Class GroupLayout

public List<MemoryLayout> memberLayouts()

Returns the member layouts associated with this group.

public String toString()

Returns a string representation of the object.

public boolean isStruct()

Is this group layout a struct?

public boolean isUnion()

Is this group layout a union?

public boolean equals(Object other)

Indicates whether some other object is "equal to" this one.

The equals method implements an equivalence relation on non-null object references:

• It is reflexive: for any non-null reference value x, x.equals(x) should return true.
• It is symmetric: for any non-null reference values x and y, x.equals(y) should return true if and only if y.equals(x) returns true.
• It is transitive: for any non-null reference values x, y, and z, if x.equals(y) returns true and y.equals(z) returns true, then x.equals(z) should return true.
• It is consistent: for any non-null reference values x and y, multiple invocations of x.equals(y) consistently return true or consistently return false, provided no information used in equals comparisons on the objects is modified.
• For any non-null reference value x, x.equals(null) should return false.

An equivalence relation partitions the elements it operates on into equivalence classes; all the members of an equivalence class are equal to each other. Members of an equivalence class are substitutable for each other, at least for some purposes.

public int hashCode()

Returns a hash code value for the object. This method is supported for the benefit of hash tables such as those provided by HashMap.

The general contract of hashCode is:

• Whenever it is invoked on the same object more than once during an execution of a Java application, the hashCode method must consistently return the same integer, provided no information used in equals comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application.
• If two objects are equal according to the equals method, then calling the hashCode method on each of the two objects must produce the same integer result.
• It is not required that if two objects are unequal according to the equals method, then calling the hashCode method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hash tables.

public Optional<DynamicConstantDesc<GroupLayout>> describeConstable()

Returns an Optional containing the nominal descriptor for this layout, if one can be constructed, or an empty Optional if one cannot be constructed.

public GroupLayout withName(String name)

Creates a new layout which features the desired layout name.

This is equivalent to the following code:

    withAttribute(LAYOUT_NAME, name);
 

public GroupLayout withBitAlignment(long alignmentBits)

Creates a new layout which features the desired alignment constraint.

public GroupLayout withAttribute(String name, Constable value)

Returns a new memory layout which features the same attributes as this layout, plus the newly specified attribute. If this layout already contains an attribute with the same name, the existing attribute value is overwritten in the returned layout.

public final Optional<String> name()

Return the name (if any) associated with this layout.

This is equivalent to the following code:

    attribute(LAYOUT_NAME).map(String.class::cast);
 

public Optional<Constable> attribute(String name)

Returns the attribute with the given name (if it exists).

public Stream<String> attributes()

Returns a stream of the attribute names associated with this layout.

public final long bitAlignment()

Returns the alignment constraint associated with this layout, expressed in bits. Layout alignment defines a power of two A which is the bit-wise alignment of the layout. If A <= 8 then A/8 is the number of bytes that must be aligned for any pointer that correctly points to this layout. Thus:

• A=8 means unaligned (in the usual sense), which is common in packets.
• A=64 means word aligned (on LP64), A=32 int aligned, A=16 short aligned, etc.
• A=512 is the most strict alignment required by the x86/SV ABI (for AVX-512 data).

If no explicit alignment constraint was set on this layout (see MemoryLayout.withBitAlignment(long)), then this method returns the natural alignment constraint (in bits) associated with this layout.

public boolean hasSize()

Does this layout have a specified size? A layout does not have a specified size if it is (or contains) a sequence layout whose size is unspecified (see SequenceLayout.elementCount()). Value layouts (see ValueLayout) and padding layouts (see MemoryLayout.paddingLayout(long)) always have a specified size, therefore this method always returns true in these cases.

public long bitSize()

Computes the layout size, in bits.

public boolean isPadding()

Is this a padding layout (e.g. a layout created from MemoryLayout.paddingLayout(long)) ?