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Implement rich comparison for _sre.SRE_Pattern

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Issue #28727: Regular expression patterns, _sre.SRE_Pattern objects created by
re.compile(), become comparable (only x==y and x!=y operators). This change
should fix the issue #18383: don't duplicate warning filters when the warnings
module is reloaded (thing usually only done in unit tests).
This commit is contained in:
Victor Stinner 2016-11-21 16:35:08 +01:00
parent a2f7ee8b26
commit b44fb128ae
3 changed files with 118 additions and 9 deletions
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73
Modules/_sre.c
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@ -1506,14 +1506,12 @@ _sre_compile_impl(PyObject *module, PyObject *pattern, int flags,
self->groups = groups;
Py_XINCREF(groupindex);
Py_INCREF(groupindex);
self->groupindex = groupindex;
Py_XINCREF(indexgroup);
Py_INCREF(indexgroup);
self->indexgroup = indexgroup;
self->weakreflist = NULL;
if (!_validate(self)) {
Py_DECREF(self);
return NULL;
@ -2649,6 +2647,69 @@ pattern_scanner(PatternObject *self, PyObject *string, Py_ssize_t pos, Py_ssize_
return (PyObject*) scanner;
}
static Py_hash_t
pattern_hash(PatternObject *self)
{
Py_hash_t hash, hash2;
hash = PyObject_Hash(self->pattern);
if (hash == -1) {
return -1;
}
hash2 = _Py_HashBytes(self->code, sizeof(self->code[0]) * self->codesize);
hash ^= hash2;
hash ^= self->flags;
hash ^= self->isbytes;
hash ^= self->codesize;
if (hash == -1) {
hash = -2;
}
return hash;
}
static PyObject*
pattern_richcompare(PyObject *lefto, PyObject *righto, int op)
{
PatternObject *left, *right;
int cmp;
if (op != Py_EQ && op != Py_NE) {
Py_RETURN_NOTIMPLEMENTED;
}
if (Py_TYPE(lefto) != &Pattern_Type || Py_TYPE(righto) != &Pattern_Type) {
Py_RETURN_NOTIMPLEMENTED;
}
left = (PatternObject *)lefto;
right = (PatternObject *)righto;
cmp = (left->flags == right->flags
&& left->isbytes == right->isbytes
&& left->codesize && right->codesize);
if (cmp) {
/* Compare the code and the pattern because the same pattern can
produce different codes depending on the locale used to compile the
pattern when the re.LOCALE flag is used. Don't compare groups,
indexgroup nor groupindex: they are derivated from the pattern. */
cmp = (memcmp(left->code, right->code,
sizeof(left->code[0]) * left->codesize) == 0);
}
if (cmp) {
cmp = PyObject_RichCompareBool(left->pattern, right->pattern,
Py_EQ);
if (cmp < 0) {
return NULL;
}
}
if (op == Py_NE) {
cmp = !cmp;
}
return PyBool_FromLong(cmp);
}
#include "clinic/_sre.c.h"
static PyMethodDef pattern_methods[] = {
@ -2693,7 +2754,7 @@ static PyTypeObject Pattern_Type = {
0, /* tp_as_number */
0, /* tp_as_sequence */
0, /* tp_as_mapping */
0, /* tp_hash */
(hashfunc)pattern_hash, /* tp_hash */
0, /* tp_call */
0, /* tp_str */
0, /* tp_getattro */
@ -2703,7 +2764,7 @@ static PyTypeObject Pattern_Type = {
pattern_doc, /* tp_doc */
0, /* tp_traverse */
0, /* tp_clear */
0, /* tp_richcompare */
pattern_richcompare, /* tp_richcompare */
offsetof(PatternObject, weakreflist), /* tp_weaklistoffset */
0, /* tp_iter */
0, /* tp_iternext */