hhr293 commented on code in PR #12299:
URL: https://github.com/apache/gluten/pull/12299#discussion_r3457191249
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cpp/core/utils/tac/ffor.hpp:
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@@ -418,82 +452,245 @@ inline size_t compress64(const uint64_t* input, size_t
num, uint8_t* output) {
}
// Template-based decompress with alignment dispatch.
+// decodeBlock requires aligned uint64_t* input; when the caller's input
+// buffer is unaligned, we stage through tmpIn and memcpy in.
template <bool InAligned, bool OutAligned>
-inline size_t decompress64Impl(const uint8_t* input, size_t inputSize,
uint64_t* output) {
- alignas(64) uint64_t tmpIn[kMaxValuesPerBlock];
+inline size_t decompress64Impl(const uint8_t* input, size_t inputSize,
uint64_t* output, size_t outputSize) {
+ alignas(64) uint64_t tmpIn[kMaxValuesPerBlock + 2];
alignas(64) uint64_t tmpOut[kMaxValuesPerBlock];
const uint8_t* inPtr = input;
const uint8_t* inEnd = input + inputSize;
+ const size_t outValuesMax = outputSize / sizeof(uint64_t);
size_t nDecoded = 0;
while (inPtr + kHeaderSize <= inEnd) {
- uint8_t bw;
- uint8_t count;
- uint64_t base;
- readHeader(inPtr, bw, count, base);
- inPtr += kHeaderSize;
-
- if (bw == kBwTailMarker) {
- if (count > 0) {
- // memcpy handles any alignment, no special case needed.
- std::memcpy(reinterpret_cast<uint8_t*>(output) + nDecoded *
sizeof(uint64_t), inPtr, count * sizeof(uint64_t));
+ if (inPtr[0] == kBwTailMarker) {
+ const uint8_t count = inPtr[1];
+ inPtr += kHeaderSize;
+ const size_t tailBytes = static_cast<size_t>(count) * sizeof(uint64_t);
+ if (count > 0 && inPtr + tailBytes <= inEnd && count <= outValuesMax -
nDecoded) {
+ std::memcpy(reinterpret_cast<uint8_t*>(output) + nDecoded *
sizeof(uint64_t), inPtr, tailBytes);
nDecoded += count;
}
break;
}
Review Comment:
OOB is already closed by count > outValuesMax - nDecoded — any count is
memory-safe. The tail path is a raw memcpy, not a parse, so count >= kLanes is
well-defined to decode. The < kLanes invariant lives on the encoder side (while
(remaining >= kLanes)), and the existing TypeAwareCompressCodec value-count
check already surfaces malformed streams to the caller. Adding the check just
moves which line the early-break triggers on without catching anything new.
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