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/ADT/SmallString.h"
17 #include "llvm/Support/ErrorOr.h"
18 #include "llvm/Support/MemoryBuffer.h"
19 #include "llvm/Support/raw_ostream.h"
26 #include <system_error>
30 static bool isSignedChar(char C) {
31 return (C == '+' || C == '-');
34 static bool isExponentChar(char C) {
36 case 'D': // Strange exponential notation.
37 case 'd': // Strange exponential notation.
39 case 'E': return true;
40 default: return false;
44 static bool isNumberChar(char C) {
46 case '0': case '1': case '2': case '3': case '4':
47 case '5': case '6': case '7': case '8': case '9':
48 case '.': return true;
49 default: return isSignedChar(C) || isExponentChar(C);
53 static const char *BackupNumber(const char *Pos, const char *FirstChar) {
54 // If we didn't stop in the middle of a number, don't backup.
55 if (!isNumberChar(*Pos)) return Pos;
57 // Otherwise, return to the start of the number.
58 bool HasPeriod = false;
59 while (Pos > FirstChar && isNumberChar(Pos[-1])) {
60 // Backup over at most one period.
68 if (Pos > FirstChar && isSignedChar(Pos[0]) && !isExponentChar(Pos[-1]))
74 /// EndOfNumber - Return the first character that is not part of the specified
75 /// number. This assumes that the buffer is null terminated, so it won't fall
77 static const char *EndOfNumber(const char *Pos) {
78 while (isNumberChar(*Pos))
83 /// CompareNumbers - compare two numbers, returning true if they are different.
84 static bool CompareNumbers(const char *&F1P, const char *&F2P,
85 const char *F1End, const char *F2End,
86 double AbsTolerance, double RelTolerance,
87 std::string *ErrorMsg) {
88 const char *F1NumEnd, *F2NumEnd;
89 double V1 = 0.0, V2 = 0.0;
91 // If one of the positions is at a space and the other isn't, chomp up 'til
92 // the end of the space.
93 while (isspace(static_cast<unsigned char>(*F1P)) && F1P != F1End)
95 while (isspace(static_cast<unsigned char>(*F2P)) && F2P != F2End)
98 // If we stop on numbers, compare their difference.
99 if (!isNumberChar(*F1P) || !isNumberChar(*F2P)) {
104 // Note that some ugliness is built into this to permit support for numbers
105 // that use "D" or "d" as their exponential marker, e.g. "1.234D45". This
106 // occurs in 200.sixtrack in spec2k.
107 V1 = strtod(F1P, const_cast<char**>(&F1NumEnd));
108 V2 = strtod(F2P, const_cast<char**>(&F2NumEnd));
110 if (*F1NumEnd == 'D' || *F1NumEnd == 'd') {
111 // Copy string into tmp buffer to replace the 'D' with an 'e'.
112 SmallString<200> StrTmp(F1P, EndOfNumber(F1NumEnd)+1);
113 // Strange exponential notation!
114 StrTmp[static_cast<unsigned>(F1NumEnd-F1P)] = 'e';
116 V1 = strtod(&StrTmp[0], const_cast<char**>(&F1NumEnd));
117 F1NumEnd = F1P + (F1NumEnd-&StrTmp[0]);
120 if (*F2NumEnd == 'D' || *F2NumEnd == 'd') {
121 // Copy string into tmp buffer to replace the 'D' with an 'e'.
122 SmallString<200> StrTmp(F2P, EndOfNumber(F2NumEnd)+1);
123 // Strange exponential notation!
124 StrTmp[static_cast<unsigned>(F2NumEnd-F2P)] = 'e';
126 V2 = strtod(&StrTmp[0], const_cast<char**>(&F2NumEnd));
127 F2NumEnd = F2P + (F2NumEnd-&StrTmp[0]);
131 if (F1NumEnd == F1P || F2NumEnd == F2P) {
133 *ErrorMsg = "FP Comparison failed, not a numeric difference between '";
135 *ErrorMsg += "' and '";
142 // Check to see if these are inside the absolute tolerance
143 if (AbsTolerance < std::abs(V1-V2)) {
144 // Nope, check the relative tolerance...
147 Diff = std::abs(V1/V2 - 1.0);
149 Diff = std::abs(V2/V1 - 1.0);
151 Diff = 0; // Both zero.
152 if (Diff > RelTolerance) {
154 raw_string_ostream(*ErrorMsg)
155 << "Compared: " << V1 << " and " << V2 << '\n'
156 << "abs. diff = " << std::abs(V1-V2) << " rel.diff = " << Diff << '\n'
157 << "Out of tolerance: rel/abs: " << RelTolerance << '/'
164 // Otherwise, advance our read pointers to the end of the numbers.
165 F1P = F1NumEnd; F2P = F2NumEnd;
169 /// DiffFilesWithTolerance - Compare the two files specified, returning 0 if the
170 /// files match, 1 if they are different, and 2 if there is a file error. This
171 /// function differs from DiffFiles in that you can specify an absolete and
172 /// relative FP error that is allowed to exist. If you specify a string to fill
173 /// in for the error option, it will set the string to an error message if an
174 /// error occurs, allowing the caller to distinguish between a failed diff and a
175 /// file system error.
177 int llvm::DiffFilesWithTolerance(StringRef NameA,
179 double AbsTol, double RelTol,
180 std::string *Error) {
181 // Now its safe to mmap the files into memory because both files
182 // have a non-zero size.
183 ErrorOr<std::unique_ptr<MemoryBuffer>> F1OrErr = MemoryBuffer::getFile(NameA);
184 if (std::error_code EC = F1OrErr.getError()) {
186 *Error = EC.message();
189 MemoryBuffer &F1 = *F1OrErr.get();
191 ErrorOr<std::unique_ptr<MemoryBuffer>> F2OrErr = MemoryBuffer::getFile(NameB);
192 if (std::error_code EC = F2OrErr.getError()) {
194 *Error = EC.message();
197 MemoryBuffer &F2 = *F2OrErr.get();
199 // Okay, now that we opened the files, scan them for the first difference.
200 const char *File1Start = F1.getBufferStart();
201 const char *File2Start = F2.getBufferStart();
202 const char *File1End = F1.getBufferEnd();
203 const char *File2End = F2.getBufferEnd();
204 const char *F1P = File1Start;
205 const char *F2P = File2Start;
206 uint64_t A_size = F1.getBufferSize();
207 uint64_t B_size = F2.getBufferSize();
209 // Are the buffers identical? Common case: Handle this efficiently.
210 if (A_size == B_size &&
211 std::memcmp(File1Start, File2Start, A_size) == 0)
214 // Otherwise, we are done a tolerances are set.
215 if (AbsTol == 0 && RelTol == 0) {
217 *Error = "Files differ without tolerance allowance";
218 return 1; // Files different!
221 bool CompareFailed = false;
223 // Scan for the end of file or next difference.
224 while (F1P < File1End && F2P < File2End && *F1P == *F2P) {
229 if (F1P >= File1End || F2P >= File2End) break;
231 // Okay, we must have found a difference. Backup to the start of the
232 // current number each stream is at so that we can compare from the
234 F1P = BackupNumber(F1P, File1Start);
235 F2P = BackupNumber(F2P, File2Start);
237 // Now that we are at the start of the numbers, compare them, exiting if
239 if (CompareNumbers(F1P, F2P, File1End, File2End, AbsTol, RelTol, Error)) {
240 CompareFailed = true;
245 // Okay, we reached the end of file. If both files are at the end, we
247 bool F1AtEnd = F1P >= File1End;
248 bool F2AtEnd = F2P >= File2End;
249 if (!CompareFailed && (!F1AtEnd || !F2AtEnd)) {
250 // Else, we might have run off the end due to a number: backup and retry.
251 if (F1AtEnd && isNumberChar(F1P[-1])) --F1P;
252 if (F2AtEnd && isNumberChar(F2P[-1])) --F2P;
253 F1P = BackupNumber(F1P, File1Start);
254 F2P = BackupNumber(F2P, File2Start);
256 // Now that we are at the start of the numbers, compare them, exiting if
258 if (CompareNumbers(F1P, F2P, File1End, File2End, AbsTol, RelTol, Error))
259 CompareFailed = true;
261 // If we found the end, we succeeded.
262 if (F1P < File1End || F2P < File2End)
263 CompareFailed = true;
266 return CompareFailed;