Merge 3.3 into default.
cwr_next(): move invariants out of loops. This simplifies and clarifies the code, and gives a small speedup.
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c6171e49ab
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@ -2713,20 +2713,20 @@ cwr_next(cwrobject *co)
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PyObject *result = co->result;
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Py_ssize_t n = PyTuple_GET_SIZE(pool);
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Py_ssize_t r = co->r;
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Py_ssize_t i, j, index;
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Py_ssize_t i, index;
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if (co->stopped)
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return NULL;
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if (result == NULL) {
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/* On the first pass, initialize result tuple using the indices */
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/* On the first pass, initialize result tuple with pool[0] */
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result = PyTuple_New(r);
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if (result == NULL)
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goto empty;
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co->result = result;
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elem = PyTuple_GET_ITEM(pool, 0);
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for (i=0; i<r ; i++) {
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index = indices[i];
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elem = PyTuple_GET_ITEM(pool, index);
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assert(indices[i] == 0);
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Py_INCREF(elem);
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PyTuple_SET_ITEM(result, i, elem);
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}
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@ -2749,27 +2749,23 @@ cwr_next(cwrobject *co)
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empty tuple is a singleton and cached in PyTuple's freelist. */
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assert(r == 0 || Py_REFCNT(result) == 1);
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/* Scan indices right-to-left until finding one that is not
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* at its maximum (n-1). */
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/* Scan indices right-to-left until finding one that is not
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* at its maximum (n-1). */
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for (i=r-1 ; i >= 0 && indices[i] == n-1; i--)
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;
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/* If i is negative, then the indices are all at
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their maximum value and we're done. */
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their maximum value and we're done. */
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if (i < 0)
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goto empty;
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/* Increment the current index which we know is not at its
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maximum. Then set all to the right to the same value. */
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indices[i]++;
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for (j=i+1 ; j<r ; j++)
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indices[j] = indices[j-1];
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/* Update the result tuple for the new indices
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starting with i, the leftmost index that changed */
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maximum. Then set all to the right to the same value. */
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index = indices[i] + 1;
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assert(index < n);
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elem = PyTuple_GET_ITEM(pool, index);
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for ( ; i<r ; i++) {
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index = indices[i];
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elem = PyTuple_GET_ITEM(pool, index);
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indices[i] = index;
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Py_INCREF(elem);
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oldelem = PyTuple_GET_ITEM(result, i);
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PyTuple_SET_ITEM(result, i, elem);
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