IOStream.cxx

/*============================================================================
  KWSys - Kitware System Library
  Copyright 2000-2009 Kitware, Inc., Insight Software Consortium

  Distributed under the OSI-approved BSD License (the "License");
  see accompanying file Copyright.txt for details.

  This software is distributed WITHOUT ANY WARRANTY; without even the
  implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  See the License for more information.
============================================================================*/
#include "kwsysPrivate.h"
#include KWSYS_HEADER(Configure.hxx)

// Include the streams library.
#include <iostream>
#include KWSYS_HEADER(IOStream.hxx)

// Work-around CMake dependency scanning limitation.  This must
// duplicate the above list of headers.
#if 0
# include "Configure.hxx.in"
# include "IOStream.hxx.in"
#endif

// Implement the rest of this file only if it is needed.
#if KWSYS_IOS_NEED_OPERATORS_LL

# include <stdio.h>  // sscanf, sprintf
# include <string.h> // memchr

# if defined(_MAX_INT_DIG)
#  define KWSYS_IOS_INT64_MAX_DIG _MAX_INT_DIG
# else
#  define KWSYS_IOS_INT64_MAX_DIG 32
# endif

namespace KWSYS_NAMESPACE
{

// Scan an input stream for an integer value.
static int IOStreamScanStream(std::istream& is, char* buffer)
{
  // Prepare to write to buffer.
  char* out = buffer;
  char* end = buffer + KWSYS_IOS_INT64_MAX_DIG - 1;

  // Look for leading sign.
  if(is.peek() == '+') { *out++ = '+'; is.ignore(); }
  else if(is.peek() == '-') { *out++ = '-'; is.ignore(); }

  // Determine the base.  If not specified in the stream, try to
  // detect it from the input.  A leading 0x means hex, and a leading
  // 0 alone means octal.
  int base = 0;
  int flags = is.flags() & std::ios_base::basefield;
  if(flags == std::ios_base::oct) { base = 8; }
  else if(flags == std::ios_base::dec) { base = 10; }
  else if(flags == std::ios_base::hex) { base = 16; }
  bool foundDigit = false;
  bool foundNonZero = false;
  if(is.peek() == '0')
    {
    foundDigit = true;
    is.ignore();
    if((is.peek() == 'x' || is.peek() == 'X') && (base == 0 || base == 16))
      {
      base = 16;
      foundDigit = false;
      is.ignore();
      }
    else if (base == 0)
      {
      base = 8;
      }
    }

  // Determine the range of digits allowed for this number.
  const char* digits = "0123456789abcdefABCDEF";
  int maxDigitIndex = 10;
  if(base == 8)
    {
    maxDigitIndex = 8;
    }
  else if(base == 16)
    {
    maxDigitIndex = 10+6+6;
    }

  // Scan until an invalid digit is found.
  for(;is.peek() != EOF; is.ignore())
    {
    if(memchr(digits, *out = (char)is.peek(), maxDigitIndex) != 0)
      {
      if((foundNonZero || *out != '0') && out < end)
        {
        ++out;
        foundNonZero = true;
        }
      foundDigit = true;
      }
    else
      {
      break;
      }
    }

  // Correct the buffer contents for degenerate cases.
  if(foundDigit && !foundNonZero)
    {
    *out++ = '0';
    }
  else if (!foundDigit)
    {
    out = buffer;
    }

  // Terminate the string in the buffer.
  *out = '\0';

  return base;
}

// Read an integer value from an input stream.
template <class T>
std::istream&
IOStreamScanTemplate(std::istream& is, T& value, char type)
{
  int state = std::ios_base::goodbit;

  // Skip leading whitespace.
  std::istream::sentry okay(is);

  if(okay)
    {
    try {
    // Copy the string to a buffer and construct the format string.
    char buffer[KWSYS_IOS_INT64_MAX_DIG];
#   if defined(_MSC_VER)
    char format[] = "%I64_";
    const int typeIndex = 4;
#   else
    char format[] = "%ll_";
    const int typeIndex = 3;
#   endif
    switch(IOStreamScanStream(is, buffer))
      {
      case 8: format[typeIndex] = 'o'; break;
      case 0: // Default to decimal if not told otherwise.
      case 10: format[typeIndex] = type; break;
      case 16: format[typeIndex] = 'x'; break;
      };

    // Use sscanf to parse the number from the buffer.
    T result;
    int success = (sscanf(buffer, format, &result) == 1)?1:0;

    // Set flags for resulting state.
    if(is.peek() == EOF) { state |= std::ios_base::eofbit; }
    if(!success) { state |= std::ios_base::failbit; }
    else { value = result; }
    } catch(...) { state |= std::ios_base::badbit; }
    }

  is.setstate(std::ios_base::iostate(state));
  return is;
}

// Print an integer value to an output stream.
template <class T>
std::ostream&
IOStreamPrintTemplate(std::ostream& os, T value, char type)
{
  std::ostream::sentry okay(os);
  if(okay)
    {
    try {
    // Construct the format string.
    char format[8];
    char* f = format;
    *f++ = '%';
    if(os.flags() & std::ios_base::showpos) { *f++ = '+'; }
    if(os.flags() & std::ios_base::showbase) { *f++ = '#'; }
#   if defined(_MSC_VER)
    *f++ = 'I'; *f++ = '6'; *f++ = '4';
#   else
    *f++ = 'l'; *f++ = 'l';
#   endif
    long bflags = os.flags() & std::ios_base::basefield;
    if(bflags == std::ios_base::oct) { *f++ = 'o'; }
    else if(bflags != std::ios_base::hex) { *f++ = type; }
    else if(os.flags() & std::ios_base::uppercase) { *f++ = 'X'; }
    else { *f++ = 'x'; }
    *f = '\0';

    // Use sprintf to print to a buffer and then write the
    // buffer to the stream.
    char buffer[2*KWSYS_IOS_INT64_MAX_DIG];
    sprintf(buffer, format, value);
    os << buffer;
    } catch(...) { os.clear(os.rdstate() | std::ios_base::badbit); }
    }
  return os;
}

# if !KWSYS_IOS_HAS_ISTREAM_LONG_LONG
// Implement input stream operator for IOStreamSLL.
std::istream& IOStreamScan(std::istream& is, IOStreamSLL& value)
{
  return IOStreamScanTemplate(is, value, 'd');
}

// Implement input stream operator for IOStreamULL.
std::istream& IOStreamScan(std::istream& is, IOStreamULL& value)
{
  return IOStreamScanTemplate(is, value, 'u');
}
# endif

# if !KWSYS_IOS_HAS_OSTREAM_LONG_LONG
// Implement output stream operator for IOStreamSLL.
std::ostream& IOStreamPrint(std::ostream& os, IOStreamSLL value)
{
  return IOStreamPrintTemplate(os, value, 'd');
}

// Implement output stream operator for IOStreamULL.
std::ostream& IOStreamPrint(std::ostream& os, IOStreamULL value)
{
  return IOStreamPrintTemplate(os, value, 'u');
}
# endif

} // namespace KWSYS_NAMESPACE

#else

namespace KWSYS_NAMESPACE
{

// Create one public symbol in this object file to avoid warnings from
// archivers.
void IOStreamSymbolToAvoidWarning();
void IOStreamSymbolToAvoidWarning()
{
}

} // namespace KWSYS_NAMESPACE

#endif // KWSYS_IOS_NEED_OPERATORS_LL