// -*- C++ -*-
// Module:  Log4CPLUS
// File:    Layout.h
// Created: 6/2001
// Author:  Tad E. Smith
//
//
// Copyright 2001-2010 Tad E. Smith
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

/** @file */

#ifndef DCMTK_LOG4CPLUS_LAYOUT_HEADER_
#define DCMTK_LOG4CPLUS_LAYOUT_HEADER_

#include "dcmtk/oflog/config.h"

#if defined (DCMTK_LOG4CPLUS_HAVE_PRAGMA_ONCE)
#pragma once
#endif

#include "dcmtk/oflog/loglevel.h"
#include "dcmtk/oflog/streams.h"
#include "dcmtk/oflog/tstring.h"

#include "dcmtk/ofstd/ofvector.h"


namespace dcmtk {
namespace log4cplus {

    // Forward Declarations
    namespace pattern
    {

        class PatternConverter;

    }

    
    namespace helpers
    {

        class Properties;
        class Time;

    }


    namespace spi
    {

        class InternalLoggingEvent;

    }


    /**
     * This class is used to layout strings sent to an {@link
     * log4cplus::Appender}.
     */
    class DCMTK_LOG4CPLUS_EXPORT Layout
    {
    public:
        Layout();
        Layout(const helpers::Properties& properties);
        virtual ~Layout() = 0;

        virtual void formatAndAppend(log4cplus::tostream& output, 
            const log4cplus::spi::InternalLoggingEvent& event) = 0;

    protected:
        LogLevelManager& llmCache;
        
    private:
      // Disable copy
        Layout(const Layout&);
        Layout& operator=(Layout const &);
    };



    /**
     * SimpleLayout consists of the LogLevel of the log statement,
     * followed by " - " and then the log message itself. For example,
     *
     * <pre>
     *         DEBUG - Hello world
     * </pre>
     *
     * {@link PatternLayout} offers a much more powerful alternative.
     */
    class DCMTK_LOG4CPLUS_EXPORT SimpleLayout
        : public Layout
    {
    public:
        SimpleLayout();
        SimpleLayout(const log4cplus::helpers::Properties& properties);
        virtual ~SimpleLayout();

        virtual void formatAndAppend(log4cplus::tostream& output, 
                                     const log4cplus::spi::InternalLoggingEvent& event);

    private: 
      // Disallow copying of instances of this class
        SimpleLayout(const SimpleLayout&);
        SimpleLayout& operator=(const SimpleLayout&);
    };



    /**
     * TTCC layout format consists of time, thread, Logger and nested
     * diagnostic context information, hence the name.
     * 
     * The time format depends on the <code>DateFormat</code> used.  Use the
     * <code>Use_gmtime</code> to specify whether messages should be logged using
     * <code>localtime</code> or <code>gmtime</code>.
     * 
     * Here is an example TTCCLayout output:
     * 
     * <pre>
     * 176 [main] INFO  org.apache.log4j.examples.Sort - Populating an array of 2 elements in reverse order.
     * 225 [main] INFO  org.apache.log4j.examples.SortAlgo - Entered the sort method.
     * 262 [main] DEBUG org.apache.log4j.examples.SortAlgo.OUTER i=1 - Outer loop.
     * 276 [main] DEBUG org.apache.log4j.examples.SortAlgo.SWAP i=1 j=0 - Swapping intArray[0] = 1 and intArray[1] = 0
     * 290 [main] DEBUG org.apache.log4j.examples.SortAlgo.OUTER i=0 - Outer loop.
     * 304 [main] INFO  org.apache.log4j.examples.SortAlgo.DUMP - Dump of interger array:
     * 317 [main] INFO  org.apache.log4j.examples.SortAlgo.DUMP - Element [0] = 0
     * 331 [main] INFO  org.apache.log4j.examples.SortAlgo.DUMP - Element [1] = 1
     * 343 [main] INFO  org.apache.log4j.examples.Sort - The next log statement should be an error message.
     * 346 [main] ERROR org.apache.log4j.examples.SortAlgo.DUMP - Tried to dump an uninitialized array.
     * 467 [main] INFO  org.apache.log4j.examples.Sort - Exiting main method.
     * </pre>
     * 
     *  The first field is the number of milliseconds elapsed since the
     *  start of the program. The second field is the thread outputting the
     *  log statement. The third field is the LogLevel, the fourth field is
     *  the logger to which the statement belongs.
     * 
     *  The fifth field (just before the '-') is the nested diagnostic
     *  context.  Note the nested diagnostic context may be empty as in the
     *  first two statements. The text after the '-' is the message of the
     *  statement.
     * 
     *  PatternLayout offers a much more flexible alternative.
     */
    class DCMTK_LOG4CPLUS_EXPORT TTCCLayout
        : public Layout
    {
    public:
      // Ctor and dtor
        TTCCLayout(bool use_gmtime = false);
        TTCCLayout(const log4cplus::helpers::Properties& properties);
        virtual ~TTCCLayout();

        virtual void formatAndAppend(log4cplus::tostream& output, 
                                     const log4cplus::spi::InternalLoggingEvent& event);

    protected:
       log4cplus::tstring dateFormat;
       bool use_gmtime;
     
    private: 
      // Disallow copying of instances of this class
        TTCCLayout(const TTCCLayout&);
        TTCCLayout& operator=(const TTCCLayout&);
    };


    DCMTK_LOG4CPLUS_EXPORT helpers::Time const & getTTCCLayoutTimeBase ();


    /**
     * A flexible layout configurable with pattern string.
     * 
     * The goal of this class is to format a InternalLoggingEvent and return 
     * the results as a string. The results depend on the <em>conversion 
     * pattern</em>.
     * 
     * The conversion pattern is closely related to the conversion
     * pattern of the printf function in C. A conversion pattern is
     * composed of literal text and format control expressions called
     * <em>conversion specifiers</em>.
     *  
     * <i>You are free to insert any literal text within the conversion
     * pattern.</i>
     * 
     * Each conversion specifier starts with a percent sign (%%) and is
     * followed by optional <em>format modifiers</em> and a <em>conversion
     * character</em>. The conversion character specifies the type of
     * data, e.g. Logger, LogLevel, date, thread name. The format
     * modifiers control such things as field width, padding, left and
     * right justification. The following is a simple example.
     * 
     * Let the conversion pattern be <b>"%-5p [%t]: %m%n"</b> and assume
     * that the log4cplus environment was set to use a PatternLayout. Then the
     * statements
     * <code><pre>
     * Logger root = Logger.getRoot();
     * DCMTK_LOG4CPLUS_DEBUG(root, "Message 1");
     * DCMTK_LOG4CPLUS_WARN(root, "Message 2");
     * </pre></code>
     * would yield the output
     * <tt><pre>
     * DEBUG [main]: Message 1
     * WARN  [main]: Message 2  
     * </pre></tt>
     * 
     * Note that there is no explicit separator between text and
     * conversion specifiers. The pattern parser knows when it has reached
     * the end of a conversion specifier when it reads a conversion
     * character. In the example above the conversion specifier
     * <b>"%-5p"</b> means the LogLevel of the logging event should be left
     * justified to a width of five characters.
     * 
     * The recognized conversion characters are
     * 
     * 
     * <table border="1" CELLPADDING="8">
     * <tr>
     * <td>Conversion Character</td>
     * <td>Effect</td>
     * </tr>
     *
     * <tr>
     *   <td align=center><b>b</b></td>
     *
     *   <td>Used to output file name component of path name.
     *   E.g. <tt>main.cxx</tt> from path <tt>../../main.cxx</tt>.</td>
     * </tr>
     *
     * <tr>
     *   <td align=center><b>c</b></td>
     * 
     *   <td>Used to output the logger of the logging event. The
     *   logger conversion specifier can be optionally followed by
     *   <em>precision specifier</em>, that is a decimal constant in
     *   brackets.
     * 
     *   If a precision specifier is given, then only the corresponding
     *   number of right most components of the logger name will be
     *   printed. By default the logger name is printed in full.
     * 
     *   For example, for the logger name "a.b.c" the pattern
     *   <b>%c{2}</b> will output "b.c".
     * 
     * </td>
     * </tr>
     * 
     * <tr> 
     *   <td align=center><b>d</b></td> 
     *
     *   <td>Used to output the date of the logging event in <b>UTC</b>. 
     *
     *   The date conversion specifier may be followed by a <em>date format
     *   specifier</em> enclosed between braces. For example, <b>%%d{%%H:%%M:%%s}</b>
     *   or <b>%%d{%%d&nbsp;%%b&nbsp;%%Y&nbsp;%%H:%%M:%%s}</b>.  If no date format 
     *   specifier is given then <b>%%d{%%d&nbsp;%%m&nbsp;%%Y&nbsp;%%H:%%M:%%s}</b>
     *   is assumed.
     *
     *   The Following format options are possible:
     *   <ul>
     *   <li>%%a -- Abbreviated weekday name</li>
     *   <li>%%A -- Full weekday name</li>
     *   <li>%%b -- Abbreviated month name</li>
     *   <li>%%B -- Full month name</li>
     *   <li>%%c -- Standard date and time string</li>
     *   <li>%%d -- Day of month as a decimal(1-31)</li>
     *   <li>%%H -- Hour(0-23)</li>
     *   <li>%%I -- Hour(1-12)</li>
     *   <li>%%j -- Day of year as a decimal(1-366)</li>
     *   <li>%%m -- Month as decimal(1-12)</li>
     *   <li>%%M -- Minute as decimal(0-59)</li>
     *   <li>%%p -- Locale's equivalent of AM or PM</li>
     *   <li>%%q -- milliseconds as decimal(0-999) -- <b>Log4CPLUS specific</b>
     *   <li>%%Q -- fractional milliseconds as decimal(0-999.999) -- <b>Log4CPLUS specific</b>
     *   <li>%%S -- Second as decimal(0-59)</li>
     *   <li>%%U -- Week of year, Sunday being first day(0-53)</li>
     *   <li>%%w -- Weekday as a decimal(0-6, Sunday being 0)</li>
     *   <li>%%W -- Week of year, Monday being first day(0-53)</li>
     *   <li>%%x -- Standard date string</li>
     *   <li>%%X -- Standard time string</li>
     *   <li>%%y -- Year in decimal without century(0-99)</li>
     *   <li>%%Y -- Year including century as decimal</li>
     *   <li>%%Z -- Time zone name</li>
     *   <li>%% -- The percent sign</li>
     *   </ul>
     *
     *   Lookup the documentation for the <code>strftime()</code> function
     *   found in the <code>&lt;ctime&gt;</code> header for more information.
     * </td>
     * </tr>
     * 
     * <tr> 
     *   <td align=center><b>D</b></td> 
     *
     *   <td>Used to output the date of the logging event in <b>local</b> time.
     *
     *   All of the above information applies.
     * </td>
     * </tr>
     *
     * <tr>
     *   <td align=center><b>F</b></td>
     * 
     *   <td>Used to output the file name where the logging request was
     *   issued.
     * 
     *   <b>NOTE</b> Unlike log4j, there is no performance penalty for
     *   calling this method.</td>
     * </tr>
     * 
     * <tr> 
     *   <td align=center><b>h</b></td> 
     *
     *   <td>Used to output the hostname of this system (as returned
     *   by gethostname(2)).
     *
     *   <b>NOTE</b> The hostname is only retrieved once at
     *   initialization.
     *
     * </td>
     * </tr>
     * 
     * <tr> 
     *   <td align=center><b>H</b></td> 
     *
     *   <td>Used to output the fully-qualified domain name of this
     *   system (as returned by gethostbyname(2) for the hostname
     *   returned by gethostname(2)).
     *
     *   <b>NOTE</b> The hostname is only retrieved once at
     *   initialization.
     *
     * </td>
     * </tr>
     * 
     * <tr>
     * <td align=center><b>l</b></td>
     * 
     *   <td>Equivalent to using "%F:%L"
     * 
     *   <b>NOTE:</b> Unlike log4j, there is no performance penalty for
     *   calling this method.
     * 
     * </td>
     * </tr>
     * 
     * <tr>
     *   <td align=center><b>L</b></td>
     * 
     *   <td>Used to output the line number from where the logging request
     *   was issued.
     * 
     *   <b>NOTE:</b> Unlike log4j, there is no performance penalty for
     *   calling this method.
     * 
     * </tr>
     *
     * <tr>
     *   <td align=center><b>m</b></td>
     *   <td>Used to output the application supplied message associated with 
     *   the logging event.</td>   
     * </tr>
     *
     * <tr>
     *   <td align=center><b>M</b></td>
     *
     *   <td>Used to output function name using
     *   <code>__FUNCTION__</code> or similar macro.
     *
     *   <b>NOTE</b> The <code>__FUNCTION__</code> macro is not
     *   standard but it is common extension provided by all compilers
     *   (as of 2010). In case it is missing or in case this feature
     *   is disabled using the
     *   <code>DCMTK_LOG4CPLUS_DISABLE_FUNCTION_MACRO</code> macro, %M
     *   expands to an empty string.</td>
     * </tr>
     * 
     * <tr>
     *   <td align=center><b>n</b></td>
     *   
     *   <td>Outputs the platform dependent line separator character or
     *   characters. 
     * </tr>
     * 
     * <tr>
     *   <td align=center><b>p</b></td>
     *   <td>Used to output the LogLevel of the logging event.</td>
     * </tr>
     *
     * <tr>
     *   <td align=center><b>P</b></td>
     *   <td>Used to output the first character of the LogLevel of the logging event.
     *     <b>NOTE:</b> This pattern has been added to log4cplus.
     *   </td>
     * </tr>
     *
     * <tr>
     *   <td align=center><b>r</b></td>
     *   <td>Used to output miliseconds since program start
     *   of the logging event.</td>
     * </tr>
     * 
     * <tr>
     *   <td align=center><b>t</b></td>
     * 
     *   <td>Used to output the name of the thread that generated the
     *   logging event.</td>
     * </tr>
     *
     * <tr>
     *   <td align=center><b>T</b></td>
     * 
     *   <td>Used to output alternative name of the thread that generated the
     *   logging event.</td>
     * </tr>
     *
     * <tr>
     *   <td align=center><b>i</b></td>
     *
     *   <td>Used to output the process ID of the process that generated the
     *   logging event.</td>
     * </tr>
     *
     * <tr>
     *   <td align=center><b>x</b></td>
     * 
     *   <td>Used to output the NDC (nested diagnostic context) associated
     *   with the thread that generated the logging event.
     *   </td>     
     * </tr>
     *
     * <tr>
     *   <td align=center><b>"%%"</b></td>
     *   <td>The sequence "%%" outputs a single percent sign.
     *   </td>     
     * </tr>
     *  
     * </table>
     * 
     * By default the relevant information is output as is. However,
     * with the aid of format modifiers it is possible to change the
     * minimum field width, the maximum field width and justification.
     * 
     * The optional format modifier is placed between the percent sign
     * and the conversion character.
     * 
     * The first optional format modifier is the <em>left justification
     * flag</em> which is just the minus (-) character. Then comes the
     * optional <em>minimum field width</em> modifier. This is a decimal
     * constant that represents the minimum number of characters to
     * output. If the data item requires fewer characters, it is padded on
     * either the left or the right until the minimum width is
     * reached. The default is to pad on the left (right justify) but you
     * can specify right padding with the left justification flag. The
     * padding character is space. If the data item is larger than the
     * minimum field width, the field is expanded to accommodate the
     * data. The value is never truncated.
     * 
     * This behavior can be changed using the <em>maximum field
     * width</em> modifier which is designated by a period followed by a
     * decimal constant. If the data item is longer than the maximum
     * field, then the extra characters are removed from the
     * <em>beginning</em> of the data item and not from the end. For
     * example, it the maximum field width is eight and the data item is
     * ten characters long, then the first two characters of the data item
     * are dropped. This behavior deviates from the printf function in C
     * where truncation is done from the end.
     * 
     * Below are various format modifier examples for the logger
     * conversion specifier.
     * 
     * 
     * <TABLE BORDER=1 CELLPADDING=8>
     * <tr>
     * <td>Format modifier</td>
     * <td>left justify</td>
     * <td>minimum width</td>
     * <td>maximum width</td>
     * <td>comment</td>
     * </tr>
     *
     * <tr>
     * <td align=center>%20c</td>
     * <td align=center>false</td>
     * <td align=center>20</td>
     * <td align=center>none</td>
     * 
     * <td>Left pad with spaces if the logger name is less than 20
     * characters long.
     * </tr>
     * 
     * <tr> <td align=center>%-20c</td> <td align=center>true</td> <td
     * align=center>20</td> <td align=center>none</td> <td>Right pad with
     * spaces if the logger name is less than 20 characters long.
     * </tr>
     * 
     * <tr>
     * <td align=center>%.30c</td>
     * <td align=center>NA</td>
     * <td align=center>none</td>
     * <td align=center>30</td>
     * 
     * <td>Truncate from the beginning if the logger name is longer than 30
     * characters.
     * </tr>
     * 
     * <tr>
     * <td align=center>%20.30c</td>
     * <td align=center>false</td>
     * <td align=center>20</td>
     * <td align=center>30</td>
     * 
     * <td>Left pad with spaces if the logger name is shorter than 20
     * characters. However, if logger name is longer than 30 characters,
     * then truncate from the beginning.   
     * </tr>
     * 
     * <tr>
     * <td align=center>%-20.30c</td>
     * <td align=center>true</td>
     * <td align=center>20</td>
     * <td align=center>30</td>
     *  
     * <td>Right pad with spaces if the logger name is shorter than 20
     * characters. However, if logger name is longer than 30 characters,
     * then truncate from the beginning.   
     * </tr>
     * 
     * </table>
     * 
     * Below are some examples of conversion patterns.
     * 
     * <dl>
     * 
     * <dt><b>"%r [%t] %-5p %c %x - %m%n"</b> 
     * <dd>This is essentially the TTCC layout.
     * 
     * <dt><b>"%-6r [%15.15t] %-5p %30.30c %x - %m%n"</b>
     * 
     * <dd>Similar to the TTCC layout except that the relative time is
     * right padded if less than 6 digits, thread name is right padded if
     * less than 15 characters and truncated if longer and the logger
     * name is left padded if shorter than 30 characters and truncated if
     * longer.
     *  
     * </dl>
     * 
     * The above text is largely inspired from Peter A. Darnell and
     * Philip E. Margolis' highly recommended book "C -- a Software
     * Engineering Approach", ISBN 0-387-97389-3.
     */
    class DCMTK_LOG4CPLUS_EXPORT PatternLayout
        : public Layout
    {
    public:
      // Ctors and dtor
        PatternLayout(const log4cplus::tstring& pattern, bool formatEachLine = true);
        PatternLayout(const log4cplus::helpers::Properties& properties);
        virtual ~PatternLayout();

        virtual void formatAndAppend(log4cplus::tostream& output, 
                                     const log4cplus::spi::InternalLoggingEvent& event);

    protected:
        void init(const log4cplus::tstring& pattern, bool formatEachLine, unsigned ndcMaxDepth = 0);

      // Data
        log4cplus::tstring pattern;
        bool formatEachLine;
        OFVector<pattern::PatternConverter*> parsedPattern;

    private: 
      // Disallow copying of instances of this class
        PatternLayout(const PatternLayout&);
        PatternLayout& operator=(const PatternLayout&);
    };



} // end namespace log4cplus
} // end namespace dcmtk

#endif // DCMTK_LOG4CPLUS_LAYOUT_HEADER_

