_dbmmodule.c 10.1 KB
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/* DBM module using dictionary interface */


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#define PY_SSIZE_T_CLEAN
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#include "Python.h"
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#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
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/* Some Linux systems install gdbm/ndbm.h, but not ndbm.h.  This supports
 * whichever configure was able to locate.
 */
#if defined(HAVE_NDBM_H)
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#include <ndbm.h>
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#if defined(PYOS_OS2) && !defined(PYCC_GCC)
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static char *which_dbm = "ndbm";
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#else
static char *which_dbm = "GNU gdbm";  /* EMX port of GDBM */
#endif
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#elif defined(HAVE_GDBM_NDBM_H)
#include <gdbm/ndbm.h>
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static char *which_dbm = "GNU gdbm";
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#elif defined(HAVE_GDBM_DASH_NDBM_H)
#include <gdbm-ndbm.h>
static char *which_dbm = "GNU gdbm";
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#elif defined(HAVE_BERKDB_H)
#include <db.h>
static char *which_dbm = "Berkeley DB";
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#else
#error "No ndbm.h available!"
#endif
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typedef struct {
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	PyObject_HEAD
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	int di_size;	/* -1 means recompute */
	DBM *di_dbm;
} dbmobject;

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static PyTypeObject Dbmtype;
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#define is_dbmobject(v) (Py_TYPE(v) == &Dbmtype)
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#define check_dbmobject_open(v) if ((v)->di_dbm == NULL) \
               { PyErr_SetString(DbmError, "DBM object has already been closed"); \
                 return NULL; }
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static PyObject *DbmError;
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static PyObject *
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newdbmobject(char *file, int flags, int mode)
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{
        dbmobject *dp;

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	dp = PyObject_New(dbmobject, &Dbmtype);
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	if (dp == NULL)
		return NULL;
	dp->di_size = -1;
	if ( (dp->di_dbm = dbm_open(file, flags, mode)) == 0 ) {
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		PyErr_SetFromErrno(DbmError);
		Py_DECREF(dp);
		return NULL;
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	}
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	return (PyObject *)dp;
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}

/* Methods */

static void
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dbm_dealloc(register dbmobject *dp)
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{
        if ( dp->di_dbm )
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		dbm_close(dp->di_dbm);
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	PyObject_Del(dp);
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}

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static Py_ssize_t
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dbm_length(dbmobject *dp)
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{
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        if (dp->di_dbm == NULL) {
                 PyErr_SetString(DbmError, "DBM object has already been closed"); 
                 return -1; 
        }
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        if ( dp->di_size < 0 ) {
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		datum key;
		int size;

		size = 0;
		for ( key=dbm_firstkey(dp->di_dbm); key.dptr;
		      key = dbm_nextkey(dp->di_dbm))
			size++;
		dp->di_size = size;
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	}
	return dp->di_size;
}

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static PyObject *
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dbm_subscript(dbmobject *dp, register PyObject *key)
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{
	datum drec, krec;
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	Py_ssize_t tmp_size;
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	if (!PyArg_Parse(key, "s#", &krec.dptr, &tmp_size) )
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		return NULL;
	
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	krec.dsize = tmp_size;
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        check_dbmobject_open(dp);
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	drec = dbm_fetch(dp->di_dbm, krec);
	if ( drec.dptr == 0 ) {
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		PyErr_SetObject(PyExc_KeyError, key);
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		return NULL;
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	}
	if ( dbm_error(dp->di_dbm) ) {
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		dbm_clearerr(dp->di_dbm);
		PyErr_SetString(DbmError, "");
		return NULL;
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	}
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	return PyBytes_FromStringAndSize(drec.dptr, drec.dsize);
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}

static int
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dbm_ass_sub(dbmobject *dp, PyObject *v, PyObject *w)
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{
        datum krec, drec;
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	Py_ssize_t tmp_size;
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        if ( !PyArg_Parse(v, "s#", &krec.dptr, &tmp_size) ) {
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		PyErr_SetString(PyExc_TypeError,
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				"dbm mappings have bytes or string keys only");
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		return -1;
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	}
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	krec.dsize = tmp_size;
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        if (dp->di_dbm == NULL) {
                 PyErr_SetString(DbmError, "DBM object has already been closed"); 
                 return -1;
        }
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	dp->di_size = -1;
	if (w == NULL) {
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		if ( dbm_delete(dp->di_dbm, krec) < 0 ) {
			dbm_clearerr(dp->di_dbm);
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			PyErr_SetObject(PyExc_KeyError, v);
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			return -1;
		}
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	} else {
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		if ( !PyArg_Parse(w, "s#", &drec.dptr, &tmp_size) ) {
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			PyErr_SetString(PyExc_TypeError,
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			     "dbm mappings have byte or string elements only");
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			return -1;
		}
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		drec.dsize = tmp_size;
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		if ( dbm_store(dp->di_dbm, krec, drec, DBM_REPLACE) < 0 ) {
			dbm_clearerr(dp->di_dbm);
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			PyErr_SetString(DbmError,
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					"cannot add item to database");
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			return -1;
		}
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	}
	if ( dbm_error(dp->di_dbm) ) {
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		dbm_clearerr(dp->di_dbm);
		PyErr_SetString(DbmError, "");
		return -1;
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	}
	return 0;
}

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static PyMappingMethods dbm_as_mapping = {
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	(lenfunc)dbm_length,		/*mp_length*/
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	(binaryfunc)dbm_subscript,	/*mp_subscript*/
	(objobjargproc)dbm_ass_sub,	/*mp_ass_subscript*/
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};

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static PyObject *
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dbm__close(register dbmobject *dp, PyObject *unused)
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{
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        if (dp->di_dbm)
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		dbm_close(dp->di_dbm);
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	dp->di_dbm = NULL;
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	Py_INCREF(Py_None);
	return Py_None;
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}

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static PyObject *
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dbm_keys(register dbmobject *dp, PyObject *unused)
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{
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	register PyObject *v, *item;
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	datum key;
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	int err;
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        check_dbmobject_open(dp);
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	v = PyList_New(0);
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	if (v == NULL)
		return NULL;
	for (key = dbm_firstkey(dp->di_dbm); key.dptr;
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	     key = dbm_nextkey(dp->di_dbm)) {
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		item = PyBytes_FromStringAndSize(key.dptr, key.dsize);
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		if (item == NULL) {
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			Py_DECREF(v);
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			return NULL;
		}
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		err = PyList_Append(v, item);
		Py_DECREF(item);
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		if (err != 0) {
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			Py_DECREF(v);
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			return NULL;
		}
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	}
	return v;
}

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static int
dbm_contains(PyObject *self, PyObject *arg)
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{
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	dbmobject *dp = (dbmobject *)self;
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	datum key, val;
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	if ((dp)->di_dbm == NULL) {
		PyErr_SetString(DbmError,
				"DBM object has already been closed");
                 return -1;
	}
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	if (PyUnicode_Check(arg)) {
		arg = _PyUnicode_AsDefaultEncodedString(arg, NULL);
		if (arg == NULL)
			return -1;
	}
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	if (!PyBytes_Check(arg)) {
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		PyErr_Format(PyExc_TypeError,
			     "dbm key must be string, not %.100s",
			     arg->ob_type->tp_name);
		return -1;
	}
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	key.dptr = PyBytes_AS_STRING(arg);
	key.dsize = PyBytes_GET_SIZE(arg);
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	val = dbm_fetch(dp->di_dbm, key);
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	return val.dptr != NULL;
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}

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static PySequenceMethods dbm_as_sequence = {
	0,			/* sq_length */
	0,			/* sq_concat */
	0,			/* sq_repeat */
	0,			/* sq_item */
	0,			/* sq_slice */
	0,			/* sq_ass_item */
	0,			/* sq_ass_slice */
	dbm_contains,		/* sq_contains */
	0,			/* sq_inplace_concat */
	0,			/* sq_inplace_repeat */
};

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static PyObject *
dbm_get(register dbmobject *dp, PyObject *args)
{
	datum key, val;
	PyObject *defvalue = Py_None;
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	char *tmp_ptr;
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	Py_ssize_t tmp_size;
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	if (!PyArg_ParseTuple(args, "s#|O:get",
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                              &tmp_ptr, &tmp_size, &defvalue))
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		return NULL;
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	key.dptr = tmp_ptr;
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	key.dsize = tmp_size;
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        check_dbmobject_open(dp);
	val = dbm_fetch(dp->di_dbm, key);
	if (val.dptr != NULL)
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		return PyBytes_FromStringAndSize(val.dptr, val.dsize);
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	else {
		Py_INCREF(defvalue);
		return defvalue;
	}
}

static PyObject *
dbm_setdefault(register dbmobject *dp, PyObject *args)
{
	datum key, val;
	PyObject *defvalue = NULL;
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	char *tmp_ptr;
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	Py_ssize_t tmp_size;
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	if (!PyArg_ParseTuple(args, "s#|O:setdefault",
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                              &tmp_ptr, &tmp_size, &defvalue))
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		return NULL;
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	key.dptr = tmp_ptr;
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	key.dsize = tmp_size;
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        check_dbmobject_open(dp);
	val = dbm_fetch(dp->di_dbm, key);
	if (val.dptr != NULL)
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		return PyBytes_FromStringAndSize(val.dptr, val.dsize);
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	if (defvalue == NULL) {
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		defvalue = PyBytes_FromStringAndSize(NULL, 0);
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		if (defvalue == NULL)
			return NULL;
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		val.dptr = NULL;
		val.dsize = 0;
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	}
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	else {
		if ( !PyArg_Parse(defvalue, "s#", &val.dptr, &tmp_size) ) {
			PyErr_SetString(PyExc_TypeError,
				"dbm mappings have byte string elements only");
			return NULL;
		}
		val.dsize = tmp_size;
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		Py_INCREF(defvalue);
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	}
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	if (dbm_store(dp->di_dbm, key, val, DBM_INSERT) < 0) {
		dbm_clearerr(dp->di_dbm);
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		PyErr_SetString(DbmError, "cannot add item to database");
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		Py_DECREF(defvalue);
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		return NULL;
	}
	return defvalue;
}

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static PyMethodDef dbm_methods[] = {
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	{"close",	(PyCFunction)dbm__close,	METH_NOARGS,
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	 "close()\nClose the database."},
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	{"keys",	(PyCFunction)dbm_keys,		METH_NOARGS,
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	 "keys() -> list\nReturn a list of all keys in the database."},
	{"get",		(PyCFunction)dbm_get,		METH_VARARGS,
	 "get(key[, default]) -> value\n"
	 "Return the value for key if present, otherwise default."},
	{"setdefault",	(PyCFunction)dbm_setdefault,	METH_VARARGS,
	 "setdefault(key[, default]) -> value\n"
	 "Return the value for key if present, otherwise default.  If key\n"
	 "is not in the database, it is inserted with default as the value."},
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	{NULL,		NULL}		/* sentinel */
};

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static PyTypeObject Dbmtype = {
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	PyVarObject_HEAD_INIT(NULL, 0)
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	"_dbm.dbm",
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	sizeof(dbmobject),
	0,
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	(destructor)dbm_dealloc,  /*tp_dealloc*/
	0,			  /*tp_print*/
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	0,                        /*tp_getattr*/
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	0,			  /*tp_setattr*/
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	0,			  /*tp_reserved*/
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	0,			  /*tp_repr*/
	0,			  /*tp_as_number*/
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	&dbm_as_sequence,	  /*tp_as_sequence*/
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	&dbm_as_mapping,	  /*tp_as_mapping*/
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	0,                    /*tp_hash*/
	0,                    /*tp_call*/
	0,                    /*tp_str*/
	0,                    /*tp_getattro*/
	0,                    /*tp_setattro*/
	0,                    /*tp_as_buffer*/
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	Py_TPFLAGS_DEFAULT,   /*tp_flags*/
	0,		      /*tp_doc*/
	0,		      /*tp_traverse*/
	0,		      /*tp_clear*/
	0,		      /*tp_richcompare*/
	0,		      /*tp_weaklistoffset*/
	0,		      /*tp_iter*/
	0,		      /*tp_iternext*/
	dbm_methods,          /*tp_methods*/
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};

/* ----------------------------------------------------------------- */

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static PyObject *
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dbmopen(PyObject *self, PyObject *args)
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{
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	char *name;
	char *flags = "r";
	int iflags;
	int mode = 0666;
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        if ( !PyArg_ParseTuple(args, "s|si:open", &name, &flags, &mode) )
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		return NULL;
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	if ( strcmp(flags, "r") == 0 )
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		iflags = O_RDONLY;
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	else if ( strcmp(flags, "w") == 0 )
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		iflags = O_RDWR;
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	else if ( strcmp(flags, "rw") == 0 ) /* B/W compat */
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		iflags = O_RDWR|O_CREAT; 
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	else if ( strcmp(flags, "c") == 0 )
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		iflags = O_RDWR|O_CREAT;
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	else if ( strcmp(flags, "n") == 0 )
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		iflags = O_RDWR|O_CREAT|O_TRUNC;
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	else {
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		PyErr_SetString(DbmError,
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				"arg 2 to open should be 'r', 'w', 'c', or 'n'");
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		return NULL;
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	}
        return newdbmobject(name, iflags, mode);
}

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static PyMethodDef dbmmodule_methods[] = {
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	{ "open", (PyCFunction)dbmopen, METH_VARARGS,
	  "open(path[, flag[, mode]]) -> mapping\n"
	  "Return a database object."},
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	{ 0, 0 },
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};

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static struct PyModuleDef _dbmmodule = {
	PyModuleDef_HEAD_INIT,
	"_dbm",
	NULL,
	-1,
	dbmmodule_methods,
	NULL,
	NULL,
	NULL,
	NULL
};

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PyMODINIT_FUNC
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PyInit__dbm(void) {
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	PyObject *m, *d, *s;
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	if (PyType_Ready(&Dbmtype) < 0)
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		return NULL;
	m = PyModule_Create(&_dbmmodule);
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	if (m == NULL)
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		return NULL;
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	d = PyModule_GetDict(m);
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	if (DbmError == NULL)
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		DbmError = PyErr_NewException("_dbm.error",
					      PyExc_IOError, NULL);
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	s = PyUnicode_FromString(which_dbm);
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	if (s != NULL) {
		PyDict_SetItemString(d, "library", s);
		Py_DECREF(s);
	}
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	if (DbmError != NULL)
		PyDict_SetItemString(d, "error", DbmError);
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	if (PyErr_Occurred()) {
		Py_DECREF(m);
		m = NULL;
	}
	return m;
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}