trunk/talk git-svn-id: http://webrtc.googlecode.com/svn/trunk@4318 4adac7df-926f-26a2-2b94-8c16560cd09d
		
			
				
	
	
		
			285 lines
		
	
	
		
			8.9 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			285 lines
		
	
	
		
			8.9 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
/*
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 * libjingle
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 * Copyright 2006, Google Inc.
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 *
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 * Redistribution and use in source and binary forms, with or without 
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 * modification, are permitted provided that the following conditions are met:
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 *
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 *  1. Redistributions of source code must retain the above copyright notice, 
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 *     this list of conditions and the following disclaimer.
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 *  2. Redistributions in binary form must reproduce the above copyright notice,
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 *     this list of conditions and the following disclaimer in the documentation
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 *     and/or other materials provided with the distribution.
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 *  3. The name of the author may not be used to endorse or promote products 
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 *     derived from this software without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
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 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
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 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
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 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 
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 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
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 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 
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 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 
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 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 */
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// Originally comes from shared/commandlineflags/flags.h
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// Flags are defined and declared using DEFINE_xxx and DECLARE_xxx macros,
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// where xxx is the flag type. Flags are referred to via FLAG_yyy,
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// where yyy is the flag name. For intialization and iteration of flags,
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// see the FlagList class. For full programmatic access to any
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// flag, see the Flag class.
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//
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// The implementation only relies and basic C++ functionality
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// and needs no special library or STL support.
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#ifndef TALK_BASE_FLAGS_H__
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#define TALK_BASE_FLAGS_H__
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#include <assert.h>
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#include "talk/base/checks.h"
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#include "talk/base/common.h"
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// Internal use only.
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union FlagValue {
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  // Note: Because in C++ non-bool values are silently converted into
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  // bool values ('bool b = "false";' results in b == true!), we pass
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  // and int argument to New_BOOL as this appears to be safer - sigh.
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  // In particular, it prevents the (not uncommon!) bug where a bool
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  // flag is defined via: DEFINE_bool(flag, "false", "some comment");.
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  static FlagValue New_BOOL(int b) {
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    FlagValue v;
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    v.b = (b != 0);
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    return v;
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  }
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  static FlagValue New_INT(int i) {
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    FlagValue v;
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    v.i = i;
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    return v;
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  }
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  static FlagValue New_FLOAT(float f) {
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    FlagValue v;
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    v.f = f;
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    return v;
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  }
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  static FlagValue New_STRING(const char* s) {
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    FlagValue v;
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    v.s = s;
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    return v;
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  }
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  bool b;
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  int i;
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  double f;
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  const char* s;
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};
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// Each flag can be accessed programmatically via a Flag object.
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class Flag {
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 public:
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  enum Type { BOOL, INT, FLOAT, STRING };
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  // Internal use only.
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  Flag(const char* file, const char* name, const char* comment,
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       Type type, void* variable, FlagValue default_);
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  // General flag information
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  const char* file() const  { return file_; }
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  const char* name() const  { return name_; }
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  const char* comment() const  { return comment_; }
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  // Flag type
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  Type type() const  { return type_; }
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  // Flag variables
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  bool* bool_variable() const {
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    assert(type_ == BOOL);
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    return &variable_->b;
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  }
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  int* int_variable() const {
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    assert(type_ == INT);
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    return &variable_->i;
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  }
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  double* float_variable() const {
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    assert(type_ == FLOAT);
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    return &variable_->f;
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  }
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  const char** string_variable() const {
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    assert(type_ == STRING);
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    return &variable_->s;
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  }
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  // Default values
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  bool bool_default() const {
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    assert(type_ == BOOL);
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    return default_.b;
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  }
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  int int_default() const {
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    assert(type_ == INT);
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    return default_.i;
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  }
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  double float_default() const {
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    assert(type_ == FLOAT);
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    return default_.f;
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  }
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  const char* string_default() const {
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    assert(type_ == STRING);
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    return default_.s;
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  }
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  // Resets a flag to its default value
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  void SetToDefault();
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  // Iteration support
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  Flag* next() const  { return next_; }
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  // Prints flag information. The current flag value is only printed
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  // if print_current_value is set.
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  void Print(bool print_current_value);
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 private:
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  const char* file_;
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  const char* name_;
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  const char* comment_;
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  Type type_;
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  FlagValue* variable_;
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  FlagValue default_;
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  Flag* next_;
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  friend class FlagList;  // accesses next_
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};
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// Internal use only.
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#define DEFINE_FLAG(type, c_type, name, default, comment) \
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  /* define and initialize the flag */                    \
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  c_type FLAG_##name = (default);                         \
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  /* register the flag */                                 \
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  static Flag Flag_##name(__FILE__, #name, (comment),   \
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                          Flag::type, &FLAG_##name,       \
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                          FlagValue::New_##type(default))
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// Internal use only.
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#define DECLARE_FLAG(c_type, name)              \
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  /* declare the external flag */               \
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  extern c_type FLAG_##name
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// Use the following macros to define a new flag:
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#define DEFINE_bool(name, default, comment) \
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  DEFINE_FLAG(BOOL, bool, name, default, comment)
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#define DEFINE_int(name, default, comment) \
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  DEFINE_FLAG(INT, int, name, default, comment)
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#define DEFINE_float(name, default, comment) \
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  DEFINE_FLAG(FLOAT, double, name, default, comment)
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#define DEFINE_string(name, default, comment) \
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  DEFINE_FLAG(STRING, const char*, name, default, comment)
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// Use the following macros to declare a flag defined elsewhere:
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#define DECLARE_bool(name)  DECLARE_FLAG(bool, name)
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#define DECLARE_int(name)  DECLARE_FLAG(int, name)
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#define DECLARE_float(name)  DECLARE_FLAG(double, name)
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#define DECLARE_string(name)  DECLARE_FLAG(const char*, name)
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// The global list of all flags.
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class FlagList {
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 public:
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  FlagList();
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  // The NULL-terminated list of all flags. Traverse with Flag::next().
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  static Flag* list()  { return list_; }
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  // If file != NULL, prints information for all flags defined in file;
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  // otherwise prints information for all flags in all files. The current
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  // flag value is only printed if print_current_value is set.
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  static void Print(const char* file, bool print_current_value);
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  // Lookup a flag by name. Returns the matching flag or NULL.
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  static Flag* Lookup(const char* name);
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  // Helper function to parse flags: Takes an argument arg and splits it into
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  // a flag name and flag value (or NULL if they are missing). is_bool is set
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  // if the arg started with "-no" or "--no". The buffer may be used to NUL-
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  // terminate the name, it must be large enough to hold any possible name.
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  static void SplitArgument(const char* arg,
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                            char* buffer, int buffer_size,
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                            const char** name, const char** value,
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                            bool* is_bool);
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  // Set the flag values by parsing the command line. If remove_flags
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  // is set, the flags and associated values are removed from (argc,
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  // argv). Returns 0 if no error occurred. Otherwise, returns the
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  // argv index > 0 for the argument where an error occurred. In that
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  // case, (argc, argv) will remain unchanged indepdendent of the
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  // remove_flags value, and no assumptions about flag settings should
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  // be made.
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  //
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  // The following syntax for flags is accepted (both '-' and '--' are ok):
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  //
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  //   --flag        (bool flags only)
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  //   --noflag      (bool flags only)
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  //   --flag=value  (non-bool flags only, no spaces around '=')
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  //   --flag value  (non-bool flags only)
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  static int SetFlagsFromCommandLine(int* argc,
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                                     const char** argv,
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                                     bool remove_flags);
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  static inline int SetFlagsFromCommandLine(int* argc,
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                                            char** argv,
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                                            bool remove_flags) {
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    return SetFlagsFromCommandLine(argc, const_cast<const char**>(argv),
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                                   remove_flags);
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  }
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  // Registers a new flag. Called during program initialization. Not
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  // thread-safe.
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  static void Register(Flag* flag);
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 private:
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  static Flag* list_;
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};
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#ifdef WIN32
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// A helper class to translate Windows command line arguments into UTF8,
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// which then allows us to just pass them to the flags system.
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// This encapsulates all the work of getting the command line and translating
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// it to an array of 8-bit strings; all you have to do is create one of these,
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// and then call argc() and argv().
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class WindowsCommandLineArguments {
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 public:
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  WindowsCommandLineArguments();
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  ~WindowsCommandLineArguments();
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  int argc() { return argc_; }
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  char **argv() { return argv_; }
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 private:
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  int argc_;
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  char **argv_;
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 private:
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  DISALLOW_EVIL_CONSTRUCTORS(WindowsCommandLineArguments);
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};
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#endif  // WIN32
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#endif  // SHARED_COMMANDLINEFLAGS_FLAGS_H__
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