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Diffstat (limited to 'src/google/protobuf/stubs/stringprintf.cc')
| -rw-r--r-- | src/google/protobuf/stubs/stringprintf.cc | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/src/google/protobuf/stubs/stringprintf.cc b/src/google/protobuf/stubs/stringprintf.cc new file mode 100644 index 0000000..4a5b858 --- /dev/null +++ b/src/google/protobuf/stubs/stringprintf.cc @@ -0,0 +1,175 @@ +// Protocol Buffers - Google's data interchange format +// Copyright 2012 Google Inc. All rights reserved. +// http://code.google.com/p/protobuf/ +// +// 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/testing/googletest.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(NULL, 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 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 |