PyErr_Format(): Factor out most of this code into

    PyString_FromFormat() since it's much more generally useful than
    just for exceptions.

Python/errors.c

@@ -385,128 +385,15 @@ PyObject *
 PyErr_Format(PyObject *exception, const char *format, ...)
 {
 	va_list vargs;
-	int n, i;
-	const char* f;
-	char* s;
 	PyObject* string;
 
-	/* step 1: figure out how large a buffer we need */
-
-#ifdef HAVE_STDARG_PROTOTYPES
-	va_start(vargs, format);
-#else
-	va_start(vargs);
-#endif
-
-	n = 0;
-	for (f = format; *f; f++) {
-		if (*f == '%') {
-			const char* p = f;
-			while (*++f && *f != '%' && !isalpha(Py_CHARMASK(*f)))
-				;
-			switch (*f) {
-			case 'c':
-				(void) va_arg(vargs, int);
-				/* fall through... */
-			case '%':
-				n++;
-				break;
-			case 'd': case 'i': case 'x':
-				(void) va_arg(vargs, int);
-				/* 20 bytes should be enough to hold a 64-bit
-				   integer */
-				n = n + 20;
-				break;
-			case 's':
-				s = va_arg(vargs, char*);
-				n = n + strlen(s);
-				break;
-			default:
-				/* if we stumble upon an unknown
-				   formatting code, copy the rest of
-				   the format string to the output
-				   string. (we cannot just skip the
-				   code, since there's no way to know
-				   what's in the argument list) */ 
-				n = n + strlen(p);
-				goto expand;
-			}
-		} else
-			n = n + 1;
-	}
-	
- expand:
-	
-	string = PyString_FromStringAndSize(NULL, n);
-	if (!string)
-		return NULL;
-	
 #ifdef HAVE_STDARG_PROTOTYPES
 	va_start(vargs, format);
 #else
 	va_start(vargs);
 #endif
 
-	/* step 2: fill the buffer */
-
-	s = PyString_AsString(string);
-
-	for (f = format; *f; f++) {
-		if (*f == '%') {
-			const char* p = f++;
-			/* parse the width.precision part (we're only
-			   interested in the precision value, if any) */
-			n = 0;
-			while (isdigit(Py_CHARMASK(*f)))
-				n = (n*10) + *f++ - '0';
-			if (*f == '.') {
-				f++;
-				n = 0;
-				while (isdigit(Py_CHARMASK(*f)))
-					n = (n*10) + *f++ - '0';
-			}
-			while (*f && *f != '%' && !isalpha(Py_CHARMASK(*f)))
-				f++;
-			switch (*f) {
-			case 'c':
-				*s++ = va_arg(vargs, int);
-				break;
-			case 'd': 
-				sprintf(s, "%d", va_arg(vargs, int));
-				s = s + strlen(s);
-				break;
-			case 'i':
-				sprintf(s, "%i", va_arg(vargs, int));
-				s = s + strlen(s);
-				break;
-			case 'x':
-				sprintf(s, "%x", va_arg(vargs, int));
-				s = s + strlen(s);
-				break;
-			case 's':
-				p = va_arg(vargs, char*);
-				i = strlen(p);
-				if (n > 0 && i > n)
-					i = n;
-				memcpy(s, p, i);
-				s = s + i;
-				break;
-			case '%':
-				*s++ = '%';
-				break;
-			default:
-				strcpy(s, p);
-				s = s + strlen(s);
-				goto end;
-			}
-		} else
-			*s++ = *f;
-	}
-	
- end:
-	
-	_PyString_Resize(&string, s - PyString_AsString(string));
-	
+	string = PyString_FromFormatV(format, vargs);
 	PyErr_SetObject(exception, string);
 	Py_XDECREF(string);