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Issue #14744: Use the new _PyUnicodeWriter internal API to speed up str%args and str.format(args)

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* Formatting string, int, float and complex use the _PyUnicodeWriter API. It
   avoids a temporary buffer in most cases.
 * Add _PyUnicodeWriter_WriteStr() to restore the PyAccu optimization: just
   keep a reference to the string if the output is only composed of one string
 * Disable overallocation when formatting the last argument of str%args and
   str.format(args)
 * Overallocation allocates at least 100 characters: add min_length attribute
   to the _PyUnicodeWriter structure
 * Add new private functions: _PyUnicode_FastCopyCharacters(),
   _PyUnicode_FastFill() and _PyUnicode_FromASCII()

The speed up is around 20% in average.
This commit is contained in:
Victor Stinner 2012-05-29 12:57:52 +02:00
parent a1b0c9fc4d
commit d3f0882dfb
12 changed files with 878 additions and 437 deletions
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46
Objects/stringlib/unicode_format.h
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@ -499,26 +499,26 @@ render_field(PyObject *fieldobj, SubString *format_spec, _PyUnicodeWriter *write
int ok = 0;
PyObject *result = NULL;
PyObject *format_spec_object = NULL;
PyObject *(*formatter)(PyObject *, PyObject *, Py_ssize_t, Py_ssize_t) = NULL;
Py_ssize_t len;
int (*formatter) (_PyUnicodeWriter*, PyObject *, PyObject *, Py_ssize_t, Py_ssize_t) = NULL;
int err;
/* If we know the type exactly, skip the lookup of __format__ and just
call the formatter directly. */
if (PyUnicode_CheckExact(fieldobj))
formatter = _PyUnicode_FormatAdvanced;
formatter = _PyUnicode_FormatAdvancedWriter;
else if (PyLong_CheckExact(fieldobj))
formatter =_PyLong_FormatAdvanced;
formatter = _PyLong_FormatAdvancedWriter;
else if (PyFloat_CheckExact(fieldobj))
formatter = _PyFloat_FormatAdvanced;
/* XXX: for 2.6, convert format_spec to the appropriate type
(unicode, str) */
formatter = _PyFloat_FormatAdvancedWriter;
else if (PyComplex_CheckExact(fieldobj))
formatter = _PyComplex_FormatAdvancedWriter;
if (formatter) {
/* we know exactly which formatter will be called when __format__ is
looked up, so call it directly, instead. */
result = formatter(fieldobj, format_spec->str,
format_spec->start, format_spec->end);
err = formatter(writer, fieldobj, format_spec->str,
format_spec->start, format_spec->end);
return (err == 0);
}
else {
/* We need to create an object out of the pointers we have, because
@ -536,17 +536,11 @@ render_field(PyObject *fieldobj, SubString *format_spec, _PyUnicodeWriter *write
}
if (result == NULL)
goto done;
if (PyUnicode_READY(result) == -1)
goto done;
len = PyUnicode_GET_LENGTH(result);
if (_PyUnicodeWriter_Prepare(writer,
len, PyUnicode_MAX_CHAR_VALUE(result)) == -1)
if (_PyUnicodeWriter_WriteStr(writer, result) == -1)
goto done;
copy_characters(writer->buffer, writer->pos,
result, 0, len);
writer->pos += len;
ok = 1;
done:
Py_XDECREF(format_spec_object);
Py_XDECREF(result);
@ -897,16 +891,19 @@ do_markup(SubString *input, PyObject *args, PyObject *kwargs,
err = _PyUnicodeWriter_Prepare(writer, sublen, maxchar);
if (err == -1)
return 0;
copy_characters(writer->buffer, writer->pos,
literal.str, literal.start, sublen);
_PyUnicode_FastCopyCharacters(writer->buffer, writer->pos,
literal.str, literal.start, sublen);
writer->pos += sublen;
}
if (field_present)
if (field_present) {
if (iter.str.start == iter.str.end)
writer->flags.overallocate = 0;
if (!output_markup(&field_name, &format_spec,
format_spec_needs_expanding, conversion, writer,
args, kwargs, recursion_depth, auto_number))
return 0;
}
}
return result;
}
@ -921,7 +918,7 @@ build_string(SubString *input, PyObject *args, PyObject *kwargs,
int recursion_depth, AutoNumber *auto_number)
{
_PyUnicodeWriter writer;
Py_ssize_t initlen;
Py_ssize_t minlen;
/* check the recursion level */
if (recursion_depth <= 0) {
@ -930,9 +927,8 @@ build_string(SubString *input, PyObject *args, PyObject *kwargs,
return NULL;
}
initlen = PyUnicode_GET_LENGTH(input->str) + 100;
if (_PyUnicodeWriter_Init(&writer, initlen, 127) == -1)
return NULL;
minlen = PyUnicode_GET_LENGTH(input->str) + 100;
_PyUnicodeWriter_Init(&writer, minlen);
if (!do_markup(input, args, kwargs, &writer, recursion_depth,
auto_number)) {