utils/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 TBLGEN_STRING_TO_OFFSET_TABLE_H
  11 #define TBLGEN_STRING_TO_OFFSET_TABLE_H
  12
  13 #include "llvm/ADT/StringMap.h"
  14 #include "llvm/Support/raw_ostream.h"
  15 #include "llvm/ADT/StringExtras.h"
  16
  17 namespace llvm {
  18
  19 /// StringToOffsetTable - This class uniques a bunch of nul-terminated strings
  20 /// and keeps track of their offset in a massive contiguous string allocation.
  21 /// It can then output this string blob and use indexes into the string to
  22 /// reference each piece.
  23 class StringToOffsetTable {
  24   StringMap<unsigned> StringOffset;
  25   std::string AggregateString;
  26 public:
  27
  28   unsigned GetOrAddStringOffset(StringRef Str) {
  29     unsigned &Entry = StringOffset[Str];
  30     if (Entry == 0) {
  31       // Add the string to the aggregate if this is the first time found.
  32       Entry = AggregateString.size();
  33       AggregateString.append(Str.begin(), Str.end());
  34       AggregateString += '\0';
  35     }
  36
  37     return Entry;
  38   }
  39
  40   void EmitString(raw_ostream &O) {
  41     O << "    \"";
  42     unsigned CharsPrinted = 0;
  43     EscapeString(AggregateString);
  44     for (unsigned i = 0, e = AggregateString.size(); i != e; ++i) {
  45       if (CharsPrinted > 70) {
  46         O << "\"\n    \"";
  47         CharsPrinted = 0;
  48       }
  49       O << AggregateString[i];
  50       ++CharsPrinted;
  51
  52       // Print escape sequences all together.
  53       if (AggregateString[i] != '\\')
  54         continue;
  55
  56       assert(i+1 < AggregateString.size() && "Incomplete escape sequence!");
  57       if (isdigit(AggregateString[i+1])) {
  58         assert(isdigit(AggregateString[i+2]) &&
  59                isdigit(AggregateString[i+3]) &&
  60                "Expected 3 digit octal escape!");
  61         O << AggregateString[++i];
  62         O << AggregateString[++i];
  63         O << AggregateString[++i];
  64         CharsPrinted += 3;
  65       } else {
  66         O << AggregateString[++i];
  67         ++CharsPrinted;
  68       }
  69     }
  70     O << "\"";
  71   }
  72 };
  73
  74 } // end namespace llvm
  75
  76 #endif