github.com/vescale/zgraph@v0.0.0-20230410094002-959c02d50f95/codec/edge_key.go (about)

     1  // Copyright 2022 zGraph Authors. All rights reserved.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package codec
    16  
    17  import "errors"
    18  
    19  const (
    20  	incomingEdgeSep = 'i'
    21  	outgoingEdgeSep = 'o'
    22  )
    23  
    24  const EdgeKeyLen = 1 /*prefix*/ + 8 /*graphID*/ + 8 /*srcVertexID*/ + 1 /*edgeSep*/ + 8 /*dstVertexID*/
    25  
    26  // IncomingEdgeKey encodes the incoming edge key.
    27  //
    28  // The key format is: ${Prefix}${GraphID}${DstVertexID}${IncomingEdgeSep}${SrcVertexID}.
    29  func IncomingEdgeKey(graphID, srcVertexID, dstVertexID int64) []byte {
    30  	result := make([]byte, 0, EdgeKeyLen)
    31  	result = append(result, prefix...)
    32  	result = EncodeInt(result, graphID)
    33  	result = EncodeInt(result, dstVertexID)
    34  	result = append(result, incomingEdgeSep)
    35  	result = EncodeInt(result, srcVertexID)
    36  	return result
    37  }
    38  
    39  // ParseIncomingEdgeKey parse the incoming edge key.
    40  func ParseIncomingEdgeKey(key []byte) (graphID, srcVertexID, dstVertexID int64, err error) {
    41  	if len(key) < EdgeKeyLen {
    42  		return 0, 0, 0, errors.New("insufficient key length")
    43  	}
    44  	_, graphID, err = DecodeInt(key[len(prefix):])
    45  	if err != nil {
    46  		return
    47  	}
    48  	_, dstVertexID, err = DecodeInt(key[len(prefix)+8:])
    49  	if err != nil {
    50  		return
    51  	}
    52  	_, srcVertexID, err = DecodeInt(key[len(prefix)+8+8+1:])
    53  	return
    54  }
    55  
    56  // OutgoingEdgeKey encodes the outgoing edge key.
    57  //
    58  // The key format is: ${Prefix}${GraphID}${SrcVertexID}${outgoingEdgeSep}${DstVertexID}.
    59  func OutgoingEdgeKey(graphID, srcVertexID, dstVertexID int64) []byte {
    60  	result := make([]byte, 0, EdgeKeyLen)
    61  	result = append(result, prefix...)
    62  	result = EncodeInt(result, graphID)
    63  	result = EncodeInt(result, srcVertexID)
    64  	result = append(result, outgoingEdgeSep)
    65  	result = EncodeInt(result, dstVertexID)
    66  	return result
    67  }
    68  
    69  // ParseOutgoingEdgeKey parse the outgoing edge key.
    70  func ParseOutgoingEdgeKey(key []byte) (graphID, srcVertexID, dstVertexID int64, err error) {
    71  	if len(key) < EdgeKeyLen {
    72  		return 0, 0, 0, errors.New("insufficient key length")
    73  	}
    74  	_, graphID, err = DecodeInt(key[len(prefix):])
    75  	if err != nil {
    76  		return
    77  	}
    78  	_, srcVertexID, err = DecodeInt(key[len(prefix)+8:])
    79  	if err != nil {
    80  		return
    81  	}
    82  	_, dstVertexID, err = DecodeInt(key[len(prefix)+8+8+1:])
    83  	return
    84  }