mmapmodule.c

python s60 1.4.5版本的源代码

	{"move",	(PyCFunction) mmap_move_method,		1},
	{"read",	(PyCFunction) mmap_read_method,		1},
	{"read_byte",	(PyCFunction) mmap_read_byte_method,  	1},
	{"readline",	(PyCFunction) mmap_read_line_method,	1},
	{"resize",	(PyCFunction) mmap_resize_method,	1},
	{"seek",	(PyCFunction) mmap_seek_method,		1},
	{"size",	(PyCFunction) mmap_size_method,		1},
	{"tell",	(PyCFunction) mmap_tell_method,		1},
	{"write",	(PyCFunction) mmap_write_method,	1},
	{"write_byte",	(PyCFunction) mmap_write_byte_method,	1},
	{NULL,	   NULL}       /* sentinel */
};

/* Functions for treating an mmap'ed file as a buffer */

static int
mmap_buffer_getreadbuf(mmap_object *self, int index, const void **ptr)
{
	CHECK_VALID(-1);
	if ( index != 0 ) {
		PyErr_SetString(PyExc_SystemError,
				"Accessing non-existent mmap segment");
		return -1;
	}
	*ptr = self->data;
	return self->size;
}

static int
mmap_buffer_getwritebuf(mmap_object *self, int index, const void **ptr)
{  
	CHECK_VALID(-1);
	if ( index != 0 ) {
		PyErr_SetString(PyExc_SystemError,
				"Accessing non-existent mmap segment");
		return -1;
	}
	if (!is_writeable(self))
		return -1;
	*ptr = self->data;
	return self->size;
}

static int
mmap_buffer_getsegcount(mmap_object *self, int *lenp)
{
	CHECK_VALID(-1);
	if (lenp) 
		*lenp = self->size;
	return 1;
}

static int
mmap_buffer_getcharbuffer(mmap_object *self, int index, const void **ptr)
{
	if ( index != 0 ) {
		PyErr_SetString(PyExc_SystemError,
				"accessing non-existent buffer segment");
		return -1;
	}
	*ptr = (const char *)self->data;
	return self->size;
}

static PyObject *
mmap_object_getattr(mmap_object *self, char *name)
{
	return Py_FindMethod (mmap_object_methods, (PyObject *)self, name);
}

static int
mmap_length(mmap_object *self)
{
	CHECK_VALID(-1);
	return self->size;
}

static PyObject *
mmap_item(mmap_object *self, int i)
{
	CHECK_VALID(NULL);
	if (i < 0 || (size_t)i >= self->size) {
		PyErr_SetString(PyExc_IndexError, "mmap index out of range");
		return NULL;
	}
	return PyString_FromStringAndSize(self->data + i, 1);
}

static PyObject *
mmap_slice(mmap_object *self, int ilow, int ihigh)
{
	CHECK_VALID(NULL);
	if (ilow < 0)
		ilow = 0;
	else if ((size_t)ilow > self->size)
		ilow = self->size;
	if (ihigh < 0)
		ihigh = 0;
	if (ihigh < ilow)
		ihigh = ilow;
	else if ((size_t)ihigh > self->size)
		ihigh = self->size;
    
	return PyString_FromStringAndSize(self->data + ilow, ihigh-ilow);
}

static PyObject *
mmap_concat(mmap_object *self, PyObject *bb)
{
	CHECK_VALID(NULL);
	PyErr_SetString(PyExc_SystemError,
			"mmaps don't support concatenation");
	return NULL;
}

static PyObject *
mmap_repeat(mmap_object *self, int n)
{
	CHECK_VALID(NULL);
	PyErr_SetString(PyExc_SystemError,
			"mmaps don't support repeat operation");
	return NULL;
}

static int
mmap_ass_slice(mmap_object *self, int ilow, int ihigh, PyObject *v)
{
	const char *buf;

	CHECK_VALID(-1);
	if (ilow < 0)
		ilow = 0;
	else if ((size_t)ilow > self->size)
		ilow = self->size;
	if (ihigh < 0)
		ihigh = 0;
	if (ihigh < ilow)
		ihigh = ilow;
	else if ((size_t)ihigh > self->size)
		ihigh = self->size;
    
	if (v == NULL) {
		PyErr_SetString(PyExc_TypeError,
				"mmap object doesn't support slice deletion");
		return -1;
	}
	if (! (PyString_Check(v)) ) {
		PyErr_SetString(PyExc_IndexError, 
				"mmap slice assignment must be a string");
		return -1;
	}
	if ( PyString_Size(v) != (ihigh - ilow) ) {
		PyErr_SetString(PyExc_IndexError, 
				"mmap slice assignment is wrong size");
		return -1;
	}
	if (!is_writeable(self))
		return -1;
	buf = PyString_AsString(v);
	memcpy(self->data + ilow, buf, ihigh-ilow);
	return 0;
}

static int
mmap_ass_item(mmap_object *self, int i, PyObject *v)
{
	const char *buf;
 
	CHECK_VALID(-1);
	if (i < 0 || (size_t)i >= self->size) {
		PyErr_SetString(PyExc_IndexError, "mmap index out of range");
		return -1;
	}
	if (v == NULL) {
		PyErr_SetString(PyExc_TypeError,
				"mmap object doesn't support item deletion");
		return -1;
	}
	if (! (PyString_Check(v) && PyString_Size(v)==1) ) {
		PyErr_SetString(PyExc_IndexError, 
				"mmap assignment must be single-character string");
		return -1;
	}
	if (!is_writeable(self))
		return -1;
	buf = PyString_AsString(v);
	self->data[i] = buf[0];
	return 0;
}

static PySequenceMethods mmap_as_sequence = {
	(inquiry)mmap_length,		       /*sq_length*/
	(binaryfunc)mmap_concat,	       /*sq_concat*/
	(intargfunc)mmap_repeat,	       /*sq_repeat*/
	(intargfunc)mmap_item,		       /*sq_item*/
	(intintargfunc)mmap_slice,	       /*sq_slice*/
	(intobjargproc)mmap_ass_item,	       /*sq_ass_item*/
	(intintobjargproc)mmap_ass_slice,      /*sq_ass_slice*/
};

static PyBufferProcs mmap_as_buffer = {
	(getreadbufferproc)mmap_buffer_getreadbuf,
	(getwritebufferproc)mmap_buffer_getwritebuf,
	(getsegcountproc)mmap_buffer_getsegcount,
	(getcharbufferproc)mmap_buffer_getcharbuffer,
};

static PyTypeObject mmap_object_type = {
	PyObject_HEAD_INIT(0) /* patched in module init */
	0,					/* ob_size */
	"mmap.mmap",				/* tp_name */
	sizeof(mmap_object),			/* tp_size */
	0,					/* tp_itemsize */
	/* methods */
	(destructor) mmap_object_dealloc,	/* tp_dealloc */
	0,					/* tp_print */
	(getattrfunc) mmap_object_getattr,	/* tp_getattr */
	0,					/* tp_setattr */
	0,					/* tp_compare */
	0,					/* tp_repr */
	0,					/* tp_as_number */
	&mmap_as_sequence,			/*tp_as_sequence*/
	0,					/*tp_as_mapping*/
	0,					/*tp_hash*/
	0,					/*tp_call*/
	0,					/*tp_str*/
	0,					/*tp_getattro*/
	0,					/*tp_setattro*/
	&mmap_as_buffer,			/*tp_as_buffer*/
	Py_TPFLAGS_HAVE_GETCHARBUFFER,		/*tp_flags*/
	0,					/*tp_doc*/
};


/* extract the map size from the given PyObject

   The map size is restricted to [0, INT_MAX] because this is the current
   Python limitation on object sizes. Although the mmap object *could* handle
   a larger map size, there is no point because all the useful operations
   (len(), slicing(), sequence indexing) are limited by a C int.

   Returns -1 on error, with an appropriate Python exception raised. On
   success, the map size is returned. */
static int
_GetMapSize(PyObject *o)
{
	if (PyInt_Check(o)) {
		long i = PyInt_AsLong(o);
		if (PyErr_Occurred())
			return -1;
		if (i < 0)
			goto onnegoverflow;
		if (i > INT_MAX)
			goto onposoverflow;
		return (int)i;
	}
	else if (PyLong_Check(o)) {
		long i = PyLong_AsLong(o);
		if (PyErr_Occurred()) {
			/* yes negative overflow is mistaken for positive overflow
			   but not worth the trouble to check sign of 'i' */
			if (PyErr_ExceptionMatches(PyExc_OverflowError))
				goto onposoverflow;
			else
				return -1;
		}
		if (i < 0)
			goto onnegoverflow;
		if (i > INT_MAX)
			goto onposoverflow;
		return (int)i;
	}
	else {
		PyErr_SetString(PyExc_TypeError,
				"map size must be an integral value");
		return -1;
	}

  onnegoverflow:
	PyErr_SetString(PyExc_OverflowError,
			"memory mapped size must be positive");
	return -1;

  onposoverflow:
	PyErr_SetString(PyExc_OverflowError,
			"memory mapped size is too large (limited by C int)");
	return -1;
}

#ifdef UNIX 
static PyObject *
new_mmap_object(PyObject *self, PyObject *args, PyObject *kwdict)
{
#ifdef HAVE_FSTAT
	struct stat st;
#endif
	mmap_object *m_obj;
	PyObject *map_size_obj = NULL;
	int map_size;
	int fd, flags = MAP_SHARED, prot = PROT_WRITE | PROT_READ;
	access_mode access = ACCESS_DEFAULT;
	char *keywords[] = {"fileno", "length", 
			    "flags", "prot", 
			    "access", NULL};

	if (!PyArg_ParseTupleAndKeywords(args, kwdict, "iO|iii", keywords, 
					 &fd, &map_size_obj, &flags, &prot, &access))
		return NULL;
	map_size = _GetMapSize(map_size_obj);
	if (map_size < 0)
		return NULL;

	if ((access != ACCESS_DEFAULT) && 
	    ((flags != MAP_SHARED) || ( prot != (PROT_WRITE | PROT_READ))))
		return PyErr_Format(PyExc_ValueError, 
				    "mmap can't specify both access and flags, prot.");
	switch(access) {
	case ACCESS_READ:
		flags = MAP_SHARED;
		prot = PROT_READ;
		break;
	case ACCESS_WRITE:
		flags = MAP_SHARED;
		prot = PROT_READ | PROT_WRITE;
		break;
	case ACCESS_COPY:
		flags = MAP_PRIVATE;
		prot = PROT_READ | PROT_WRITE;
		break;
	case ACCESS_DEFAULT: 
		/* use the specified or default values of flags and prot */
		break;
	default:
		return PyErr_Format(PyExc_ValueError, 
				    "mmap invalid access parameter.");
	}

#ifdef HAVE_FSTAT
	if (fstat(fd, &st) == 0 && (size_t)map_size > st.st_size) {
		PyErr_SetString(PyExc_ValueError, 
				"mmap length is greater than file size");
		return NULL;
	}
#endif
	m_obj = PyObject_New (mmap_object, &mmap_object_type);
	if (m_obj == NULL) {return NULL;}
	m_obj->size = (size_t) map_size;
	m_obj->pos = (size_t) 0;
	m_obj->fd = fd;
	m_obj->data = mmap(NULL, map_size, 
			   prot, flags,
			   fd, 0);
	if (m_obj->data == (char *)-1) {
		Py_DECREF(m_obj);
		PyErr_SetFromErrno(mmap_module_error);
		return NULL;
	}
	m_obj->access = access;
	return (PyObject *)m_obj;
}
#endif /* UNIX */

#ifdef MS_WIN32
static PyObject *
new_mmap_object(PyObject *self, PyObject *args, PyObject *kwdict)
{
	mmap_object *m_obj;
	PyObject *map_size_obj = NULL;
	int map_size;
	char *tagname = "";
	DWORD dwErr = 0;
	int fileno;
	HANDLE fh = 0;
	access_mode   access = ACCESS_DEFAULT;
	DWORD flProtect, dwDesiredAccess;
	char *keywords[] = { "fileno", "length", 
			     "tagname", 
			     "access", NULL };

	if (!PyArg_ParseTupleAndKeywords(args, kwdict, "iO|zi", keywords,
					 &fileno, &map_size_obj, 
					 &tagname, &access)) {
		return NULL;
	}

	switch(access) {
	case ACCESS_READ:
		flProtect = PAGE_READONLY;
		dwDesiredAccess = FILE_MAP_READ;
		break;
	case ACCESS_DEFAULT:  case ACCESS_WRITE:
		flProtect = PAGE_READWRITE;
		dwDesiredAccess = FILE_MAP_WRITE;
		break;
	case ACCESS_COPY:
		flProtect = PAGE_WRITECOPY;
		dwDesiredAccess = FILE_MAP_COPY;
		break;
	default:
		return PyErr_Format(PyExc_ValueError, 
				    "mmap invalid access parameter.");
	}

	map_size = _GetMapSize(map_size_obj);
	if (map_size < 0)
		return NULL;
	
	/* if an actual filename has been specified */
	if (fileno != 0) {
		fh = (HANDLE)_get_osfhandle(fileno);
		if (fh==(HANDLE)-1) {
			PyErr_SetFromErrno(mmap_module_error);
			return NULL;
		}
		/* Win9x appears to need us seeked to zero */
		fseek(&_iob[fileno], 0, SEEK_SET);
	}

	m_obj = PyObject_New (mmap_object, &mmap_object_type);
	if (m_obj==NULL)
		return NULL;
	/* Set every field to an invalid marker, so we can safely
	   destruct the object in the face of failure */
	m_obj->data = NULL;
	m_obj->file_handle = INVALID_HANDLE_VALUE;
	m_obj->map_handle = INVALID_HANDLE_VALUE;
	m_obj->tagname = NULL;

	if (fh) {
		/* It is necessary to duplicate the handle, so the
		   Python code can close it on us */
		if (!DuplicateHandle(
			GetCurrentProcess(), /* source process handle */
			fh, /* handle to be duplicated */
			GetCurrentProcess(), /* target proc handle */
			(LPHANDLE)&m_obj->file_handle, /* result */
			0, /* access - ignored due to options value */
			FALSE, /* inherited by child processes? */
			DUPLICATE_SAME_ACCESS)) { /* options */
			dwErr = GetLastError();
			Py_DECREF(m_obj);
			PyErr_SetFromWindowsErr(dwErr);
			return NULL;
		}
		if (!map_size) {
			m_obj->size = GetFileSize (fh, NULL);
		} else {
			m_obj->size = map_size;
		}
	}
	else {
		m_obj->size = map_size;
	}

	/* set the initial position */
	m_obj->pos = (size_t) 0;

	/* set the tag name */
	if (tagname != NULL && *tagname != '\0') {
		m_obj->tagname = PyMem_Malloc(strlen(tagname)+1);
		if (m_obj->tagname == NULL) {
			PyErr_NoMemory();
			Py_DECREF(m_obj);
			return NULL;
		}
		strcpy(m_obj->tagname, tagname);
	}
	else
		m_obj->tagname = NULL;

	m_obj->access = access;
	m_obj->map_handle = CreateFileMapping (m_obj->file_handle,
					       NULL,
					       flProtect,
					       0,
					       m_obj->size,
					       m_obj->tagname);
	if (m_obj->map_handle != NULL) {
		m_obj->data = (char *) MapViewOfFile (m_obj->map_handle,
						      dwDesiredAccess,
						      0,
						      0,
						      0);
		if (m_obj->data != NULL) {
			return ((PyObject *) m_obj);
		} else {
			dwErr = GetLastError();
		}
	} else {
		dwErr = GetLastError();
	}
	Py_DECREF(m_obj);
	PyErr_SetFromWindowsErr(dwErr);
	return (NULL);
}
#endif /* MS_WIN32 */

/* List of functions exported by this module */
static struct PyMethodDef mmap_functions[] = {
	{"mmap",	(PyCFunction) new_mmap_object, 
	 METH_VARARGS|METH_KEYWORDS},
	{NULL,		NULL}	     /* Sentinel */
};

DL_EXPORT(void)
	initmmap(void)
{
	PyObject *dict, *module;

	/* Patch the object type */
	mmap_object_type.ob_type = &PyType_Type;

	module = Py_InitModule ("mmap", mmap_functions);
	dict = PyModule_GetDict (module);
	mmap_module_error = PyExc_EnvironmentError;
	Py_INCREF(mmap_module_error);
	PyDict_SetItemString (dict, "error", mmap_module_error);
#ifdef PROT_EXEC
	PyDict_SetItemString (dict, "PROT_EXEC", PyInt_FromLong(PROT_EXEC) );
#endif
#ifdef PROT_READ
	PyDict_SetItemString (dict, "PROT_READ", PyInt_FromLong(PROT_READ) );
#endif
#ifdef PROT_WRITE
	PyDict_SetItemString (dict, "PROT_WRITE", PyInt_FromLong(PROT_WRITE) );
#endif

#ifdef MAP_SHARED
	PyDict_SetItemString (dict, "MAP_SHARED", PyInt_FromLong(MAP_SHARED) );
#endif
#ifdef MAP_PRIVATE
	PyDict_SetItemString (dict, "MAP_PRIVATE",
			      PyInt_FromLong(MAP_PRIVATE) );
#endif
#ifdef MAP_DENYWRITE
	PyDict_SetItemString (dict, "MAP_DENYWRITE",
			      PyInt_FromLong(MAP_DENYWRITE) );
#endif
#ifdef MAP_EXECUTABLE
	PyDict_SetItemString (dict, "MAP_EXECUTABLE",
			      PyInt_FromLong(MAP_EXECUTABLE) );
#endif
#ifdef MAP_ANON
	PyDict_SetItemString (dict, "MAP_ANON", PyInt_FromLong(MAP_ANON) );
	PyDict_SetItemString (dict, "MAP_ANONYMOUS",
			      PyInt_FromLong(MAP_ANON) );
#endif

	PyDict_SetItemString (dict, "PAGESIZE",
			      PyInt_FromLong( (long)my_getpagesize() ) );

	PyDict_SetItemString (dict, "ACCESS_READ",	
			      PyInt_FromLong(ACCESS_READ));
	PyDict_SetItemString (dict, "ACCESS_WRITE", 
			      PyInt_FromLong(ACCESS_WRITE));
	PyDict_SetItemString (dict, "ACCESS_COPY",	
			      PyInt_FromLong(ACCESS_COPY));
}