| /* Copyright 2015 The TensorFlow Authors. All Rights Reserved. |
| |
| Licensed under the Apache License, Version 2.0 (the "License"); |
| you may not use this file except in compliance with the License. |
| You may obtain a copy of the License at |
| |
| http://www.apache.org/licenses/LICENSE-2.0 |
| |
| Unless required by applicable law or agreed to in writing, software |
| distributed under the License is distributed on an "AS IS" BASIS, |
| WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| See the License for the specific language governing permissions and |
| limitations under the License. |
| ==============================================================================*/ |
| |
| #include "tensorflow/core/platform/stringprintf.h" |
| |
| #include <errno.h> |
| #include <stdarg.h> // For va_list and related operations |
| #include <stdio.h> // MSVC requires this for _vsnprintf |
| |
| namespace tensorflow { |
| namespace strings { |
| |
| void Appendv(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; |
| } |
| |
| #ifdef _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(nullptr, 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 Printf(const char* format, ...) { |
| va_list ap; |
| va_start(ap, format); |
| string result; |
| Appendv(&result, format, ap); |
| va_end(ap); |
| return result; |
| } |
| |
| void Appendf(string* dst, const char* format, ...) { |
| va_list ap; |
| va_start(ap, format); |
| Appendv(dst, format, ap); |
| va_end(ap); |
| } |
| |
| } // namespace strings |
| } // namespace tensorflow |