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QString: fix off-by-one error

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The check for having N valid characters is ptr + N <= end, because
ptr + N == end indicates that we have exactly N characters in the
string.

Change-Id: I5d0ee9389a794d80983efffd152d28d5aa485ce4
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>
This commit is contained in:
Thiago Macieira 2018-05-09 19:52:26 -07:00
parent fae53562ae
commit 68e6d64fe3
1 changed files with 4 additions and 4 deletions
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8
src/corelib/tools/qstring.cpp
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@ -259,7 +259,7 @@ static bool simdTestMask(const char *&ptr, const char *end, quint32 maskval)
# if defined(__AVX2__)
// AVX2 implementation: test 32 bytes at a time
const __m256i mask256 = _mm256_broadcastd_epi32(_mm_cvtsi32_si128(maskval));
while (ptr + 32 < end) {
while (ptr + 32 <= end) {
__m256i data = _mm256_loadu_si256(reinterpret_cast<const __m256i *>(ptr));
if (!_mm256_testz_si256(mask256, data))
return false;
@ -271,7 +271,7 @@ static bool simdTestMask(const char *&ptr, const char *end, quint32 maskval)
// SSE 4.1 implementation: test 32 bytes at a time (two 16-byte
// comparisons, unrolled)
const __m128i mask = _mm_set1_epi32(maskval);
while (ptr + 32 < end) {
while (ptr + 32 <= end) {
__m128i data1 = _mm_loadu_si128(reinterpret_cast<const __m128i *>(ptr));
__m128i data2 = _mm_loadu_si128(reinterpret_cast<const __m128i *>(ptr + 16));
if (!_mm_testz_si128(mask, data1))
@ -283,7 +283,7 @@ static bool simdTestMask(const char *&ptr, const char *end, quint32 maskval)
# endif
# if defined(__SSE4_1__)
// AVX2 and SSE4.1: final 16-byte comparison
if (ptr + 16 < end) {
if (ptr + 16 <= end) {
__m128i data1 = _mm_loadu_si128(reinterpret_cast<const __m128i *>(ptr));
if (!_mm_testz_si128(mask, data1))
return false;
@ -325,7 +325,7 @@ bool QtPrivate::isAscii(QLatin1String s) Q_DECL_NOTHROW
}
#endif
while (ptr + 4 < end) {
while (ptr + 4 <= end) {
quint32 data = qFromUnaligned<quint32>(ptr);
if (data & 0x80808080U)
return false;