java.lang.Object
- io.netty.buffer.SizeClasses

All Implemented Interfaces:

SizeClassesMetric
```
final class SizeClasses
extends java.lang.Object
implements SizeClassesMetric
```
SizeClasses requires pageShifts to be defined prior to inclusion, and it in turn defines:
LOG2_SIZE_CLASS_GROUP: Log of size class count for each size doubling. LOG2_MAX_LOOKUP_SIZE: Log of max size class in the lookup table. sizeClasses: Complete table of [index, log2Group, log2Delta, nDelta, isMultiPageSize, isSubPage, log2DeltaLookup] tuples. index: Size class index. log2Group: Log of group base size (no deltas added). log2Delta: Log of delta to previous size class. nDelta: Delta multiplier. isMultiPageSize: 'yes' if a multiple of the page size, 'no' otherwise. isSubPage: 'yes' if a subpage size class, 'no' otherwise. log2DeltaLookup: Same as log2Delta if a lookup table size class, 'no' otherwise.
nSubpages: Number of subpages size classes. nSizes: Number of size classes. nPSizes: Number of size classes that are multiples of pageSize. smallMaxSizeIdx: Maximum small size class index. lookupMaxClass: Maximum size class included in lookup table. log2NormalMinClass: Log of minimum normal size class.
The first size class and spacing are 1 << LOG2_QUANTUM. Each group has 1 << LOG2_SIZE_CLASS_GROUP of size classes. size = 1 << log2Group + nDelta * (1 << log2Delta) The first size class has an unusual encoding, because the size has to be split between group and delta*nDelta. If pageShift = 13, sizeClasses looks like this: (index, log2Group, log2Delta, nDelta, isMultiPageSize, isSubPage, log2DeltaLookup)
( 0, 4, 4, 0, no, yes, 4) ( 1, 4, 4, 1, no, yes, 4) ( 2, 4, 4, 2, no, yes, 4) ( 3, 4, 4, 3, no, yes, 4)
( 4, 6, 4, 1, no, yes, 4) ( 5, 6, 4, 2, no, yes, 4) ( 6, 6, 4, 3, no, yes, 4) ( 7, 6, 4, 4, no, yes, 4)
( 8, 7, 5, 1, no, yes, 5) ( 9, 7, 5, 2, no, yes, 5) ( 10, 7, 5, 3, no, yes, 5) ( 11, 7, 5, 4, no, yes, 5) ... ... ( 72, 23, 21, 1, yes, no, no) ( 73, 23, 21, 2, yes, no, no) ( 74, 23, 21, 3, yes, no, no) ( 75, 23, 21, 4, yes, no, no)
( 76, 24, 22, 1, yes, no, no)

Field Summary

Fields
Modifier and Type	Field	Description
`(package private) int`	`chunkSize`
`(package private) int`	`directMemoryCacheAlignment`
`private static int`	`LOG2_DELTA_LOOKUP_IDX`
`private static int`	`LOG2_MAX_LOOKUP_SIZE`
`(package private) static int`	`LOG2_QUANTUM`
`private static int`	`LOG2_SIZE_CLASS_GROUP`
`private static int`	`LOG2DELTA_IDX`
`private static int`	`LOG2GROUP_IDX`
`(package private) int`	`lookupMaxSize`
`private static int`	`NDELTA_IDX`
`private static byte`	`no`
`(package private) int`	`nPSizes`
`(package private) int`	`nSizes`
`(package private) int`	`nSubpages`
`private int[]`	`pageIdx2sizeTab`
`(package private) int`	`pageShifts`
`(package private) int`	`pageSize`
`private static int`	`PAGESIZE_IDX`
`private int[]`	`size2idxTab`
`private int[]`	`sizeIdx2sizeTab`
`(package private) int`	`smallMaxSizeIdx`
`private static int`	`SUBPAGE_IDX`
`private static byte`	`yes`

Constructor Summary

Constructors
Constructor Description

SizeClasses(int pageSize, int pageShifts, int chunkSize, int directMemoryCacheAlignment)

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`private static int`	`alignSizeIfNeeded(int size, int directMemoryCacheAlignment)`
`private static int`	`calculateSize(int log2Group, int nDelta, int log2Delta)`
`private static int[]`	`newIdx2SizeTab(short[][] sizeClasses, int nSizes, int directMemoryCacheAlignment)`
`private static int[]`	`newPageIdx2sizeTab(short[][] sizeClasses, int nSizes, int nPSizes, int directMemoryCacheAlignment)`
`private static int[]`	`newSize2idxTab(int lookupMaxSize, short[][] sizeClasses)`
`private static short[]`	`newSizeClass(int index, int log2Group, int log2Delta, int nDelta, int pageShifts)`
`int`	`normalizeSize(int size)`	Normalizes usable size that would result from allocating an object with the specified size and alignment.
`private static int`	`normalizeSizeCompute(int size)`
`long`	`pageIdx2size(int pageIdx)`	Computes size from lookup table according to pageIdx.
`long`	`pageIdx2sizeCompute(int pageIdx)`	Computes size according to pageIdx.
`int`	`pages2pageIdx(int pages)`	Normalizes request size up to the nearest pageSize class.
`private int`	`pages2pageIdxCompute(int pages, boolean floor)`
`int`	`pages2pageIdxFloor(int pages)`	Normalizes request size down to the nearest pageSize class.
`int`	`size2SizeIdx(int size)`	Normalizes request size up to the nearest size class.
`int`	`sizeIdx2size(int sizeIdx)`	Computes size from lookup table according to sizeIdx.
`int`	`sizeIdx2sizeCompute(int sizeIdx)`	Computes size according to sizeIdx.
`private static int`	`sizeOf(short[] sizeClass, int directMemoryCacheAlignment)`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - LOG2_QUANTUM
```
static final int LOG2_QUANTUM
```
    See Also:
    
    Constant Field Values
  - LOG2_SIZE_CLASS_GROUP
```
private static final int LOG2_SIZE_CLASS_GROUP
```
    See Also:
    
    Constant Field Values
  - LOG2_MAX_LOOKUP_SIZE
```
private static final int LOG2_MAX_LOOKUP_SIZE
```
    See Also:
    
    Constant Field Values
  - LOG2GROUP_IDX
```
private static final int LOG2GROUP_IDX
```
    See Also:
    
    Constant Field Values
  - LOG2DELTA_IDX
```
private static final int LOG2DELTA_IDX
```
    See Also:
    
    Constant Field Values
  - NDELTA_IDX
```
private static final int NDELTA_IDX
```
    See Also:
    
    Constant Field Values
  - PAGESIZE_IDX
```
private static final int PAGESIZE_IDX
```
    See Also:
    
    Constant Field Values
  - SUBPAGE_IDX
```
private static final int SUBPAGE_IDX
```
    See Also:
    
    Constant Field Values
  - LOG2_DELTA_LOOKUP_IDX
```
private static final int LOG2_DELTA_LOOKUP_IDX
```
    See Also:
    
    Constant Field Values
  - no
```
private static final byte no
```
    See Also:
    
    Constant Field Values
  - yes
```
private static final byte yes
```
    See Also:
    
    Constant Field Values
  - pageSize
```
final int pageSize
```
  - pageShifts
```
final int pageShifts
```
  - chunkSize
```
final int chunkSize
```
  - directMemoryCacheAlignment
```
final int directMemoryCacheAlignment
```
  - nSizes
```
final int nSizes
```
  - nSubpages
```
final int nSubpages
```
  - nPSizes
```
final int nPSizes
```
  - lookupMaxSize
```
final int lookupMaxSize
```
  - smallMaxSizeIdx
```
final int smallMaxSizeIdx
```
  - pageIdx2sizeTab
```
private final int[] pageIdx2sizeTab
```
  - sizeIdx2sizeTab
```
private final int[] sizeIdx2sizeTab
```
  - size2idxTab
```
private final int[] size2idxTab
```
- Constructor Detail
  - SizeClasses
```
SizeClasses(int pageSize,
            int pageShifts,
            int chunkSize,
            int directMemoryCacheAlignment)
```
- Method Detail
  - newSizeClass
```
private static short[] newSizeClass(int index,
                                    int log2Group,
                                    int log2Delta,
                                    int nDelta,
                                    int pageShifts)
```
  - newIdx2SizeTab
```
private static int[] newIdx2SizeTab(short[][] sizeClasses,
                                    int nSizes,
                                    int directMemoryCacheAlignment)
```
  - calculateSize
```
private static int calculateSize(int log2Group,
                                 int nDelta,
                                 int log2Delta)
```
  - sizeOf
```
private static int sizeOf(short[] sizeClass,
                          int directMemoryCacheAlignment)
```
  - newPageIdx2sizeTab
```
private static int[] newPageIdx2sizeTab(short[][] sizeClasses,
                                        int nSizes,
                                        int nPSizes,
                                        int directMemoryCacheAlignment)
```
  - newSize2idxTab
```
private static int[] newSize2idxTab(int lookupMaxSize,
                                    short[][] sizeClasses)
```
  - sizeIdx2size
```
public int sizeIdx2size(int sizeIdx)
```
    Description copied from interface: SizeClassesMetric
    
    Computes size from lookup table according to sizeIdx.
    
    Specified by:
    
    sizeIdx2size in interface SizeClassesMetric
    
    Returns:
    
    size
  - sizeIdx2sizeCompute
```
public int sizeIdx2sizeCompute(int sizeIdx)
```
    Description copied from interface: SizeClassesMetric
    
    Computes size according to sizeIdx.
    
    Specified by:
    
    sizeIdx2sizeCompute in interface SizeClassesMetric
    
    Returns:
    
    size
  - pageIdx2size
```
public long pageIdx2size(int pageIdx)
```
    Description copied from interface: SizeClassesMetric
    
    Computes size from lookup table according to pageIdx.
    
    Specified by:
    
    pageIdx2size in interface SizeClassesMetric
    
    Returns:
    
    size which is multiples of pageSize.
  - pageIdx2sizeCompute
```
public long pageIdx2sizeCompute(int pageIdx)
```
    Description copied from interface: SizeClassesMetric
    
    Computes size according to pageIdx.
    
    Specified by:
    
    pageIdx2sizeCompute in interface SizeClassesMetric
    
    Returns:
    
    size which is multiples of pageSize
  - size2SizeIdx
```
public int size2SizeIdx(int size)
```
    Description copied from interface: SizeClassesMetric
    
    Normalizes request size up to the nearest size class.
    
    Specified by:
    
    size2SizeIdx in interface SizeClassesMetric
    
    Parameters:
    
    size - request size
    
    Returns:
    
    sizeIdx of the size class
  - pages2pageIdx
```
public int pages2pageIdx(int pages)
```
    Description copied from interface: SizeClassesMetric
    
    Normalizes request size up to the nearest pageSize class.
    
    Specified by:
    
    pages2pageIdx in interface SizeClassesMetric
    
    Parameters:
    
    pages - multiples of pageSizes
    
    Returns:
    
    pageIdx of the pageSize class
  - pages2pageIdxFloor
```
public int pages2pageIdxFloor(int pages)
```
    Description copied from interface: SizeClassesMetric
    
    Normalizes request size down to the nearest pageSize class.
    
    Specified by:
    
    pages2pageIdxFloor in interface SizeClassesMetric
    
    Parameters:
    
    pages - multiples of pageSizes
    
    Returns:
    
    pageIdx of the pageSize class
  - pages2pageIdxCompute
```
private int pages2pageIdxCompute(int pages,
                                 boolean floor)
```
  - alignSizeIfNeeded
```
private static int alignSizeIfNeeded(int size,
                                     int directMemoryCacheAlignment)
```
  - normalizeSize
```
public int normalizeSize(int size)
```
    Description copied from interface: SizeClassesMetric
    
    Normalizes usable size that would result from allocating an object with the specified size and alignment.
    
    Specified by:
    
    normalizeSize in interface SizeClassesMetric
    
    Parameters:
    
    size - request size
    
    Returns:
    
    normalized size
  - normalizeSizeCompute
```
private static int normalizeSizeCompute(int size)
```

Class SizeClasses

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

LOG2_QUANTUM

LOG2_SIZE_CLASS_GROUP

LOG2_MAX_LOOKUP_SIZE

LOG2GROUP_IDX

LOG2DELTA_IDX

NDELTA_IDX

PAGESIZE_IDX

SUBPAGE_IDX

LOG2_DELTA_LOOKUP_IDX

no

yes

pageSize

pageShifts

chunkSize

directMemoryCacheAlignment

nSizes

nSubpages

nPSizes

lookupMaxSize

smallMaxSizeIdx

pageIdx2sizeTab

sizeIdx2sizeTab

size2idxTab

Constructor Detail

SizeClasses

Method Detail

newSizeClass

newIdx2SizeTab

calculateSize

sizeOf

newPageIdx2sizeTab

newSize2idxTab

sizeIdx2size

sizeIdx2sizeCompute

pageIdx2size

pageIdx2sizeCompute

size2SizeIdx

pages2pageIdx

pages2pageIdxFloor

pages2pageIdxCompute

alignSizeIfNeeded

normalizeSize

normalizeSizeCompute