1 //===- LineIterator.cpp - Implementation of line iteration ----------------===//
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 #include "llvm/Support/LineIterator.h"
11 #include "llvm/Support/MemoryBuffer.h"
12
13 using namespace llvm;
14
isAtLineEnd(const char * P)15 static bool isAtLineEnd(const char *P) {
16 if (*P == '\n')
17 return true;
18 if (*P == '\r' && *(P + 1) == '\n')
19 return true;
20 return false;
21 }
22
skipIfAtLineEnd(const char * & P)23 static bool skipIfAtLineEnd(const char *&P) {
24 if (*P == '\n') {
25 ++P;
26 return true;
27 }
28 if (*P == '\r' && *(P + 1) == '\n') {
29 P += 2;
30 return true;
31 }
32 return false;
33 }
34
line_iterator(const MemoryBuffer & Buffer,bool SkipBlanks,char CommentMarker)35 line_iterator::line_iterator(const MemoryBuffer &Buffer, bool SkipBlanks,
36 char CommentMarker)
37 : Buffer(Buffer.getBufferSize() ? &Buffer : nullptr),
38 CommentMarker(CommentMarker), SkipBlanks(SkipBlanks), LineNumber(1),
39 CurrentLine(Buffer.getBufferSize() ? Buffer.getBufferStart() : nullptr,
40 0) {
41 // Ensure that if we are constructed on a non-empty memory buffer that it is
42 // a null terminated buffer.
43 if (Buffer.getBufferSize()) {
44 assert(Buffer.getBufferEnd()[0] == '\0');
45 // Make sure we don't skip a leading newline if we're keeping blanks
46 if (SkipBlanks || !isAtLineEnd(Buffer.getBufferStart()))
47 advance();
48 }
49 }
50
advance()51 void line_iterator::advance() {
52 assert(Buffer && "Cannot advance past the end!");
53
54 const char *Pos = CurrentLine.end();
55 assert(Pos == Buffer->getBufferStart() || isAtLineEnd(Pos) || *Pos == '\0');
56
57 if (skipIfAtLineEnd(Pos))
58 ++LineNumber;
59 if (!SkipBlanks && isAtLineEnd(Pos)) {
60 // Nothing to do for a blank line.
61 } else if (CommentMarker == '\0') {
62 // If we're not stripping comments, this is simpler.
63 while (skipIfAtLineEnd(Pos))
64 ++LineNumber;
65 } else {
66 // Skip comments and count line numbers, which is a bit more complex.
67 for (;;) {
68 if (isAtLineEnd(Pos) && !SkipBlanks)
69 break;
70 if (*Pos == CommentMarker)
71 do {
72 ++Pos;
73 } while (*Pos != '\0' && !isAtLineEnd(Pos));
74 if (!skipIfAtLineEnd(Pos))
75 break;
76 ++LineNumber;
77 }
78 }
79
80 if (*Pos == '\0') {
81 // We've hit the end of the buffer, reset ourselves to the end state.
82 Buffer = nullptr;
83 CurrentLine = StringRef();
84 return;
85 }
86
87 // Measure the line.
88 size_t Length = 0;
89 while (Pos[Length] != '\0' && !isAtLineEnd(&Pos[Length])) {
90 ++Length;
91 }
92
93 CurrentLine = StringRef(Pos, Length);
94 }
95