github.com/m3db/m3@v1.5.0/src/dbnode/encoding/annotation_holder.go (about)

     1  // Copyright (c) 2021 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 encoding
    22  
    23  import "github.com/m3db/m3/src/dbnode/ts"
    24  
    25  // annotationHolder holds annotations up to ts.OptimizedAnnotationLen bytes long within
    26  // inlined backing array, and only allocates a new byte slice for longer annotations.
    27  type annotationHolder struct {
    28  	inlineAnnotationBytes [ts.OptimizedAnnotationLen]byte
    29  	inlineAnnotationLen   int
    30  	allocatedAnnotation   ts.Annotation
    31  }
    32  
    33  func (a *annotationHolder) get() ts.Annotation {
    34  	if a.inlineAnnotationLen > 0 {
    35  		return a.inlineAnnotationBytes[:a.inlineAnnotationLen]
    36  	}
    37  
    38  	return a.allocatedAnnotation
    39  }
    40  
    41  func (a *annotationHolder) set(annotation ts.Annotation) {
    42  	if l := len(annotation); l <= len(a.inlineAnnotationBytes) {
    43  		copy(a.inlineAnnotationBytes[:l], annotation)
    44  		a.inlineAnnotationLen = l
    45  		a.allocatedAnnotation = nil
    46  		return
    47  	}
    48  
    49  	a.allocatedAnnotation = append(a.allocatedAnnotation[:0], annotation...)
    50  	a.inlineAnnotationLen = 0
    51  }
    52  
    53  func (a *annotationHolder) reset() {
    54  	a.inlineAnnotationLen = 0
    55  	a.allocatedAnnotation = nil
    56  }