core/sql/common/ComSafePrinter.cpp

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// Licensed to the Apache Software Foundation (ASF) under one
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/* -*-C++-*-
******************************************************************************
*
* File:         ComSafePrinter.cpp
* Description:  Safe versions of some sprintf-style functions. They are
*               "safe" in the sense that they prevent writing beyond the
*               end of the target buffer. Some platforms, but not OSS,
*               provide similar functions in the stdio library.
*
* Created:      June 2003
* Language:     C++
*
*
*
******************************************************************************
*/

#include "ComSafePrinter.h"
#include <limits.h>

#define FILENO _fileno

THREAD_P FILE *ComSafePrinter::outfile_ = NULL;

ComSafePrinter::ComSafePrinter()
{
}

ComSafePrinter::~ComSafePrinter()
{
}

Int32 ComSafePrinter::vsnPrintf(char *str, size_t n,
                              const char *format, va_list args)
{

  if (!str || n == 0 || !format)
  {
    return 0;
  }

  Int32 targetLen = (n > INT_MAX ? INT_MAX : (Int32) n);
  Int32 result = -1;


  // Otherwise we buffer data in a temporary file
  if (!outfile_)
  {
    outfile_ = tmpfile();
#ifdef _DEBUG
    if (!outfile_)
    {
      fprintf(stderr,
              "*** WARNING: ComSafePrinter temp file could not be created");
    }
#endif
  }

  if (outfile_)
  {
    rewind(outfile_);
    result = vfprintf(outfile_, format, args);
  }

  if (result > 0)
  {
    Int32 totalLength = result;
    Int32 numWritten = 0;

    if (totalLength < targetLen)
    {
      numWritten = vsprintf(str, format, args);
      if (numWritten == totalLength)
      {
        result = numWritten;
      }
      else
      {
        result = -1;
      }
    }
    else
    {
      rewind(outfile_);
      numWritten = (Int32) fread(str, sizeof(char), targetLen - 1, outfile_);
      if (numWritten == (targetLen - 1))
      {
        str[targetLen - 1] = 0;
        result = numWritten;
      }
      else
      {
        result = -1;
      }
    }
  }
  
  return result;


} // ComSafePrinter::vsnPrintf()

Int32 ComSafePrinter::snPrintf(char *str, size_t n, const char *format, ...)
{
  va_list args;
  va_start(args, format);
  Int32 result = vsnPrintf(str, n, format, args);
  va_end(args);
  return result;
}