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 "jvm.h"
  29 #include "utilities/globalDefinitions.hpp"
  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
--- EOF ---