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llvm-mirror/lib/Support/FileUtilities.cpp
Chris Lattner f4c7ceebaf Change Path::getStatusInfo to return a boolean and error string on an error
instead of throwing an exception.  This reduces the amount of code that is
exposed to exceptions (e.g. FileUtilities), though it is clearly only one step
along the way.

llvm-svn: 29395
2006-07-28 22:03:44 +00:00

253 lines
8.6 KiB
C++

//===- Support/FileUtilities.cpp - File System Utilities ------------------===//
//
// 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.
//
//===----------------------------------------------------------------------===//
//
// This file implements a family of utility functions which are useful for doing
// various things with files.
//
//===----------------------------------------------------------------------===//
#include "llvm/Support/FileUtilities.h"
#include "llvm/System/Path.h"
#include "llvm/System/MappedFile.h"
#include "llvm/ADT/StringExtras.h"
#include <cmath>
#include <cstring>
#include <cctype>
using namespace llvm;
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 'D': // Strange exponential notation.
case 'd': // Strange exponential notation.
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;
}
/// CompareNumbers - compare two numbers, returning true if they are different.
static bool CompareNumbers(char *&F1P, char *&F2P, char *F1End, char *F2End,
double AbsTolerance, double RelTolerance,
std::string *ErrorMsg) {
char *F1NumEnd, *F2NumEnd;
double V1 = 0.0, V2 = 0.0;
// If one of the positions is at a space and the other isn't, chomp up 'til
// the end of the space.
while (isspace(*F1P) && F1P != F1End)
++F1P;
while (isspace(*F2P) && F2P != F2End)
++F2P;
// If we stop on numbers, compare their difference. Note that some ugliness
// is built into this to permit support for numbers that use "D" or "d" as
// their exponential marker, e.g. "1.234D45". This occurs in 200.sixtrack in
// spec2k.
if (isNumberChar(*F1P) && isNumberChar(*F2P)) {
bool isDNotation;
do {
isDNotation = false;
V1 = strtod(F1P, &F1NumEnd);
V2 = strtod(F2P, &F2NumEnd);
if (*F1NumEnd == 'D' || *F1NumEnd == 'd') {
*F1NumEnd = 'e'; // Strange exponential notation!
isDNotation = true;
}
if (*F2NumEnd == 'D' || *F2NumEnd == 'd') {
*F2NumEnd = 'e'; // Strange exponential notation!
isDNotation = true;
}
} while (isDNotation);
} else {
// Otherwise, the diff failed.
F1NumEnd = F1P;
F2NumEnd = F2P;
}
if (F1NumEnd == F1P || F2NumEnd == F2P) {
if (ErrorMsg) *ErrorMsg = "Comparison failed, not a numeric difference.";
return true;
}
// 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) {
if (ErrorMsg) {
*ErrorMsg = "Compared: " + ftostr(V1) + " and " + ftostr(V2) +
": diff = " + ftostr(Diff) + "\n";
*ErrorMsg += "Out of tolerance: rel/abs: " + ftostr(RelTolerance) +
"/" + ftostr(AbsTolerance);
}
return true;
}
}
// Otherwise, advance our read pointers to the end of the numbers.
F1P = F1NumEnd; F2P = F2NumEnd;
return false;
}
// 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 (FileStart-FileEnd < 2 ||
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;
}
}
/// DiffFilesWithTolerance - Compare the two files specified, returning 0 if the
/// files match, 1 if they are different, and 2 if there is a file error. This
/// function differs from DiffFiles in that you can specify an absolete and
/// relative FP error that is allowed to exist. If you specify a string to fill
/// in for the error option, it will set the string to an error message if an
/// error occurs, allowing the caller to distinguish between a failed diff and a
/// file system error.
///
int llvm::DiffFilesWithTolerance(const sys::Path &FileA,
const sys::Path &FileB,
double AbsTol, double RelTol,
std::string *Error) {
sys::FileStatus FileAStat, FileBStat;
if (FileA.getFileStatus(FileAStat, Error) ||
FileB.getFileStatus(FileBStat, Error))
return 2;
// Check for zero length files because some systems croak when you try to
// mmap an empty file.
size_t A_size = FileAStat.getSize();
size_t B_size = FileBStat.getSize();
// If they are both zero sized then they're the same
if (A_size == 0 && B_size == 0)
return 0;
// If only one of them is zero sized then they can't be the same
if ((A_size == 0 || B_size == 0))
return 1;
try {
// Now its safe to mmap the files into memory becasue both files
// have a non-zero size.
sys::MappedFile F1(FileA);
sys::MappedFile F2(FileB);
F1.map();
F2.map();
// Okay, now that we opened the files, scan them for the first difference.
char *File1Start = F1.charBase();
char *File2Start = F2.charBase();
char *File1End = File1Start+A_size;
char *File2End = File2Start+B_size;
char *F1P = File1Start;
char *F2P = File2Start;
if (A_size == B_size) {
// Are the buffers identical?
if (std::memcmp(File1Start, File2Start, A_size) == 0)
return 0;
if (AbsTol == 0 && RelTol == 0)
return 1; // Files different!
}
char *OrigFile1Start = File1Start;
char *OrigFile2Start = File2Start;
// If the files need padding, do so now.
PadFileIfNeeded(File1Start, File1End, F1P);
PadFileIfNeeded(File2Start, File2End, F2P);
bool CompareFailed = false;
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.
if (CompareNumbers(F1P, F2P, File1End, File2End, AbsTol, RelTol, Error)) {
CompareFailed = true;
break;
}
}
// 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 (!CompareFailed && (!F1AtEnd || !F2AtEnd)) {
// Else, 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.
if (CompareNumbers(F1P, F2P, File1End, File2End, AbsTol, RelTol, Error))
CompareFailed = true;
// If we found the end, we succeeded.
if (F1P < File1End || F2P < File2End)
CompareFailed = true;
}
if (OrigFile1Start != File1Start)
delete[] (File1Start-1); // Back up past null byte
if (OrigFile2Start != File2Start)
delete[] (File2Start-1); // Back up past null byte
return CompareFailed;
} catch (const std::string &Msg) {
if (Error) *Error = Msg;
return 2;
} catch (...) {
*Error = "Unknown Exception Occurred";
return 2;
}
}