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/* Copyright (C) 2009 Canonical Ltd
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef _STATIC_TUPLE_H_
#define _STATIC_TUPLE_H_
#include <Python.h>
#include <string.h>
#define STATIC_TUPLE_HAS_HASH 0
/* Caching the hash adds memory, but allows us to save a little time during
* lookups. TIMEIT hash(key) shows it as
* 0.108usec w/ hash
* 0.160usec w/o hash
* Note that the entries themselves are strings, which already cache their
* hashes. So while there is a 1.5:1 difference in the time for hash(), it is
* already a function which is quite fast. Probably the only reason we might
* want to do so, is if we customized SimpleSet to the point that the item
* pointers were exactly certain types, and then accessed table[i]->hash
* directly. So far StaticTuple_hash() is fast enough to not warrant the memory
* difference.
*/
/* This defines a single variable-width key.
* It is basically the same as a tuple, but
* 1) Lighter weight in memory
* 2) Only supports strings or other static types (that don't reference other
* objects.)
*/
#define STATIC_TUPLE_INTERNED_FLAG 0x01
typedef struct {
PyObject_HEAD
// We could go with unsigned short here, and support 64k width tuples
// without any memory impact, might be worthwhile
unsigned char size;
unsigned char flags;
unsigned char _unused0;
unsigned char _unused1;
// Note that on 64-bit, we actually have 4-more unused bytes
// because items will always be aligned to a 64-bit boundary
#if STATIC_TUPLE_HAS_HASH
long hash;
#endif
PyObject *items[0];
} StaticTuple;
extern PyTypeObject StaticTuple_Type;
typedef struct {
PyObject_VAR_HEAD
PyObject *table[0];
} KeyIntern;
#define StaticTuple_SET_ITEM(key, offset, val) \
((((StaticTuple*)(key))->items[(offset)]) = ((PyObject *)(val)))
#define StaticTuple_GET_ITEM(key, offset) (((StaticTuple*)key)->items[offset])
#ifdef STATIC_TUPLE_MODULE
/* Used when compiling _static_tuple_c.c */
static StaticTuple * StaticTuple_New(Py_ssize_t);
static StaticTuple * StaticTuple_Intern(StaticTuple *self);
#define StaticTuple_CheckExact(op) (Py_TYPE(op) == &StaticTuple_Type)
#else
/* Used as the foreign api */
#include "_import_c_api.h"
static StaticTuple *(*StaticTuple_New)(Py_ssize_t);
static StaticTuple *(*StaticTuple_Intern)(StaticTuple *);
static PyTypeObject *_p_StaticTuple_Type;
#define StaticTuple_CheckExact(op) (Py_TYPE(op) == _p_StaticTuple_Type)
static int (*_StaticTuple_CheckExact)(PyObject *);
/* Return -1 and set exception on error, 0 on success */
static int
import_static_tuple_c(void)
{
struct function_description functions[] = {
{"StaticTuple_New", (void **)&StaticTuple_New,
"StaticTuple *(Py_ssize_t)"},
{"StaticTuple_Intern", (void **)&StaticTuple_Intern,
"StaticTuple *(StaticTuple *)"},
{"_StaticTuple_CheckExact", (void **)&_StaticTuple_CheckExact,
"int(PyObject *)"},
{NULL}};
struct type_description types[] = {
{"StaticTuple", &_p_StaticTuple_Type},
{NULL}};
return _import_extension_module("bzrlib._static_tuple_c",
functions, types);
}
#endif // !STATIC_TUPLE_MODULE
#endif // !_STATIC_TUPLE_H_
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