1 //===- fpcmp.cpp - A fuzzy "cmp" that permits floating point noise --------===//
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 // fpcmp is a tool that basically works like the 'cmp' tool, except that it can
11 // tolerate errors due to floating point noise, with the -r option.
13 //===----------------------------------------------------------------------===//
15 #include "Support/CommandLine.h"
16 #include "Support/FileUtilities.h"
17 #include "Config/fcntl.h"
18 #include "Config/sys/mman.h"
26 File1(cl::Positional, cl::desc("<input file #1>"), cl::Required);
28 File2(cl::Positional, cl::desc("<input file #2>"), cl::Required);
31 RelTolerance("r", cl::desc("Relative error tolerated"), cl::init(0));
33 AbsTolerance("a", cl::desc("Absolute error tolerated"), cl::init(0));
37 /// OpenFile - mmap the specified file into the address space for reading, and
38 /// return the length and address of the buffer.
39 static void OpenFile(const std::string &Filename, unsigned &Len, char* &BufPtr){
40 int FD = open(Filename.c_str(), O_RDONLY);
41 if (FD == -1 || (Len = getFileSize(Filename)) == ~0U) {
42 std::cerr << "Error: cannot open file '" << Filename << "'\n";
46 // mmap in the file all at once...
47 BufPtr = (char*)mmap(0, Len, PROT_READ, MAP_PRIVATE, FD, 0);
49 if (BufPtr == (char*)MAP_FAILED) {
50 std::cerr << "Error: cannot open file '" << Filename << "'\n";
54 // If mmap decided that the files were empty, it might have returned a
55 // null pointer. If so, make a new, fake pointer -- it shouldn't matter
56 // what it contains, because Len is 0, and it should never be read.
57 if (BufPtr == 0 && Len == 0)
61 static bool isNumberChar(char C) {
63 case '0': case '1': case '2': case '3': case '4':
64 case '5': case '6': case '7': case '8': case '9':
65 case '.': case '+': case '-':
67 case 'E': return true;
68 default: return false;
72 static char *BackupNumber(char *Pos, char *FirstChar) {
73 while (Pos > FirstChar && isNumberChar(Pos[-1]))
78 static void CompareNumbers(char *&F1P, char *&F2P, char *F1End, char *F2End) {
79 char *F1NumEnd, *F2NumEnd;
80 double V1 = strtod(F1P, &F1NumEnd);
81 double V2 = strtod(F2P, &F2NumEnd);
83 if (F1NumEnd == F1P || F2NumEnd == F2P) {
84 std::cerr << "Comparison failed, not a numeric difference.\n";
88 // Check to see if these are inside the absolute tolerance
89 if (AbsTolerance < std::abs(V1-V2)) {
90 // Nope, check the relative tolerance...
93 Diff = std::abs(V1/V2 - 1.0);
95 Diff = std::abs(V2/V1 - 1.0);
97 Diff = 0; // Both zero.
98 if (Diff > RelTolerance) {
99 std::cerr << "Compared: " << V1 << " and " << V2 << ": diff = "
101 std::cerr << "Out of tolerance: rel/abs: " << RelTolerance
102 << "/" << AbsTolerance << "\n";
107 // Otherwise, advance our read pointers to the end of the numbers.
108 F1P = F1NumEnd; F2P = F2NumEnd;
112 int main(int argc, char **argv) {
113 cl::ParseCommandLineOptions(argc, argv);
115 // mmap in the files.
116 unsigned File1Len, File2Len;
117 char *File1Start, *File2Start;
118 OpenFile(File1, File1Len, File1Start);
119 OpenFile(File2, File2Len, File2Start);
121 // Okay, now that we opened the files, scan them for the first difference.
122 char *File1End = File1Start+File1Len;
123 char *File2End = File2Start+File2Len;
124 char *F1P = File1Start;
125 char *F2P = File2Start;
128 // Scan for the end of file or first difference.
129 while (F1P < File1End && F2P < File2End && *F1P == *F2P)
132 if (F1P >= File1End || F2P >= File2End) break;
134 // Okay, we must have found a difference. Backup to the start of the
135 // current number each stream is at so that we can compare from the
137 F1P = BackupNumber(F1P, File1Start);
138 F2P = BackupNumber(F2P, File2Start);
140 // Now that we are at the start of the numbers, compare them, exiting if
142 CompareNumbers(F1P, F2P, File1End, File2End);
145 // Okay, we reached the end of file. If both files are at the end, we
147 if (F1P >= File1End && F2P >= File2End) return 0;
149 // Otherwise, we might have run off the end due to a number, backup and retry.
150 F1P = BackupNumber(F1P, File1Start);
151 F2P = BackupNumber(F2P, File2Start);
153 // Now that we are at the start of the numbers, compare them, exiting if
155 CompareNumbers(F1P, F2P, File1End, File2End);
157 // If we found the end, we succeeded.
158 if (F1P >= File1End && F2P >= File2End) return 0;