lib/Support/FileUtilities.cpp

   1 //===- Support/FileUtilities.cpp - File System Utilities ------------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This file implements a family of utility functions which are useful for doing
  11 // various things with files.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "llvm/Support/FileUtilities.h"
  16 #include "llvm/Support/MemoryBuffer.h"
  17 #include "llvm/Support/raw_ostream.h"
  18 #include "llvm/System/Path.h"
  19 #include "llvm/ADT/OwningPtr.h"
  20 #include "llvm/ADT/SmallString.h"
  21 #include <cstdlib>
  22 #include <cstring>
  23 #include <cctype>
  24 using namespace llvm;
  25
  26 static bool isSignedChar(char C) {
  27   return (C == '+' || C == '-');
  28 }
  29
  30 static bool isExponentChar(char C) {
  31   switch (C) {
  32   case 'D':  // Strange exponential notation.
  33   case 'd':  // Strange exponential notation.
  34   case 'e':
  35   case 'E': return true;
  36   default: return false;
  37   }
  38 }
  39
  40 static bool isNumberChar(char C) {
  41   switch (C) {
  42   case '0': case '1': case '2': case '3': case '4':
  43   case '5': case '6': case '7': case '8': case '9':
  44   case '.': return true;
  45   default: return isSignedChar(C) || isExponentChar(C);
  46   }
  47 }
  48
  49 static const char *BackupNumber(const char *Pos, const char *FirstChar) {
  50   // If we didn't stop in the middle of a number, don't backup.
  51   if (!isNumberChar(*Pos)) return Pos;
  52
  53   // Otherwise, return to the start of the number.
  54   bool HasPeriod = false;
  55   while (Pos > FirstChar && isNumberChar(Pos[-1])) {
  56     // Backup over at most one period.
  57     if (Pos[-1] == '.') {
  58       if (HasPeriod)
  59         break;
  60       HasPeriod = true;
  61     }
  62
  63     --Pos;
  64     if (Pos > FirstChar && isSignedChar(Pos[0]) && !isExponentChar(Pos[-1]))
  65       break;
  66   }
  67   return Pos;
  68 }
  69
  70 /// EndOfNumber - Return the first character that is not part of the specified
  71 /// number.  This assumes that the buffer is null terminated, so it won't fall
  72 /// off the end.
  73 static const char *EndOfNumber(const char *Pos) {
  74   while (isNumberChar(*Pos))
  75     ++Pos;
  76   return Pos;
  77 }
  78
  79 /// CompareNumbers - compare two numbers, returning true if they are different.
  80 static bool CompareNumbers(const char *&F1P, const char *&F2P,
  81                            const char *F1End, const char *F2End,
  82                            double AbsTolerance, double RelTolerance,
  83                            std::string *ErrorMsg) {
  84   const char *F1NumEnd, *F2NumEnd;
  85   double V1 = 0.0, V2 = 0.0;
  86
  87   // If one of the positions is at a space and the other isn't, chomp up 'til
  88   // the end of the space.
  89   while (isspace(*F1P) && F1P != F1End)
  90     ++F1P;
  91   while (isspace(*F2P) && F2P != F2End)
  92     ++F2P;
  93
  94   // If we stop on numbers, compare their difference.
  95   if (!isNumberChar(*F1P) || !isNumberChar(*F2P)) {
  96     // The diff failed.
  97     F1NumEnd = F1P;
  98     F2NumEnd = F2P;
  99   } else {
 100     // Note that some ugliness is built into this to permit support for numbers
 101     // that use "D" or "d" as their exponential marker, e.g. "1.234D45".  This
 102     // occurs in 200.sixtrack in spec2k.
 103     V1 = strtod(F1P, const_cast<char**>(&F1NumEnd));
 104     V2 = strtod(F2P, const_cast<char**>(&F2NumEnd));
 105
 106     if (*F1NumEnd == 'D' || *F1NumEnd == 'd') {
 107       // Copy string into tmp buffer to replace the 'D' with an 'e'.
 108       SmallString<200> StrTmp(F1P, EndOfNumber(F1NumEnd)+1);
 109       // Strange exponential notation!
 110       StrTmp[static_cast<unsigned>(F1NumEnd-F1P)] = 'e';
 111
 112       V1 = strtod(&StrTmp[0], const_cast<char**>(&F1NumEnd));
 113       F1NumEnd = F1P + (F1NumEnd-&StrTmp[0]);
 114     }
 115
 116     if (*F2NumEnd == 'D' || *F2NumEnd == 'd') {
 117       // Copy string into tmp buffer to replace the 'D' with an 'e'.
 118       SmallString<200> StrTmp(F2P, EndOfNumber(F2NumEnd)+1);
 119       // Strange exponential notation!
 120       StrTmp[static_cast<unsigned>(F2NumEnd-F2P)] = 'e';
 121
 122       V2 = strtod(&StrTmp[0], const_cast<char**>(&F2NumEnd));
 123       F2NumEnd = F2P + (F2NumEnd-&StrTmp[0]);
 124     }
 125   }
 126
 127   if (F1NumEnd == F1P || F2NumEnd == F2P) {
 128     if (ErrorMsg) {
 129       *ErrorMsg = "FP Comparison failed, not a numeric difference between '";
 130       *ErrorMsg += F1P[0];
 131       *ErrorMsg += "' and '";
 132       *ErrorMsg += F2P[0];
 133       *ErrorMsg += "'";
 134     }
 135     return true;
 136   }
 137
 138   // Check to see if these are inside the absolute tolerance
 139   if (AbsTolerance < std::abs(V1-V2)) {
 140     // Nope, check the relative tolerance...
 141     double Diff;
 142     if (V2)
 143       Diff = std::abs(V1/V2 - 1.0);
 144     else if (V1)
 145       Diff = std::abs(V2/V1 - 1.0);
 146     else
 147       Diff = 0;  // Both zero.
 148     if (Diff > RelTolerance) {
 149       if (ErrorMsg) {
 150         raw_string_ostream(*ErrorMsg)
 151           << "Compared: " << V1 << " and " << V2 << '\n'
 152           << "abs. diff = " << std::abs(V1-V2) << " rel.diff = " << Diff << '\n'
 153           << "Out of tolerance: rel/abs: " << RelTolerance << '/'
 154           << AbsTolerance;
 155       }
 156       return true;
 157     }
 158   }
 159
 160   // Otherwise, advance our read pointers to the end of the numbers.
 161   F1P = F1NumEnd;  F2P = F2NumEnd;
 162   return false;
 163 }
 164
 165 /// DiffFilesWithTolerance - Compare the two files specified, returning 0 if the
 166 /// files match, 1 if they are different, and 2 if there is a file error.  This
 167 /// function differs from DiffFiles in that you can specify an absolete and
 168 /// relative FP error that is allowed to exist.  If you specify a string to fill
 169 /// in for the error option, it will set the string to an error message if an
 170 /// error occurs, allowing the caller to distinguish between a failed diff and a
 171 /// file system error.
 172 ///
 173 int llvm::DiffFilesWithTolerance(const sys::PathWithStatus &FileA,
 174                                  const sys::PathWithStatus &FileB,
 175                                  double AbsTol, double RelTol,
 176                                  std::string *Error) {
 177   const sys::FileStatus *FileAStat = FileA.getFileStatus(false, Error);
 178   if (!FileAStat)
 179     return 2;
 180   const sys::FileStatus *FileBStat = FileB.getFileStatus(false, Error);
 181   if (!FileBStat)
 182     return 2;
 183
 184   // Check for zero length files because some systems croak when you try to
 185   // mmap an empty file.
 186   size_t A_size = FileAStat->getSize();
 187   size_t B_size = FileBStat->getSize();
 188
 189   // If they are both zero sized then they're the same
 190   if (A_size == 0 && B_size == 0)
 191     return 0;
 192
 193   // If only one of them is zero sized then they can't be the same
 194   if ((A_size == 0 || B_size == 0)) {
 195     if (Error)
 196       *Error = "Files differ: one is zero-sized, the other isn't";
 197     return 1;
 198   }
 199
 200   // Now its safe to mmap the files into memory becasue both files
 201   // have a non-zero size.
 202   OwningPtr<MemoryBuffer> F1(MemoryBuffer::getFile(FileA.c_str(), Error));
 203   OwningPtr<MemoryBuffer> F2(MemoryBuffer::getFile(FileB.c_str(), Error));
 204   if (F1 == 0 || F2 == 0)
 205     return 2;
 206
 207   // Okay, now that we opened the files, scan them for the first difference.
 208   const char *File1Start = F1->getBufferStart();
 209   const char *File2Start = F2->getBufferStart();
 210   const char *File1End = F1->getBufferEnd();
 211   const char *File2End = F2->getBufferEnd();
 212   const char *F1P = File1Start;
 213   const char *F2P = File2Start;
 214
 215   // Are the buffers identical?  Common case: Handle this efficiently.
 216   if (A_size == B_size &&
 217       std::memcmp(File1Start, File2Start, A_size) == 0)
 218     return 0;
 219
 220   // Otherwise, we are done a tolerances are set.
 221   if (AbsTol == 0 && RelTol == 0) {
 222     if (Error)
 223       *Error = "Files differ without tolerance allowance";
 224     return 1;   // Files different!
 225   }
 226
 227   bool CompareFailed = false;
 228   while (1) {
 229     // Scan for the end of file or next difference.
 230     while (F1P < File1End && F2P < File2End && *F1P == *F2P)
 231       ++F1P, ++F2P;
 232
 233     if (F1P >= File1End || F2P >= File2End) break;
 234
 235     // Okay, we must have found a difference.  Backup to the start of the
 236     // current number each stream is at so that we can compare from the
 237     // beginning.
 238     F1P = BackupNumber(F1P, File1Start);
 239     F2P = BackupNumber(F2P, File2Start);
 240
 241     // Now that we are at the start of the numbers, compare them, exiting if
 242     // they don't match.
 243     if (CompareNumbers(F1P, F2P, File1End, File2End, AbsTol, RelTol, Error)) {
 244       CompareFailed = true;
 245       break;
 246     }
 247   }
 248
 249   // Okay, we reached the end of file.  If both files are at the end, we
 250   // succeeded.
 251   bool F1AtEnd = F1P >= File1End;
 252   bool F2AtEnd = F2P >= File2End;
 253   if (!CompareFailed && (!F1AtEnd || !F2AtEnd)) {
 254     // Else, we might have run off the end due to a number: backup and retry.
 255     if (F1AtEnd && isNumberChar(F1P[-1])) --F1P;
 256     if (F2AtEnd && isNumberChar(F2P[-1])) --F2P;
 257     F1P = BackupNumber(F1P, File1Start);
 258     F2P = BackupNumber(F2P, File2Start);
 259
 260     // Now that we are at the start of the numbers, compare them, exiting if
 261     // they don't match.
 262     if (CompareNumbers(F1P, F2P, File1End, File2End, AbsTol, RelTol, Error))
 263       CompareFailed = true;
 264
 265     // If we found the end, we succeeded.
 266     if (F1P < File1End || F2P < File2End)
 267       CompareFailed = true;
 268   }
 269
 270   return CompareFailed;
 271 }