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PyUnicode_Join(): Rewrote to use PySequence_Fast(). This doesn't do
much to reduce the size of the code, but greatly improves its clarity. It's also quicker in what's probably the most common case (the argument iterable is a list). Against it, if the iterable isn't a list or a tuple, a temp tuple is materialized containing the entire input sequence, and that's a bigger temp memory burden. Yawn.
This commit is contained in:
Tim Peters
parent
cca018356d
commit
05eba1fdc8
1 changed files with 96 additions and 126 deletions
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@ -3979,159 +3979,129 @@ PyObject *
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PyUnicode_Join(PyObject *separator, PyObject *seq)
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PyUnicode_Join(PyObject *separator, PyObject *seq)
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{
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{
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PyObject *internal_separator = NULL;
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PyObject *internal_separator = NULL;
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Py_UNICODE *sep;
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const Py_UNICODE *sep;
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size_t seplen;
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size_t seplen;
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PyUnicodeObject *res = NULL;
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PyUnicodeObject *res = NULL; /* the result */
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size_t sz; /* # allocated bytes for string in res */
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size_t res_alloc = 100; /* # allocated bytes for string in res */
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size_t reslen; /* # used bytes */
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size_t res_used; /* # used bytes */
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Py_UNICODE *p; /* pointer to free byte in res's string area */
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Py_UNICODE *res_p; /* pointer to free byte in res's string area */
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PyObject *it; /* iterator */
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PyObject *fseq; /* PySequence_Fast(seq) */
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int seqlen; /* len(fseq) -- number of items in sequence */
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const Py_UNICODE blank = ' ';
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PyObject *item;
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PyObject *item;
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int i;
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int i;
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PyObject *temp;
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it = PyObject_GetIter(seq);
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fseq = PySequence_Fast(seq, "");
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if (it == NULL)
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if (fseq == NULL) {
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return NULL;
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if (PyErr_ExceptionMatches(PyExc_TypeError))
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PyErr_Format(PyExc_TypeError,
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item = PyIter_Next(it);
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"sequence expected, %.80s found",
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if (item == NULL) {
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seq->ob_type->tp_name);
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if (PyErr_Occurred())
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return NULL;
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goto onError;
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/* empty sequence; return u"" */
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res = _PyUnicode_New(0);
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goto Done;
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}
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}
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/* If this is the only item, maybe we can get out cheap. */
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seqlen = PySequence_Fast_GET_SIZE(fseq);
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res = (PyUnicodeObject *)item;
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/* If empty sequence, return u"". */
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item = PyIter_Next(it);
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if (seqlen == 0) {
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if (item == NULL) {
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res = _PyUnicode_New(0); /* empty sequence; return u"" */
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if (PyErr_Occurred())
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goto Done;
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goto onError;
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}
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/* There's only one item in the sequence. */
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/* If singleton sequence with an exact Unicode, return that. */
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if (PyUnicode_CheckExact(res)) /* whatever.join([u]) -> u */
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if (seqlen == 1) {
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goto Done;
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item = PySequence_Fast_GET_ITEM(fseq, 0);
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if (PyUnicode_CheckExact(item)) {
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Py_INCREF(item);
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res = (PyUnicodeObject *)item;
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goto Done;
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}
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}
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}
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/* There are at least two to join (item != NULL), or there's only
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/* At least two items to join, or one that isn't exact Unicode. */
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* one but it's not an exact Unicode (item == NULL). res needs
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if (seqlen > 1) {
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* conversion to Unicode in either case.
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/* Set up sep and seplen -- they're needed. */
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* Caution: we may need to ensure a copy is made, and that's trickier
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if (separator == NULL) {
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* than it sounds because, e.g., PyUnicode_FromObject() may return
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sep = ␣
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* a shared object (which must not be mutated).
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seplen = 1;
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*/
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}
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if (! PyUnicode_Check(res) && ! PyString_Check(res)) {
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else {
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PyErr_Format(PyExc_TypeError,
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internal_separator = PyUnicode_FromObject(separator);
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"sequence item 0: expected string or Unicode,"
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if (internal_separator == NULL)
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" %.80s found",
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goto onError;
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res->ob_type->tp_name);
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sep = PyUnicode_AS_UNICODE(internal_separator);
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Py_XDECREF(item);
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seplen = PyUnicode_GET_SIZE(internal_separator);
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}
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}
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/* Get space. */
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res = _PyUnicode_New((int)res_alloc);
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if (res == NULL)
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goto onError;
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goto onError;
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}
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res_p = PyUnicode_AS_UNICODE(res);
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temp = PyUnicode_FromObject((PyObject *)res);
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res_used = 0;
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if (temp == NULL) {
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Py_XDECREF(item);
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goto onError;
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}
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Py_DECREF(res);
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if (item == NULL) {
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/* res was the only item */
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res = (PyUnicodeObject *)temp;
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goto Done;
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}
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/* There are at least two items. As above, temp may be a shared object,
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* so we need to copy it.
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*/
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reslen = PyUnicode_GET_SIZE(temp);
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sz = reslen + 100; /* breathing room */
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if (sz < reslen || sz > INT_MAX) /* overflow -- no breathing room */
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sz = reslen;
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res = _PyUnicode_New((int)sz);
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if (res == NULL) {
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Py_DECREF(item);
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goto onError;
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}
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p = PyUnicode_AS_UNICODE(res);
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Py_UNICODE_COPY(p, PyUnicode_AS_UNICODE(temp), (int)reslen);
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p += reslen;
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Py_DECREF(temp);
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if (separator == NULL) {
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for (i = 0; i < seqlen; ++i) {
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Py_UNICODE blank = ' ';
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size_t itemlen;
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sep = ␣
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size_t new_res_used;
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seplen = 1;
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}
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item = PySequence_Fast_GET_ITEM(fseq, i);
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else {
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/* Convert item to Unicode. */
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internal_separator = PyUnicode_FromObject(separator);
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if (! PyUnicode_Check(item) && ! PyString_Check(item)) {
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if (internal_separator == NULL) {
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PyErr_Format(PyExc_TypeError,
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Py_DECREF(item);
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"sequence item %i: expected string or Unicode,"
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" %.80s found",
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i, item->ob_type->tp_name);
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goto onError;
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goto onError;
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}
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}
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sep = PyUnicode_AS_UNICODE(internal_separator);
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item = PyUnicode_FromObject(item);
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seplen = PyUnicode_GET_SIZE(internal_separator);
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if (item == NULL)
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}
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goto onError;
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/* We own a reference to item from here on. */
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i = 1;
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do {
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size_t itemlen;
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size_t newreslen;
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/* Catenate the separator, then item. */
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/* First convert item to Unicode. */
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if (!PyUnicode_Check(item)) {
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PyObject *v;
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if (!PyString_Check(item)) {
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PyErr_Format(PyExc_TypeError,
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"sequence item %i: expected string or Unicode,"
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" %.80s found",
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i, item->ob_type->tp_name);
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Py_DECREF(item);
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goto onError;
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}
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v = PyUnicode_FromObject(item);
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Py_DECREF(item);
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item = v;
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if (item == NULL)
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goto onError;
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}
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/* Make sure we have enough space for the separator and the item. */
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/* Make sure we have enough space for the separator and the item. */
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itemlen = PyUnicode_GET_SIZE(item);
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itemlen = PyUnicode_GET_SIZE(item);
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newreslen = reslen + seplen + itemlen;
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new_res_used = res_used + itemlen;
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if (newreslen < reslen || newreslen > INT_MAX)
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if (new_res_used < res_used || new_res_used > INT_MAX)
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goto Overflow;
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goto Overflow;
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if (newreslen > sz) {
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if (i < seqlen - 1) {
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new_res_used += seplen;
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if (new_res_used < res_used || new_res_used > INT_MAX)
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goto Overflow;
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}
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if (new_res_used > res_alloc) {
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/* double allocated size until it's big enough */
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do {
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do {
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size_t oldsize = sz;
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size_t oldsize = res_alloc;
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sz += sz;
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res_alloc += res_alloc;
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if (sz < oldsize || sz > INT_MAX)
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if (res_alloc < oldsize || res_alloc > INT_MAX)
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goto Overflow;
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goto Overflow;
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} while (newreslen > sz);
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} while (new_res_used > res_alloc);
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if (_PyUnicode_Resize(&res, (int)sz) < 0) {
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if (_PyUnicode_Resize(&res, (int)res_alloc) < 0) {
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Py_DECREF(item);
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Py_DECREF(item);
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goto onError;
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goto onError;
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}
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}
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p = PyUnicode_AS_UNICODE(res) + reslen;
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res_p = PyUnicode_AS_UNICODE(res) + res_used;
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}
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/* Copy item, and maybe the separator. */
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Py_UNICODE_COPY(res_p, PyUnicode_AS_UNICODE(item), (int)itemlen);
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res_p += itemlen;
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if (i < seqlen - 1) {
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Py_UNICODE_COPY(res_p, sep, (int)seplen);
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res_p += seplen;
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}
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}
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Py_UNICODE_COPY(p, sep, (int)seplen);
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p += seplen;
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Py_UNICODE_COPY(p, PyUnicode_AS_UNICODE(item), (int)itemlen);
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p += itemlen;
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Py_DECREF(item);
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Py_DECREF(item);
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reslen = newreslen;
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res_used = new_res_used;
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}
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++i;
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/* Shrink res to match the used area; this probably can't fail,
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item = PyIter_Next(it);
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* but it's cheap to check.
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} while (item != NULL);
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*/
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if (PyErr_Occurred())
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if (_PyUnicode_Resize(&res, (int)res_used) < 0)
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goto onError;
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if (_PyUnicode_Resize(&res, (int)reslen) < 0)
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goto onError;
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goto onError;
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Done:
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Done:
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Py_XDECREF(internal_separator);
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Py_XDECREF(internal_separator);
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Py_DECREF(it);
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Py_DECREF(fseq);
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return (PyObject *)res;
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return (PyObject *)res;
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Overflow:
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Overflow:
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@ -4142,7 +4112,7 @@ PyUnicode_Join(PyObject *separator, PyObject *seq)
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onError:
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onError:
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Py_XDECREF(internal_separator);
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Py_XDECREF(internal_separator);
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Py_DECREF(it);
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Py_DECREF(fseq);
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Py_XDECREF(res);
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Py_XDECREF(res);
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return NULL;
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return NULL;
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}
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}
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