src/hotspot/share/utilities/formatBuffer.hpp

*** 1,7 ****
  /*
!  * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.
--- 1,7 ----
  /*
!  * Copyright (c) 2017, 2018, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.
*** 43,52 ****
--- 43,68 ----
  class FormatBufferResource : public FormatBufferBase {
   public:
    FormatBufferResource(const char * format, ...) ATTRIBUTE_PRINTF(2, 3);
  };
  
+ // Use malloc() for buffer
+ class FormatBufferDynamic : public FormatBufferBase {
+  protected:
+   int bufsz;
+ 
+  public:
+   inline FormatBufferDynamic();
+   ~FormatBufferDynamic();
+   inline void append(const char* format, ...) ATTRIBUTE_PRINTF(2, 3);
+   inline void print(const char* format, ...) ATTRIBUTE_PRINTF(2, 3);
+   inline void printv(const char* format, va_list ap) ATTRIBUTE_PRINTF(2, 0);
+ 
+   char* buffer() { return _buf; }
+   int size() { return bufsz; }
+ };
+ 
  class FormatBufferDummy {};
  
  // Use stack for buffer
  template <size_t bufsz = FormatBufferBase::BufferSize>
  class FormatBuffer : public FormatBufferBase {
*** 67,76 ****
--- 83,141 ----
  
   protected:
    inline FormatBuffer();
  };
  
+ FormatBufferDynamic::FormatBufferDynamic() : FormatBufferBase(NULL), bufsz(-1) {
+   // do nothing
+ }
+ 
+ void FormatBufferDynamic::append(const char* format, ...) {
+   va_list argp;
+ 
+   va_start(argp, format);
+   int append_len = jio_vsnprintf(NULL, 0, format, argp) + 1;
+   va_end(argp);
+ 
+   char *append_str = (char *)os::malloc(append_len, mtInternal);
+   va_start(argp, format);
+   jio_vsnprintf(append_str, append_len, format, argp);
+   va_end(argp);
+ 
+   if (_buf == NULL) {
+     bufsz = append_len;
+     _buf = append_str;
+   } else {
+     bufsz += append_len - 1;
+     _buf = (char *)os::realloc(_buf, bufsz, mtInternal);
+     strcat(_buf, append_str);
+     os::free(append_str);
+   }
+ }
+ 
+ void FormatBufferDynamic::print(const char * format, ...) {
+   va_list argp;
+   va_start(argp, format);
+   printv(format, argp);
+   va_end(argp);
+ }
+ 
+ void FormatBufferDynamic::printv(const char * format, va_list argp) {
+   if (_buf != NULL) {
+     os::free(_buf);
+     bufsz = -1;
+   }
+ 
+   va_list argp_local;
+   va_copy(argp_local, argp);
+   bufsz = jio_vsnprintf(NULL, 0, format, argp_local) + 1;
+   va_end(argp_local);
+ 
+   _buf = (char *)os::malloc(bufsz, mtInternal);
+   jio_vsnprintf(_buf, bufsz, format, argp);
+ }
+ 
  template <size_t bufsz>
  FormatBuffer<bufsz>::FormatBuffer(const char * format, ...) : FormatBufferBase(_buffer) {
    va_list argp;
    va_start(argp, format);
    jio_vsnprintf(_buf, bufsz, format, argp);