//===-- ConvertUTFWrapper.cpp - Wrap ConvertUTF.h with clang data types -----===

//

// 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/ArrayRef.h"

#include "llvm/ADT/StringRef.h"

#include "llvm/Support/ConvertUTF.h"

#include "llvm/Support/ErrorHandling.h"

#include "llvm/Support/SwapByteOrder.h"

#include <string>

#include <vector>

namespace llvm {

bool ConvertUTF8toWide(unsigned WideCharWidth, llvm::StringRef Source,

                       char *&ResultPtr, const UTF8 *&ErrorPtr) {

  assert(WideCharWidth == 1 || WideCharWidth == 2 || WideCharWidth == 4);

  ConversionResult result = conversionOK;

  // Copy the character span over.

  if (WideCharWidth == 1) {

    const UTF8 *Pos = reinterpret_cast<const UTF8*>(Source.begin());

    if (!isLegalUTF8String(&Pos, reinterpret_cast<const UTF8*>(Source.end()))) {

      result = sourceIllegal;

      ErrorPtr = Pos;

    } else {

      memcpy(ResultPtr, Source.data(), Source.size());

      ResultPtr += Source.size();

    }

  } else if (WideCharWidth == 2) {

    const UTF8 *sourceStart = (const UTF8*)Source.data();

    // FIXME: Make the type of the result buffer correct instead of

    // using reinterpret_cast.

    UTF16 *targetStart = reinterpret_cast<UTF16*>(ResultPtr);

    ConversionFlags flags = strictConversion;

    result = ConvertUTF8toUTF16(

        &sourceStart, sourceStart + Source.size(),

        &targetStart, targetStart + Source.size(), flags);

    if (result == conversionOK)

      ResultPtr = reinterpret_cast<char*>(targetStart);

    else

      ErrorPtr = sourceStart;

  } else if (WideCharWidth == 4) {

    const UTF8 *sourceStart = (const UTF8*)Source.data();

    // FIXME: Make the type of the result buffer correct instead of

    // using reinterpret_cast.

    UTF32 *targetStart = reinterpret_cast<UTF32*>(ResultPtr);

    ConversionFlags flags = strictConversion;

    result = ConvertUTF8toUTF32(

        &sourceStart, sourceStart + Source.size(),

        &targetStart, targetStart + Source.size(), flags);

    if (result == conversionOK)

      ResultPtr = reinterpret_cast<char*>(targetStart);

    else

      ErrorPtr = sourceStart;

  }

  assert((result != targetExhausted)

         && "ConvertUTF8toUTFXX exhausted target buffer");

  return result == conversionOK;

}

bool ConvertCodePointToUTF8(unsigned Source, char *&ResultPtr) {

  const UTF32 *SourceStart = &Source;

  const UTF32 *SourceEnd = SourceStart + 1;

  UTF8 *TargetStart = reinterpret_cast<UTF8 *>(ResultPtr);

  UTF8 *TargetEnd = TargetStart + 4;

  ConversionResult CR = ConvertUTF32toUTF8(&SourceStart, SourceEnd,

                                           &TargetStart, TargetEnd,

                                           strictConversion);

  if (CR != conversionOK)

    return false;

  ResultPtr = reinterpret_cast<char*>(TargetStart);

  return true;

}

bool hasUTF16ByteOrderMark(ArrayRef<char> S) {

  return (S.size() >= 2 &&

          ((S[0] == '\xff' && S[1] == '\xfe') ||

           (S[0] == '\xfe' && S[1] == '\xff')));

}

bool convertUTF16ToUTF8String(ArrayRef<char> SrcBytes, std::string &Out) {

  assert(Out.empty());

  // Error out on an uneven byte count.

  if (SrcBytes.size() % 2)

    return false;

  // Avoid OOB by returning early on empty input.

  if (SrcBytes.empty())

    return true;

  const UTF16 *Src = reinterpret_cast<const UTF16 *>(SrcBytes.begin());

  const UTF16 *SrcEnd = reinterpret_cast<const UTF16 *>(SrcBytes.end());

  // Byteswap if necessary.

  std::vector<UTF16> ByteSwapped;

  if (Src[0] == UNI_UTF16_BYTE_ORDER_MARK_SWAPPED) {

    ByteSwapped.insert(ByteSwapped.end(), Src, SrcEnd);

    for (unsigned I = 0, E = ByteSwapped.size(); I != E; ++I)

      ByteSwapped[I] = llvm::ByteSwap_16(ByteSwapped[I]);

    Src = &ByteSwapped[0];

    SrcEnd = &ByteSwapped[ByteSwapped.size() - 1] + 1;

  }

  // Skip the BOM for conversion.

  if (Src[0] == UNI_UTF16_BYTE_ORDER_MARK_NATIVE)

    Src++;

  // Just allocate enough space up front.  We'll shrink it later.  Allocate

  // enough that we can fit a null terminator without reallocating.

  Out.resize(SrcBytes.size() * UNI_MAX_UTF8_BYTES_PER_CODE_POINT + 1);

  UTF8 *Dst = reinterpret_cast<UTF8 *>(&Out[0]);

  UTF8 *DstEnd = Dst + Out.size();

  ConversionResult CR =

      ConvertUTF16toUTF8(&Src, SrcEnd, &Dst, DstEnd, strictConversion);

  assert(CR != targetExhausted);

  if (CR != conversionOK) {

    Out.clear();

    return false;

  }

  Out.resize(reinterpret_cast<char *>(Dst) - &Out[0]);

  Out.push_back(0);

  Out.pop_back();

  return true;

}

bool convertUTF16ToUTF8String(ArrayRef<UTF16> Src, std::string &Out)

{

  return convertUTF16ToUTF8String(

      llvm::ArrayRef<char>(reinterpret_cast<const char *>(Src.data()),

      Src.size() * sizeof(UTF16)), Out);

}

bool convertUTF8ToUTF16String(StringRef SrcUTF8,

                              SmallVectorImpl<UTF16> &DstUTF16) {

  assert(DstUTF16.empty());

  // Avoid OOB by returning early on empty input.

  if (SrcUTF8.empty()) {

    DstUTF16.push_back(0);

    DstUTF16.pop_back();

    return true;

  }

  const UTF8 *Src = reinterpret_cast<const UTF8 *>(SrcUTF8.begin());

  const UTF8 *SrcEnd = reinterpret_cast<const UTF8 *>(SrcUTF8.end());

  // Allocate the same number of UTF-16 code units as UTF-8 code units. Encoding

  // as UTF-16 should always require the same amount or less code units than the

  // UTF-8 encoding.  Allocate one extra byte for the null terminator though,

  // so that someone calling DstUTF16.data() gets a null terminated string.

  // We resize down later so we don't have to worry that this over allocates.

  DstUTF16.resize(SrcUTF8.size()+1);

  UTF16 *Dst = &DstUTF16[0];

  UTF16 *DstEnd = Dst + DstUTF16.size();

  ConversionResult CR =

      ConvertUTF8toUTF16(&Src, SrcEnd, &Dst, DstEnd, strictConversion);

  assert(CR != targetExhausted);

  if (CR != conversionOK) {

    DstUTF16.clear();

    return false;

  }

  DstUTF16.resize(Dst - &DstUTF16[0]);

  DstUTF16.push_back(0);

  DstUTF16.pop_back();

  return true;

}

static_assert(sizeof(wchar_t) == 1 || sizeof(wchar_t) == 2 ||

                  sizeof(wchar_t) == 4,

              "Expected wchar_t to be 1, 2, or 4 bytes");

template <typename TResult>

static inline bool ConvertUTF8toWideInternal(llvm::StringRef Source,

                                             TResult &Result) {

  // Even in the case of UTF-16, the number of bytes in a UTF-8 string is

  // at least as large as the number of elements in the resulting wide

  // string, because surrogate pairs take at least 4 bytes in UTF-8.

  Result.resize(Source.size() + 1);

  char *ResultPtr = reinterpret_cast<char *>(&Result[0]);

  const UTF8 *ErrorPtr;

  if (!ConvertUTF8toWide(sizeof(wchar_t), Source, ResultPtr, ErrorPtr)) {

    Result.clear();

    return false;

  }

  Result.resize(reinterpret_cast<wchar_t *>(ResultPtr) - &Result[0]);

  return true;

}

bool ConvertUTF8toWide(llvm::StringRef Source, std::wstring &Result) {

  return ConvertUTF8toWideInternal(Source, Result);

}

bool ConvertUTF8toWide(const char *Source, std::wstring &Result) {

  if (!Source) {

    Result.clear();

    return true;

  }

  return ConvertUTF8toWide(llvm::StringRef(Source), Result);

}

bool convertWideToUTF8(const std::wstring &Source, std::string &Result) {

  if (sizeof(wchar_t) == 1) {

    const UTF8 *Start = reinterpret_cast<const UTF8 *>(Source.data());

    const UTF8 *End =

        reinterpret_cast<const UTF8 *>(Source.data() + Source.size());

    if (!isLegalUTF8String(&Start, End))

      return false;

    Result.resize(Source.size());

    memcpy(&Result[0], Source.data(), Source.size());

    return true;

  } else if (sizeof(wchar_t) == 2) {

    return convertUTF16ToUTF8String(

        llvm::ArrayRef<UTF16>(reinterpret_cast<const UTF16 *>(Source.data()),

                              Source.size()),

        Result);

  } else if (sizeof(wchar_t) == 4) {

    const UTF32 *Start = reinterpret_cast<const UTF32 *>(Source.data());

    const UTF32 *End =

        reinterpret_cast<const UTF32 *>(Source.data() + Source.size());

    Result.resize(UNI_MAX_UTF8_BYTES_PER_CODE_POINT * Source.size());

    UTF8 *ResultPtr = reinterpret_cast<UTF8 *>(&Result[0]);

    UTF8 *ResultEnd = reinterpret_cast<UTF8 *>(&Result[0] + Result.size());

    if (ConvertUTF32toUTF8(&Start, End, &ResultPtr, ResultEnd,

                           strictConversion) == conversionOK) {

      Result.resize(reinterpret_cast<char *>(ResultPtr) - &Result[0]);

      return true;

    } else {

      Result.clear();

      return false;

    }

  } else {

    llvm_unreachable(

        "Control should never reach this point; see static_assert further up");

  }

}

} // end namespace llvm