src/llvm/include/llvm/TableGen/StringToOffsetTable.h

   1 //===- StringToOffsetTable.h - Emit a big concatenated string ---*- C++ -*-===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9
  10 #ifndef LLVM_TABLEGEN_STRINGTOOFFSETTABLE_H
  11 #define LLVM_TABLEGEN_STRINGTOOFFSETTABLE_H
  12
  13 #include "llvm/ADT/SmallString.h"
  14 #include "llvm/ADT/StringExtras.h"
  15 #include "llvm/ADT/StringMap.h"
  16 #include "llvm/Support/raw_ostream.h"
  17 #include <cctype>
  18
  19 namespace llvm {
  20
  21 /// StringToOffsetTable - This class uniques a bunch of nul-terminated strings
  22 /// and keeps track of their offset in a massive contiguous string allocation.
  23 /// It can then output this string blob and use indexes into the string to
  24 /// reference each piece.
  25 class StringToOffsetTable {
  26   StringMap<unsigned> StringOffset;
  27   std::string AggregateString;
  28
  29 public:
  30   unsigned GetOrAddStringOffset(StringRef Str, bool appendZero = true) {
  31     auto IterBool =
  32         StringOffset.insert(std::make_pair(Str, AggregateString.size()));
  33     if (IterBool.second) {
  34       // Add the string to the aggregate if this is the first time found.
  35       AggregateString.append(Str.begin(), Str.end());
  36       if (appendZero)
  37         AggregateString += '\0';
  38     }
  39
  40     return IterBool.first->second;
  41   }
  42
  43   void EmitString(raw_ostream &O) {
  44     // Escape the string.
  45     SmallString<256> Str;
  46     raw_svector_ostream(Str).write_escaped(AggregateString);
  47     AggregateString = Str.str();
  48
  49     O << "    \"";
  50     unsigned CharsPrinted = 0;
  51     for (unsigned i = 0, e = AggregateString.size(); i != e; ++i) {
  52       if (CharsPrinted > 70) {
  53         O << "\"\n    \"";
  54         CharsPrinted = 0;
  55       }
  56       O << AggregateString[i];
  57       ++CharsPrinted;
  58
  59       // Print escape sequences all together.
  60       if (AggregateString[i] != '\\')
  61         continue;
  62
  63       assert(i+1 < AggregateString.size() && "Incomplete escape sequence!");
  64       if (isdigit(AggregateString[i+1])) {
  65         assert(isdigit(AggregateString[i+2]) &&
  66                isdigit(AggregateString[i+3]) &&
  67                "Expected 3 digit octal escape!");
  68         O << AggregateString[++i];
  69         O << AggregateString[++i];
  70         O << AggregateString[++i];
  71         CharsPrinted += 3;
  72       } else {
  73         O << AggregateString[++i];
  74         ++CharsPrinted;
  75       }
  76     }
  77     O << "\"";
  78   }
  79 };
  80
  81 } // end namespace llvm
  82
  83 #endif