github.com/m3db/m3@v1.5.0/src/metrics/aggregation/id_compress.go (about)

     1  // Copyright (c) 2017 Uber Technologies, Inc.
     2  //
     3  // Permission is hereby granted, free of charge, to any person obtaining a copy
     4  // of this software and associated documentation files (the "Software"), to deal
     5  // in the Software without restriction, including without limitation the rights
     6  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
     7  // copies of the Software, and to permit persons to whom the Software is
     8  // furnished to do so, subject to the following conditions:
     9  //
    10  // The above copyright notice and this permission notice shall be included in
    11  // all copies or substantial portions of the Software.
    12  //
    13  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    14  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    15  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    16  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    17  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    18  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    19  // THE SOFTWARE.
    20  
    21  package aggregation
    22  
    23  import (
    24  	"fmt"
    25  
    26  	"github.com/willf/bitset"
    27  )
    28  
    29  // IDCompressor can compress Types into an ID.
    30  type IDCompressor interface {
    31  	// Compress compresses a set of aggregation types into an aggregation id.
    32  	Compress(aggTypes Types) (ID, error)
    33  
    34  	// MustCompress compresses a set of aggregation types into an aggregation id,
    35  	// and panics if an error is encountered.
    36  	MustCompress(aggTypes Types) ID
    37  }
    38  
    39  // IDDecompressor can decompress ID.
    40  type IDDecompressor interface {
    41  	// Decompress decompresses an aggregation id into a set of aggregation types.
    42  	Decompress(id ID) (Types, error)
    43  
    44  	// MustDecompress decompresses an aggregation id into a set of aggregation types,
    45  	// and panics if an error is encountered.
    46  	MustDecompress(id ID) Types
    47  }
    48  
    49  type idCompressor struct {
    50  	bs *bitset.BitSet
    51  }
    52  
    53  // NewIDCompressor returns a new IDCompressor.
    54  func NewIDCompressor() IDCompressor {
    55  	// NB(cw): If we start to support more than 64 types, the library will
    56  	// expand the underlying word list itself.
    57  	return &idCompressor{
    58  		bs: bitset.New(maxTypeID),
    59  	}
    60  }
    61  
    62  func (c *idCompressor) Compress(aggTypes Types) (ID, error) {
    63  	c.bs.ClearAll()
    64  	for _, aggType := range aggTypes {
    65  		if !aggType.IsValid() {
    66  			return DefaultID, fmt.Errorf("could not compress invalid Type %v", aggType)
    67  		}
    68  		c.bs.Set(uint(aggType.ID()))
    69  	}
    70  
    71  	codes := c.bs.Bytes()
    72  	var id ID
    73  	// NB(cw) it's guaranteed that len(id) == len(codes) == IDLen, we need to copy
    74  	// the words in bitset out because the bitset contains a slice internally.
    75  	for i := 0; i < IDLen; i++ {
    76  		id[i] = codes[i]
    77  	}
    78  	return id, nil
    79  }
    80  
    81  func (c *idCompressor) MustCompress(aggTypes Types) ID {
    82  	id, err := c.Compress(aggTypes)
    83  	if err != nil {
    84  		panic(fmt.Errorf("unable to compress %v: %v", aggTypes, err))
    85  	}
    86  	return id
    87  }
    88  
    89  type idDecompressor struct {
    90  	bs   *bitset.BitSet
    91  	buf  []uint64
    92  	pool TypesPool
    93  }
    94  
    95  // NewIDDecompressor returns a new IDDecompressor.
    96  func NewIDDecompressor() IDDecompressor {
    97  	return NewPooledIDDecompressor(nil)
    98  }
    99  
   100  // NewPooledIDDecompressor returns a new pooled TypeDecompressor.
   101  func NewPooledIDDecompressor(pool TypesPool) IDDecompressor {
   102  	bs := bitset.New(maxTypeID)
   103  	return &idDecompressor{
   104  		bs:   bs,
   105  		buf:  bs.Bytes(),
   106  		pool: pool,
   107  	}
   108  }
   109  
   110  func (d *idDecompressor) Decompress(id ID) (Types, error) {
   111  	if id.IsDefault() {
   112  		return DefaultTypes, nil
   113  	}
   114  	// NB(cw) it's guaranteed that len(c.buf) == len(id) == IDLen, we need to copy
   115  	// the words from id into a slice to be used in bitset.
   116  	for i := range id {
   117  		d.buf[i] = id[i]
   118  	}
   119  
   120  	var res Types
   121  	if d.pool == nil {
   122  		res = make(Types, 0, maxTypeID)
   123  	} else {
   124  		res = d.pool.Get()
   125  	}
   126  
   127  	for i, e := d.bs.NextSet(0); e; i, e = d.bs.NextSet(i + 1) {
   128  		aggType := Type(i)
   129  		if !aggType.IsValid() {
   130  			return DefaultTypes, fmt.Errorf("invalid Type: %s", aggType.String())
   131  		}
   132  
   133  		res = append(res, aggType)
   134  	}
   135  
   136  	return res, nil
   137  }
   138  
   139  func (d *idDecompressor) MustDecompress(id ID) Types {
   140  	aggTypes, err := d.Decompress(id)
   141  	if err != nil {
   142  		panic(fmt.Errorf("unable to decompress %v: %v", id, err))
   143  	}
   144  	return aggTypes
   145  }