github.com/m3db/m3@v1.5.0/src/x/generics/hashmap/idkey/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 idkey
    22  
    23  import (
    24  	"github.com/m3db/m3/src/x/ident"
    25  	"github.com/m3db/m3/src/x/pool"
    26  
    27  	"github.com/cespare/xxhash/v2"
    28  	"github.com/mauricelam/genny/generic"
    29  )
    30  
    31  // MapValue is the generic type that needs to be specified when generating.
    32  type MapValue generic.Type
    33  
    34  // MapOptions provides options used when created the map.
    35  type MapOptions struct {
    36  	InitialSize int
    37  	KeyCopyPool pool.BytesPool
    38  }
    39  
    40  // NewMap returns a new byte keyed map.
    41  func NewMap(opts MapOptions) *Map {
    42  	var (
    43  		copyFn     CopyFn
    44  		finalizeFn FinalizeFn
    45  	)
    46  	if pool := opts.KeyCopyPool; pool == nil {
    47  		copyFn = func(k ident.ID) ident.ID {
    48  			return ident.BytesID(append([]byte(nil), k.Bytes()...))
    49  		}
    50  	} else {
    51  		copyFn = func(k ident.ID) ident.ID {
    52  			bytes := k.Bytes()
    53  			keyLen := len(bytes)
    54  			pooled := pool.Get(keyLen)[:keyLen]
    55  			copy(pooled, bytes)
    56  			return ident.BytesID(pooled)
    57  		}
    58  		finalizeFn = func(k ident.ID) {
    59  			if slice, ok := k.(ident.BytesID); ok {
    60  				pool.Put(slice)
    61  			}
    62  		}
    63  	}
    64  	return mapAlloc(mapOptions{
    65  		hash: func(id ident.ID) MapHash {
    66  			return MapHash(xxhash.Sum64(id.Bytes()))
    67  		},
    68  		equals: func(x, y ident.ID) bool {
    69  			return x.Equal(y)
    70  		},
    71  		copy:        copyFn,
    72  		finalize:    finalizeFn,
    73  		initialSize: opts.InitialSize,
    74  	})
    75  }