey, i, err = encoding.DecodeVarintDescending(key)
		}
		return parser.DBool(i != 0), rkey, err
	case parser.DInt:
		var i int64
		if dir == encoding.Ascending {
			rkey, i, err = encoding.DecodeVarintAscending(key)
		} else {
			rkey, i, err = encoding.DecodeVarintDescending(key)
		}
		return parser.DInt(i), rkey, err
	case parser.DFloat:
		var f float64
		if dir == encoding.Ascending {
			rkey, f, err = encoding.DecodeFloatAscending(key, nil)
		} else {
			rkey, f, err = encoding.DecodeFloatDescending(key, nil)
		}
		return parser.DFloat(f), rkey, err
	case *parser.DDecimal:
		var d *inf.Dec
		if dir == encoding.Ascending {
			rkey, d, err = encoding.DecodeDecimalAscending(key, nil)
		} else {
			rkey, d, err = encoding.DecodeDecimalDescending(key, nil)
		}
		dd := &parser.DDecimal{}
		dd.Set(d)
		return dd, rkey, err
	case parser.DString:
		var r string
		if dir == encoding.Ascending {
			rkey, r, err = encoding.DecodeStringAscending(key, nil)
		} else {
			rkey, r, err = encoding.DecodeStringDescending(key, nil)
		}
		return parser.DString(r), rkey, err
	case parser.DBytes:
		var r []byte
		if dir == encoding.Ascending {
			rkey, r, err = encoding.DecodeBytesAscending(key, nil)
		} else {
			rkey, r, err = encoding.DecodeBytesDescending(key, nil)
		}
		return parser.DBytes(r), rkey, err
	case parser.DDate:
		var t int64
		if dir == encoding.Ascending {
			rkey, t, err = encoding.DecodeVarintAscending(key)
		} else {
			rkey, t, err = encoding.DecodeVarintDescending(key)
		}
		return parser.DDate(t), rkey, err
	case parser.DTimestamp:
		var t time.Time
		if dir == encoding.Ascending {
			rkey, t, err = encoding.DecodeTimeAscending(key)
		} else {
			rkey, t, err = encoding.DecodeTimeDescending(key)
		}
		return parser.DTimestamp{Time: t}, rkey, err
	case parser.DInterval:
		var d int64
		if dir == encoding.Ascending {
			rkey, d, err = encoding.DecodeVarintAscending(key)
		} else {
			rkey, d, err = encoding.DecodeVarintDescending(key)
		}
		return parser.DInterval{Duration: time.Duration(d)}, rkey, err
	default:
		return nil, nil, util.Errorf("TODO(pmattis): decoded index key: %s", valType.Type())
	}
}