Package org.eclipse.mat.parser.index
Class IndexWriter.SizeIndexCollectorUncompressed
java.lang.Object
org.eclipse.mat.parser.index.IndexWriter.IntIndexCollectorUncompressed
org.eclipse.mat.parser.index.IndexWriter.SizeIndexCollectorUncompressed
- Enclosing class:
- IndexWriter
public static class IndexWriter.SizeIndexCollectorUncompressed
extends IndexWriter.IntIndexCollectorUncompressed
Store sizes of objects by
compressing the size to a 32-bit int.
- Since:
- 1.0
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Constructor Summary
ConstructorsConstructorDescriptionSizeIndexCollectorUncompressed(int size) Create a collector of the required size. -
Method Summary
Modifier and TypeMethodDescriptionstatic intcompress(long y) Cope with objects of size in bytes bigger than Integer.MAX_VALUE.static longexpand(int x) Expand the result of the compressionlonggetSize(int index) Get the expanded size.voidset(int index, long value) Set the size for an object.Store the collector to a file.Methods inherited from class org.eclipse.mat.parser.index.IndexWriter.IntIndexCollectorUncompressed
get, set
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Constructor Details
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SizeIndexCollectorUncompressed
public SizeIndexCollectorUncompressed(int size) Create a collector of the required size.- Parameters:
size- the number of entries
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Method Details
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compress
public static int compress(long y) Cope with objects of size in bytes bigger than Integer.MAX_VALUE. E.g. double[Integer.MAX_VALUE] The original problem was that the array to size mapping had an integer as the size (IntIndexCollectorUncompressed). This array would be approximately 0x18 + 0x8 * 0x7fffffff = 0x400000010 bytes, too big for an int. Expanding the array size array to longs could be overkill. Instead we do some simple compression - values 0 - 0x7fffffff convert as now, int values 0x80000000 to 0xffffffff convert to(n & 0x7fffffffL)*8 + 0x80000000L.- Parameters:
y- the long value in the range -1 to 0x7fffffff, 0x80000000L to 0x400000000L- Returns:
- the compressed value as an int
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expand
public static long expand(int x) Expand the result of the compression- Parameters:
x- the compressed value- Returns:
- the expanded value as a long in the range -1 to 0x7fffffff, 0x80000000L to 0x400000000L
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set
public void set(int index, long value) Set the size for an object.- Parameters:
index- the object IDvalue- the size
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getSize
public long getSize(int index) Get the expanded size.- Parameters:
index- the object ID- Returns:
- the size
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writeTo
Description copied from class:IndexWriter.IntIndexCollectorUncompressedStore the collector to a file.- Overrides:
writeToin classIndexWriter.IntIndexCollectorUncompressed- Parameters:
indexFile- the file- Returns:
- an index which holds the same values as the collector
- Throws:
IOException- if a problem occurred with the write
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