llvm-6502/lib/Support/LineIterator.cpp

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//===- LineIterator.cpp - Implementation of line iteration ----------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/Support/LineIterator.h"
#include "llvm/Support/MemoryBuffer.h"
using namespace llvm;
line_iterator::line_iterator(const MemoryBuffer &Buffer, char CommentMarker)
: Buffer(Buffer.getBufferSize() ? &Buffer : nullptr),
CommentMarker(CommentMarker), LineNumber(1),
CurrentLine(Buffer.getBufferSize() ? Buffer.getBufferStart() : nullptr,
0) {
// Ensure that if we are constructed on a non-empty memory buffer that it is
// a null terminated buffer.
if (Buffer.getBufferSize()) {
assert(Buffer.getBufferEnd()[0] == '\0');
advance();
}
}
void line_iterator::advance() {
assert(Buffer && "Cannot advance past the end!");
const char *Pos = CurrentLine.end();
assert(Pos == Buffer->getBufferStart() || *Pos == '\n' || *Pos == '\0');
if (CommentMarker == '\0') {
// If we're not stripping comments, this is simpler.
size_t Blanks = 0;
while (Pos[Blanks] == '\n')
++Blanks;
Pos += Blanks;
LineNumber += Blanks;
} else {
// Skip comments and count line numbers, which is a bit more complex.
for (;;) {
if (*Pos == CommentMarker)
do {
++Pos;
} while (*Pos != '\0' && *Pos != '\n');
if (*Pos != '\n')
break;
++Pos;
++LineNumber;
}
}
if (*Pos == '\0') {
// We've hit the end of the buffer, reset ourselves to the end state.
Buffer = nullptr;
CurrentLine = StringRef();
return;
}
// Measure the line.
size_t Length = 0;
do {
++Length;
} while (Pos[Length] != '\0' && Pos[Length] != '\n');
CurrentLine = StringRef(Pos, Length);
}