github.com/m3db/m3@v1.5.0/src/x/generics/hashmap/byteskey/new_map.go (about)

     1  // Copyright (c) 2018 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 byteskey
    22  
    23  import (
    24  	"bytes"
    25  
    26  	"github.com/m3db/m3/src/x/pool"
    27  
    28  	"github.com/cespare/xxhash/v2"
    29  	"github.com/mauricelam/genny/generic"
    30  )
    31  
    32  // MapValue is the generic type that needs to be specified when generating.
    33  type MapValue generic.Type
    34  
    35  // MapOptions provides options used when created the map.
    36  type MapOptions struct {
    37  	InitialSize int
    38  	KeyCopyPool pool.BytesPool
    39  }
    40  
    41  // NewMap returns a new byte keyed map.
    42  func NewMap(opts MapOptions) *Map {
    43  	var (
    44  		copyFn     CopyFn
    45  		finalizeFn FinalizeFn
    46  	)
    47  	if pool := opts.KeyCopyPool; pool == nil {
    48  		copyFn = func(k []byte) []byte {
    49  			return append([]byte(nil), k...)
    50  		}
    51  	} else {
    52  		copyFn = func(k []byte) []byte {
    53  			keyLen := len(k)
    54  			pooled := pool.Get(keyLen)[:keyLen]
    55  			copy(pooled, k)
    56  			return pooled
    57  		}
    58  		finalizeFn = func(k []byte) {
    59  			pool.Put(k)
    60  		}
    61  	}
    62  	return mapAlloc(mapOptions{
    63  		hash: func(k []byte) MapHash {
    64  			return MapHash(xxhash.Sum64(k))
    65  		},
    66  		equals:      bytes.Equal,
    67  		copy:        copyFn,
    68  		finalize:    finalizeFn,
    69  		initialSize: opts.InitialSize,
    70  	})
    71  }