1 /* 2 * Copyright (C) 2011 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #include "stringprintf.h" 18 19 #include <stdio.h> 20 21 namespace art { 22 23 void StringAppendV(std::string* dst, const char* format, va_list ap) { 24 // First try with a small fixed size buffer 25 char space[1024]; 26 27 // It's possible for methods that use a va_list to invalidate 28 // the data in it upon use. The fix is to make a copy 29 // of the structure before using it and use that copy instead. 30 va_list backup_ap; 31 va_copy(backup_ap, ap); 32 int result = vsnprintf(space, sizeof(space), format, backup_ap); 33 va_end(backup_ap); 34 35 if (result < static_cast<int>(sizeof(space))) { 36 if (result >= 0) { 37 // Normal case -- everything fit. 38 dst->append(space, result); 39 return; 40 } 41 42 if (result < 0) { 43 // Just an error. 44 return; 45 } 46 } 47 48 // Increase the buffer size to the size requested by vsnprintf, 49 // plus one for the closing \0. 50 int length = result+1; 51 char* buf = new char[length]; 52 53 // Restore the va_list before we use it again 54 va_copy(backup_ap, ap); 55 result = vsnprintf(buf, length, format, backup_ap); 56 va_end(backup_ap); 57 58 if (result >= 0 && result < length) { 59 // It fit 60 dst->append(buf, result); 61 } 62 delete[] buf; 63 } 64 65 std::string StringPrintf(const char* fmt, ...) { 66 va_list ap; 67 va_start(ap, fmt); 68 std::string result; 69 StringAppendV(&result, fmt, ap); 70 va_end(ap); 71 return result; 72 } 73 74 void StringAppendF(std::string* dst, const char* format, ...) { 75 va_list ap; 76 va_start(ap, format); 77 StringAppendV(dst, format, ap); 78 va_end(ap); 79 } 80 81 } // namespace art 82
