1//===- StringToOffsetTable.h - Emit a big concatenated string ---*- C++ -*-===//
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#ifndef LLVM_TABLEGEN_STRINGTOOFFSETTABLE_H
10#define LLVM_TABLEGEN_STRINGTOOFFSETTABLE_H
11
12#include "llvm/ADT/SmallString.h"
13#include "llvm/ADT/StringExtras.h"
14#include "llvm/ADT/StringMap.h"
15#include "llvm/Support/raw_ostream.h"
16#include <cctype>
17
18namespace llvm {
19
20/// StringToOffsetTable - This class uniques a bunch of nul-terminated strings
21/// and keeps track of their offset in a massive contiguous string allocation.
22/// It can then output this string blob and use indexes into the string to
23/// reference each piece.
24class StringToOffsetTable {
25 StringMap<unsigned> StringOffset;
26 std::string AggregateString;
27
28public:
29 bool Empty() const { return StringOffset.empty(); }
30
31 unsigned GetOrAddStringOffset(StringRef Str, bool appendZero = true) {
32 auto IterBool =
33 StringOffset.insert(KV: std::make_pair(x&: Str, y: AggregateString.size()));
34 if (IterBool.second) {
35 // Add the string to the aggregate if this is the first time found.
36 AggregateString.append(first: Str.begin(), last: Str.end());
37 if (appendZero)
38 AggregateString += '\0';
39 }
40
41 return IterBool.first->second;
42 }
43
44 void EmitString(raw_ostream &O) {
45 // Escape the string.
46 SmallString<256> Str;
47 raw_svector_ostream(Str).write_escaped(Str: AggregateString);
48 AggregateString = std::string(Str);
49
50 O << " \"";
51 unsigned CharsPrinted = 0;
52 for (unsigned i = 0, e = AggregateString.size(); i != e; ++i) {
53 if (CharsPrinted > 70) {
54 O << "\"\n \"";
55 CharsPrinted = 0;
56 }
57 O << AggregateString[i];
58 ++CharsPrinted;
59
60 // Print escape sequences all together.
61 if (AggregateString[i] != '\\')
62 continue;
63
64 assert(i + 1 < AggregateString.size() && "Incomplete escape sequence!");
65 if (isdigit(AggregateString[i + 1])) {
66 assert(isdigit(AggregateString[i + 2]) &&
67 isdigit(AggregateString[i + 3]) &&
68 "Expected 3 digit octal escape!");
69 O << AggregateString[++i];
70 O << AggregateString[++i];
71 O << AggregateString[++i];
72 CharsPrinted += 3;
73 } else {
74 O << AggregateString[++i];
75 ++CharsPrinted;
76 }
77 }
78 O << "\"";
79 }
80
81 /// Emit the string using character literals. MSVC has a limitation that
82 /// string literals cannot be longer than 64K.
83 void EmitCharArray(raw_ostream &O) {
84 assert(AggregateString.find(')') == std::string::npos &&
85 "can't emit raw string with closing parens");
86 int Count = 0;
87 O << ' ';
88 for (char C : AggregateString) {
89 O << " \'";
90 O.write_escaped(Str: StringRef(&C, 1));
91 O << "\',";
92 Count++;
93 if (Count > 14) {
94 O << "\n ";
95 Count = 0;
96 }
97 }
98 O << '\n';
99 }
100};
101
102} // end namespace llvm
103
104#endif
105

source code of llvm/include/llvm/TableGen/StringToOffsetTable.h