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