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//===- fpcmp.cpp - A fuzzy "cmp" that permits floating point noise --------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// fpcmp is a tool that basically works like the 'cmp' tool, except that it can
// tolerate errors due to floating point noise, with the -r option.
//
//===----------------------------------------------------------------------===//
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/FileUtilities.h"
#include <iostream>
#include <cmath>
using namespace llvm;
namespace {
cl::opt<std::string>
File1(cl::Positional, cl::desc("<input file #1>"), cl::Required);
cl::opt<std::string>
File2(cl::Positional, cl::desc("<input file #2>"), cl::Required);
cl::opt<double>
RelTolerance("r", cl::desc("Relative error tolerated"), cl::init(0));
cl::opt<double>
AbsTolerance("a", cl::desc("Absolute error tolerated"), cl::init(0));
}
/// OpenFile - mmap the specified file into the address space for reading, and
/// return the length and address of the buffer.
static void OpenFile(const std::string &Filename, unsigned &Len, char* &BufPtr){
BufPtr = (char*)ReadFileIntoAddressSpace(Filename, Len);
if (BufPtr == 0) {
std::cerr << "Error: cannot open file '" << Filename << "'\n";
exit(2);
}
}
static bool isNumberChar(char C) {
switch (C) {
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
case '.': case '+': case '-':
case 'e':
case 'E': return true;
default: return false;
}
}
static char *BackupNumber(char *Pos, char *FirstChar) {
// If we didn't stop in the middle of a number, don't backup.
if (!isNumberChar(*Pos)) return Pos;
// Otherwise, return to the start of the number.
while (Pos > FirstChar && isNumberChar(Pos[-1]))
--Pos;
return Pos;
}
static void CompareNumbers(char *&F1P, char *&F2P, char *F1End, char *F2End) {
char *F1NumEnd, *F2NumEnd;
double V1 = 0.0, V2 = 0.0;
// If we stop on numbers, compare their difference.
if (isNumberChar(*F1P) && isNumberChar(*F2P)) {
V1 = strtod(F1P, &F1NumEnd);
V2 = strtod(F2P, &F2NumEnd);
} else {
// Otherwise, the diff failed.
F1NumEnd = F1P;
F2NumEnd = F2P;
}
if (F1NumEnd == F1P || F2NumEnd == F2P) {
std::cerr << "Comparison failed, not a numeric difference.\n";
exit(1);
}
// Check to see if these are inside the absolute tolerance
if (AbsTolerance < std::abs(V1-V2)) {
// Nope, check the relative tolerance...
double Diff;
if (V2)
Diff = std::abs(V1/V2 - 1.0);
else if (V1)
Diff = std::abs(V2/V1 - 1.0);
else
Diff = 0; // Both zero.
if (Diff > RelTolerance) {
std::cerr << "Compared: " << V1 << " and " << V2 << ": diff = "
<< Diff << "\n";
std::cerr << "Out of tolerance: rel/abs: " << RelTolerance
<< "/" << AbsTolerance << "\n";
exit(1);
}
}
// Otherwise, advance our read pointers to the end of the numbers.
F1P = F1NumEnd; F2P = F2NumEnd;
}
// PadFileIfNeeded - If the files are not identical, we will have to be doing
// numeric comparisons in here. There are bad cases involved where we (i.e.,
// strtod) might run off the beginning or end of the file if it starts or ends
// with a number. Because of this, if needed, we pad the file so that it starts
// and ends with a null character.
static void PadFileIfNeeded(char *&FileStart, char *&FileEnd, char *&FP) {
if (isNumberChar(FileStart[0]) || isNumberChar(FileEnd[-1])) {
unsigned FileLen = FileEnd-FileStart;
char *NewFile = new char[FileLen+2];
NewFile[0] = 0; // Add null padding
NewFile[FileLen+1] = 0; // Add null padding
memcpy(NewFile+1, FileStart, FileLen);
FP = NewFile+(FP-FileStart)+1;
FileStart = NewFile+1;
FileEnd = FileStart+FileLen;
}
}
int main(int argc, char **argv) {
cl::ParseCommandLineOptions(argc, argv);
// mmap in the files.
unsigned File1Len, File2Len;
char *File1Start, *File2Start;
OpenFile(File1, File1Len, File1Start);
OpenFile(File2, File2Len, File2Start);
// Okay, now that we opened the files, scan them for the first difference.
char *File1End = File1Start+File1Len;
char *File2End = File2Start+File2Len;
char *F1P = File1Start;
char *F2P = File2Start;
// Scan for the end of file or first difference.
while (F1P < File1End && F2P < File2End && *F1P == *F2P)
++F1P, ++F2P;
// Common case: identifical files.
if (F1P == File1End && F2P == File2End) return 0;
// If the files need padding, do so now.
PadFileIfNeeded(File1Start, File1End, F1P);
PadFileIfNeeded(File2Start, File2End, F2P);
while (1) {
// Scan for the end of file or next difference.
while (F1P < File1End && F2P < File2End && *F1P == *F2P)
++F1P, ++F2P;
if (F1P >= File1End || F2P >= File2End) break;
// Okay, we must have found a difference. Backup to the start of the
// current number each stream is at so that we can compare from the
// beginning.
F1P = BackupNumber(F1P, File1Start);
F2P = BackupNumber(F2P, File2Start);
// Now that we are at the start of the numbers, compare them, exiting if
// they don't match.
CompareNumbers(F1P, F2P, File1End, File2End);
}
// Okay, we reached the end of file. If both files are at the end, we
// succeeded.
bool F1AtEnd = F1P >= File1End;
bool F2AtEnd = F2P >= File2End;
if (F1AtEnd & F2AtEnd) return 0;
// Otherwise, we might have run off the end due to a number: backup and retry.
if (F1AtEnd && isNumberChar(F1P[-1])) --F1P;
if (F2AtEnd && isNumberChar(F2P[-1])) --F2P;
F1P = BackupNumber(F1P, File1Start);
F2P = BackupNumber(F2P, File2Start);
// Now that we are at the start of the numbers, compare them, exiting if
// they don't match.
CompareNumbers(F1P, F2P, File1End, File2End);
// If we found the end, we succeeded.
if (F1P >= File1End && F2P >= File2End) return 0;
return 1;
}
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