llvm-project/llvm/unittests/ADT/TwineTest.cpp

//===- TwineTest.cpp - Twine unit tests -----------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//

#include "llvm/ADT/Twine.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/Support/FormatAdapters.h"
#include "llvm/Support/FormatVariadic.h"
#include "llvm/Support/raw_ostream.h"
#include "gtest/gtest.h"
using namespace llvm;

namespace {

std::string repr(const Twine &Value) {
  std::string res;
  llvm::raw_string_ostream OS(res);
  Value.printRepr(OS);
  return OS.str();
}

TEST(TwineTest, Construction) {
  EXPECT_EQ("", Twine().str());
  EXPECT_EQ("hi", Twine("hi").str());
  EXPECT_EQ("hi", Twine(std::string("hi")).str());
  EXPECT_EQ("hi", Twine(StringRef("hi")).str());
  EXPECT_EQ("hi", Twine(StringRef(std::string("hi"))).str());
  EXPECT_EQ("hi", Twine(StringRef("hithere", 2)).str());
  EXPECT_EQ("hi", Twine(SmallString<4>("hi")).str());
  EXPECT_EQ("hi", Twine(formatv("{0}", "hi")).str());
#if __cplusplus > 201402L
  EXPECT_EQ("hi", Twine(std::string_view("hi")).str());
#endif
}

TEST(TwineTest, Numbers) {
  EXPECT_EQ("123", Twine(123U).str());
  EXPECT_EQ("123", Twine(123).str());
  EXPECT_EQ("-123", Twine(-123).str());
  EXPECT_EQ("123", Twine(123).str());
  EXPECT_EQ("-123", Twine(-123).str());

  EXPECT_EQ("7b", Twine::utohexstr(123).str());
}

TEST(TwineTest, Characters) {
  EXPECT_EQ("x", Twine('x').str());
  EXPECT_EQ("x", Twine(static_cast<unsigned char>('x')).str());
  EXPECT_EQ("x", Twine(static_cast<signed char>('x')).str());
}

TEST(TwineTest, Concat) {
  // Check verse repr, since we care about the actual representation not just
  // the result.

  // Concat with null.
  EXPECT_EQ("(Twine null empty)", 
            repr(Twine("hi").concat(Twine::createNull())));
  EXPECT_EQ("(Twine null empty)", 
            repr(Twine::createNull().concat(Twine("hi"))));
  
  // Concat with empty.
  EXPECT_EQ("(Twine cstring:\"hi\" empty)", 
            repr(Twine("hi").concat(Twine())));
  EXPECT_EQ("(Twine cstring:\"hi\" empty)", 
            repr(Twine().concat(Twine("hi"))));
  EXPECT_EQ("(Twine ptrAndLength:\"hi\" empty)",
            repr(Twine().concat(Twine(SmallString<5>("hi")))));
  EXPECT_EQ("(Twine formatv:\"howdy\" empty)",
            repr(Twine(formatv("howdy")).concat(Twine())));
  EXPECT_EQ("(Twine formatv:\"howdy\" empty)",
            repr(Twine().concat(Twine(formatv("howdy")))));
  EXPECT_EQ("(Twine ptrAndLength:\"hey\" cstring:\"there\")",
            repr(Twine(SmallString<7>("hey")).concat(Twine("there"))));
#if __cplusplus > 201402L
  EXPECT_EQ("(Twine ptrAndLength:\"hey\" cstring:\"there\")",
            repr(Twine(std::string_view("hey")).concat(Twine("there"))));
#endif

  // Concatenation of unary ropes.
  EXPECT_EQ("(Twine cstring:\"a\" cstring:\"b\")", 
            repr(Twine("a").concat(Twine("b"))));

  // Concatenation of other ropes.
  EXPECT_EQ("(Twine rope:(Twine cstring:\"a\" cstring:\"b\") cstring:\"c\")", 
            repr(Twine("a").concat(Twine("b")).concat(Twine("c"))));
  EXPECT_EQ("(Twine cstring:\"a\" rope:(Twine cstring:\"b\" cstring:\"c\"))",
            repr(Twine("a").concat(Twine("b").concat(Twine("c")))));
  EXPECT_EQ(
      "(Twine cstring:\"a\" rope:(Twine ptrAndLength:\"b\" cstring:\"c\"))",
      repr(Twine("a").concat(Twine(SmallString<3>("b")).concat(Twine("c")))));
}

TEST(TwineTest, toNullTerminatedStringRef) {
  SmallString<8> storage;
  EXPECT_EQ(0, *Twine("hello").toNullTerminatedStringRef(storage).end());
  EXPECT_EQ(0,
           *Twine(StringRef("hello")).toNullTerminatedStringRef(storage).end());
  EXPECT_EQ(0, *Twine(SmallString<11>("hello"))
                    .toNullTerminatedStringRef(storage)
                    .end());
  EXPECT_EQ(0, *Twine(formatv("{0}{1}", "how", "dy"))
                    .toNullTerminatedStringRef(storage)
                    .end());
}

TEST(TwineTest, LazyEvaluation) {
  struct formatter : FormatAdapter<int> {
    explicit formatter(int &Count) : FormatAdapter(0), Count(Count) {}
    int &Count;

    void format(raw_ostream &OS, StringRef Style) override { ++Count; }
  };

  int Count = 0;
  formatter Formatter(Count);
  (void)Twine(formatv("{0}", Formatter));
  EXPECT_EQ(0, Count);
  (void)Twine(formatv("{0}", Formatter)).str();
  EXPECT_EQ(1, Count);
}

  // I suppose linking in the entire code generator to add a unit test to check
  // the code size of the concat operation is overkill... :)

} // end anonymous namespace