1 //===- LineIterator.cpp - Implementation of line iteration ----------------===//
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 #include "llvm/Support/LineIterator.h"
10 #include "llvm/Support/MemoryBuffer.h"
11
12 using namespace llvm;
13
isAtLineEnd(const char * P)14 static bool isAtLineEnd(const char *P) {
15 if (*P == '\n')
16 return true;
17 if (*P == '\r' && *(P + 1) == '\n')
18 return true;
19 return false;
20 }
21
skipIfAtLineEnd(const char * & P)22 static bool skipIfAtLineEnd(const char *&P) {
23 if (*P == '\n') {
24 ++P;
25 return true;
26 }
27 if (*P == '\r' && *(P + 1) == '\n') {
28 P += 2;
29 return true;
30 }
31 return false;
32 }
33
line_iterator(const MemoryBuffer & Buffer,bool SkipBlanks,char CommentMarker)34 line_iterator::line_iterator(const MemoryBuffer &Buffer, bool SkipBlanks,
35 char CommentMarker)
36 : line_iterator(Buffer.getMemBufferRef(), SkipBlanks, CommentMarker) {}
37
line_iterator(const MemoryBufferRef & Buffer,bool SkipBlanks,char CommentMarker)38 line_iterator::line_iterator(const MemoryBufferRef &Buffer, bool SkipBlanks,
39 char CommentMarker)
40 : Buffer(Buffer.getBufferSize() ? Optional<MemoryBufferRef>(Buffer) : None),
41 CommentMarker(CommentMarker), SkipBlanks(SkipBlanks), LineNumber(1),
42 CurrentLine(Buffer.getBufferSize() ? Buffer.getBufferStart() : nullptr,
43 0) {
44 // Ensure that if we are constructed on a non-empty memory buffer that it is
45 // a null terminated buffer.
46 if (Buffer.getBufferSize()) {
47 assert(Buffer.getBufferEnd()[0] == '\0');
48 // Make sure we don't skip a leading newline if we're keeping blanks
49 if (SkipBlanks || !isAtLineEnd(Buffer.getBufferStart()))
50 advance();
51 }
52 }
53
advance()54 void line_iterator::advance() {
55 assert(Buffer && "Cannot advance past the end!");
56
57 const char *Pos = CurrentLine.end();
58 assert(Pos == Buffer->getBufferStart() || isAtLineEnd(Pos) || *Pos == '\0');
59
60 if (skipIfAtLineEnd(Pos))
61 ++LineNumber;
62 if (!SkipBlanks && isAtLineEnd(Pos)) {
63 // Nothing to do for a blank line.
64 } else if (CommentMarker == '\0') {
65 // If we're not stripping comments, this is simpler.
66 while (skipIfAtLineEnd(Pos))
67 ++LineNumber;
68 } else {
69 // Skip comments and count line numbers, which is a bit more complex.
70 for (;;) {
71 if (isAtLineEnd(Pos) && !SkipBlanks)
72 break;
73 if (*Pos == CommentMarker)
74 do {
75 ++Pos;
76 } while (*Pos != '\0' && !isAtLineEnd(Pos));
77 if (!skipIfAtLineEnd(Pos))
78 break;
79 ++LineNumber;
80 }
81 }
82
83 if (*Pos == '\0') {
84 // We've hit the end of the buffer, reset ourselves to the end state.
85 Buffer = None;
86 CurrentLine = StringRef();
87 return;
88 }
89
90 // Measure the line.
91 size_t Length = 0;
92 while (Pos[Length] != '\0' && !isAtLineEnd(&Pos[Length])) {
93 ++Length;
94 }
95
96 CurrentLine = StringRef(Pos, Length);
97 }
98