1 //===- Support/FileUtilities.cpp - File System Utilities ------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // 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/Support/MemoryBuffer.h"
18 #include "llvm/ADT/OwningPtr.h"
19 #include "llvm/ADT/SmallString.h"
20 #include "llvm/ADT/StringExtras.h"
26 static bool isSignedChar(char C) {
27 return (C == '+' || C == '-');
30 static bool isExponentChar(char C) {
32 case 'D': // Strange exponential notation.
33 case 'd': // Strange exponential notation.
35 case 'E': return true;
36 default: return false;
40 static bool isNumberChar(char 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);
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;
53 // Otherwise, return to the start of the number.
54 while (Pos > FirstChar && isNumberChar(Pos[-1])) {
56 if (Pos > FirstChar && isSignedChar(Pos[0]) && !isExponentChar(Pos[-1]))
62 /// EndOfNumber - Return the first character that is not part of the specified
63 /// number. This assumes that the buffer is null terminated, so it won't fall
65 static const char *EndOfNumber(const char *Pos) {
66 while (isNumberChar(*Pos))
71 /// CompareNumbers - compare two numbers, returning true if they are different.
72 static bool CompareNumbers(const char *&F1P, const char *&F2P,
73 const char *F1End, const char *F2End,
74 double AbsTolerance, double RelTolerance,
75 std::string *ErrorMsg) {
76 const char *F1NumEnd, *F2NumEnd;
77 double V1 = 0.0, V2 = 0.0;
79 // If one of the positions is at a space and the other isn't, chomp up 'til
80 // the end of the space.
81 while (isspace(*F1P) && F1P != F1End)
83 while (isspace(*F2P) && F2P != F2End)
86 // If we stop on numbers, compare their difference.
87 if (!isNumberChar(*F1P) || !isNumberChar(*F2P)) {
92 // Note that some ugliness is built into this to permit support for numbers
93 // that use "D" or "d" as their exponential marker, e.g. "1.234D45". This
94 // occurs in 200.sixtrack in spec2k.
95 V1 = strtod(F1P, const_cast<char**>(&F1NumEnd));
96 V2 = strtod(F2P, const_cast<char**>(&F2NumEnd));
98 if (*F1NumEnd == 'D' || *F1NumEnd == 'd') {
99 // Copy string into tmp buffer to replace the 'D' with an 'e'.
100 SmallString<200> StrTmp(F1P, EndOfNumber(F1NumEnd)+1);
101 StrTmp[F1NumEnd-F1P] = 'e'; // Strange exponential notation!
103 V1 = strtod(&StrTmp[0], const_cast<char**>(&F1NumEnd));
104 F1NumEnd = F1P + (F1NumEnd-&StrTmp[0]);
107 if (*F2NumEnd == 'D' || *F2NumEnd == 'd') {
108 // Copy string into tmp buffer to replace the 'D' with an 'e'.
109 SmallString<200> StrTmp(F2P, EndOfNumber(F2NumEnd)+1);
110 StrTmp[F2NumEnd-F2P] = 'e'; // Strange exponential notation!
112 V2 = strtod(&StrTmp[0], const_cast<char**>(&F2NumEnd));
113 F2NumEnd = F2P + (F2NumEnd-&StrTmp[0]);
117 if (F1NumEnd == F1P || F2NumEnd == F2P) {
119 *ErrorMsg = "FP Comparison failed, not a numeric difference between '";
121 *ErrorMsg += "' and '";
128 // Check to see if these are inside the absolute tolerance
129 if (AbsTolerance < std::abs(V1-V2)) {
130 // Nope, check the relative tolerance...
133 Diff = std::abs(V1/V2 - 1.0);
135 Diff = std::abs(V2/V1 - 1.0);
137 Diff = 0; // Both zero.
138 if (Diff > RelTolerance) {
140 *ErrorMsg = "Compared: " + ftostr(V1) + " and " + ftostr(V2) + "\n";
141 *ErrorMsg += "abs. diff = " + ftostr(std::abs(V1-V2)) +
142 " rel.diff = " + ftostr(Diff) + "\n";
143 *ErrorMsg += "Out of tolerance: rel/abs: " + ftostr(RelTolerance) +
144 "/" + ftostr(AbsTolerance);
150 // Otherwise, advance our read pointers to the end of the numbers.
151 F1P = F1NumEnd; F2P = F2NumEnd;
155 /// DiffFilesWithTolerance - Compare the two files specified, returning 0 if the
156 /// files match, 1 if they are different, and 2 if there is a file error. This
157 /// function differs from DiffFiles in that you can specify an absolete and
158 /// relative FP error that is allowed to exist. If you specify a string to fill
159 /// in for the error option, it will set the string to an error message if an
160 /// error occurs, allowing the caller to distinguish between a failed diff and a
161 /// file system error.
163 int llvm::DiffFilesWithTolerance(const sys::PathWithStatus &FileA,
164 const sys::PathWithStatus &FileB,
165 double AbsTol, double RelTol,
166 std::string *Error) {
167 const sys::FileStatus *FileAStat = FileA.getFileStatus(false, Error);
170 const sys::FileStatus *FileBStat = FileB.getFileStatus(false, Error);
174 // Check for zero length files because some systems croak when you try to
175 // mmap an empty file.
176 size_t A_size = FileAStat->getSize();
177 size_t B_size = FileBStat->getSize();
179 // If they are both zero sized then they're the same
180 if (A_size == 0 && B_size == 0)
183 // If only one of them is zero sized then they can't be the same
184 if ((A_size == 0 || B_size == 0)) {
186 *Error = "Files differ: one is zero-sized, the other isn't";
190 // Now its safe to mmap the files into memory becasue both files
191 // have a non-zero size.
192 OwningPtr<MemoryBuffer> F1(MemoryBuffer::getFile(FileA.c_str(), Error));
193 OwningPtr<MemoryBuffer> F2(MemoryBuffer::getFile(FileB.c_str(), Error));
194 if (F1 == 0 || F2 == 0)
197 // Okay, now that we opened the files, scan them for the first difference.
198 const char *File1Start = F1->getBufferStart();
199 const char *File2Start = F2->getBufferStart();
200 const char *File1End = F1->getBufferEnd();
201 const char *File2End = F2->getBufferEnd();
202 const char *F1P = File1Start;
203 const char *F2P = File2Start;
205 if (A_size == B_size) {
206 // Are the buffers identical? Common case: Handle this efficiently.
207 if (std::memcmp(File1Start, File2Start, A_size) == 0)
210 if (AbsTol == 0 && RelTol == 0) {
212 *Error = "Files differ without tolerance allowance";
213 return 1; // Files different!
217 bool CompareFailed = false;
219 // Scan for the end of file or next difference.
220 while (F1P < File1End && F2P < File2End && *F1P == *F2P)
223 if (F1P >= File1End || F2P >= File2End) break;
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
228 F1P = BackupNumber(F1P, File1Start);
229 F2P = BackupNumber(F2P, File2Start);
231 // Now that we are at the start of the numbers, compare them, exiting if
233 if (CompareNumbers(F1P, F2P, File1End, File2End, AbsTol, RelTol, Error)) {
234 CompareFailed = true;
239 // Okay, we reached the end of file. If both files are at the end, we
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);
250 // Now that we are at the start of the numbers, compare them, exiting if
252 if (CompareNumbers(F1P, F2P, File1End, File2End, AbsTol, RelTol, Error))
253 CompareFailed = true;
255 // If we found the end, we succeeded.
256 if (F1P < File1End || F2P < File2End)
257 CompareFailed = true;
260 return CompareFailed;