1 /* 2 * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #ifndef SHARE_VM_UTILITIES_FORMATBUFFER_HPP 26 #define SHARE_VM_UTILITIES_FORMATBUFFER_HPP 27 28 #include "utilities/globalDefinitions.hpp" 29 #include "prims/jvm.h" 30 #include <stdarg.h> 31 32 // Simple class to format the ctor arguments into a fixed-sized buffer. 33 class FormatBufferBase { 34 protected: 35 char* _buf; 36 inline FormatBufferBase(char* buf) : _buf(buf) {} 37 public: 38 static const int BufferSize = 256; 39 operator const char *() const { return _buf; } 40 }; 41 42 // Use resource area for buffer 43 class FormatBufferResource : public FormatBufferBase { 44 public: 45 FormatBufferResource(const char * format, ...) ATTRIBUTE_PRINTF(2, 3); 46 }; 47 48 class FormatBufferDummy {}; 49 50 // Use stack for buffer 51 template <size_t bufsz = FormatBufferBase::BufferSize> 52 class FormatBuffer : public FormatBufferBase { 53 public: 54 inline FormatBuffer(const char* format, ...) ATTRIBUTE_PRINTF(2, 3); 55 // since va_list is unspecified type (can be char*), we use FormatBufferDummy to disambiguate these constructors 56 inline FormatBuffer(FormatBufferDummy dummy, const char* format, va_list ap) ATTRIBUTE_PRINTF(3, 0); 57 inline void append(const char* format, ...) ATTRIBUTE_PRINTF(2, 3); 58 inline void print(const char* format, ...) ATTRIBUTE_PRINTF(2, 3); 59 inline void printv(const char* format, va_list ap) ATTRIBUTE_PRINTF(2, 0); 60 61 char* buffer() { return _buf; } 62 int size() { return bufsz; } 63 64 private: 65 FormatBuffer(const FormatBuffer &); // prevent copies 66 char _buffer[bufsz]; 67 68 protected: 69 inline FormatBuffer(); 70 }; 71 72 template <size_t bufsz> 73 FormatBuffer<bufsz>::FormatBuffer(const char * format, ...) : FormatBufferBase(_buffer) { 74 va_list argp; 75 va_start(argp, format); 76 jio_vsnprintf(_buf, bufsz, format, argp); 77 va_end(argp); 78 } 79 80 template <size_t bufsz> 81 FormatBuffer<bufsz>::FormatBuffer(FormatBufferDummy dummy, const char * format, va_list ap) : FormatBufferBase(_buffer) { 82 jio_vsnprintf(_buf, bufsz, format, ap); 83 } 84 85 template <size_t bufsz> 86 FormatBuffer<bufsz>::FormatBuffer() : FormatBufferBase(_buffer) { 87 _buf[0] = '\0'; 88 } 89 90 template <size_t bufsz> 91 void FormatBuffer<bufsz>::print(const char * format, ...) { 92 va_list argp; 93 va_start(argp, format); 94 jio_vsnprintf(_buf, bufsz, format, argp); 95 va_end(argp); 96 } 97 98 template <size_t bufsz> 99 void FormatBuffer<bufsz>::printv(const char * format, va_list argp) { 100 jio_vsnprintf(_buf, bufsz, format, argp); 101 } 102 103 template <size_t bufsz> 104 void FormatBuffer<bufsz>::append(const char* format, ...) { 105 // Given that the constructor does a vsnprintf we can assume that 106 // _buf is already initialized. 107 size_t len = strlen(_buf); 108 char* buf_end = _buf + len; 109 110 va_list argp; 111 va_start(argp, format); 112 jio_vsnprintf(buf_end, bufsz - len, format, argp); 113 va_end(argp); 114 } 115 116 // Used to format messages. 117 typedef FormatBuffer<> err_msg; 118 119 #endif // SHARE_VM_UTILITIES_FORMATBUFFER_HPP