diff options
Diffstat (limited to 'source/core/slang-byte-encode-util.cpp')
| -rw-r--r-- | source/core/slang-byte-encode-util.cpp | 26 |
1 files changed, 18 insertions, 8 deletions
diff --git a/source/core/slang-byte-encode-util.cpp b/source/core/slang-byte-encode-util.cpp index 32eb96a29..c542cc265 100644 --- a/source/core/slang-byte-encode-util.cpp +++ b/source/core/slang-byte-encode-util.cpp @@ -256,20 +256,30 @@ static const uint32_t s_unalignedUInt32Mask[5] = int numBytesRemaining = b0 - kLiteCut2 + 2 - 1; #if SLANG_BYTE_ENCODE_USE_UNALIGNED_ACCESS - const uint32_t mask = s_unalignedUInt32Mask[numBytesRemaining]; - //const uint32_t mask = ~(uint32_t(0xffffff00) << ((numBytesRemaining - 1) * 8)); - const uint32_t value = (*(const uint32_t*)encodeIn) & mask; -#else - // This works on all cpus although slower - uint32_t value = encodeIn[0]; - switch (numBytesRemaining) + uint32_t value = 0; + // Do not use unaligned access for the last two values, + // (3rd last is safe because this value will have at least 2 bytes, followed by at worst two 1-byte values) + // otherwise we can access outside the bounds of the encoded array + // This prevents memory validation tools from causing an exception here + if (i < numValues - 2) + { + const uint32_t mask = s_unalignedUInt32Mask[numBytesRemaining]; + //const uint32_t mask = ~(uint32_t(0xffffff00) << ((numBytesRemaining - 1) * 8)); + value = (*(const uint32_t*)encodeIn) & mask; + } + else +#endif { + // This works on all cpus although slower + value = encodeIn[0]; + switch (numBytesRemaining) + { case 4: value |= uint32_t(encodeIn[3]) << 24; /* fall thru */ case 3: value |= uint32_t(encodeIn[2]) << 16; /* fall thru */ case 2: value |= uint32_t(encodeIn[1]) << 8; /* fall thru */ case 1: break; + } } -#endif valuesOut[i] = value; encodeIn += numBytesRemaining; } |