[libc-commits] [libc] [libc][regex] Add 256-bit ByteSet and '.' wildcard (PR #233561)

[Michael Jones via libc-commits]

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@@ -222,6 +227,51 @@ ErrorOr<ExprId> ExprPool::make_lit(char c) {
   return intern(Expr::make_literal(c));
 }
 
+ErrorOr<ExprId> ExprPool::make_byte_set(const ByteSet &bs) {
+  size_t count = 0;
+  size_t last_bit = 0;
+  for (size_t b = 0; b < BYTE_SET_BITS; ++b) {
+    if (bs.test(b)) {
+      ++count;
+      last_bit = b;
+    }
+  }
+  if (count == 0)
+    return empty_set();
+  if (count == 1)
+    return make_lit(static_cast<char>(last_bit));
+
+  uint32_t bs_id = 0;
+  for (const ByteSet &existing : active_byte_sets()) {
+    if (existing == bs)
+      return intern(Expr::make_byte_set(bs_id));
+    ++bs_id;
+  }
+
+  if (byte_set_count == byte_sets.size()) {
+    size_t new_cap =
+        byte_sets.empty() ? INITIAL_BYTE_SETS_CAPACITY : byte_sets.size() * 2;
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michaelrj-google wrote:

nit: iirc there's a scaling factor constant, should that be used here instead of just 2?

https://github.com/llvm/llvm-project/pull/233561