From: Victor Stinner <vstinner@python.org>
Date: Wed, 11 May 2022 22:12:42 +0000 (+0200)
Subject: gh-89653: Add assertions to unicodeobject.h functions (#92692)
X-Git-Tag: v3.12.0a1~1576
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=d492f0ab2add26d89474b002a9a5a2da306222c5;p=thirdparty%2FPython%2Fcpython.git

gh-89653: Add assertions to unicodeobject.h functions (#92692)
---

diff --git a/Include/cpython/unicodeobject.h b/Include/cpython/unicodeobject.h
index 4d7173f4213d..b271b610f6d6 100644
--- a/Include/cpython/unicodeobject.h
+++ b/Include/cpython/unicodeobject.h
@@ -28,16 +28,22 @@ static inline int Py_UNICODE_IS_LOW_SURROGATE(Py_UCS4 ch) {
 
 // Join two surrogate characters and return a single Py_UCS4 value.
 static inline Py_UCS4 Py_UNICODE_JOIN_SURROGATES(Py_UCS4 high, Py_UCS4 low)  {
+    assert(Py_UNICODE_IS_HIGH_SURROGATE(high));
+    assert(Py_UNICODE_IS_LOW_SURROGATE(low));
     return 0x10000 + (((high & 0x03FF) << 10) | (low & 0x03FF));
 }
 
-// High surrogate = top 10 bits added to D800
+// High surrogate = top 10 bits added to 0xD800.
+// The character must be in the range [U+10000; U+10ffff].
 static inline Py_UCS4 Py_UNICODE_HIGH_SURROGATE(Py_UCS4 ch) {
+    assert(0x10000 <= ch && ch <= 0x10ffff);
     return (0xD800 - (0x10000 >> 10) + (ch >> 10));
 }
 
-// Low surrogate = bottom 10 bits added to DC00
+// Low surrogate = bottom 10 bits added to 0xDC00.
+// The character must be in the range [U+10000; U+10ffff].
 static inline Py_UCS4 Py_UNICODE_LOW_SURROGATE(Py_UCS4 ch) {
+    assert(0x10000 <= ch && ch <= 0x10ffff);
     return (0xDC00 + (ch & 0x3FF));
 }