//===--- ClangCommentHTMLNamedCharacterReferenceEmitter.cpp -----------------=//

//

// 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

//

//===----------------------------------------------------------------------===//

//

// This tablegen backend emits an efficient function to translate HTML named

// character references to UTF-8 sequences.

//

//===----------------------------------------------------------------------===//

#include "TableGenBackends.h"

#include "llvm/ADT/SmallString.h"

#include "llvm/Support/ConvertUTF.h"

#include "llvm/TableGen/Error.h"

#include "llvm/TableGen/Record.h"

#include "llvm/TableGen/StringMatcher.h"

#include "llvm/TableGen/TableGenBackend.h"

#include <vector>

using namespace llvm;

/// Convert a code point to the corresponding UTF-8 sequence represented

/// as a C string literal.

///

/// \returns true on success.

static bool translateCodePointToUTF8(unsigned CodePoint,

                                     SmallVectorImpl<char> &CLiteral) {

  char Translated[UNI_MAX_UTF8_BYTES_PER_CODE_POINT];

  char *TranslatedPtr = Translated;

  if (!ConvertCodePointToUTF8(CodePoint, TranslatedPtr))

    return false;

  StringRef UTF8(Translated, TranslatedPtr - Translated);

  raw_svector_ostream OS(CLiteral);

  OS << "\"";

  for (size_t i = 0, e = UTF8.size(); i != e; ++i) {

    OS << "\\x";

    OS.write_hex(static_cast<unsigned char>(UTF8[i]));

  }

  OS << "\"";

  return true;

}

void clang::EmitClangCommentHTMLNamedCharacterReferences(RecordKeeper &Records,

                                                         raw_ostream &OS) {

  std::vector<Record *> Tags = Records.getAllDerivedDefinitions("NCR");

  std::vector<StringMatcher::StringPair> NameToUTF8;

  SmallString<32> CLiteral;

  for (std::vector<Record *>::iterator I = Tags.begin(), E = Tags.end();

       I != E; ++I) {

    Record &Tag = **I;

    std::string Spelling = std::string(Tag.getValueAsString("Spelling"));

    uint64_t CodePoint = Tag.getValueAsInt("CodePoint");

    CLiteral.clear();

    CLiteral.append("return ");

    if (!translateCodePointToUTF8(CodePoint, CLiteral)) {

      SrcMgr.PrintMessage(Tag.getLoc().front(),

                          SourceMgr::DK_Error,

                          Twine("invalid code point"));

      continue;

    }

    CLiteral.append(";");

    StringMatcher::StringPair Match(Spelling, std::string(CLiteral.str()));

    NameToUTF8.push_back(Match);

  }

  emitSourceFileHeader("HTML named character reference to UTF-8 "

                       "translation", OS);

  OS << "StringRef translateHTMLNamedCharacterReferenceToUTF8(\n"

        "                                             StringRef Name) {\n";

  StringMatcher("Name", NameToUTF8, OS).Emit();

  OS << "  return StringRef();\n"

     << "}\n\n";

}