python-clinic / Modules / _ctypes / ctypes.h

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#if defined (__SVR4) && defined (__sun)
#   include <alloca.h>

#ifndef MS_WIN32
#define max(a, b) ((a) > (b) ? (a) : (b))
#define min(a, b) ((a) < (b) ? (a) : (b))

#define PARAMFLAG_FIN 0x1
#define PARAMFLAG_FOUT 0x2

typedef struct tagPyCArgObject PyCArgObject;
typedef struct tagCDataObject CDataObject;
typedef PyObject *(* GETFUNC)(void *, Py_ssize_t size);
typedef PyObject *(* SETFUNC)(void *, PyObject *value, Py_ssize_t size);
typedef PyCArgObject *(* PARAMFUNC)(CDataObject *obj);

/* A default buffer in CDataObject, which can be used for small C types.  If
this buffer is too small, PyMem_Malloc will be called to create a larger one,
and this one is not used.

Making CDataObject a variable size object would be a better solution, but more
difficult in the presence of PyCFuncPtrObject.  Maybe later.
union value {
                char c[16];
                short s;
                int i;
                long l;
                float f;
                double d;
                PY_LONG_LONG ll;
                long double D;

  Hm. Are there CDataObject's which do not need the b_objects member?  In
  this case we probably should introduce b_flags to mark it as present...  If
  b_objects is not present/unused b_length is unneeded as well.

struct tagCDataObject {
    char *b_ptr;                /* pointer to memory block */
    int  b_needsfree;           /* need _we_ free the memory? */
    CDataObject *b_base;        /* pointer to base object or NULL */
    Py_ssize_t b_size;          /* size of memory block in bytes */
    Py_ssize_t b_length;        /* number of references we need */
    Py_ssize_t b_index;         /* index of this object into base's
                               b_object list */
    PyObject *b_objects;        /* dictionary of references we need to keep, or Py_None */
    union value b_value;

typedef struct {
    ffi_closure *pcl_write; /* the C callable, writeable */
    void *pcl_exec;         /* the C callable, executable */
    ffi_cif cif;
    int flags;
    PyObject *converters;
    PyObject *callable;
    PyObject *restype;
    SETFUNC setfunc;
    ffi_type *ffi_restype;
    ffi_type *atypes[1];
} CThunkObject;
extern PyTypeObject PyCThunk_Type;
#define CThunk_CheckExact(v)        ((v)->ob_type == &PyCThunk_Type)

typedef struct {
    /* First part identical to tagCDataObject */
    char *b_ptr;                /* pointer to memory block */
    int  b_needsfree;           /* need _we_ free the memory? */
    CDataObject *b_base;        /* pointer to base object or NULL */
    Py_ssize_t b_size;          /* size of memory block in bytes */
    Py_ssize_t b_length;        /* number of references we need */
    Py_ssize_t b_index;         /* index of this object into base's
                               b_object list */
    PyObject *b_objects;        /* list of references we need to keep */
    union value b_value;
    /* end of tagCDataObject, additional fields follow */

    CThunkObject *thunk;
    PyObject *callable;

    /* These two fields will override the ones in the type's stgdict if
       they are set */
    PyObject *converters;
    PyObject *argtypes;
    PyObject *restype;
    PyObject *checker;
    PyObject *errcheck;
#ifdef MS_WIN32
    int index;
    GUID *iid;
    PyObject *paramflags;
} PyCFuncPtrObject;

extern PyTypeObject PyCStgDict_Type;
#define PyCStgDict_CheckExact(v)            ((v)->ob_type == &PyCStgDict_Type)
#define PyCStgDict_Check(v)         PyObject_TypeCheck(v, &PyCStgDict_Type)

extern int PyCStructUnionType_update_stgdict(PyObject *fields, PyObject *type, int isStruct);
extern int PyType_stginfo(PyTypeObject *self, Py_ssize_t *psize, Py_ssize_t *palign, Py_ssize_t *plength);
extern int PyObject_stginfo(PyObject *self, Py_ssize_t *psize, Py_ssize_t *palign, Py_ssize_t *plength);

extern PyTypeObject PyCData_Type;
#define CDataObject_CheckExact(v)       ((v)->ob_type == &PyCData_Type)
#define CDataObject_Check(v)            PyObject_TypeCheck(v, &PyCData_Type)
#define _CDataObject_HasExternalBuffer(v)  ((v)->b_ptr != (char *)&(v)->b_value)

extern PyTypeObject PyCSimpleType_Type;
#define PyCSimpleTypeObject_CheckExact(v)       ((v)->ob_type == &PyCSimpleType_Type)
#define PyCSimpleTypeObject_Check(v)    PyObject_TypeCheck(v, &PyCSimpleType_Type)

extern PyTypeObject PyCField_Type;
extern struct fielddesc *_ctypes_get_fielddesc(const char *fmt);

extern PyObject *
PyCField_FromDesc(PyObject *desc, Py_ssize_t index,
                Py_ssize_t *pfield_size, int bitsize, int *pbitofs,
                Py_ssize_t *psize, Py_ssize_t *poffset, Py_ssize_t *palign,
                int pack, int is_big_endian);

extern PyObject *PyCData_AtAddress(PyObject *type, void *buf);
extern PyObject *PyCData_FromBytes(PyObject *type, char *data, Py_ssize_t length);

extern PyTypeObject PyCArrayType_Type;
extern PyTypeObject PyCArray_Type;
extern PyTypeObject PyCPointerType_Type;
extern PyTypeObject PyCPointer_Type;
extern PyTypeObject PyCFuncPtr_Type;
extern PyTypeObject PyCFuncPtrType_Type;
extern PyTypeObject PyCStructType_Type;

#define PyCArrayTypeObject_Check(v)     PyObject_TypeCheck(v, &PyCArrayType_Type)
#define ArrayObject_Check(v)            PyObject_TypeCheck(v, &PyCArray_Type)
#define PointerObject_Check(v)          PyObject_TypeCheck(v, &PyCPointer_Type)
#define PyCPointerTypeObject_Check(v)   PyObject_TypeCheck(v, &PyCPointerType_Type)
#define PyCFuncPtrObject_Check(v)               PyObject_TypeCheck(v, &PyCFuncPtr_Type)
#define PyCFuncPtrTypeObject_Check(v)   PyObject_TypeCheck(v, &PyCFuncPtrType_Type)
#define PyCStructTypeObject_Check(v)    PyObject_TypeCheck(v, &PyCStructType_Type)

extern PyObject *
PyCArrayType_from_ctype(PyObject *itemtype, Py_ssize_t length);

extern PyMethodDef _ctypes_module_methods[];

extern CThunkObject *_ctypes_alloc_callback(PyObject *callable,
                                           PyObject *converters,
                                           PyObject *restype,
                                           int flags);
/* a table entry describing a predefined ctypes type */
struct fielddesc {
    char code;
    SETFUNC setfunc;
    GETFUNC getfunc;
    ffi_type *pffi_type; /* always statically allocated */
    SETFUNC setfunc_swapped;
    GETFUNC getfunc_swapped;

typedef struct {
    Py_ssize_t offset;
    Py_ssize_t size;
    Py_ssize_t index;                   /* Index into CDataObject's
                                       object array */
    PyObject *proto;                    /* a type or NULL */
    GETFUNC getfunc;                    /* getter function if proto is NULL */
    SETFUNC setfunc;                    /* setter function if proto is NULL */
    int anonymous;
} CFieldObject;

/* A subclass of PyDictObject, used as the instance dictionary of ctypes
   metatypes */
typedef struct {
    PyDictObject dict;          /* first part identical to PyDictObject */
/* The size and align fields are unneeded, they are in ffi_type as well.  As
   an experiment shows, it's trivial to get rid of them, the only thing to
   remember is that in PyCArrayType_new the ffi_type fields must be filled in -
   so far it was unneeded because libffi doesn't support arrays at all
   (because they are passed as pointers to function calls anyway).  But it's
   too much risk to change that now, and there are other fields which doen't
   belong into this structure anyway.  Maybe in ctypes 2.0... (ctypes 2000?)
    Py_ssize_t size;            /* number of bytes */
    Py_ssize_t align;           /* alignment requirements */
    Py_ssize_t length;          /* number of fields */
    ffi_type ffi_type_pointer;
    PyObject *proto;            /* Only for Pointer/ArrayObject */
    SETFUNC setfunc;            /* Only for simple objects */
    GETFUNC getfunc;            /* Only for simple objects */
    PARAMFUNC paramfunc;

    /* Following fields only used by PyCFuncPtrType_Type instances */
    PyObject *argtypes;         /* tuple of CDataObjects */
    PyObject *converters;       /* tuple([t.from_param for t in argtypes]) */
    PyObject *restype;          /* CDataObject or NULL */
    PyObject *checker;
    int flags;                  /* calling convention and such */

    /* pep3118 fields, pointers neeed PyMem_Free */
    char *format;
    int ndim;
    Py_ssize_t *shape;
/*      Py_ssize_t *strides;    */ /* unused in ctypes */
/*      Py_ssize_t *suboffsets; */ /* unused in ctypes */

} StgDictObject;

 StgDictObject fields

 setfunc and getfunc is only set for simple data types, it is copied from the
 corresponding fielddesc entry.  These are functions to set and get the value
 in a memory block.
 They should probably by used by other types as well.

 proto is only used for Pointer and Array types - it points to the item type

 Probably all the magic ctypes methods (like from_param) should have C
 callable wrappers in the StgDictObject.  For simple data type, for example,
 the fielddesc table could have entries for C codec from_param functions or
 other methods as well, if a subtype overrides this method in Python at
 construction time, or assigns to it later, tp_setattro should update the
 StgDictObject function to a generic one.

 Currently, PyCFuncPtr types have 'converters' and 'checker' entries in their
 type dict.  They are only used to cache attributes from other entries, whihc
 is wrong.

 One use case is the .value attribute that all simple types have.  But some
 complex structures, like VARIANT, represent a single value also, and should
 have this attribute.

 Another use case is a _check_retval_ function, which is called when a ctypes
 type is used as return type of a function to validate and compute the return

 Common ctypes protocol:

  - setfunc: store a python value in a memory block
  - getfunc: convert data from a memory block into a python value

  - checkfunc: validate and convert a return value from a function call
  - toparamfunc: convert a python value into a function argument


/* May return NULL, but does not set an exception! */
extern StgDictObject *PyType_stgdict(PyObject *obj);

/* May return NULL, but does not set an exception! */
extern StgDictObject *PyObject_stgdict(PyObject *self);

extern int PyCStgDict_clone(StgDictObject *src, StgDictObject *dst);

typedef int(* PPROC)(void);

PyObject *_ctypes_callproc(PPROC pProc,
                    PyObject *arguments,
#ifdef MS_WIN32
                    IUnknown *pIUnk,
                    GUID *iid,
                    int flags,
                    PyObject *argtypes,
                    PyObject *restype,
                    PyObject *checker);

#define FUNCFLAG_CDECL   0x1


#define DICTFLAG_FINAL 0x1000

struct tagPyCArgObject {
    ffi_type *pffi_type;
    char tag;
    union {
        char c;
        char b;
        short h;
        int i;
        long l;
        PY_LONG_LONG q;
        long double D;
        double d;
        float f;
        void *p;
    } value;
    PyObject *obj;
    Py_ssize_t size; /* for the 'V' tag */

extern PyTypeObject PyCArg_Type;
#define PyCArg_CheckExact(v)        ((v)->ob_type == &PyCArg_Type)
extern PyCArgObject *PyCArgObject_new(void);

extern PyObject *
PyCData_get(PyObject *type, GETFUNC getfunc, PyObject *src,
          Py_ssize_t index, Py_ssize_t size, char *ptr);

extern int
PyCData_set(PyObject *dst, PyObject *type, SETFUNC setfunc, PyObject *value,
          Py_ssize_t index, Py_ssize_t size, char *ptr);

extern void _ctypes_extend_error(PyObject *exc_class, char *fmt, ...);

struct basespec {
    CDataObject *base;
    Py_ssize_t index;
    char *adr;

extern char basespec_string[];

extern ffi_type *_ctypes_get_ffi_type(PyObject *obj);

/* exception classes */
extern PyObject *PyExc_ArgError;

extern char *_ctypes_conversion_encoding;
extern char *_ctypes_conversion_errors;

#if defined(HAVE_WCHAR_H)

extern void _ctypes_free_closure(void *);
extern void *_ctypes_alloc_closure(void);

extern void _ctypes_add_traceback(char *, char *, int);

extern PyObject *PyCData_FromBaseObj(PyObject *type, PyObject *base, Py_ssize_t index, char *adr);
extern char *_ctypes_alloc_format_string(const char *prefix, const char *suffix);

extern int _ctypes_simple_instance(PyObject *obj);

extern PyObject *_ctypes_ptrtype_cache;
PyObject *_ctypes_get_errobj(int **pspace);

#ifdef MS_WIN32
extern PyObject *ComError;

 Local Variables:
 compile-command: "python -q build install --home ~"