diff options
Diffstat (limited to 'Include/stringobject.h')
| -rw-r--r-- | Include/stringobject.h | 26 |
1 files changed, 23 insertions, 3 deletions
diff --git a/Include/stringobject.h b/Include/stringobject.h index c2565d8..8466821 100644 --- a/Include/stringobject.h +++ b/Include/stringobject.h @@ -52,16 +52,28 @@ variant that assumes a zero-terminated string. Note that none of the functions should be applied to nil objects. */ -/* NB The type is revealed here only because it is used in dictobject.c */ - -/* Take this out to save 4 bytes per string object and to lose 2% speedup */ +/* Two speedup hacks. Caching the hash saves recalculation of a + string's hash value. Interning strings (which requires hash + caching) tries to ensure that only one string object with a given + value exists, so equality tests are one pointer comparison. + Together, these can speed the interpreter up by as much as 20%. + Each costs the size of a long or pointer per string object. In + addition, interned strings live until the end of times. If you are + concerned about memory footprint, simply comment the #define out + here (and rebuild everything!). */ #define CACHE_HASH +#ifdef CACHE_HASH +#define INTERN_STRINGS +#endif typedef struct { PyObject_VAR_HEAD #ifdef CACHE_HASH long ob_shash; #endif +#ifdef INTERN_STRINGS + PyObject *ob_sinterned; +#endif char ob_sval[1]; } PyStringObject; @@ -78,6 +90,14 @@ extern void PyString_ConcatAndDel Py_PROTO((PyObject **, PyObject *)); extern int _PyString_Resize Py_PROTO((PyObject **, int)); extern PyObject *PyString_Format Py_PROTO((PyObject *, PyObject *)); +#ifdef INTERN_STRINGS +extern void PyString_InternInPlace Py_PROTO((PyObject **)); +extern PyObject *PyString_InternFromString Py_PROTO((const char *)); +#else +#define PyString_InternInPlace(p) +#define PyString_InternFromString(cp) PyString_FromString(cp) +#endif + /* Macro, trading safety for speed */ #define PyString_AS_STRING(op) (((PyStringObject *)(op))->ob_sval) #define PyString_GET_SIZE(op) (((PyStringObject *)(op))->ob_size) |