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//===-- SourceFile.cpp - SourceFile implementation for the debugger -------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the SourceFile class for the LLVM debugger.
//
//===----------------------------------------------------------------------===//
#include "llvm/Debugger/SourceFile.h"
#include "llvm/Support/MemoryBuffer.h"
#include <cassert>
using namespace llvm;
static const char EmptyFile = 0;
SourceFile::SourceFile(const std::string &fn, const GlobalVariable *Desc)
: Filename(fn), Descriptor(Desc) {
File.reset(MemoryBuffer::getFileOrSTDIN(fn));
// On error, return an empty buffer.
if (File == 0)
File.reset(MemoryBuffer::getMemBuffer(&EmptyFile, &EmptyFile));
}
SourceFile::~SourceFile() {
}
/// calculateLineOffsets - Compute the LineOffset vector for the current file.
///
void SourceFile::calculateLineOffsets() const {
assert(LineOffset.empty() && "Line offsets already computed!");
const char *BufPtr = File->getBufferStart();
const char *FileStart = BufPtr;
const char *FileEnd = File->getBufferEnd();
do {
LineOffset.push_back(BufPtr-FileStart);
// Scan until we get to a newline.
while (BufPtr != FileEnd && *BufPtr != '\n' && *BufPtr != '\r')
++BufPtr;
if (BufPtr != FileEnd) {
++BufPtr; // Skip over the \n or \r
if (BufPtr[-1] == '\r' && BufPtr != FileEnd && BufPtr[0] == '\n')
++BufPtr; // Skip over dos/windows style \r\n's
}
} while (BufPtr != FileEnd);
}
/// getSourceLine - Given a line number, return the start and end of the line
/// in the file. If the line number is invalid, or if the file could not be
/// loaded, null pointers are returned for the start and end of the file. Note
/// that line numbers start with 0, not 1.
void SourceFile::getSourceLine(unsigned LineNo, const char *&LineStart,
const char *&LineEnd) const {
LineStart = LineEnd = 0;
if (LineOffset.empty()) calculateLineOffsets();
// Asking for an out-of-range line number?
if (LineNo >= LineOffset.size()) return;
// Otherwise, they are asking for a valid line, which we can fulfill.
LineStart = File->getBufferStart()+LineOffset[LineNo];
if (LineNo+1 < LineOffset.size())
LineEnd = File->getBufferStart()+LineOffset[LineNo+1];
else
LineEnd = File->getBufferEnd();
// If the line ended with a newline, strip it off.
while (LineEnd != LineStart && (LineEnd[-1] == '\n' || LineEnd[-1] == '\r'))
--LineEnd;
assert(LineEnd >= LineStart && "We somehow got our pointers swizzled!");
}
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