/* SWIG (www.swig.org) interface file for the dbf interface of shapelib
*
* At the moment (Dec 2000) this file is only useful to generate Python
* bindings. Invoke swig as follows:
*
* swig -python -shadow dbflib.i
*
* to generate dbflib_wrap.c and dbflib.py. dbflib_wrap.c defines a
* bunch of Python-functions that wrap the appripriate dbflib functions
* and dbflib.py contains an object oriented wrapper around
* dbflib_wrap.c.
*
* This module defines one object type: DBFFile.
*/
/* this is the dbflib module */
%module dbflib
/* first a %{,%} block. These blocks are copied verbatim to the
* dbflib_wrap.c file and are not parsed by SWIG. This is the place to
* import headerfiles and define helper-functions that are needed by the
* automatically generated wrappers.
*/
%{
#include "shapefil.h"
/* Read one attribute from the dbf handle and return it as a new python object
*
* If an error occurs, set the appropriate Python exception and return
* NULL.
*
* Assume that the values of the record and field arguments are valid.
* The name argument will be passed to DBFGetFieldInfo as is and should
* thus be either NULL or a pointer to an array of at least 12 chars
*/
static PyObject *
do_read_attribute(DBFInfo * handle, int record, int field, char * name)
{
int type, width;
PyObject *value;
type = DBFGetFieldInfo(handle, field, name, &width, NULL);
/* For strings NULL and the empty string are indistinguishable
* in DBF files. We prefer empty strings instead for backwards
* compatibility reasons because older wrapper versions returned
* emtpy strings as empty strings.
*/
if (type != FTString && DBFIsAttributeNULL(handle, record, field))
{
value = Py_None;
Py_INCREF(value);
}
else
{
switch (type)
{
case FTString:
{
const char * temp = DBFReadStringAttribute(handle, record, field);
if (temp)
{
value = PyString_FromString(temp);
}
else
{
PyErr_Format(PyExc_IOError,
"Can't read value for row %d column %d",
record, field);
value = NULL;
}
break;
}
case FTInteger:
value = PyInt_FromLong(DBFReadIntegerAttribute(handle, record,
field));
break;
case FTDouble:
value = PyFloat_FromDouble(DBFReadDoubleAttribute(handle, record,
field));
break;
default:
PyErr_Format(PyExc_TypeError, "Invalid field data type %d",
type);
value = NULL;
}
}
if (!value)
return NULL;
return value;
}
/* the read_attribute method. Return the value of the given record and
* field as a python object of the appropriate type.
*
* In case of error, set a python exception and return NULL. Since that
* value will be returned to the python interpreter as is, the
* interpreter should recognize the exception.
*/
static PyObject *
DBFInfo_read_attribute(DBFInfo * handle, int record, int field)
{
if (record < 0 || record >= DBFGetRecordCount(handle))
{
PyErr_Format(PyExc_ValueError,
"record index %d out of bounds (record count: %d)",
record, DBFGetRecordCount(handle));
return NULL;
}
if (field < 0 || field >= DBFGetFieldCount(handle))
{
PyErr_Format(PyExc_ValueError,
"field index %d out of bounds (field count: %d)",
field, DBFGetFieldCount(handle));
return NULL;
}
return do_read_attribute(handle, record, field, NULL);
}
/* the read_record method. Return the record record as a dictionary with
* whose keys are the names of the fields, and their values as the
* appropriate Python type.
*
* In case of error, set a python exception and return NULL. Since that
* value will be returned to the python interpreter as is, the
* interpreter should recognize the exception.
*/
static PyObject *
DBFInfo_read_record(DBFInfo * handle, int record)
{
int num_fields;
int i;
int type, width;
char name[12];
PyObject *dict;
PyObject *value;
if (record < 0 || record >= DBFGetRecordCount(handle))
{
PyErr_Format(PyExc_ValueError,
"record index %d out of bounds (record count: %d)",
record, DBFGetRecordCount(handle));
return NULL;
}
dict = PyDict_New();
if (!dict)
return NULL;
num_fields = DBFGetFieldCount(handle);
for (i = 0; i < num_fields; i++)
{
value = do_read_attribute(handle, record, i, name);
if (!value)
goto fail;
PyDict_SetItemString(dict, name, value);
Py_DECREF(value);
}
return dict;
fail:
Py_XDECREF(dict);
return NULL;
}
/* the write_record method. Write the record record given wither as a
* dictionary or a sequence (i.e. a list or a tuple).
*
* If it's a dictionary the keys must be the names of the fields and
* their value must have a suitable type. Only the fields actually
* contained in the dictionary are written. Fields for which there's no
* item in the dict are not modified.
*
* If it's a sequence, all fields must be present in the right order.
*
* In case of error, set a python exception and return NULL. Since that
* value will be returned to the python interpreter as is, the
* interpreter should recognize the exception.
*
* The method is implemented with two c-functions, write_field to write
* a single field and DBFInfo_write_record as the front-end.
*/
/* write a single field of a record. */
static int
write_field(DBFHandle handle, int record, int field, int type,
PyObject * value)
{
char * string_value;
int int_value;
double double_value;
if (value == Py_None)
{
if (!DBFWriteNULLAttribute(handle, record, field))
{
PyErr_Format(PyExc_IOError,
"can't write NULL field %d of record %d",
field, record);
return 0;
}
}
else
{
switch (type)
{
case FTString:
string_value = PyString_AsString(value);
if (!string_value)
return 0;
if (!DBFWriteStringAttribute(handle, record, field, string_value))
{
PyErr_Format(PyExc_IOError,
"can't write field %d of record %d",
field, record);
return 0;
}
break;
case FTInteger:
int_value = PyInt_AsLong(value);
if (int_value == -1 && PyErr_Occurred())
return 0;
if (!DBFWriteIntegerAttribute(handle, record, field, int_value))
{
PyErr_Format(PyExc_IOError,
"can't write field %d of record %d",
field, record);
return 0;
}
break;
case FTDouble:
double_value = PyFloat_AsDouble(value);
if (double_value == -1 && PyErr_Occurred())
return 0;
if (!DBFWriteDoubleAttribute(handle, record, field, double_value))
{
PyErr_Format(PyExc_IOError,
"can't write field %d of record %d",
field, record);
return 0;
}
break;
default:
PyErr_Format(PyExc_TypeError, "Invalid field data type %d", type);
return 0;
}
}
return 1;
}
static
PyObject *
DBFInfo_write_record(DBFHandle handle, int record, PyObject *record_object)
{
int num_fields;
int i, length;
int type, width;
char name[12];
PyObject * value = NULL;
num_fields = DBFGetFieldCount(handle);
/* We used to use PyMapping_Check to test whether record_object is a
* dictionary like object instead of PySequence_Check to test
* whether it's a sequence. Unfortunately in Python 2.3
* PyMapping_Check returns true for lists and tuples too so the old
* approach doesn't work anymore.
*/
if (PySequence_Check(record_object))
{
/* It's a sequence object. Iterate through all items in the
* sequence and write them to the appropriate field.
*/
length = PySequence_Length(record_object);
if (length != num_fields)
{
PyErr_SetString(PyExc_TypeError,
"record must have one item for each field");
goto fail;
}
for (i = 0; i < length; i++)
{
type = DBFGetFieldInfo(handle, i, name, &width, NULL);
value = PySequence_GetItem(record_object, i);
if (value)
{
if (!write_field(handle, record, i, type, value))
goto fail;
Py_DECREF(value);
}
else
{
goto fail;
}
}
}
else
{
/* It's a dictionary-like object. Iterate over the names of the
* known fields and write the corresponding item
*/
for (i = 0; i < num_fields; i++)
{
type = DBFGetFieldInfo(handle, i, name, &width, NULL);
/* if the dictionary has the key name write that object to
* the appropriate field, other wise just clear the python
* exception and do nothing.
*/
value = PyMapping_GetItemString(record_object, name);
if (value)
{
if (!write_field(handle, record, i, type, value))
goto fail;
Py_DECREF(value);
}
else
{
PyErr_Clear();
}
}
}
Py_INCREF(Py_None);
return Py_None;
fail:
Py_XDECREF(value);
return NULL;
}
%}
/* The commit method implementation
*
* The method relies on the DBFUpdateHeader method which is not
* available in shapelib <= 1.2.10. setup.py defines
* HAVE_UPDATE_HEADER's value depending on whether the function is
* available in the shapelib version the code is compiled with.
*/
%{
static
void
DBFInfo_commit(DBFHandle handle)
{
#if HAVE_UPDATE_HEADER
DBFUpdateHeader(handle);
#endif
}
%}
/*
* The SWIG Interface definition.
*/
/* include some common SWIG type definitions and standard exception
handling code */
%include typemaps.i
%include exception.i
/* As for ShapeFile in shapelib.i, We define a new C-struct that holds
* the DBFHandle. This is mainly done so we can separate the close()
* method from the destructor but it also helps with exception handling.
*
* After the DBFFile has been opened or created the handle is not NULL.
* The close() method closes the file and sets handle to NULL as an
* indicator that the file has been closed.
*/
%{
typedef struct {
DBFHandle handle;
} DBFFile;
%}
/* The first argument to the DBFFile methods is a DBFFile pointer.
* We have to check whether handle is not NULL in most methods but not
* all. In the destructor and the close method, it's OK for handle to be
* NULL. We achieve this by checking whether the preprocessor macro
* NOCHECK_$name is defined. SWIG replaces $name with the name of the
* function for which the code is inserted. In the %{,%}-block below we
* define the macros for the destructor and the close() method.
*/
%typemap(python,check) DBFFile *{
%#ifndef NOCHECK_$name
if (!$target || !$target->handle)
SWIG_exception(SWIG_TypeError, "dbffile already closed");
%#endif
}
%{
#define NOCHECK_delete_DBFFile
#define NOCHECK_DBFFile_close
%}
/* An exception handle for the constructor and the module level open()
* and create() functions.
*
* Annoyingly, we *have* to put braces around the SWIG_exception()
* calls, at least in the python case, because of the way the macro is
* written. Of course, always putting braces around the branches of an
* if-statement is often considered good practice.
*/
%typemap(python,except) DBFFile * {
$function;
if (!$source)
{
SWIG_exception(SWIG_MemoryError, "no memory");
}
else if (!$source->handle)
{
SWIG_exception(SWIG_IOError, "$name failed");
}
}
/* Exception handler for the add_field method */
%typemap(python,except) int DBFFile_add_field {
$function;
if ($source < 0)
{
SWIG_exception(SWIG_RuntimeError, "add_field failed");
}
}
/* define and use some typemaps for the field_info() method whose
* C-implementation has three output parameters that are returned
* through pointers passed into the function. SWIG already has
* definitions for common types such as int* and we can use those for
* the last two parameters:
*/
%apply int * OUTPUT { int * output_width }
%apply int * OUTPUT { int * output_decimals }
/* the fieldname has to be defined manually: */
%typemap(python,ignore) char *fieldname_out(char temp[12]) {
$target = temp;
}
%typemap(python,argout) char *fieldname_out() {
PyObject * string = PyString_FromString($source);
$target = t_output_helper($target,string);
}
/*
* The SWIG-version of the DBFFile struct
*/
typedef struct
{
%addmethods {
DBFFile(const char *file, const char * mode = "rb") {
DBFFile * self = malloc(sizeof(DBFFile));
if (self)
self->handle = DBFOpen(file, mode);
return self;
}
~DBFFile() {
if (self->handle)
DBFClose(self->handle);
free(self);
}
void close() {
if (self->handle)
DBFClose(self->handle);
self->handle = NULL;
}
int field_count() {
return DBFGetFieldCount(self->handle);
}
int record_count() {
return DBFGetRecordCount(self->handle);
}
int field_info(int iField, char * fieldname_out,
int * output_width, int * output_decimals) {
return DBFGetFieldInfo(self->handle, iField, fieldname_out,
output_width, output_decimals);
}
PyObject * read_record(int record) {
return DBFInfo_read_record(self->handle, record);
}
PyObject * read_attribute(int record, int field) {
return DBFInfo_read_attribute(self->handle, record, field);
}
int add_field(const char * pszFieldName, DBFFieldType eType,
int nWidth, int nDecimals) {
return DBFAddField(self->handle, pszFieldName, eType, nWidth,
nDecimals);
}
PyObject *write_record(int record, PyObject *dict_or_sequence) {
return DBFInfo_write_record(self->handle, record,
dict_or_sequence);
}
void commit() {
DBFInfo_commit(self->handle);
}
/* Delete the commit method from the class if it doesn't have a
* real implementation.
*/
%pragma(python) addtomethod="__class__:if not dbflibc._have_commit: del commit"
/* The __del__ method generated by the old SWIG version we're
* tries to access self.thisown which may not be set at all when
* there was an exception during construction. Therefore we
* override it with our own version.
* FIXME: It would be better to upgrade to a newer SWIG version
* or to get rid of SWIG entirely.
*/
%pragma(python) addtoclass = "
def __del__(self,dbflibc=dbflibc):
if getattr(self, 'thisown', 0):
dbflibc.delete_DBFFile(self)
"
}
} DBFFile;
/*
* Two module level functions, open() and create() that correspond to
* DBFOpen and DBFCreate respectively. open() is equivalent to the
* DBFFile constructor.
*/
%{
DBFFile * open_DBFFile(const char * file, const char * mode)
{
DBFFile * self = malloc(sizeof(DBFFile));
if (self)
self->handle = DBFOpen(file, mode);
return self;
}
%}
%name(open) %new DBFFile * open_DBFFile(const char * file,
const char * mode = "rb");
%{
DBFFile * create_DBFFile(const char * file)
{
DBFFile * self = malloc(sizeof(DBFFile));
if (self)
self->handle = DBFCreate(file);
return self;
}
%}
%name(create) %new DBFFile * create_DBFFile(const char * file);
/* constant definitions copied from shapefil.h */
typedef enum {
FTString,
FTInteger,
FTDouble,
FTInvalid
} DBFFieldType;
/* Put the value of the HAVE_UPDATE_HEADER preprocessor macro into the
* wrapper so that the __class__ pragma above knows when to remove the
* commit method
*/
const int _have_commit = HAVE_UPDATE_HEADER;
