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StringToOffsetTable.h
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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/SmallString.h"
14 #include "llvm/ADT/StringExtras.h"
15 #include "llvm/ADT/StringMap.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.
26  StringMap<unsigned> StringOffset;
27  std::string AggregateString;
28 public:
29 
30  unsigned GetOrAddStringOffset(StringRef Str, bool appendZero = true) {
31  StringMapEntry<unsigned> &Entry = StringOffset.GetOrCreateValue(Str, -1U);
32  if (Entry.getValue() == -1U) {
33  // Add the string to the aggregate if this is the first time found.
34  Entry.setValue(AggregateString.size());
35  AggregateString.append(Str.begin(), Str.end());
36  if (appendZero)
37  AggregateString += '\0';
38  }
39 
40  return Entry.getValue();
41  }
42 
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
const ValueTy & getValue() const
Definition: StringMap.h:132
void setValue(const ValueTy &V)
Definition: StringMap.h:135
int isdigit(int c);
unsigned GetOrAddStringOffset(StringRef Str, bool appendZero=true)
iterator begin() const
Definition: StringRef.h:97
void EmitString(raw_ostream &O)
raw_ostream & write_escaped(StringRef Str, bool UseHexEscapes=false)
StringRef str() const
Explicit conversion to StringRef.
Definition: SmallString.h:270
MapEntryTy & GetOrCreateValue(StringRef Key, InitTy Val)
Definition: StringMap.h:361
iterator end() const
Definition: StringRef.h:99