// Protocol Buffers - Google's data interchange format

// Copyright 2012 Google Inc.  All rights reserved.

// https://developers.google.com/protocol-buffers/

//

// 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.

// from google3/base/stringprintf.cc

#include <google/protobuf/stubs/stringprintf.h>

#include <errno.h>

#include <stdarg.h> // For va_list and related operations

#include <stdio.h> // MSVC requires this for _vsnprintf

#include <vector>

#include <google/protobuf/stubs/common.h>

#include <google/protobuf/stubs/logging.h>

namespace google {

namespace protobuf {

#ifdef _MSC_VER

enum { IS_COMPILER_MSVC = 1 };

#ifndef va_copy

// Define va_copy for MSVC. This is a hack, assuming va_list is simply a

// pointer into the stack and is safe to copy.

#define va_copy(dest, src) ((dest) = (src))

#endif

#else

enum { IS_COMPILER_MSVC = 0 };

#endif

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

  // First try with a small fixed size buffer

  static const int kSpaceLength = 1024;

  char space[kSpaceLength];

  // 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, kSpaceLength, format, backup_ap);

  va_end(backup_ap);

  if (result < kSpaceLength) {

    if (result >= 0) {

      // Normal case -- everything fit.

      dst->append(space, result);

      return;

    }

    if (IS_COMPILER_MSVC) {

      // 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(nullptr, 0, format, backup_ap);

      va_end(backup_ap);

    }

    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;

}

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

  va_list ap;

  va_start(ap, format);

  std::string result;

  StringAppendV(&result, format, ap);

  va_end(ap);

  return result;

}

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

  va_list ap;

  va_start(ap, format);

  StringAppendV(dst, format, ap);

  va_end(ap);

}

// Max arguments supported by StringPrintVector

const int kStringPrintfVectorMaxArgs = 32;

// An empty block of zero for filler arguments.  This is const so that if

// printf tries to write to it (via %n) then the program gets a SIGSEGV

// and we can fix the problem or protect against an attack.

static const char string_printf_empty_block[256] = { '\0' };

std::string StringPrintfVector(const char* format,

                               const std::vector<std::string>& v) {

  GOOGLE_CHECK_LE(v.size(), kStringPrintfVectorMaxArgs)

      << "StringPrintfVector currently only supports up to "

      << kStringPrintfVectorMaxArgs << " arguments. "

      << "Feel free to add support for more if you need it.";

  // Add filler arguments so that bogus format+args have a harder time

  // crashing the program, corrupting the program (%n),

  // or displaying random chunks of memory to users.

  const char* cstr[kStringPrintfVectorMaxArgs];

  for (int i = 0; i < v.size(); ++i) {

    cstr[i] = v[i].c_str();

  }

  for (int i = v.size(); i < GOOGLE_ARRAYSIZE(cstr); ++i) {

    cstr[i] = &string_printf_empty_block[0];

  }

  // I do not know any way to pass kStringPrintfVectorMaxArgs arguments,

  // or any way to build a va_list by hand, or any API for printf

  // that accepts an array of arguments.  The best I can do is stick

  // this COMPILE_ASSERT right next to the actual statement.

  GOOGLE_COMPILE_ASSERT(kStringPrintfVectorMaxArgs == 32, arg_count_mismatch);

  return StringPrintf(format,

                      cstr[0], cstr[1], cstr[2], cstr[3], cstr[4],

                      cstr[5], cstr[6], cstr[7], cstr[8], cstr[9],

                      cstr[10], cstr[11], cstr[12], cstr[13], cstr[14],

                      cstr[15], cstr[16], cstr[17], cstr[18], cstr[19],

                      cstr[20], cstr[21], cstr[22], cstr[23], cstr[24],

                      cstr[25], cstr[26], cstr[27], cstr[28], cstr[29],

                      cstr[30], cstr[31]);

}

}  // namespace protobuf

}  // namespace google