[flang-commits] [flang] [llvm] [Flang] Introduce *Value classes with unittests (PR #216958)

[Michael Kruse via flang-commits]

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@@ -0,0 +1,250 @@
+//===-- include/flang/Evaluate/character-value.h ----------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef FORTRAN_EVALUATE_CHARACTER_VALUE_H_
+#define FORTRAN_EVALUATE_CHARACTER_VALUE_H_
+
+#include "flang/Evaluate/common.h"
+#include "flang/Evaluate/object-sizes.h"
+#include "flang/Evaluate/type.h"
+#include "llvm/Support/Compiler.h"
+#include "llvm/Support/raw_ostream.h"
+#include <cstddef>
+#include <iosfwd>
+#include <optional>
+#include <string>
+
+namespace Fortran::evaluate::value {
+class CharacterValueImpl;
+
+/// A character string with dynamic character representation with
+/// std::basic_string-like API.
+///
+/// The character type is dynamic between char, char16_t, and char32_t. As being
+/// able to represent all values, char32_t is used when passing single
+/// characters. It is also kind-aware, i.e. knows which CHARACTER kind it
+/// currently represents.
+///
+/// The implementation is hidden from this header using a pImpl-like idiom.
+class CharacterValue {
+public:
+  // rule-of-five
+  ~CharacterValue();
+  CharacterValue(const CharacterValue &);
+  CharacterValue(CharacterValue &&);
+  CharacterValue &operator=(const CharacterValue &);
+  CharacterValue &operator=(CharacterValue &&);
+
+  // ctors
+
+  /// A default-initialized CharacterValue is in a null state; it
+  /// represents an empty string, but its kind is not yet known. Not all
+  /// operations are supported in this state.
+  CharacterValue();
+
+  explicit CharacterValue(int kind, std::string s);
+  explicit CharacterValue(int kind, std::u16string s);
+  explicit CharacterValue(int kind, std::u32string s);
+
+  /// Fill constructor: create a string of n copies of the given character.
+  CharacterValue(int kind, std::size_t n, char32_t c);
+
+  // Named ctors
+  static CharacterValue Zero(int kind);
+
+  static CharacterValue FromRawBytes(
+      int kind, const void *raw, size_t byteSize);
+
+  void print(llvm::raw_ostream &os) const;
+
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
+  LLVM_DUMP_METHOD void dump() const;
+#endif
+
+  /// Whether this object represents a default-initialized value (zero) of
+  /// not-yet-known kind.
+  bool IsNull() const;
+
+  /// The kind of the value currently stored.
+  int kind() const;
+
+  bool empty() const;
+  std::size_t size() const;
+  std::size_t length() const { return size(); }
+
+  /// Byte size of one character unit (1, 2, or 4).
+  std::size_t charSize() const { return kind(); }
+
+  /// Number of bytes accessed by FromRawBytes/StoreRawBytes
+  size_t bytesStored() const { return length() * charSize(); }
+
+  // Casting to other representations
+  std::optional<llvm::StringRef> AsStringRef() const;
+  std::optional<std::string> AsStdString() const {
+    if (auto str{AsStringRef()}) {
+      return str->str();
+    }
+    return std::nullopt;
+  }
+  std::optional<std::u16string> AsU16String() const;
+  std::optional<std::u32string> AsU32String() const;
+
+  /// Force conversion to Ascii even if this means loss of information
+  std::string ToStdString() const;
+
+  template <typename CharT, typename = std::void_t<std::basic_string<CharT>>>
+  std::optional<std::basic_string<CharT>> AsBasicString() const {
+    if constexpr (std::is_same_v<char, CharT>) {
+      return AsStdString();
+    } else if constexpr (std::is_same_v<char16_t, CharT>) {
+      return AsU16String();
+    } else if constexpr (std::is_same_v<char32_t, CharT>) {
+      return AsU32String();
+    } else {
+      static_assert(false, "Must be one of the supported character types");
----------------
Meinersbur wrote:

fixed in next update

https://github.com/llvm/llvm-project/pull/216958