// Ceres Solver - A fast non-linear least squares minimizer

// Copyright 2015 Google Inc. All rights reserved.

// http://ceres-solver.org/

//

// Redistribution and use in source and binary forms, with or without

// modification, are permitted provided that the following conditions are met:

//

// * Redistributions of source code must retain the above copyright notice,

//   this list of conditions and the following disclaimer.

// * Redistributions in binary form must reproduce the above copyright notice,

//   this list of conditions and the following disclaimer in the documentation

//   and/or other materials provided with the distribution.

// * Neither the name of Google Inc. nor the names of its contributors may be

//   used to endorse or promote products derived from this software without

//   specific prior written permission.

//

// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE

// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR

// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN

// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE

// POSSIBILITY OF SUCH DAMAGE.

//

// Author: Sanjay Ghemawat

#include "ceres/stringprintf.h"

#include <cerrno>

#include <cstdarg>  // For va_list and related operations

#include <cstdio>   // MSVC requires this for _vsnprintf

#include <string>

#include <vector>

#include "ceres/internal/port.h"

namespace ceres {

namespace internal {

using std::string;

// va_copy() was defined in the C99 standard.  However, it did not appear in the

// C++ standard until C++11.  This means that if Ceres is being compiled with a

// strict pre-C++11 standard (e.g. -std=c++03), va_copy() will NOT be defined,

// as we are using the C++ compiler (it would however be defined if we were

// using the C compiler).  Note however that both GCC & Clang will in fact

// define va_copy() when compiling for C++ if the C++ standard is not explicitly

// specified (i.e. no -std=c++<XX> arg), even though it should not strictly be

// defined unless -std=c++11 (or greater) was passed.

#if !defined(va_copy)

#if defined (__GNUC__)

// On GCC/Clang, if va_copy() is not defined (C++ standard < C++11 explicitly

// specified), use the internal __va_copy() version, which should be present

// in even very old GCC versions.

#define va_copy(d, s) __va_copy(d, s)

#else

// Some older versions of MSVC do not have va_copy(), in which case define it.

// Although this is required for older MSVC versions, it should also work for

// other non-GCC/Clang compilers which also do not defined va_copy().

#define va_copy(d, s) ((d) = (s))

#endif  // defined (__GNUC__)

#endif  // !defined(va_copy)

void StringAppendV(string* dst, const char* format, va_list ap) {

  // First try with a small fixed size buffer

  char space[1024];

  // It's possible for methods that use a va_list to invalidate

  // the data in it upon use.  The fix is to make a copy

  // of the structure before using it and use that copy instead.

  va_list backup_ap;

  va_copy(backup_ap, ap);

  int result = vsnprintf(space, sizeof(space), format, backup_ap);

  va_end(backup_ap);

  if (result < sizeof(space)) {

    if (result >= 0) {

      // Normal case -- everything fit.

      dst->append(space, result);

      return;

    }

#if defined (_MSC_VER)

    // Error or MSVC running out of space.  MSVC 8.0 and higher

    // can be asked about space needed with the special idiom below:

    va_copy(backup_ap, ap);

    result = vsnprintf(NULL, 0, format, backup_ap);

    va_end(backup_ap);

#endif

    if (result < 0) {

      // Just an error.

      return;

    }

  }

  // Increase the buffer size to the size requested by vsnprintf,

  // plus one for the closing \0.

  int length = result+1;

  char* buf = new char[length];

  // Restore the va_list before we use it again

  va_copy(backup_ap, ap);

  result = vsnprintf(buf, length, format, backup_ap);

  va_end(backup_ap);

  if (result >= 0 && result < length) {

    // It fit

    dst->append(buf, result);

  }

  delete[] buf;

}

string StringPrintf(const char* format, ...) {

  va_list ap;

  va_start(ap, format);

  string result;

  StringAppendV(&result, format, ap);

  va_end(ap);

  return result;

}

const string& SStringPrintf(string* dst, const char* format, ...) {

  va_list ap;

  va_start(ap, format);

  dst->clear();

  StringAppendV(dst, format, ap);

  va_end(ap);

  return *dst;

}

void StringAppendF(string* dst, const char* format, ...) {

  va_list ap;

  va_start(ap, format);

  StringAppendV(dst, format, ap);

  va_end(ap);

}

}  // namespace internal

}  // namespace ceres