1 //===- Support/FileUtilities.cpp - File System Utilities ------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements a family of utility functions which are useful for doing
11 // various things with files.
13 //===----------------------------------------------------------------------===//
15 #include "llvm/Support/FileUtilities.h"
16 #include "llvm/System/Path.h"
17 #include "llvm/System/MappedFile.h"
18 #include "llvm/ADT/StringExtras.h"
24 static bool isNumberChar(char C) {
26 case '0': case '1': case '2': case '3': case '4':
27 case '5': case '6': case '7': case '8': case '9':
28 case '.': case '+': case '-':
29 case 'D': // Strange exponential notation.
30 case 'd': // Strange exponential notation.
32 case 'E': return true;
33 default: return false;
37 static char *BackupNumber(char *Pos, char *FirstChar) {
38 // If we didn't stop in the middle of a number, don't backup.
39 if (!isNumberChar(*Pos)) return Pos;
41 // Otherwise, return to the start of the number.
42 while (Pos > FirstChar && isNumberChar(Pos[-1]))
47 /// CompareNumbers - compare two numbers, returning true if they are different.
48 static bool CompareNumbers(char *&F1P, char *&F2P, char *F1End, char *F2End,
49 double AbsTolerance, double RelTolerance,
50 std::string *ErrorMsg) {
51 char *F1NumEnd, *F2NumEnd;
52 double V1 = 0.0, V2 = 0.0;
54 // If one of the positions is at a space and the other isn't, chomp up 'til
55 // the end of the space.
56 while (isspace(*F1P) && F1P != F1End)
58 while (isspace(*F2P) && F2P != F2End)
61 // If we stop on numbers, compare their difference. Note that some ugliness
62 // is built into this to permit support for numbers that use "D" or "d" as
63 // their exponential marker, e.g. "1.234D45". This occurs in 200.sixtrack in
65 if (isNumberChar(*F1P) && isNumberChar(*F2P)) {
69 V1 = strtod(F1P, &F1NumEnd);
70 V2 = strtod(F2P, &F2NumEnd);
72 if (*F1NumEnd == 'D' || *F1NumEnd == 'd') {
73 *F1NumEnd = 'e'; // Strange exponential notation!
76 if (*F2NumEnd == 'D' || *F2NumEnd == 'd') {
77 *F2NumEnd = 'e'; // Strange exponential notation!
80 } while (isDNotation);
82 // Otherwise, the diff failed.
87 if (F1NumEnd == F1P || F2NumEnd == F2P) {
88 if (ErrorMsg) *ErrorMsg = "Comparison failed, not a numeric difference.";
92 // Check to see if these are inside the absolute tolerance
93 if (AbsTolerance < std::abs(V1-V2)) {
94 // Nope, check the relative tolerance...
97 Diff = std::abs(V1/V2 - 1.0);
99 Diff = std::abs(V2/V1 - 1.0);
101 Diff = 0; // Both zero.
102 if (Diff > RelTolerance) {
104 *ErrorMsg = "Compared: " + ftostr(V1) + " and " + ftostr(V2) +
105 ": diff = " + ftostr(Diff) + "\n";
106 *ErrorMsg += "Out of tolerance: rel/abs: " + ftostr(RelTolerance) +
107 "/" + ftostr(AbsTolerance);
113 // Otherwise, advance our read pointers to the end of the numbers.
114 F1P = F1NumEnd; F2P = F2NumEnd;
118 // PadFileIfNeeded - If the files are not identical, we will have to be doing
119 // numeric comparisons in here. There are bad cases involved where we (i.e.,
120 // strtod) might run off the beginning or end of the file if it starts or ends
121 // with a number. Because of this, if needed, we pad the file so that it starts
122 // and ends with a null character.
123 static void PadFileIfNeeded(char *&FileStart, char *&FileEnd, char *&FP) {
124 if (FileStart-FileEnd < 2 ||
125 isNumberChar(FileStart[0]) || isNumberChar(FileEnd[-1])) {
126 unsigned FileLen = FileEnd-FileStart;
127 char *NewFile = new char[FileLen+2];
128 NewFile[0] = 0; // Add null padding
129 NewFile[FileLen+1] = 0; // Add null padding
130 memcpy(NewFile+1, FileStart, FileLen);
131 FP = NewFile+(FP-FileStart)+1;
132 FileStart = NewFile+1;
133 FileEnd = FileStart+FileLen;
137 /// DiffFilesWithTolerance - Compare the two files specified, returning 0 if the
138 /// files match, 1 if they are different, and 2 if there is a file error. This
139 /// function differs from DiffFiles in that you can specify an absolete and
140 /// relative FP error that is allowed to exist. If you specify a string to fill
141 /// in for the error option, it will set the string to an error message if an
142 /// error occurs, allowing the caller to distinguish between a failed diff and a
143 /// file system error.
145 int llvm::DiffFilesWithTolerance(const sys::Path &FileA,
146 const sys::Path &FileB,
147 double AbsTol, double RelTol,
148 std::string *Error) {
149 sys::FileStatus FileAStat, FileBStat;
150 if (FileA.getFileStatus(FileAStat, Error) ||
151 FileB.getFileStatus(FileBStat, Error))
153 // Check for zero length files because some systems croak when you try to
154 // mmap an empty file.
155 size_t A_size = FileAStat.getSize();
156 size_t B_size = FileBStat.getSize();
158 // If they are both zero sized then they're the same
159 if (A_size == 0 && B_size == 0)
161 // If only one of them is zero sized then they can't be the same
162 if ((A_size == 0 || B_size == 0))
166 // Now its safe to mmap the files into memory becasue both files
167 // have a non-zero size.
168 sys::MappedFile F1(FileA);
169 sys::MappedFile F2(FileB);
173 // Okay, now that we opened the files, scan them for the first difference.
174 char *File1Start = F1.charBase();
175 char *File2Start = F2.charBase();
176 char *File1End = File1Start+A_size;
177 char *File2End = File2Start+B_size;
178 char *F1P = File1Start;
179 char *F2P = File2Start;
181 if (A_size == B_size) {
182 // Are the buffers identical?
183 if (std::memcmp(File1Start, File2Start, A_size) == 0)
186 if (AbsTol == 0 && RelTol == 0)
187 return 1; // Files different!
190 char *OrigFile1Start = File1Start;
191 char *OrigFile2Start = File2Start;
193 // If the files need padding, do so now.
194 PadFileIfNeeded(File1Start, File1End, F1P);
195 PadFileIfNeeded(File2Start, File2End, F2P);
197 bool CompareFailed = false;
199 // Scan for the end of file or next difference.
200 while (F1P < File1End && F2P < File2End && *F1P == *F2P)
203 if (F1P >= File1End || F2P >= File2End) break;
205 // Okay, we must have found a difference. Backup to the start of the
206 // current number each stream is at so that we can compare from the
208 F1P = BackupNumber(F1P, File1Start);
209 F2P = BackupNumber(F2P, File2Start);
211 // Now that we are at the start of the numbers, compare them, exiting if
213 if (CompareNumbers(F1P, F2P, File1End, File2End, AbsTol, RelTol, Error)) {
214 CompareFailed = true;
219 // Okay, we reached the end of file. If both files are at the end, we
221 bool F1AtEnd = F1P >= File1End;
222 bool F2AtEnd = F2P >= File2End;
223 if (!CompareFailed && (!F1AtEnd || !F2AtEnd)) {
224 // Else, we might have run off the end due to a number: backup and retry.
225 if (F1AtEnd && isNumberChar(F1P[-1])) --F1P;
226 if (F2AtEnd && isNumberChar(F2P[-1])) --F2P;
227 F1P = BackupNumber(F1P, File1Start);
228 F2P = BackupNumber(F2P, File2Start);
230 // Now that we are at the start of the numbers, compare them, exiting if
232 if (CompareNumbers(F1P, F2P, File1End, File2End, AbsTol, RelTol, Error))
233 CompareFailed = true;
235 // If we found the end, we succeeded.
236 if (F1P < File1End || F2P < File2End)
237 CompareFailed = true;
240 if (OrigFile1Start != File1Start)
241 delete[] (File1Start-1); // Back up past null byte
242 if (OrigFile2Start != File2Start)
243 delete[] (File2Start-1); // Back up past null byte
244 return CompareFailed;
245 } catch (const std::string &Msg) {
246 if (Error) *Error = Msg;
249 *Error = "Unknown Exception Occurred";