我发现了我的python代码中的瓶颈,与psycho等一起玩.然后决定为性能编写ac/c ++扩展.
在swig的帮助下,你几乎不需要关心论点等.一切正常.
现在我的问题是:swig创建了一个非常大的py文件,它在调用实际的.pyd或.so代码之前执行了很多'checkings'和'PySwigObject'.
如果你手写这个文件或者让swig这样做,你们中是否有人有任何经验可以获得更多的性能.
如果你不打算为swig生成其他语言的绑定,你应该考虑Boost.Python.
如果要绑定很多函数和类,Py ++是一个很好的工具,可以自动生成所需的代码来进行绑定.
Pybindgen 也可能是一个选项,但它是一个新项目,并且不如Boost.Python完整.
编辑:
也许我需要更明确的支持和利弊.
痛饮:
亲:您可以为许多脚本语言生成绑定.
缺点:我不喜欢解析器的工作方式.我不知道是否取得了一些进展,但两年前C++解析器是非常有限的.大多数时候我不得不复制/通过我的.h标题添加一些%
字符并给swig解析器提供额外的提示.
我还需要不时地处理Python C-API(不是那么)复杂的类型转换.
我不再使用它了.
Boost.Python的:
亲:这是一个非常完整的图书馆.它允许您使用C-API完成几乎所有可能的操作,但是在C++中.我从来没有用这个库编写C-API代码.我也从未遇到过因库而导致的bug.绑定代码可以像魅力或拒绝编译一样工作.
如果您已经有一些要绑定的C++库,它可能是当前可用的最佳解决方案之一.但是如果你只有一个小的C函数来重写,我可能会尝试使用Cython.
缺点:如果你没有预先编译好的Boost.Python库,那么你将使用Bjam(有点替换).我真的很讨厌Bjam及其语法.
用BP创建的Python库往往会变得肥胖.编译它们也需要很多时间.
Py ++(已停刊):它的Boost.Python变得简单了.Py ++使用C++解析器来读取您的代码,然后自动生成Boost.Python代码.你也得到了作者的大力支持(不,不是我;-)).
缺点:只有Boost.Python本身引起的问题.更新:截至2014年,该项目现已暂停.
Pybindgen:
它生成处理C-API的代码.您可以在Python文件中描述函数和类,或者让Pybindgen自动读取标题并生成绑定(为此它使用pygccxml,Py ++的作者编写的python库).
缺点:这是一个年轻的项目,团队规模比Boost.Python小.仍然存在一些限制:您不能对C++类使用多重继承,回调(不是自动,可以编写自定义回调处理代码).将Python异常翻译为C.
这绝对值得一看.
一个新的:在2009年1月20日,Py ++的作者宣布了一个新的软件包,用于连接C/C++代码和python.它基于ctypes.我没有尝试过,但我会的!注意:这个项目看起来像Py ++一样不受欢迎.
CFFI:直到最近我才知道这个存在,所以现在我不能发表意见.看起来你可以在Python字符串中定义C函数并直接从同一个Python模块调用它们.
Cython:这是我目前在项目中使用的方法.基本上你用特殊的.pyx文件编写代码.这些文件被编译(转换)成C代码,而C代码又被编译为CPython模块.Cython代码看起来像普通的Python(实际上纯Python是有效的.pyx Cython文件),但您也可以获得更多信息,如变量类型.这种可选的输入允许Cython生成更快的C代码.Cython文件中的代码既可以调用纯Python函数,也可以调用C和C++函数(以及C++方法).
我花了一些时间在Cython中思考,在相同的代码中调用C和C++函数,混合Python和C变量,依此类推.但它是一种非常强大的语言,具有活跃(2014年)和友好的社区.
SWIG 2.0.4引入了一种新的-builtin选项,可以提高性能.我使用一个示例程序进行了一些基准测试,该程序对C++扩展进行了大量快速调用.我使用boost.python,PyBindGen,SIP和SWIG使用和不使用-builtin选项构建了扩展.以下是结果(平均100次运行):
SWIG with -builtin 2.67s SIP 2.70s PyBindGen 2.74s boost.python 3.07s SWIG without -builtin 4.65s
SWIG曾经是最慢的.使用新的-builtin选项,SWIG似乎是最快的.
当然,手动执行此操作总会获得性能提升,但与实现此目的所需的工作量相比,增益将非常小.我没有任何数字可以给你,但我不推荐这个,因为你需要手动维护界面,如果你的模块很大,这不是一个选项!
您选择使用脚本语言是正确的,因为您需要快速开发.这样你就避免了早期的优化综合症,现在你想要优化瓶颈部件,太棒了!但是,如果您手动执行C/python接口,您肯定会陷入早期优化综合症.
如果你想要更少的接口代码,你可以考虑从你的C代码创建一个DLL,并直接从python与cstruct使用该库.
如果你想在程序中只使用python代码,也要考虑Cython.
使用Cython非常好.您可以使用类似Python的语法编写C扩展,并生成C代码.锅炉包括在内.由于您已经在python中使用了代码,因此您只需对瓶颈代码进行一些更改,就可以从中生成C代码.
例.hello.pyx
:
cdef int hello(int a, int b): return a + b
这会生成601行样板代码:
/* Generated by Cython 0.10.3 on Mon Jan 19 08:24:44 2009 */ #define PY_SSIZE_T_CLEAN #include "Python.h" #include "structmember.h" #ifndef PY_LONG_LONG #define PY_LONG_LONG LONG_LONG #endif #ifndef DL_EXPORT #define DL_EXPORT(t) t #endif #if PY_VERSION_HEX < 0x02040000 #define METH_COEXIST 0 #endif #if PY_VERSION_HEX < 0x02050000 typedef int Py_ssize_t; #define PY_SSIZE_T_MAX INT_MAX #define PY_SSIZE_T_MIN INT_MIN #define PyInt_FromSsize_t(z) PyInt_FromLong(z) #define PyInt_AsSsize_t(o) PyInt_AsLong(o) #define PyNumber_Index(o) PyNumber_Int(o) #define PyIndex_Check(o) PyNumber_Check(o) #endif #if PY_VERSION_HEX < 0x02060000 #define Py_REFCNT(ob) (((PyObject*)(ob))->ob_refcnt) #define Py_TYPE(ob) (((PyObject*)(ob))->ob_type) #define Py_SIZE(ob) (((PyVarObject*)(ob))->ob_size) #define PyVarObject_HEAD_INIT(type, size) \ PyObject_HEAD_INIT(type) size, #define PyType_Modified(t) typedef struct { void *buf; PyObject *obj; Py_ssize_t len; Py_ssize_t itemsize; int readonly; int ndim; char *format; Py_ssize_t *shape; Py_ssize_t *strides; Py_ssize_t *suboffsets; void *internal; } Py_buffer; #define PyBUF_SIMPLE 0 #define PyBUF_WRITABLE 0x0001 #define PyBUF_LOCK 0x0002 #define PyBUF_FORMAT 0x0004 #define PyBUF_ND 0x0008 #define PyBUF_STRIDES (0x0010 | PyBUF_ND) #define PyBUF_C_CONTIGUOUS (0x0020 | PyBUF_STRIDES) #define PyBUF_F_CONTIGUOUS (0x0040 | PyBUF_STRIDES) #define PyBUF_ANY_CONTIGUOUS (0x0080 | PyBUF_STRIDES) #define PyBUF_INDIRECT (0x0100 | PyBUF_STRIDES) #endif #if PY_MAJOR_VERSION < 3 #define __Pyx_BUILTIN_MODULE_NAME "__builtin__" #else #define __Pyx_BUILTIN_MODULE_NAME "builtins" #endif #if PY_MAJOR_VERSION >= 3 #define Py_TPFLAGS_CHECKTYPES 0 #define Py_TPFLAGS_HAVE_INDEX 0 #endif #if (PY_VERSION_HEX < 0x02060000) || (PY_MAJOR_VERSION >= 3) #define Py_TPFLAGS_HAVE_NEWBUFFER 0 #endif #if PY_MAJOR_VERSION >= 3 #define PyBaseString_Type PyUnicode_Type #define PyString_Type PyBytes_Type #define PyInt_Type PyLong_Type #define PyInt_Check(op) PyLong_Check(op) #define PyInt_CheckExact(op) PyLong_CheckExact(op) #define PyInt_FromString PyLong_FromString #define PyInt_FromUnicode PyLong_FromUnicode #define PyInt_FromLong PyLong_FromLong #define PyInt_FromSize_t PyLong_FromSize_t #define PyInt_FromSsize_t PyLong_FromSsize_t #define PyInt_AsLong PyLong_AsLong #define PyInt_AS_LONG PyLong_AS_LONG #define PyInt_AsSsize_t PyLong_AsSsize_t #define PyInt_AsUnsignedLongMask PyLong_AsUnsignedLongMask #define PyInt_AsUnsignedLongLongMask PyLong_AsUnsignedLongLongMask #define __Pyx_PyNumber_Divide(x,y) PyNumber_TrueDivide(x,y) #else #define __Pyx_PyNumber_Divide(x,y) PyNumber_Divide(x,y) #define PyBytes_Type PyString_Type #endif #if PY_MAJOR_VERSION >= 3 #define PyMethod_New(func, self, klass) PyInstanceMethod_New(func) #endif #if !defined(WIN32) && !defined(MS_WINDOWS) #ifndef __stdcall #define __stdcall #endif #ifndef __cdecl #define __cdecl #endif #else #define _USE_MATH_DEFINES #endif #ifdef __cplusplus #define __PYX_EXTERN_C extern "C" #else #define __PYX_EXTERN_C extern #endif #include#define __PYX_HAVE_API__helloworld #ifdef __GNUC__ #define INLINE __inline__ #elif _WIN32 #define INLINE __inline #else #define INLINE #endif typedef struct {PyObject **p; char *s; long n; char is_unicode; char intern; char is_identifier;} __Pyx_StringTabEntry; /*proto*/ static int __pyx_skip_dispatch = 0; /* Type Conversion Predeclarations */ #if PY_MAJOR_VERSION < 3 #define __Pyx_PyBytes_FromString PyString_FromString #define __Pyx_PyBytes_AsString PyString_AsString #else #define __Pyx_PyBytes_FromString PyBytes_FromString #define __Pyx_PyBytes_AsString PyBytes_AsString #endif #define __Pyx_PyBool_FromLong(b) ((b) ? (Py_INCREF(Py_True), Py_True) : (Py_INCREF(Py_False), Py_False)) static INLINE int __Pyx_PyObject_IsTrue(PyObject* x); static INLINE PY_LONG_LONG __pyx_PyInt_AsLongLong(PyObject* x); static INLINE unsigned PY_LONG_LONG __pyx_PyInt_AsUnsignedLongLong(PyObject* x); static INLINE Py_ssize_t __pyx_PyIndex_AsSsize_t(PyObject* b); #define __pyx_PyInt_AsLong(x) (PyInt_CheckExact(x) ? PyInt_AS_LONG(x) : PyInt_AsLong(x)) #define __pyx_PyFloat_AsDouble(x) (PyFloat_CheckExact(x) ? PyFloat_AS_DOUBLE(x) : PyFloat_AsDouble(x)) static INLINE unsigned char __pyx_PyInt_unsigned_char(PyObject* x); static INLINE unsigned short __pyx_PyInt_unsigned_short(PyObject* x); static INLINE char __pyx_PyInt_char(PyObject* x); static INLINE short __pyx_PyInt_short(PyObject* x); static INLINE int __pyx_PyInt_int(PyObject* x); static INLINE long __pyx_PyInt_long(PyObject* x); static INLINE signed char __pyx_PyInt_signed_char(PyObject* x); static INLINE signed short __pyx_PyInt_signed_short(PyObject* x); static INLINE signed int __pyx_PyInt_signed_int(PyObject* x); static INLINE signed long __pyx_PyInt_signed_long(PyObject* x); static INLINE long double __pyx_PyInt_long_double(PyObject* x); #ifdef __GNUC__ /* Test for GCC > 2.95 */ #if __GNUC__ > 2 || (__GNUC__ == 2 && (__GNUC_MINOR__ > 95)) #define likely(x) __builtin_expect(!!(x), 1) #define unlikely(x) __builtin_expect(!!(x), 0) #else /* __GNUC__ > 2 ... */ #define likely(x) (x) #define unlikely(x) (x) #endif /* __GNUC__ > 2 ... */ #else /* __GNUC__ */ #define likely(x) (x) #define unlikely(x) (x) #endif /* __GNUC__ */ static PyObject *__pyx_m; static PyObject *__pyx_b; static PyObject *__pyx_empty_tuple; static int __pyx_lineno; static int __pyx_clineno = 0; static const char * __pyx_cfilenm= __FILE__; static const char *__pyx_filename; static const char **__pyx_f; static void __Pyx_AddTraceback(const char *funcname); /*proto*/ /* Type declarations */ /* Module declarations from helloworld */ static int __pyx_f_10helloworld_hello(int, int); /*proto*/ /* Implementation of helloworld */ /* "/home/nosklo/devel/ctest/hello.pyx":1 * cdef int hello(int a, int b): # <<<<<<<<<<<<<< * return a + b * */ static int __pyx_f_10helloworld_hello(int __pyx_v_a, int __pyx_v_b) { int __pyx_r; /* "/home/nosklo/devel/ctest/hello.pyx":2 * cdef int hello(int a, int b): * return a + b # <<<<<<<<<<<<<< * */ __pyx_r = (__pyx_v_a + __pyx_v_b); goto __pyx_L0; __pyx_r = 0; __pyx_L0:; return __pyx_r; } static struct PyMethodDef __pyx_methods[] = { {0, 0, 0, 0} }; static void __pyx_init_filenames(void); /*proto*/ #if PY_MAJOR_VERSION >= 3 static struct PyModuleDef __pyx_moduledef = { PyModuleDef_HEAD_INIT, "helloworld", 0, /* m_doc */ -1, /* m_size */ __pyx_methods /* m_methods */, NULL, /* m_reload */ NULL, /* m_traverse */ NULL, /* m_clear */ NULL /* m_free */ }; #endif static int __Pyx_InitCachedBuiltins(void) { return 0; return -1; } static int __Pyx_InitGlobals(void) { return 0; return -1; } #if PY_MAJOR_VERSION < 3 PyMODINIT_FUNC inithelloworld(void); /*proto*/ PyMODINIT_FUNC inithelloworld(void) #else PyMODINIT_FUNC PyInit_helloworld(void); /*proto*/ PyMODINIT_FUNC PyInit_helloworld(void) #endif { __pyx_empty_tuple = PyTuple_New(0); if (unlikely(!__pyx_empty_tuple)) {__pyx_filename = __pyx_f[0]; __pyx_lineno = 1; __pyx_clineno = __LINE__; goto __pyx_L1_error;} /*--- Library function declarations ---*/ __pyx_init_filenames(); /*--- Initialize various global constants etc. ---*/ if (unlikely(__Pyx_InitGlobals() < 0)) {__pyx_filename = __pyx_f[0]; __pyx_lineno = 1; __pyx_clineno = __LINE__; goto __pyx_L1_error;} /*--- Module creation code ---*/ #if PY_MAJOR_VERSION < 3 __pyx_m = Py_InitModule4("helloworld", __pyx_methods, 0, 0, PYTHON_API_VERSION); #else __pyx_m = PyModule_Create(&__pyx_moduledef); #endif if (!__pyx_m) {__pyx_filename = __pyx_f[0]; __pyx_lineno = 1; __pyx_clineno = __LINE__; goto __pyx_L1_error;}; #if PY_MAJOR_VERSION < 3 Py_INCREF(__pyx_m); #endif __pyx_b = PyImport_AddModule(__Pyx_BUILTIN_MODULE_NAME); if (!__pyx_b) {__pyx_filename = __pyx_f[0]; __pyx_lineno = 1; __pyx_clineno = __LINE__; goto __pyx_L1_error;}; if (PyObject_SetAttrString(__pyx_m, "__builtins__", __pyx_b) < 0) {__pyx_filename = __pyx_f[0]; __pyx_lineno = 1; __pyx_clineno = __LINE__; goto __pyx_L1_error;}; /*--- Builtin init code ---*/ if (unlikely(__Pyx_InitCachedBuiltins() < 0)) {__pyx_filename = __pyx_f[0]; __pyx_lineno = 1; __pyx_clineno = __LINE__; goto __pyx_L1_error;} __pyx_skip_dispatch = 0; /*--- Global init code ---*/ /*--- Function export code ---*/ /*--- Type init code ---*/ /*--- Type import code ---*/ /*--- Function import code ---*/ /*--- Execution code ---*/ /* "/home/nosklo/devel/ctest/hello.pyx":1 * cdef int hello(int a, int b): # <<<<<<<<<<<<<< * return a + b * */ #if PY_MAJOR_VERSION < 3 return; #else return __pyx_m; #endif __pyx_L1_error:; __Pyx_AddTraceback("helloworld"); #if PY_MAJOR_VERSION >= 3 return NULL; #endif } static const char *__pyx_filenames[] = { "hello.pyx", }; /* Runtime support code */ static void __pyx_init_filenames(void) { __pyx_f = __pyx_filenames; } #include "compile.h" #include "frameobject.h" #include "traceback.h" static void __Pyx_AddTraceback(const char *funcname) { PyObject *py_srcfile = 0; PyObject *py_funcname = 0; PyObject *py_globals = 0; PyObject *empty_string = 0; PyCodeObject *py_code = 0; PyFrameObject *py_frame = 0; #if PY_MAJOR_VERSION < 3 py_srcfile = PyString_FromString(__pyx_filename); #else py_srcfile = PyUnicode_FromString(__pyx_filename); #endif if (!py_srcfile) goto bad; if (__pyx_clineno) { #if PY_MAJOR_VERSION < 3 py_funcname = PyString_FromFormat( "%s (%s:%d)", funcname, __pyx_cfilenm, __pyx_clineno); #else py_funcname = PyUnicode_FromFormat( "%s (%s:%d)", funcname, __pyx_cfilenm, __pyx_clineno); #endif } else { #if PY_MAJOR_VERSION < 3 py_funcname = PyString_FromString(funcname); #else py_funcname = PyUnicode_FromString(funcname); #endif } if (!py_funcname) goto bad; py_globals = PyModule_GetDict(__pyx_m); if (!py_globals) goto bad; #if PY_MAJOR_VERSION < 3 empty_string = PyString_FromStringAndSize("", 0); #else empty_string = PyBytes_FromStringAndSize("", 0); #endif if (!empty_string) goto bad; py_code = PyCode_New( 0, /*int argcount,*/ #if PY_MAJOR_VERSION >= 3 0, /*int kwonlyargcount,*/ #endif 0, /*int nlocals,*/ 0, /*int stacksize,*/ 0, /*int flags,*/ empty_string, /*PyObject *code,*/ __pyx_empty_tuple, /*PyObject *consts,*/ __pyx_empty_tuple, /*PyObject *names,*/ __pyx_empty_tuple, /*PyObject *varnames,*/ __pyx_empty_tuple, /*PyObject *freevars,*/ __pyx_empty_tuple, /*PyObject *cellvars,*/ py_srcfile, /*PyObject *filename,*/ py_funcname, /*PyObject *name,*/ __pyx_lineno, /*int firstlineno,*/ empty_string /*PyObject *lnotab*/ ); if (!py_code) goto bad; py_frame = PyFrame_New( PyThreadState_GET(), /*PyThreadState *tstate,*/ py_code, /*PyCodeObject *code,*/ py_globals, /*PyObject *globals,*/ 0 /*PyObject *locals*/ ); if (!py_frame) goto bad; py_frame->f_lineno = __pyx_lineno; PyTraceBack_Here(py_frame); bad: Py_XDECREF(py_srcfile); Py_XDECREF(py_funcname); Py_XDECREF(empty_string); Py_XDECREF(py_code); Py_XDECREF(py_frame); } /* Type Conversion Functions */ static INLINE Py_ssize_t __pyx_PyIndex_AsSsize_t(PyObject* b) { Py_ssize_t ival; PyObject* x = PyNumber_Index(b); if (!x) return -1; ival = PyInt_AsSsize_t(x); Py_DECREF(x); return ival; } static INLINE int __Pyx_PyObject_IsTrue(PyObject* x) { if (x == Py_True) return 1; else if (x == Py_False) return 0; else return PyObject_IsTrue(x); } static INLINE PY_LONG_LONG __pyx_PyInt_AsLongLong(PyObject* x) { if (PyInt_CheckExact(x)) { return PyInt_AS_LONG(x); } else if (PyLong_CheckExact(x)) { return PyLong_AsLongLong(x); } else { PY_LONG_LONG val; PyObject* tmp = PyNumber_Int(x); if (!tmp) return (PY_LONG_LONG)-1; val = __pyx_PyInt_AsLongLong(tmp); Py_DECREF(tmp); return val; } } static INLINE unsigned PY_LONG_LONG __pyx_PyInt_AsUnsignedLongLong(PyObject* x) { if (PyInt_CheckExact(x)) { long val = PyInt_AS_LONG(x); if (unlikely(val < 0)) { PyErr_SetString(PyExc_TypeError, "Negative assignment to unsigned type."); return (unsigned PY_LONG_LONG)-1; } return val; } else if (PyLong_CheckExact(x)) { return PyLong_AsUnsignedLongLong(x); } else { PY_LONG_LONG val; PyObject* tmp = PyNumber_Int(x); if (!tmp) return (PY_LONG_LONG)-1; val = __pyx_PyInt_AsUnsignedLongLong(tmp); Py_DECREF(tmp); return val; } } static INLINE unsigned char __pyx_PyInt_unsigned_char(PyObject* x) { if (sizeof(unsigned char) < sizeof(long)) { long long_val = __pyx_PyInt_AsLong(x); unsigned char val = (unsigned char)long_val; if (unlikely((val != long_val) || (long_val < 0))) { PyErr_SetString(PyExc_OverflowError, "value too large to convert to unsigned char"); return (unsigned char)-1; } return val; } else { return __pyx_PyInt_AsLong(x); } } static INLINE unsigned short __pyx_PyInt_unsigned_short(PyObject* x) { if (sizeof(unsigned short) < sizeof(long)) { long long_val = __pyx_PyInt_AsLong(x); unsigned short val = (unsigned short)long_val; if (unlikely((val != long_val) || (long_val < 0))) { PyErr_SetString(PyExc_OverflowError, "value too large to convert to unsigned short"); return (unsigned short)-1; } return val; } else { return __pyx_PyInt_AsLong(x); } } static INLINE char __pyx_PyInt_char(PyObject* x) { if (sizeof(char) < sizeof(long)) { long long_val = __pyx_PyInt_AsLong(x); char val = (char)long_val; if (unlikely((val != long_val) )) { PyErr_SetString(PyExc_OverflowError, "value too large to convert to char"); return (char)-1; } return val; } else { return __pyx_PyInt_AsLong(x); } } static INLINE short __pyx_PyInt_short(PyObject* x) { if (sizeof(short) < sizeof(long)) { long long_val = __pyx_PyInt_AsLong(x); short val = (short)long_val; if (unlikely((val != long_val) )) { PyErr_SetString(PyExc_OverflowError, "value too large to convert to short"); return (short)-1; } return val; } else { return __pyx_PyInt_AsLong(x); } } static INLINE int __pyx_PyInt_int(PyObject* x) { if (sizeof(int) < sizeof(long)) { long long_val = __pyx_PyInt_AsLong(x); int val = (int)long_val; if (unlikely((val != long_val) )) { PyErr_SetString(PyExc_OverflowError, "value too large to convert to int"); return (int)-1; } return val; } else { return __pyx_PyInt_AsLong(x); } } static INLINE long __pyx_PyInt_long(PyObject* x) { if (sizeof(long) < sizeof(long)) { long long_val = __pyx_PyInt_AsLong(x); long val = (long)long_val; if (unlikely((val != long_val) )) { PyErr_SetString(PyExc_OverflowError, "value too large to convert to long"); return (long)-1; } return val; } else { return __pyx_PyInt_AsLong(x); } } static INLINE signed char __pyx_PyInt_signed_char(PyObject* x) { if (sizeof(signed char) < sizeof(long)) { long long_val = __pyx_PyInt_AsLong(x); signed char val = (signed char)long_val; if (unlikely((val != long_val) )) { PyErr_SetString(PyExc_OverflowError, "value too large to convert to signed char"); return (signed char)-1; } return val; } else { return __pyx_PyInt_AsLong(x); } } static INLINE signed short __pyx_PyInt_signed_short(PyObject* x) { if (sizeof(signed short) < sizeof(long)) { long long_val = __pyx_PyInt_AsLong(x); signed short val = (signed short)long_val; if (unlikely((val != long_val) )) { PyErr_SetString(PyExc_OverflowError, "value too large to convert to signed short"); return (signed short)-1; } return val; } else { return __pyx_PyInt_AsLong(x); } } static INLINE signed int __pyx_PyInt_signed_int(PyObject* x) { if (sizeof(signed int) < sizeof(long)) { long long_val = __pyx_PyInt_AsLong(x); signed int val = (signed int)long_val; if (unlikely((val != long_val) )) { PyErr_SetString(PyExc_OverflowError, "value too large to convert to signed int"); return (signed int)-1; } return val; } else { return __pyx_PyInt_AsLong(x); } } static INLINE signed long __pyx_PyInt_signed_long(PyObject* x) { if (sizeof(signed long) < sizeof(long)) { long long_val = __pyx_PyInt_AsLong(x); signed long val = (signed long)long_val; if (unlikely((val != long_val) )) { PyErr_SetString(PyExc_OverflowError, "value too large to convert to signed long"); return (signed long)-1; } return val; } else { return __pyx_PyInt_AsLong(x); } } static INLINE long double __pyx_PyInt_long_double(PyObject* x) { if (sizeof(long double) < sizeof(long)) { long long_val = __pyx_PyInt_AsLong(x); long double val = (long double)long_val; if (unlikely((val != long_val) )) { PyErr_SetString(PyExc_OverflowError, "value too large to convert to long double"); return (long double)-1; } return val; } else { return __pyx_PyInt_AsLong(x); } }
观察:基于pybindgen开发人员进行的基准测试,boost.python和swig之间没有显着差异.我没有做自己的基准测试来验证这有多少取决于正确使用boost.python功能.
还要注意,可能有一个原因,pybindgen似乎通常比swig和boost.python快得多:它可能不会像其他两个一样产生多功能的绑定.例如,异常传播,调用参数类型检查等.我还没有机会使用pybindgen,但我打算.
Boost通常是一个非常大的安装包,最后我看到你不能只安装boost python你几乎需要整个Boost库.正如其他人所提到的,由于大量使用模板编程,编译将会很慢,这也意味着编译时通常会有相当神秘的错误消息.
总结:鉴于SWIG的安装和使用是多么容易,它生成了强大而通用的合适绑定,并且一个接口文件允许您的C++ DLL可以从其他几种语言(如LUA,C#和Java)获得,我赞成它通过boost.python.但除非你真的需要多语言支持,否则我会仔细研究PyBindGen,因为它声称速度很快,并密切关注它产生的绑定的稳健性和多功能性.
既然你关心速度和开销,我建议考虑使用PyBindGen.
我有使用它来包装大型内部C++库的经验.在尝试了SWIG,SIP和Boost.Python后,我更喜欢PyBindGen,原因如下:
PyBindGen包装器是纯Python,不需要学习其他文件格式
PyBindGen直接生成Python C API调用,没有像SWIG那样的速度抢夺间接层.
生成的C代码干净且易于理解.我也喜欢Cython,但有时候尝试读取它的C输出很困难.
支持STL序列容器(我们使用了很多std :: vector)
这里有龙.不要大喊大叫,不要提振.对于任何复杂的项目,您必须自己填写的代码才能使它们工作变得难以管理.如果它是您库的普通C API(没有类),您可以使用ctypes.这将是简单而轻松的,您不必花费数小时浏览这些迷宫包装项目的文档,试图找到关于您需要的功能的一个小小的注释.