LLVM  3.7.0
FileUtilities.cpp
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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 
16 #include "llvm/ADT/SmallString.h"
18 #include "llvm/Support/Path.h"
20 #include <cctype>
21 #include <cstdlib>
22 #include <cstring>
23 #include <system_error>
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(static_cast<unsigned char>(*F1P)) && F1P != F1End)
90  ++F1P;
91  while (isspace(static_cast<unsigned char>(*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 ///
174  StringRef NameB,
175  double AbsTol, double RelTol,
176  std::string *Error) {
177  // Now its safe to mmap the files into memory because both files
178  // have a non-zero size.
180  if (std::error_code EC = F1OrErr.getError()) {
181  if (Error)
182  *Error = EC.message();
183  return 2;
184  }
185  MemoryBuffer &F1 = *F1OrErr.get();
186 
188  if (std::error_code EC = F2OrErr.getError()) {
189  if (Error)
190  *Error = EC.message();
191  return 2;
192  }
193  MemoryBuffer &F2 = *F2OrErr.get();
194 
195  // Okay, now that we opened the files, scan them for the first difference.
196  const char *File1Start = F1.getBufferStart();
197  const char *File2Start = F2.getBufferStart();
198  const char *File1End = F1.getBufferEnd();
199  const char *File2End = F2.getBufferEnd();
200  const char *F1P = File1Start;
201  const char *F2P = File2Start;
202  uint64_t A_size = F1.getBufferSize();
203  uint64_t B_size = F2.getBufferSize();
204 
205  // Are the buffers identical? Common case: Handle this efficiently.
206  if (A_size == B_size &&
207  std::memcmp(File1Start, File2Start, A_size) == 0)
208  return 0;
209 
210  // Otherwise, we are done a tolerances are set.
211  if (AbsTol == 0 && RelTol == 0) {
212  if (Error)
213  *Error = "Files differ without tolerance allowance";
214  return 1; // Files different!
215  }
216 
217  bool CompareFailed = false;
218  while (1) {
219  // Scan for the end of file or next difference.
220  while (F1P < File1End && F2P < File2End && *F1P == *F2P)
221  ++F1P, ++F2P;
222 
223  if (F1P >= File1End || F2P >= File2End) break;
224 
225  // Okay, we must have found a difference. Backup to the start of the
226  // current number each stream is at so that we can compare from the
227  // beginning.
228  F1P = BackupNumber(F1P, File1Start);
229  F2P = BackupNumber(F2P, File2Start);
230 
231  // Now that we are at the start of the numbers, compare them, exiting if
232  // they don't match.
233  if (CompareNumbers(F1P, F2P, File1End, File2End, AbsTol, RelTol, Error)) {
234  CompareFailed = true;
235  break;
236  }
237  }
238 
239  // Okay, we reached the end of file. If both files are at the end, we
240  // succeeded.
241  bool F1AtEnd = F1P >= File1End;
242  bool F2AtEnd = F2P >= File2End;
243  if (!CompareFailed && (!F1AtEnd || !F2AtEnd)) {
244  // Else, we might have run off the end due to a number: backup and retry.
245  if (F1AtEnd && isNumberChar(F1P[-1])) --F1P;
246  if (F2AtEnd && isNumberChar(F2P[-1])) --F2P;
247  F1P = BackupNumber(F1P, File1Start);
248  F2P = BackupNumber(F2P, File2Start);
249 
250  // Now that we are at the start of the numbers, compare them, exiting if
251  // they don't match.
252  if (CompareNumbers(F1P, F2P, File1End, File2End, AbsTol, RelTol, Error))
253  CompareFailed = true;
254 
255  // If we found the end, we succeeded.
256  if (F1P < File1End || F2P < File2End)
257  CompareFailed = true;
258  }
259 
260  return CompareFailed;
261 }
std::error_code getError() const
Definition: ErrorOr.h:178
Represents either an error or a value T.
Definition: ErrorOr.h:82
const char * getBufferStart() const
Definition: MemoryBuffer.h:50
static const char * BackupNumber(const char *Pos, const char *FirstChar)
static const char * EndOfNumber(const char *Pos)
EndOfNumber - Return the first character that is not part of the specified number.
int DiffFilesWithTolerance(StringRef FileA, StringRef FileB, double AbsTol, double RelTol, std::string *Error=nullptr)
DiffFilesWithTolerance - Compare the two files specified, returning 0 if the files match...
SmallString - A SmallString is just a SmallVector with methods and accessors that make it work better...
Definition: SmallString.h:25
static bool CompareNumbers(const char *&F1P, const char *&F2P, const char *F1End, const char *F2End, double AbsTolerance, double RelTolerance, std::string *ErrorMsg)
CompareNumbers - compare two numbers, returning true if they are different.
static bool isNumberChar(char C)
static bool isSignedChar(char C)
This interface provides simple read-only access to a block of memory, and provides simple methods for...
Definition: MemoryBuffer.h:37
size_t getBufferSize() const
Definition: MemoryBuffer.h:52
static ErrorOr< std::unique_ptr< MemoryBuffer > > getFile(const Twine &Filename, int64_t FileSize=-1, bool RequiresNullTerminator=true, bool IsVolatileSize=false)
Open the specified file as a MemoryBuffer, returning a new MemoryBuffer if successful, otherwise returning null.
APFloat abs(APFloat X)
Returns the absolute value of the argument.
Definition: APFloat.h:651
const char * getBufferEnd() const
Definition: MemoryBuffer.h:51
A raw_ostream that writes to an std::string.
Definition: raw_ostream.h:465
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:40
static bool isExponentChar(char C)
reference get()
Definition: ErrorOr.h:175