xpcom/string/nsPrintfCString.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef nsPrintfCString_h___
   8 #define nsPrintfCString_h___
   9
  10 #include "nsString.h"
  11
  12 /**
  13  * nsPrintfCString lets you create a nsCString using a printf-style format
  14  * string.  For example:
  15  *
  16  *   NS_WARNING(nsPrintfCString("Unexpected value: %f", 13.917).get());
  17  *
  18  * nsPrintfCString has a small built-in auto-buffer.  For larger strings, it
  19  * will allocate on the heap.
  20  *
  21  * See also nsCString::AppendPrintf().
  22  */
  23 class nsPrintfCString : public nsAutoCStringN<16> {
  24   typedef nsCString string_type;
  25
  26  public:
  27   explicit nsPrintfCString(const char_type* aFormat, ...)
  28       MOZ_FORMAT_PRINTF(2, 3) {
  29     va_list ap;
  30     va_start(ap, aFormat);
  31     AppendVprintf(aFormat, ap);
  32     va_end(ap);
  33   }
  34 };
  35
  36 /**
  37  *
  38  *
  39  * nsVPrintfCString is like nsPrinfCString but is created using vprintf style
  40  * args. This is useful for functions that have already received variadic
  41  * arguments and want to create a nsPrintfCString. For example:
  42  *
  43  * void LogToSeveralLocations(const char* aFormat,...) {
  44  *   va_list ap;
  45  *   va_start(ap, aFormat);
  46  *   nsPrintfCString logString(aFormat, ap);
  47  *   va_end(ap);
  48  *   // Use logString
  49  *  }
  50  *
  51  * See also nsCString::AppendVprintf().
  52  */
  53
  54 class nsVprintfCString : public nsAutoCStringN<16> {
  55   typedef nsCString string_type;
  56
  57  public:
  58   nsVprintfCString(const char_type* aFormat, va_list aArgs)
  59       MOZ_FORMAT_PRINTF(2, 0) {
  60     AppendVprintf(aFormat, aArgs);
  61   }
  62 };
  63
  64 #endif  // !defined(nsPrintfCString_h___)