[libc-commits] [libc] [libc] [search] improve hsearch robustness (PR #73896)

[Schrodinger ZHU Yifan via libc-commits]

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@@ -128,6 +147,107 @@ struct HashTable {
     control(index2) = value;
   }
 
+  LIBC_INLINE size_t find(const char *key, uint64_t primary) {
+    uint8_t secondary = secondary_hash(primary);
+    ProbeSequence sequence{static_cast<size_t>(primary), 0, entries_mask};
+    while (true) {
+      size_t pos = sequence.next();
+      Group ctrls = Group::load(&control(pos));
+      IteratableBitMask masks = ctrls.match_byte(secondary);
+      for (size_t i : masks) {
+        size_t index = (pos + i) & entries_mask;
+        ENTRY &entry = this->entry(index);
+        if (LIBC_LIKELY(entry.key != nullptr && strcmp(entry.key, key) == 0))
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SchrodingerZhu wrote:

I suppose that may not be needed. For one thing, it is not that trivial to check nul termination. For the other thing, if we get to this point, both `entry.key` and `key` has been passed into `strlen` for hash somewhere. (Though the user can change the string in some wrong way as we only record the pointers)

https://github.com/llvm/llvm-project/pull/73896