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
line_iterator(const MemoryBuffer & Buffer,char CommentMarker)15 line_iterator::line_iterator(const MemoryBuffer &Buffer, char CommentMarker)
16 : Buffer(Buffer.getBufferSize() ? &Buffer : nullptr),
17 CommentMarker(CommentMarker), LineNumber(1),
18 CurrentLine(Buffer.getBufferSize() ? Buffer.getBufferStart() : nullptr,
19 0) {
20 // Ensure that if we are constructed on a non-empty memory buffer that it is
21 // a null terminated buffer.
22 if (Buffer.getBufferSize()) {
23 assert(Buffer.getBufferEnd()[0] == '\0');
24 advance();
25 }
26 }
27
advance()28 void line_iterator::advance() {
29 assert(Buffer && "Cannot advance past the end!");
30
31 const char *Pos = CurrentLine.end();
32 assert(Pos == Buffer->getBufferStart() || *Pos == '\n' || *Pos == '\0');
33
34 if (CommentMarker == '\0') {
35 // If we're not stripping comments, this is simpler.
36 size_t Blanks = 0;
37 while (Pos[Blanks] == '\n')
38 ++Blanks;
39 Pos += Blanks;
40 LineNumber += Blanks;
41 } else {
42 // Skip comments and count line numbers, which is a bit more complex.
43 for (;;) {
44 if (*Pos == CommentMarker)
45 do {
46 ++Pos;
47 } while (*Pos != '\0' && *Pos != '\n');
48 if (*Pos != '\n')
49 break;
50 ++Pos;
51 ++LineNumber;
52 }
53 }
54
55 if (*Pos == '\0') {
56 // We've hit the end of the buffer, reset ourselves to the end state.
57 Buffer = nullptr;
58 CurrentLine = StringRef();
59 return;
60 }
61
62 // Measure the line.
63 size_t Length = 0;
64 do {
65 ++Length;
66 } while (Pos[Length] != '\0' && Pos[Length] != '\n');
67
68 CurrentLine = StringRef(Pos, Length);
69 }
70