lib/Support/ConvertUTFWrapper.cpp

   1 //===-- ConvertUTFWrapper.cpp - Wrap ConvertUTF.h with clang data types -----===
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "llvm/ADT/ArrayRef.h"
  10 #include "llvm/ADT/StringRef.h"
  11 #include "llvm/Support/ConvertUTF.h"
  12 #include "llvm/Support/ErrorHandling.h"
  13 #include "llvm/Support/SwapByteOrder.h"
  14 #include <string>
  15 #include <vector>
  16
  17 namespace llvm {
  18
  19 bool ConvertUTF8toWide(unsigned WideCharWidth, llvm::StringRef Source,
  20                        char *&ResultPtr, const UTF8 *&ErrorPtr) {
  21   assert(WideCharWidth == 1 || WideCharWidth == 2 || WideCharWidth == 4);
  22   ConversionResult result = conversionOK;
  23   // Copy the character span over.
  24   if (WideCharWidth == 1) {
  25     const UTF8 *Pos = reinterpret_cast<const UTF8*>(Source.begin());
  26     if (!isLegalUTF8String(&Pos, reinterpret_cast<const UTF8*>(Source.end()))) {
  27       result = sourceIllegal;
  28       ErrorPtr = Pos;
  29     } else {
  30       memcpy(ResultPtr, Source.data(), Source.size());
  31       ResultPtr += Source.size();
  32     }
  33   } else if (WideCharWidth == 2) {
  34     const UTF8 *sourceStart = (const UTF8*)Source.data();
  35     // FIXME: Make the type of the result buffer correct instead of
  36     // using reinterpret_cast.
  37     UTF16 *targetStart = reinterpret_cast<UTF16*>(ResultPtr);
  38     ConversionFlags flags = strictConversion;
  39     result = ConvertUTF8toUTF16(
  40         &sourceStart, sourceStart + Source.size(),
  41         &targetStart, targetStart + Source.size(), flags);
  42     if (result == conversionOK)
  43       ResultPtr = reinterpret_cast<char*>(targetStart);
  44     else
  45       ErrorPtr = sourceStart;
  46   } else if (WideCharWidth == 4) {
  47     const UTF8 *sourceStart = (const UTF8*)Source.data();
  48     // FIXME: Make the type of the result buffer correct instead of
  49     // using reinterpret_cast.
  50     UTF32 *targetStart = reinterpret_cast<UTF32*>(ResultPtr);
  51     ConversionFlags flags = strictConversion;
  52     result = ConvertUTF8toUTF32(
  53         &sourceStart, sourceStart + Source.size(),
  54         &targetStart, targetStart + Source.size(), flags);
  55     if (result == conversionOK)
  56       ResultPtr = reinterpret_cast<char*>(targetStart);
  57     else
  58       ErrorPtr = sourceStart;
  59   }
  60   assert((result != targetExhausted)
  61          && "ConvertUTF8toUTFXX exhausted target buffer");
  62   return result == conversionOK;
  63 }
  64
  65 bool ConvertCodePointToUTF8(unsigned Source, char *&ResultPtr) {
  66   const UTF32 *SourceStart = &Source;
  67   const UTF32 *SourceEnd = SourceStart + 1;
  68   UTF8 *TargetStart = reinterpret_cast<UTF8 *>(ResultPtr);
  69   UTF8 *TargetEnd = TargetStart + 4;
  70   ConversionResult CR = ConvertUTF32toUTF8(&SourceStart, SourceEnd,
  71                                            &TargetStart, TargetEnd,
  72                                            strictConversion);
  73   if (CR != conversionOK)
  74     return false;
  75
  76   ResultPtr = reinterpret_cast<char*>(TargetStart);
  77   return true;
  78 }
  79
  80 bool hasUTF16ByteOrderMark(ArrayRef<char> S) {
  81   return (S.size() >= 2 &&
  82           ((S[0] == '\xff' && S[1] == '\xfe') ||
  83            (S[0] == '\xfe' && S[1] == '\xff')));
  84 }
  85
  86 bool convertUTF16ToUTF8String(ArrayRef<char> SrcBytes, std::string &Out) {
  87   assert(Out.empty());
  88
  89   // Error out on an uneven byte count.
  90   if (SrcBytes.size() % 2)
  91     return false;
  92
  93   // Avoid OOB by returning early on empty input.
  94   if (SrcBytes.empty())
  95     return true;
  96
  97   const UTF16 *Src = reinterpret_cast<const UTF16 *>(SrcBytes.begin());
  98   const UTF16 *SrcEnd = reinterpret_cast<const UTF16 *>(SrcBytes.end());
  99
 100   // Byteswap if necessary.
 101   std::vector<UTF16> ByteSwapped;
 102   if (Src[0] == UNI_UTF16_BYTE_ORDER_MARK_SWAPPED) {
 103     ByteSwapped.insert(ByteSwapped.end(), Src, SrcEnd);
 104     for (unsigned I = 0, E = ByteSwapped.size(); I != E; ++I)
 105       ByteSwapped[I] = llvm::sys::SwapByteOrder_16(ByteSwapped[I]);
 106     Src = &ByteSwapped[0];
 107     SrcEnd = &ByteSwapped[ByteSwapped.size() - 1] + 1;
 108   }
 109
 110   // Skip the BOM for conversion.
 111   if (Src[0] == UNI_UTF16_BYTE_ORDER_MARK_NATIVE)
 112     Src++;
 113
 114   // Just allocate enough space up front.  We'll shrink it later.  Allocate
 115   // enough that we can fit a null terminator without reallocating.
 116   Out.resize(SrcBytes.size() * UNI_MAX_UTF8_BYTES_PER_CODE_POINT + 1);
 117   UTF8 *Dst = reinterpret_cast<UTF8 *>(&Out[0]);
 118   UTF8 *DstEnd = Dst + Out.size();
 119
 120   ConversionResult CR =
 121       ConvertUTF16toUTF8(&Src, SrcEnd, &Dst, DstEnd, strictConversion);
 122   assert(CR != targetExhausted);
 123
 124   if (CR != conversionOK) {
 125     Out.clear();
 126     return false;
 127   }
 128
 129   Out.resize(reinterpret_cast<char *>(Dst) - &Out[0]);
 130   Out.push_back(0);
 131   Out.pop_back();
 132   return true;
 133 }
 134
 135 bool convertUTF16ToUTF8String(ArrayRef<UTF16> Src, std::string &Out)
 136 {
 137   return convertUTF16ToUTF8String(
 138       llvm::ArrayRef<char>(reinterpret_cast<const char *>(Src.data()),
 139       Src.size() * sizeof(UTF16)), Out);
 140 }
 141
 142 bool convertUTF8ToUTF16String(StringRef SrcUTF8,
 143                               SmallVectorImpl<UTF16> &DstUTF16) {
 144   assert(DstUTF16.empty());
 145
 146   // Avoid OOB by returning early on empty input.
 147   if (SrcUTF8.empty()) {
 148     DstUTF16.push_back(0);
 149     DstUTF16.pop_back();
 150     return true;
 151   }
 152
 153   const UTF8 *Src = reinterpret_cast<const UTF8 *>(SrcUTF8.begin());
 154   const UTF8 *SrcEnd = reinterpret_cast<const UTF8 *>(SrcUTF8.end());
 155
 156   // Allocate the same number of UTF-16 code units as UTF-8 code units. Encoding
 157   // as UTF-16 should always require the same amount or less code units than the
 158   // UTF-8 encoding.  Allocate one extra byte for the null terminator though,
 159   // so that someone calling DstUTF16.data() gets a null terminated string.
 160   // We resize down later so we don't have to worry that this over allocates.
 161   DstUTF16.resize(SrcUTF8.size()+1);
 162   UTF16 *Dst = &DstUTF16[0];
 163   UTF16 *DstEnd = Dst + DstUTF16.size();
 164
 165   ConversionResult CR =
 166       ConvertUTF8toUTF16(&Src, SrcEnd, &Dst, DstEnd, strictConversion);
 167   assert(CR != targetExhausted);
 168
 169   if (CR != conversionOK) {
 170     DstUTF16.clear();
 171     return false;
 172   }
 173
 174   DstUTF16.resize(Dst - &DstUTF16[0]);
 175   DstUTF16.push_back(0);
 176   DstUTF16.pop_back();
 177   return true;
 178 }
 179
 180 static_assert(sizeof(wchar_t) == 1 || sizeof(wchar_t) == 2 ||
 181                   sizeof(wchar_t) == 4,
 182               "Expected wchar_t to be 1, 2, or 4 bytes");
 183
 184 template <typename TResult>
 185 static inline bool ConvertUTF8toWideInternal(llvm::StringRef Source,
 186                                              TResult &Result) {
 187   // Even in the case of UTF-16, the number of bytes in a UTF-8 string is
 188   // at least as large as the number of elements in the resulting wide
 189   // string, because surrogate pairs take at least 4 bytes in UTF-8.
 190   Result.resize(Source.size() + 1);
 191   char *ResultPtr = reinterpret_cast<char *>(&Result[0]);
 192   const UTF8 *ErrorPtr;
 193   if (!ConvertUTF8toWide(sizeof(wchar_t), Source, ResultPtr, ErrorPtr)) {
 194     Result.clear();
 195     return false;
 196   }
 197   Result.resize(reinterpret_cast<wchar_t *>(ResultPtr) - &Result[0]);
 198   return true;
 199 }
 200
 201 bool ConvertUTF8toWide(llvm::StringRef Source, std::wstring &Result) {
 202   return ConvertUTF8toWideInternal(Source, Result);
 203 }
 204
 205 bool ConvertUTF8toWide(const char *Source, std::wstring &Result) {
 206   if (!Source) {
 207     Result.clear();
 208     return true;
 209   }
 210   return ConvertUTF8toWide(llvm::StringRef(Source), Result);
 211 }
 212
 213 bool convertWideToUTF8(const std::wstring &Source, std::string &Result) {
 214   if (sizeof(wchar_t) == 1) {
 215     const UTF8 *Start = reinterpret_cast<const UTF8 *>(Source.data());
 216     const UTF8 *End =
 217         reinterpret_cast<const UTF8 *>(Source.data() + Source.size());
 218     if (!isLegalUTF8String(&Start, End))
 219       return false;
 220     Result.resize(Source.size());
 221     memcpy(&Result[0], Source.data(), Source.size());
 222     return true;
 223   } else if (sizeof(wchar_t) == 2) {
 224     return convertUTF16ToUTF8String(
 225         llvm::ArrayRef<UTF16>(reinterpret_cast<const UTF16 *>(Source.data()),
 226                               Source.size()),
 227         Result);
 228   } else if (sizeof(wchar_t) == 4) {
 229     const UTF32 *Start = reinterpret_cast<const UTF32 *>(Source.data());
 230     const UTF32 *End =
 231         reinterpret_cast<const UTF32 *>(Source.data() + Source.size());
 232     Result.resize(UNI_MAX_UTF8_BYTES_PER_CODE_POINT * Source.size());
 233     UTF8 *ResultPtr = reinterpret_cast<UTF8 *>(&Result[0]);
 234     UTF8 *ResultEnd = reinterpret_cast<UTF8 *>(&Result[0] + Result.size());
 235     if (ConvertUTF32toUTF8(&Start, End, &ResultPtr, ResultEnd,
 236                            strictConversion) == conversionOK) {
 237       Result.resize(reinterpret_cast<char *>(ResultPtr) - &Result[0]);
 238       return true;
 239     } else {
 240       Result.clear();
 241       return false;
 242     }
 243   } else {
 244     llvm_unreachable(
 245         "Control should never reach this point; see static_assert further up");
 246   }
 247 }
 248
 249 } // end namespace llvm
 250