Add asciilib: similar to ucs1, ucs2 and ucs4 library, but specialized to ASCII

ucs1, ucs2 and ucs4 libraries have to scan created substring to find the
maximum character, whereas it is not need to ASCII strings. Because ASCII
strings are common, it is useful to optimize ASCII.

Include/unicodeobject.h

@@ -1851,6 +1851,7 @@ PyAPI_FUNC(Py_ssize_t) _PyUnicode_InsertThousandsGroupingLocale(Py_UNICODE *buff
    see Objects/stringlib/localeutil.h */
 #ifndef Py_LIMITED_API
 PyAPI_FUNC(Py_ssize_t) _PyUnicode_InsertThousandsGrouping(
+    PyObject *unicode,
     int kind,
     void *buffer,
     Py_ssize_t n_buffer,

Objects/stringlib/asciilib.h

+/* this is sort of a hack.  there's at least one place (formatting
+   floats) where some stringlib code takes a different path if it's
+   compiled as unicode. */
+#define STRINGLIB_IS_UNICODE     1
+
+#define FASTSEARCH               asciilib_fastsearch
+#define STRINGLIB(F)             asciilib_##F
+#define STRINGLIB_OBJECT         PyUnicodeObject
+#define STRINGLIB_CHAR           Py_UCS1
+#define STRINGLIB_TYPE_NAME      "unicode"
+#define STRINGLIB_PARSE_CODE     "U"
+#define STRINGLIB_EMPTY          unicode_empty
+#define STRINGLIB_ISSPACE        Py_UNICODE_ISSPACE
+#define STRINGLIB_ISLINEBREAK    BLOOM_LINEBREAK
+#define STRINGLIB_ISDECIMAL      Py_UNICODE_ISDECIMAL
+#define STRINGLIB_TODECIMAL      Py_UNICODE_TODECIMAL
+#define STRINGLIB_TOUPPER        Py_UNICODE_TOUPPER
+#define STRINGLIB_TOLOWER        Py_UNICODE_TOLOWER
+#define STRINGLIB_FILL           Py_UNICODE_FILL
+#define STRINGLIB_STR            PyUnicode_1BYTE_DATA
+#define STRINGLIB_LEN            PyUnicode_GET_LENGTH
+#define STRINGLIB_NEW            unicode_fromascii
+#define STRINGLIB_RESIZE         not_supported
+#define STRINGLIB_CHECK          PyUnicode_Check
+#define STRINGLIB_CHECK_EXACT    PyUnicode_CheckExact
+#define STRINGLIB_GROUPING       _PyUnicode_InsertThousandsGrouping
+#define STRINGLIB_GROUPING_LOCALE _PyUnicode_InsertThousandsGroupingLocale
+
+#define STRINGLIB_TOSTR          PyObject_Str
+#define STRINGLIB_TOASCII        PyObject_ASCII
+
+#define _Py_InsertThousandsGrouping _PyUnicode_ascii_InsertThousandsGrouping
+#define _Py_InsertThousandsGroupingLocale _PyUnicode_ascii_InsertThousandsGroupingLocale
+

Python/formatter_unicode.c

@@ -501,7 +501,7 @@ calc_number_widths(NumberFieldWidths *spec, Py_ssize_t n_prefix,
         spec->n_grouped_digits = 0;
     else
         spec->n_grouped_digits = _PyUnicode_InsertThousandsGrouping(
-            PyUnicode_1BYTE_KIND, NULL, 0, NULL,
+            NULL, PyUnicode_1BYTE_KIND, NULL, 0, NULL,
             spec->n_digits, spec->n_min_width,
             locale->grouping, locale->thousands_sep);
 
@@ -603,7 +603,7 @@ fill_number(PyObject *out, Py_ssize_t pos, const NumberFieldWidths *spec,
         r =
 #endif
             _PyUnicode_InsertThousandsGrouping(
-                kind,
+                out, kind,
                 (char*)data + PyUnicode_KIND_SIZE(kind, pos),
                 spec->n_grouped_digits,
                 pdigits + PyUnicode_KIND_SIZE(kind, d_pos),