Logo ROOT  
Reference Guide
 
Loading...
Searching...
No Matches
RRawFileWin.cxx
Go to the documentation of this file.
1// @(#)root/io:$Id$
2// Author: Jakob Blomer
3
4/*************************************************************************
5 * Copyright (C) 1995-2018, Rene Brun and Fons Rademakers. *
6 * All rights reserved. *
7 * *
8 * For the licensing terms see $ROOTSYS/LICENSE. *
9 * For the list of contributors see $ROOTSYS/README/CREDITS. *
10 *************************************************************************/
11
12#include "ROOT/RRawFileWin.hxx"
13#include "ROOT/RMakeUnique.hxx"
14
15#include "TError.h"
16
17#include <cerrno>
18#include <cstddef>
19#include <cstdint>
20#include <cstdio>
21#include <cstring>
22#include <stdexcept>
23#include <string>
24
25namespace {
26constexpr int kDefaultBlockSize = 4096; // Read files in 4k pages unless told otherwise
27} // anonymous namespace
28
30 : RRawFile(url, options), fFilePtr(nullptr)
31{
32}
33
35{
36 if (fFilePtr != nullptr)
37 fclose(fFilePtr);
38}
39
40std::unique_ptr<ROOT::Internal::RRawFile> ROOT::Internal::RRawFileWin::Clone() const
41{
42 return std::make_unique<RRawFileWin>(fUrl, fOptions);
43}
44
46{
47 Seek(0L, SEEK_END);
48 long size = ftell(fFilePtr);
49 if (size < 0)
50 throw std::runtime_error("Cannot tell position counter in '" + fUrl +
51 "', error: " + std::string(strerror(errno)));
52 Seek(fFilePos, SEEK_SET);
53 return size;
54}
55
57{
58 fFilePtr = fopen(GetLocation(fUrl).c_str(), "rb");
59 if (fFilePtr == nullptr)
60 throw std::runtime_error("Cannot open '" + fUrl + "', error: " + std::string(strerror(errno)));
61 // Prevent double buffering
62 int res = setvbuf(fFilePtr, nullptr, _IONBF, 0);
63 R__ASSERT(res == 0);
64 if (fOptions.fBlockSize < 0)
65 fOptions.fBlockSize = kDefaultBlockSize;
66}
67
68size_t ROOT::Internal::RRawFileWin::ReadAtImpl(void *buffer, size_t nbytes, std::uint64_t offset)
69{
70 Seek(offset, SEEK_SET);
71 size_t res = fread(buffer, 1, nbytes, fFilePtr);
72 if ((res < nbytes) && (ferror(fFilePtr) != 0)) {
73 clearerr(fFilePtr);
74 throw std::runtime_error("Cannot read from '" + fUrl + "', error: " + std::string(strerror(errno)));
75 }
76 return res;
77}
78
79void ROOT::Internal::RRawFileWin::Seek(long offset, int whence)
80{
81 int res = fseek(fFilePtr, offset, whence);
82 if (res != 0)
83 throw std::runtime_error("Cannot seek in '" + fUrl + "', error: " + std::string(strerror(errno)));
84}
#define R__ASSERT(e)
Definition TError.h:120
RRawFileWin(std::string_view url, RRawFile::ROptions options)
size_t ReadAtImpl(void *buffer, size_t nbytes, std::uint64_t offset) final
Derived classes should implement low-level reading without buffering.
std::unique_ptr< RRawFile > Clone() const final
Create a new RawFile that accesses the same resource. The file pointer is reset to zero.
std::uint64_t GetSizeImpl() final
Derived classes should return the file size or kUnknownFileSize.
void Seek(long offset, int whence)
void OpenImpl() final
OpenImpl() is called at most once and before any call to either DoReadAt or DoGetSize.
The RRawFile provides read-only access to local and remote files.
Definition RRawFile.hxx:43
On construction, an ROptions parameter can customize the RRawFile behavior.
Definition RRawFile.hxx:59