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 
EmitString(raw_ostream & O)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
84