[Python-checkins] bpo-33954: Rewrite FILL() macro of unicodeobject.c (GH-10740)

Tue Nov 27 08:31:01 EST 2018

https://github.com/python/cpython/commit/54fa83e0a3f3b077763cb50705d7a7dbe4a40a4a
commit: 54fa83e0a3f3b077763cb50705d7a7dbe4a40a4a
branch: 3.6
author: Victor Stinner <vstinner at redhat.com>
committer: GitHub <noreply at github.com>
date: 2018年11月27日T14:30:55+01:00
summary:
bpo-33954: Rewrite FILL() macro of unicodeobject.c (GH-10740)
Copy code from master: add assertions on start and value, replace 'i'
iterator with 'end' pointer for the loop stop condition.
_PyUnicode_FastFill(): fix type of 'data', it must not be constant,
since data is modified by FILL().
files:
M Objects/unicodeobject.c

diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index 6bfcddaa64e4..29b019887ac0 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -205,22 +205,30 @@ static PyObject *unicode_empty = NULL;
 
 #define FILL(kind, data, value, start, length) \
 do { \
- Py_ssize_t i_ = 0; \
+ assert(0 <= start); \
 assert(kind != PyUnicode_WCHAR_KIND); \
- switch ((kind)) { \
+ switch (kind) { \
 case PyUnicode_1BYTE_KIND: { \
- unsigned char * to_ = (unsigned char *)((data)) + (start); \
- memset(to_, (unsigned char)value, (length)); \
+ assert(value <= 0xff); \
+ Py_UCS1 ch = (unsigned char)value; \
+ Py_UCS1 *to = (Py_UCS1 *)data + start; \
+ memset(to, ch, length); \
 break; \
 } \
 case PyUnicode_2BYTE_KIND: { \
- Py_UCS2 * to_ = (Py_UCS2 *)((data)) + (start); \
- for (; i_ < (length); ++i_, ++to_) *to_ = (value); \
+ assert(value <= 0xffff); \
+ Py_UCS2 ch = (Py_UCS2)value; \
+ Py_UCS2 *to = (Py_UCS2 *)data + start; \
+ const Py_UCS2 *end = to + length; \
+ for (; to < end; ++to) *to = ch; \
 break; \
 } \
 case PyUnicode_4BYTE_KIND: { \
- Py_UCS4 * to_ = (Py_UCS4 *)((data)) + (start); \
- for (; i_ < (length); ++i_, ++to_) *to_ = (value); \
+ assert(value <= MAX_UNICODE); \
+ Py_UCS4 ch = value; \
+ Py_UCS4 * to = (Py_UCS4 *)data + start; \
+ const Py_UCS4 *end = to + length; \
+ for (; to < end; ++to) *to = ch; \
 break; \
 } \
 default: assert(0); \
@@ -10262,7 +10270,7 @@ _PyUnicode_FastFill(PyObject *unicode, Py_ssize_t start, Py_ssize_t length,
 Py_UCS4 fill_char)
 {
 const enum PyUnicode_Kind kind = PyUnicode_KIND(unicode);
- const void *data = PyUnicode_DATA(unicode);
+ void *data = PyUnicode_DATA(unicode);
 assert(PyUnicode_IS_READY(unicode));
 assert(unicode_modifiable(unicode));
 assert(fill_char <= PyUnicode_MAX_CHAR_VALUE(unicode));
