mirrors
/
cpython
mirror of https://github.com/python/cpython.git
2
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

More bug 460020: lots of string optimizations inhibited for string 

subclasses, all "the usual" ones (slicing etc), plus replace, translate,
ljust, rjust, center and strip.  I don't know how to be sure they've all
been caught.

Question:  Should we complain if someone tries to intern an instance of
a string subclass?  I hate to slow any code on those paths.
This commit is contained in:
Tim Peters 2001-09-12 02:18:30 +00:00
parent ee0fe0b743
commit 8fa5dd0601
2 changed files with 71 additions and 81 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

27
Lib/test/test_descr.py
View File

@ -1481,9 +1481,32 @@ def rev(self):
verify(str(s) == "12345") verify(str(s) == "12345")
verify(str(s).__class__ is str) verify(str(s).__class__ is str)
s = madstring("\x00" * 5) base = "\x00" * 5
verify(str(s) == "\x00" * 5) s = madstring(base)
verify(str(s) == base)
verify(str(s).__class__ is str) verify(str(s).__class__ is str)
verify((s + "").__class__ is str)
verify(("" + s).__class__ is str)
verify((s * 0).__class__ is str)
verify((s * 1).__class__ is str)
verify((s * 2).__class__ is str)
verify(s[:].__class__ is str)
verify(s[0:0].__class__ is str)
verify(s.strip().__class__ is str)
identitytab = ''.join([chr(i) for i in range(256)])
verify(s.translate(identitytab).__class__ is str)
verify(s.translate(identitytab) == base)
verify(s.translate(identitytab, "x").__class__ is str)
verify(s.translate(identitytab, "x") == base)
verify(s.translate(identitytab, "\x00") == "")
verify(s.replace("x", "x").__class__ is str)
verify(s.replace("x", "x") == base)
verify(s.ljust(len(s)).__class__ is str)
verify(s.ljust(len(s)) == base)
verify(s.rjust(len(s)).__class__ is str)
verify(s.rjust(len(s)) == base)
verify(s.center(len(s)).__class__ is str)
verify(s.center(len(s)) == base)
class madunicode(unicode): class madunicode(unicode):
_rev = None _rev = None

125
Objects/stringobject.c
View File

@ -673,11 +673,12 @@ string_concat(register PyStringObject *a, register PyObject *bb)
} }
#define b ((PyStringObject *)bb) #define b ((PyStringObject *)bb)
/* Optimize cases with empty left or right operand */ /* Optimize cases with empty left or right operand */
if (a->ob_size == 0) { if ((a->ob_size == 0 || b->ob_size == 0) &&
Py_INCREF(bb); PyString_CheckExact(a) && PyString_CheckExact(b)) {
return bb; if (a->ob_size == 0) {
} Py_INCREF(bb);
if (b->ob_size == 0) { return bb;
}
Py_INCREF(a); Py_INCREF(a);
return (PyObject *)a; return (PyObject *)a;
} }
@ -719,7 +720,7 @@ string_repeat(register PyStringObject *a, register int n)
"repeated string is too long"); "repeated string is too long");
return NULL; return NULL;
} }
if (size == a->ob_size) { if (size == a->ob_size && PyString_CheckExact(a)) {
Py_INCREF(a); Py_INCREF(a);
return (PyObject *)a; return (PyObject *)a;
} }
@ -759,7 +760,8 @@ string_slice(register PyStringObject *a, register int i, register int j)
j = 0; /* Avoid signed/unsigned bug in next line */ j = 0; /* Avoid signed/unsigned bug in next line */
if (j > a->ob_size) if (j > a->ob_size)
j = a->ob_size; j = a->ob_size;
if (i == 0 && j == a->ob_size) { /* It's the same as a */ if (i == 0 && j == a->ob_size && PyString_CheckExact(a)) {
/* It's the same as a */
Py_INCREF(a); Py_INCREF(a);
return (PyObject *)a; return (PyObject *)a;
} }
@ -1378,7 +1380,7 @@ do_strip(PyStringObject *self, int striptype)
j++; j++;
} }
if (i == 0 && j == len) { if (i == 0 && j == len && PyString_CheckExact(self)) {
Py_INCREF(self); Py_INCREF(self);
return (PyObject*)self; return (PyObject*)self;
} }
@ -1735,7 +1737,7 @@ string_translate(PyStringObject *self, PyObject *args)
if (Py_CHARMASK((*output++ = table[c])) != c) if (Py_CHARMASK((*output++ = table[c])) != c)
changed = 1; changed = 1;
} }
if (changed) if (changed || !PyString_CheckExact(input_obj))
return result; return result;
Py_DECREF(result); Py_DECREF(result);
Py_INCREF(input_obj); Py_INCREF(input_obj);
@ -1755,7 +1757,7 @@ string_translate(PyStringObject *self, PyObject *args)
continue; continue;
changed = 1; changed = 1;
} }
if (!changed) { if (!changed && PyString_CheckExact(input_obj)) {
Py_DECREF(result); Py_DECREF(result);
Py_INCREF(input_obj); Py_INCREF(input_obj);
return input_obj; return input_obj;
@ -1917,7 +1919,8 @@ string_replace(PyStringObject *self, PyObject *args)
{ {
const char *str = PyString_AS_STRING(self), *sub, *repl; const char *str = PyString_AS_STRING(self), *sub, *repl;
char *new_s; char *new_s;
int len = PyString_GET_SIZE(self), sub_len, repl_len, out_len; const int len = PyString_GET_SIZE(self);
int sub_len, repl_len, out_len;
int count = -1; int count = -1;
PyObject *new; PyObject *new;
PyObject *subobj, *replobj; PyObject *subobj, *replobj;
@ -1960,9 +1963,16 @@ string_replace(PyStringObject *self, PyObject *args)
return NULL; return NULL;
} }
if (out_len == -1) { if (out_len == -1) {
/* we're returning another reference to self */ if (PyString_CheckExact(self)) {
new = (PyObject*)self; /* we're returning another reference to self */
Py_INCREF(new); new = (PyObject*)self;
Py_INCREF(new);
}
else {
new = PyString_FromStringAndSize(str, len);
if (new == NULL)
return NULL;
}
} }
else { else {
new = PyString_FromStringAndSize(new_s, out_len); new = PyString_FromStringAndSize(new_s, out_len);
@ -2182,11 +2192,8 @@ string_expandtabs(PyStringObject *self, PyObject *args)
return u; return u;
} }
static static PyObject *
PyObject *pad(PyStringObject *self, pad(PyStringObject *self, int left, int right, char fill)
int left,
int right,
char fill)
{ {
PyObject *u; PyObject *u;
@ -2195,7 +2202,7 @@ PyObject *pad(PyStringObject *self,
if (right < 0) if (right < 0)
right = 0; right = 0;
if (left == 0 && right == 0) { if (left == 0 && right == 0 && PyString_CheckExact(self)) {
Py_INCREF(self); Py_INCREF(self);
return (PyObject *)self; return (PyObject *)self;
} }
@ -2217,10 +2224,10 @@ PyObject *pad(PyStringObject *self,
} }
static char ljust__doc__[] = static char ljust__doc__[] =
"S.ljust(width) -> string\n\ "S.ljust(width) -> string\n"
\n\ "\n"
Return S left justified in a string of length width. Padding is\n\ "Return S left justified in a string of length width. Padding is\n"
done using spaces."; "done using spaces.";
static PyObject * static PyObject *
string_ljust(PyStringObject *self, PyObject *args) string_ljust(PyStringObject *self, PyObject *args)
@ -2229,7 +2236,7 @@ string_ljust(PyStringObject *self, PyObject *args)
if (!PyArg_ParseTuple(args, "i:ljust", &width)) if (!PyArg_ParseTuple(args, "i:ljust", &width))
return NULL; return NULL;
if (PyString_GET_SIZE(self) >= width) { if (PyString_GET_SIZE(self) >= width && PyString_CheckExact(self)) {
Py_INCREF(self); Py_INCREF(self);
return (PyObject*) self; return (PyObject*) self;
} }
@ -2239,10 +2246,10 @@ string_ljust(PyStringObject *self, PyObject *args)
static char rjust__doc__[] = static char rjust__doc__[] =
"S.rjust(width) -> string\n\ "S.rjust(width) -> string\n"
\n\ "\n"
Return S right justified in a string of length width. Padding is\n\ "Return S right justified in a string of length width. Padding is\n"
done using spaces."; "done using spaces.";
static PyObject * static PyObject *
string_rjust(PyStringObject *self, PyObject *args) string_rjust(PyStringObject *self, PyObject *args)
@ -2251,7 +2258,7 @@ string_rjust(PyStringObject *self, PyObject *args)
if (!PyArg_ParseTuple(args, "i:rjust", &width)) if (!PyArg_ParseTuple(args, "i:rjust", &width))
return NULL; return NULL;
if (PyString_GET_SIZE(self) >= width) { if (PyString_GET_SIZE(self) >= width && PyString_CheckExact(self)) {
Py_INCREF(self); Py_INCREF(self);
return (PyObject*) self; return (PyObject*) self;
} }
@ -2261,10 +2268,10 @@ string_rjust(PyStringObject *self, PyObject *args)
static char center__doc__[] = static char center__doc__[] =
"S.center(width) -> string\n\ "S.center(width) -> string\n"
\n\ "\n"
Return S centered in a string of length width. Padding is done\n\ "Return S centered in a string of length width. Padding is done\n"
using spaces."; "using spaces.";
static PyObject * static PyObject *
string_center(PyStringObject *self, PyObject *args) string_center(PyStringObject *self, PyObject *args)
@ -2275,7 +2282,7 @@ string_center(PyStringObject *self, PyObject *args)
if (!PyArg_ParseTuple(args, "i:center", &width)) if (!PyArg_ParseTuple(args, "i:center", &width))
return NULL; return NULL;
if (PyString_GET_SIZE(self) >= width) { if (PyString_GET_SIZE(self) >= width && PyString_CheckExact(self)) {
Py_INCREF(self); Py_INCREF(self);
return (PyObject*) self; return (PyObject*) self;
} }
@ -2286,51 +2293,11 @@ string_center(PyStringObject *self, PyObject *args)
return pad(self, left, marg - left, ' '); return pad(self, left, marg - left, ' ');
} }
#if 0
static char zfill__doc__[] =
"S.zfill(width) -> string\n\
\n\
Pad a numeric string x with zeros on the left, to fill a field\n\
of the specified width. The string x is never truncated.";
static PyObject *
string_zfill(PyStringObject *self, PyObject *args)
{
int fill;
PyObject *u;
char *str;
int width;
if (!PyArg_ParseTuple(args, "i:zfill", &width))
return NULL;
if (PyString_GET_SIZE(self) >= width) {
Py_INCREF(self);
return (PyObject*) self;
}
fill = width - PyString_GET_SIZE(self);
u = pad(self, fill, 0, '0');
if (u == NULL)
return NULL;
str = PyString_AS_STRING(u);
if (str[fill] == '+' || str[fill] == '-') {
/* move sign to beginning of string */
str[0] = str[fill];
str[fill] = '0';
}
return u;
}
#endif
static char isspace__doc__[] = static char isspace__doc__[] =
"S.isspace() -> int\n\ "S.isspace() -> int\n"
\n\ "\n"
Return 1 if there are only whitespace characters in S,\n\ "Return 1 if there are only whitespace characters in S,\n"
0 otherwise."; "0 otherwise.";
static PyObject* static PyObject*
string_isspace(PyStringObject *self) string_isspace(PyStringObject *self)