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//===- Support/FileUtilities.cpp - File System Utilities ------------------===//
//
// This file implements a family of utility functions which are useful for doing
// various things with files.
//
//===----------------------------------------------------------------------===//
#include "Support/FileUtilities.h"
#include <fstream>
#include <iostream>
#include <cstdio>
/// DiffFiles - Compare the two files specified, returning true if they are
/// different or if there is a file error. If you specify a string to fill in
/// for the error option, it will set the string to an error message if an error
/// occurs, allowing the caller to distinguish between a failed diff and a file
/// system error.
///
bool DiffFiles(const std::string &FileA, const std::string &FileB,
std::string *Error) {
std::ifstream FileAStream(FileA.c_str());
if (!FileAStream) {
if (Error) *Error = "Couldn't open file '" + FileA + "'";
return true;
}
std::ifstream FileBStream(FileB.c_str());
if (!FileBStream) {
if (Error) *Error = "Couldn't open file '" + FileB + "'";
return true;
}
// Compare the two files...
int C1, C2;
do {
C1 = FileAStream.get();
C2 = FileBStream.get();
if (C1 != C2) return true;
} while (C1 != EOF);
return false;
}
/// MoveFileOverIfUpdated - If the file specified by New is different than Old,
/// or if Old does not exist, move the New file over the Old file. Otherwise,
/// remove the New file.
///
void MoveFileOverIfUpdated(const std::string &New, const std::string &Old) {
if (DiffFiles(New, Old)) {
if (std::rename(New.c_str(), Old.c_str()))
std::cerr << "Error renaming '" << New << "' to '" << Old << "'!\n";
} else {
std::remove(New.c_str());
}
}
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