# Package com.jogamp.gluegen

JogAmp GlueGen Code Generator

See: Description

- Interface Summary
  Interface | Description
  --- | ---
  CodeGenUtils.EmissionCallback | A class that emits source code of some time when activated.
  CommentEmitter |
  GlueEmitter | Specifies the interface by which GlueGen requests glue code to be generated.
  GlueEmitterControls | Specifies the interface by which a GlueEmitter can request additional information from the glue generator.
  SymbolFilter | Provides a mechanism by which the GlueEmitter can look at all of the #defines, enum values and function symbols and perform certain filtering and processing which requires all of them to be visible simultaneously.

- Class Summary
  Class | Description
  --- | ---
  ArrayTypes | Convenience class containing the Class objects corresponding to arrays of various types (e.g., `ArrayTypes.booleanArrayClass` is the Class of Java type "boolean[]").
  CMethodBindingEmitter | Emits the C-side component of the Java<->C JNI binding.
  CMethodBindingEmitter.DefaultCommentEmitter | Class that emits a generic comment for CMethodBindingEmitters; the comment includes the C signature of the native method that is being bound by the emitter java method.
  CodeGenUtils |
  ConstantDefinition | Represents the definition of a constant which was provided either via a #define statement or through an enum definition.
  DebugEmitter | Debug emitter which prints the parsing results to standard output.
  FunctionEmitter |
  FunctionEmitter.EmissionModifier |
  GlueGen | Glue code generator for C functions and data structures.
  JavaConfiguration | Parses and provides access to the contents of .cfg files for the JavaEmitter.
  JavaEmitter |
  JavaMethodBindingEmitter | An emitter that emits only the interface for a Java<->C JNI binding.
  JavaType | Describes a java-side representation of a type that is used to represent the same data on both the Java-side and C-side during a JNI operation.
  Logging |
  MethodBinding | Represents the binding of a C function to a Java method.
  ReferencedStructs |
  TypeInfo | Utility class for handling Opaque directives for JavaEmitter.

- Enum Summary
  Enum | Description
  --- | ---
  JavaEmitter.EmissionStyle | Style of code emission.
  JavaEmitter.MethodAccess | Access control for emitted Java methods.

## Package com.jogamp.gluegen Description

## JogAmp GlueGen Code Generator

#### GlueGen Data Type Mapping

Gluegen has build-in types (terminal symbols) for:

type | java bits | native bits | type | signed | origin
--- | --- | --- | --- | --- | ---
|  | x32 | x64 |  |  |
void | 0 | 0 | 0 | void | void | ANSI-C
char | 8 | 8 | 8 | integer | any | ANSI-C
short | 16 | 16 | 16 | integer | any | ANSI-C
int | 32 | 32 | 32 | integer | any | ANSI-C
long | 64 | 32 | 321 | integer | any | ANSI-C - Windows
long | 64 | 32 | 64 | integer | any | ANSI-C - Unix
float | 32 | 32 | 32 | float | signed | ANSI-C
double | 64 | 64 | 64 | double | signed | ANSI-C
__int32 | 32 | 32 | 32 | integer | any | windows
__int64 | 64 | 64 | 64 | integer | any | windows
int8_t | 8 | 8 | 8 | integer | signed | stdint.h
uint8_t | 8 | 8 | 8 | integer | unsigned | stdint.h
int16_t | 16 | 16 | 16 | integer | signed | stdint.h
uint16_t | 16 | 16 | 16 | integer | unsigned | stdint.h
int32_t | 32 | 32 | 32 | integer | signed | stdint.h
uint32_t | 32 | 32 | 32 | integer | unsigned | stdint.h
int64_t | 64 | 64 | 64 | integer | signed | stdint.h
uint64_t | 64 | 64 | 64 | integer | unsigned | stdint.h
intptr_t | 64 | 32 | 64 | integer | signed | stdint.h
uintptr_t | 64 | 32 | 64 | integer | unsigned | stdint.h
ptrdiff_t | 64 | 32 | 64 | integer | signed | stddef.h
size_t | 64 | 32 | 64 | integer | unsigned | stddef.h
wchar_t | 32 | 32 | 32 | integer | signed | stddef.h

Warning: Try to avoid unspecified bit sized types, especially long, since it differs on Unix and Windows!
Notes:

1. Type long will result in broken code on Windows, since we don't differentiate the OS and it's bit size is ambiguous.
2. Anonymous void-pointer void* are mapped to NIO Buffer.
3. Pointers to pointer-size types like intptr_t*, uintptr_t*, ptrdiff_t* and size_t* are mapped to PointerBuffer, to reflect the architecture depending storage size.

#### GlueGen Internal Alignment for Compound Data

In general, depending on CPU and it's configuration (OS), alignment is set up for each type (char, short, int, long, ..).

Compounds (structures) are aligned naturally, i.e. their inner components are aligned
and are itself aligned to it's largest element.

See:

- Wikipedia Data Structure Alignment
- Wikipedia Data Structure Alignment - Padding
- Viva64 Data Alignment
- Apple: Darwin 64bit Porting - Data Type Size & Alignment

##### Simple alignment arithmetic

> remainder = offset % alignment

since alignment is a multiple of 2 `-> x % 2n == x & (2n - 1)`

> remainder = offset & ( alignment - 1 )

> padding = (remainder > 0) ? alignment - remainder : 0 ;
> aligned_offset = offset + padding ;

##### Type Size & Alignment for x86, x86_64, armv6l-32bit-eabi and Window(mingw/mingw64)

Runtime query is implemented as follows:

       typedef struct {
         char   fill;  // nibble one byte
                       // padding to align s1: padding_0
         type_t s1;    //
       } test_struct_type_t;

                 padding_0 = sizeof(test_struct_type_t) - sizeof(type_t) - sizeof(char) ;
       alignmentOf(type_t) = sizeof(test_struct_type_t) - sizeof(type_t) ;

type | 32 bits | 64 bits
--- | --- | ---
| size | alignment | size | alignment
char | 1 | 1 | 1 | 1
short | 2 | 2 | 2 | 2
int | 4 | 4 | 4 | 4
float | 4 | 4 | 4 | 4
long | 4 | 4 | 8†,4∗ | 8†,4∗
pointer | 4 | 4 | 8 | 8
long long | 8 | 4†,8∗+ | 8 | 8
double | 8 | 4†,8∗+ | 8 | 8
long double | 12†∗,8+,16- | 4†∗,8+,16- | 16 | 16

† Linux, Darwin
+armv7l-eabi
- MacOsX-32bit-gcc4
∗ Windows

#### GlueGen Platform Header Files

GlueGen provides convenient platform headers,
which can be included in your C header files for native compilation and GlueGen code generation.
Example:

       #include <gluegen_stdint.h>
       #include <gluegen_stddef.h>

       uint64_t test64;
       size_t size1;
       ptrdiff_t ptr1;

To compile this file you have to include the following folder to your compilers system includes, ie `-I`:

        gluegen/make/stub_includes/platform

To generate code for this file you have to include the following folder to your GlueGen `includeRefid` element:

        gluegen/make/stub_includes/gluegen

#### GlueGen Pre-Defined Macros

To identity a GlueGen code generation run, GlueGen defines the following macros:

         #define __GLUEGEN__ 2