From aad7cf00bda1209980f2f611f2d60a9cf53db94d Mon Sep 17 00:00:00 2001
From: Martin Marinov <Martin.Marinov@autodesk.com>
Date: Wed, 6 Apr 2022 21:06:29 +0100
Subject: [PATCH] MTBR-925 Add BufferedOutputFile (#79)
Add buffered text output file for faster text writes. Improve platform compatibility for printing.
---
Utils/BufferedOutputFile.hh | 102 ++++++++++++++++++++++++++++++++++++
Utils/CMakeLists.txt | 1 +
Utils/OStringStream.cc | 24 +++++----
3 files changed, 116 insertions(+), 11 deletions(-)
create mode 100644 Utils/BufferedOutputFile.hh
diff --git a/Utils/BufferedOutputFile.hh b/Utils/BufferedOutputFile.hh
new file mode 100644
index 0000000..61222b1
--- /dev/null
+++ b/Utils/BufferedOutputFile.hh
@@ -0,0 +1,102 @@
+// (C) Copyright 2022 by Autodesk, Inc.
+
+#ifndef BASE_BUFFEREDOUTPUTFILE_HH_INCLUDED
+#define BASE_BUFFEREDOUTPUTFILE_HH_INCLUDED
+
+#include <Base/Config/BaseDefines.hh>
+#include <Base/Utils/IOutputStream.hh>
+#include <Base/Debug/DebOut.hh>
+
+#include <cstdio>
+#include <vector>
+
+namespace Base
+{
+
+// Provide buffered text print operations to a FILE, helps with the performance
+// when storing large text data.
+class BufferedOutputFile
+{
+public:
+ BufferedOutputFile(const char* const _flnm, // filename
+ const size_t _flsh_size = 1 << 20, // buffer size that forces flush (1Mb)
+ const size_t _ovfl_size = 1 << 10 // "overflow" space in the buffer, also
+ // sets the maximum amount of characters that can be printed at once (1Kb)
+ )
+ : flsh_size_(_flsh_size), ovfl_size_(_ovfl_size),
+ bffr_(flsh_size_ + ovfl_size_), bffr_end_(bffr_.data())
+ {
+ const char* const MODE = "wb"; // open as write binary
+
+#ifdef _MSC_VER
+ fopen_s(&file_, _flnm, MODE);
+#else
+ file_ = std::fopen(_flnm, MODE);
+#endif
+ }
+
+ ~BufferedOutputFile()
+ {
+ if (!opened())
+ return;
+ flush();
+ fclose(file_);
+ }
+
+ bool opened() const { return file_ != nullptr; }
+
+#define DEB_check_opened \
+ DEB_error_if(!opened(), "Write access to a file that has failed open")
+
+ void flush()
+ {
+ DEB_check_opened;
+ const auto bffr_size = buffer_size();
+ if (bffr_size == 0)
+ return;
+ fwrite(bffr_.data(), sizeof(char), bffr_size, file_);
+ bffr_end_ = bffr_.data();
+ }
+
+ template <typename... ArgT> void print(const ArgT&... _args)
+ {
+ DEB_check_opened;
+ const auto char_nmbr = Base::print(bffr_end_, ovfl_size_, _args...);
+ DEB_error_if(char_nmbr < 0 || char_nmbr >= static_cast<int>(ovfl_size_),
+ "print() result = "
+ << char_nmbr << " is unclear, consider using larger overflow size");
+ bffr_end_ += char_nmbr;
+ if (buffer_size() + ovfl_size_ >= bffr_.size()) // make sure we always have
+ flush(); // at least ovfl_size_ space in the buffer
+ }
+
+ template <typename T> void write(const T* const _ptr, const size_t _nmbr)
+ {
+ DEB_check_opened;
+ flush();
+ fwrite(_ptr, sizeof(T), _nmbr, file_);
+ }
+
+ // Access the file, but make sure we have flushed first
+ FILE* file()
+ {
+ DEB_check_opened;
+ flush();
+ return file_;
+ }
+
+#undef DEB_check_opened
+
+private:
+ const size_t flsh_size_; // number of bytes to trigger flushing the buffer
+ const size_t ovfl_size_; // number of bytes to print in a single print() call
+ std::vector<char> bffr_; // buffer
+ char* bffr_end_; // end of the buffer
+ FILE* file_ = nullptr;
+
+ size_t buffer_size() const { return bffr_end_ - bffr_.data(); }
+};
+
+} // namespace Base
+
+#endif // BASE_BUFFEREDOUTPUTFILE_HH_INCLUDED
diff --git a/Utils/CMakeLists.txt b/Utils/CMakeLists.txt
index 7fc0247..80ca9e9 100644
--- a/Utils/CMakeLists.txt
+++ b/Utils/CMakeLists.txt
@@ -1,6 +1,7 @@
set(my_headers
${CMAKE_CURRENT_SOURCE_DIR}/BaseError.hh
${CMAKE_CURRENT_SOURCE_DIR}/BaseErrorInc.hh
+ ${CMAKE_CURRENT_SOURCE_DIR}/BufferedOutputFile.hh
${CMAKE_CURRENT_SOURCE_DIR}/Environment.hh
${CMAKE_CURRENT_SOURCE_DIR}/FileOutput.hh
${CMAKE_CURRENT_SOURCE_DIR}/IOutputStream.hh
diff --git a/Utils/OStringStream.cc b/Utils/OStringStream.cc
index 5eba038..f1cf110 100644
--- a/Utils/OStringStream.cc
+++ b/Utils/OStringStream.cc
@@ -1,4 +1,4 @@
-// (C) Copyright 2019 by Autodesk, Inc.
+// (C) Copyright 2022 by Autodesk, Inc.
#include "Base/Security/Mandatory.hh"
#include "OStringStream.hh"
@@ -26,16 +26,22 @@ namespace Base
namespace
{
+// Cross-platform approach to avoid buffer overflow when printing. However,
+// there are subtle differences between these functions, see here for details:
+// https://stackoverflow.com/questions/46485639/what-is-the-difference-between-vsnprintf-and-vsprintf-s
+
+#ifdef _MSC_VER
+ #define VSNPRINTF vsprintf_s
+#else
+ #define VSNPRINTF vsnprintf
+#endif
+
template <size_t _bffr_size>
int sprintf_s(char (&_bffr)[_bffr_size], const char* _frmt, ...)
{
va_list arg_ptr;
va_start(arg_ptr, _frmt);
-#ifdef _MSC_VER
- int res = vsprintf_s(_bffr, _bffr_size, _frmt, arg_ptr);
-#else
- int res = vsprintf(_bffr, _frmt, arg_ptr);
-#endif // _MSC_VER
+ int res = VSNPRINTF(_bffr, _bffr_size, _frmt, arg_ptr);
va_end(arg_ptr);
return res;
}
@@ -46,11 +52,7 @@ int print(char* _bffr, const size_t _bffr_size, const char* _frmt, ...)
{
va_list arg_ptr;
va_start(arg_ptr, _frmt);
-#ifdef _MSC_VER
- int res = vsprintf_s(_bffr, _bffr_size, _frmt, arg_ptr);
-#else
- int res = vsprintf(_bffr, _frmt, arg_ptr);
-#endif
+ int res = VSNPRINTF(_bffr, _bffr_size, _frmt, arg_ptr);
va_end(arg_ptr);
return res;
}
--
GitLab