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// 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>
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(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;
}
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);
}
// 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' };
string StringPrintfVector(const char* format, const std::vector<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
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