/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.
 *
 * Note: This file has been modified from its original form.
 */
#include <log4cxx/logstring.h>
#include <log4cxx/helpers/charsetdecoder.h>
#include <log4cxx/helpers/bytebuffer.h>
#include <log4cxx/helpers/exception.h>
#include <log4cxx/helpers/mutex.h>
#include <log4cxx/helpers/synchronized.h>
#include <log4cxx/helpers/pool.h>
#include <apr_xlate.h>
#if !defined(LOG4CXX)
#define LOG4CXX 1
#endif
#include <log4cxx/private/log4cxx_private.h>
#include <locale.h>
#include <apr_portable.h>
#include <log4cxx/helpers/stringhelper.h>
#include <log4cxx/helpers/transcoder.h>

using namespace log4cxx;
using namespace log4cxx::helpers;

IMPLEMENT_LOG4CXX_OBJECT(CharsetDecoder)


namespace log4cxx
{
        namespace helpers {

#if APR_HAS_XLATE
          /**
           *  Converts from an arbitrary encoding to LogString
           *    using apr_xlate.  Requires real iconv implementation,
         *    apr-iconv will crash in use.
           */
          class APRCharsetDecoder : public CharsetDecoder
          {
          public:
           /**
            *  Creates a new instance.
            *  @param frompage name of source encoding.
            */
              APRCharsetDecoder(const LogString& frompage) : pool(), mutex(pool) {
#if LOG4CXX_LOGCHAR_IS_WCHAR
                const char* topage = "WCHAR_T";
#endif
#if LOG4CXX_LOGCHAR_IS_UTF8
                const char* topage = "UTF-8";
#endif
#if LOG4CXX_LOGCHAR_IS_UNICHAR
                const char* topage = "UTF-16";
#endif
                std::string fpage(Transcoder::encodeCharsetName(frompage));
                apr_status_t stat = apr_xlate_open(&convset,
                    topage,
                    fpage.c_str(),
                    pool.getAPRPool());
                if (stat != APR_SUCCESS) {
                    throw IllegalArgumentException(frompage);
                }
              }

           /**
            *  Destructor.
            */
              virtual ~APRCharsetDecoder() {
              }

              virtual log4cxx_status_t decode(ByteBuffer& in,
                  LogString& out) {
                  enum { BUFSIZE = 256 };
                  logchar buf[BUFSIZE];
                  const apr_size_t initial_outbytes_left = BUFSIZE * sizeof(logchar);
                  apr_status_t stat = APR_SUCCESS;
                  if (in.remaining() == 0) {
                    size_t outbytes_left = initial_outbytes_left;
                    {
                      synchronized sync(mutex);
                      stat = apr_xlate_conv_buffer((apr_xlate_t*) convset,
                        NULL, NULL, (char*) buf, &outbytes_left);
                    }
                    out.append(buf, (initial_outbytes_left - outbytes_left)/sizeof(logchar));
                  } else {
                    while(in.remaining() > 0 && stat == APR_SUCCESS) {
                      size_t inbytes_left = in.remaining();
                      size_t initial_inbytes_left = inbytes_left;
                      size_t pos = in.position();
                      apr_size_t outbytes_left = initial_outbytes_left;
                      {
                        synchronized sync(mutex);
                        stat = apr_xlate_conv_buffer((apr_xlate_t*) convset,
                           in.data() + pos,
                           &inbytes_left,
                           (char*) buf,
                           &outbytes_left);
                      }
                      out.append(buf, (initial_outbytes_left - outbytes_left)/sizeof(logchar));
                      in.position(pos + (initial_inbytes_left - inbytes_left));
                    }
                  }
                  return stat;
              }

          private:
                  APRCharsetDecoder(const APRCharsetDecoder&);
                  APRCharsetDecoder& operator=(const APRCharsetDecoder&);
                  log4cxx::helpers::Pool pool;
                  Mutex mutex;
                  apr_xlate_t *convset;
          };
          
#endif

#if LOG4CXX_LOGCHAR_IS_WCHAR && LOG4CXX_HAS_MBSRTOWCS
          /**
          *    Converts from the default multi-byte string to
          *        LogString using mbstowcs.
          *
          */
          class MbstowcsCharsetDecoder : public CharsetDecoder
          {
          public:
              MbstowcsCharsetDecoder() {
              }

              virtual ~MbstowcsCharsetDecoder() {
              }

          private:
              inline log4cxx_status_t append(LogString& out, const wchar_t* buf) {
                  out.append(buf);
                  return APR_SUCCESS;
              }

              virtual log4cxx_status_t decode(ByteBuffer& in,
                  LogString& out) {
                  log4cxx_status_t stat = APR_SUCCESS;
                  enum { BUFSIZE = 256 };
                  wchar_t buf[BUFSIZE];

                  mbstate_t mbstate;
                  memset(&mbstate, 0, sizeof(mbstate));

                  while(in.remaining() > 0) {
                      size_t requested = in.remaining();
                      if (requested > BUFSIZE - 1) {
                          requested = BUFSIZE - 1;
                      }

                      memset(buf, 0, BUFSIZE*sizeof(wchar_t));
                      const char* src = in.current();
                      if(*src == 0) {
                           out.append(1, (logchar) 0);
                           in.position(in.position() + 1);
                      } else {
                           size_t converted = mbsrtowcs(buf,
                               &src,
                               requested,
                               &mbstate);
                           if (converted == (size_t) -1) {
                               stat = APR_BADARG;
                               in.position(src - in.data());
                               break;
                           } else {
                               stat = append(out, buf);
                               in.position(in.position() + converted);
                           }
                      }
                  }
                  return stat;
              }



          private:
                  MbstowcsCharsetDecoder(const MbstowcsCharsetDecoder&);
                  MbstowcsCharsetDecoder& operator=(const MbstowcsCharsetDecoder&);
          };
#endif


          /**
          *    Decoder used when the external and internal charsets
          *    are the same.
          *
          */
          class TrivialCharsetDecoder : public CharsetDecoder
          {
          public:
              TrivialCharsetDecoder() {
              }

              virtual ~TrivialCharsetDecoder() {
              }

              virtual log4cxx_status_t decode(ByteBuffer& in,
                  LogString& out) {
                  size_t remaining = in.remaining();
              if( remaining > 0) {
               const logchar* src = (const logchar*) (in.data() + in.position());
               size_t count = remaining / sizeof(logchar);
               out.append(src, count);
               in.position(in.position() + remaining);
              }
                  return APR_SUCCESS;
              }



          private:
                  TrivialCharsetDecoder(const TrivialCharsetDecoder&);
                  TrivialCharsetDecoder& operator=(const TrivialCharsetDecoder&);
          };


#if LOG4CXX_LOGCHAR_IS_UTF8
typedef TrivialCharsetDecoder UTF8CharsetDecoder;
#else
/**
*    Converts from UTF-8 to std::wstring
*
*/
class UTF8CharsetDecoder : public CharsetDecoder
{
public:
    UTF8CharsetDecoder() {
    }

    virtual ~UTF8CharsetDecoder() {
    }

private:
    virtual log4cxx_status_t decode(ByteBuffer& in,
        LogString& out) {
        if (in.remaining() > 0) {
          std::string tmp(in.current(), in.remaining());
          std::string::const_iterator iter = tmp.begin();
          while(iter != tmp.end()) {
               unsigned int sv = Transcoder::decode(tmp, iter);
               if (sv == 0xFFFF) {
                   size_t offset = iter - tmp.begin();
                   in.position(in.position() + offset);
                   return APR_BADARG;
               } else {
                   Transcoder::encode(sv, out);
               }
          }
          in.position(in.limit());
        }
        return APR_SUCCESS;
    }

private:
        UTF8CharsetDecoder(const UTF8CharsetDecoder&);
        UTF8CharsetDecoder& operator=(const UTF8CharsetDecoder&);
};
#endif

/**
*    Converts from ISO-8859-1 to LogString.
*
*/
class ISOLatinCharsetDecoder : public CharsetDecoder
{
public:
    ISOLatinCharsetDecoder() {
    }

    virtual ~ISOLatinCharsetDecoder() {
    }

private:
    virtual log4cxx_status_t decode(ByteBuffer& in,
        LogString& out) {
        if (in.remaining() > 0) {

          const unsigned char* src = (unsigned char*) in.current();
          const unsigned char* srcEnd = src + in.remaining();
          while(src < srcEnd) {
             unsigned int sv = *(src++);
             Transcoder::encode(sv, out);
          }
          in.position(in.limit());
        }
        return APR_SUCCESS;
    }



private:
        ISOLatinCharsetDecoder(const ISOLatinCharsetDecoder&);
        ISOLatinCharsetDecoder& operator=(const ISOLatinCharsetDecoder&);
};


/**
*    Converts from US-ASCII to LogString.
*
*/
class USASCIICharsetDecoder : public CharsetDecoder
{
public:
    USASCIICharsetDecoder() {
    }

    virtual ~USASCIICharsetDecoder() {
    }

private:

  virtual log4cxx_status_t decode(ByteBuffer& in,
      LogString& out) {
      log4cxx_status_t stat = APR_SUCCESS;
      if (in.remaining() > 0) {

        const unsigned char* src = (unsigned char*) in.current();
        const unsigned char* srcEnd = src + in.remaining();
        while(src < srcEnd) {
           unsigned char sv = *src;
           if (sv < 0x80) {
              src++;
              Transcoder::encode(sv, out);
           } else {
             stat = APR_BADARG;
             break;
           }
        }
        in.position(src - (const unsigned char*) in.data());
      }
      return stat;
    }



private:
        USASCIICharsetDecoder(const USASCIICharsetDecoder&);
        USASCIICharsetDecoder& operator=(const USASCIICharsetDecoder&);
};

          /**
           *    Charset decoder that uses an embedded CharsetDecoder consistent
           *     with current locale settings.
           */
          class LocaleCharsetDecoder : public CharsetDecoder {
          public:
               LocaleCharsetDecoder() : pool(), mutex(pool), decoder(), encoding() {
               }
               virtual ~LocaleCharsetDecoder() {
               }
               virtual log4cxx_status_t decode(ByteBuffer& in,
                  LogString& out) {
                  const char* p = in.current();
                  size_t i = in.position();
#if !LOG4CXX_CHARSET_EBCDIC                  
                  for (; i < in.limit() && ((unsigned int) *p) < 0x80; i++, p++) {
                      out.append(1, *p);
                  }
                  in.position(i);
#endif                  
                  if (i < in.limit()) {
                           Pool subpool;
                           const char* enc = apr_os_locale_encoding(subpool.getAPRPool());
                           {
                                synchronized sync(mutex);
                                if (enc == 0) {
                                    if (decoder == 0) {
                                        encoding = "C";
                                        decoder = new USASCIICharsetDecoder();
                                    }
                                } else if (encoding != enc) {
                                    encoding = enc;
                                    try {
                                       LogString e;
                                       Transcoder::decode(encoding, e);
                                       decoder = getDecoder(e);
                                    } catch (IllegalArgumentException& ex) {
                                       decoder = new USASCIICharsetDecoder();
                                    }
                                }
                            }
                            return decoder->decode(in, out);        
                  }
                  return APR_SUCCESS;  
               }
          private:
               Pool pool;
               Mutex mutex;
               CharsetDecoderPtr decoder;
               std::string encoding;
          };



        } // namespace helpers

}  //namespace log4cxx


CharsetDecoder::CharsetDecoder() {
}


CharsetDecoder::~CharsetDecoder() {
}

CharsetDecoder* CharsetDecoder::createDefaultDecoder() {
#if LOG4CXX_CHARSET_UTF8
     return new UTF8CharsetDecoder();
#elif LOG4CXX_CHARSET_ISO88591 || defined(_WIN32_WCE)
     return new ISOLatinCharsetDecoder();
#elif LOG4CXX_CHARSET_USASCII
     return new USASCIICharsetDecoder();
#elif LOG4CXX_LOGCHAR_IS_WCHAR && LOG4CXX_HAS_MBSRTOWCS
    return new MbstowcsCharsetDecoder();
#else
    return new LocaleCharsetDecoder();
#endif
}

CharsetDecoderPtr CharsetDecoder::getDefaultDecoder() {
    static CharsetDecoderPtr decoder(createDefaultDecoder());
    //
    //  if invoked after static variable destruction
    //     (if logging is called in the destructor of a static object)
    //     then create a new decoder.
    //
    if (decoder == 0) {
       return createDefaultDecoder();
    }
    return decoder;
}

CharsetDecoderPtr CharsetDecoder::getUTF8Decoder() {
    static CharsetDecoderPtr decoder(new UTF8CharsetDecoder());
    //
    //  if invoked after static variable destruction
    //     (if logging is called in the destructor of a static object)
    //     then create a new decoder.
    //
    if (decoder == 0) {
       return new UTF8CharsetDecoder();
    }
    return decoder;
}

CharsetDecoderPtr CharsetDecoder::getISOLatinDecoder() {
    return new ISOLatinCharsetDecoder();
}


CharsetDecoderPtr CharsetDecoder::getDecoder(const LogString& charset) {
    if (StringHelper::equalsIgnoreCase(charset, LOG4CXX_STR("UTF-8"), LOG4CXX_STR("utf-8")) ||
        StringHelper::equalsIgnoreCase(charset, LOG4CXX_STR("UTF8"), LOG4CXX_STR("utf8"))) {
        return new UTF8CharsetDecoder();
    } else if (StringHelper::equalsIgnoreCase(charset, LOG4CXX_STR("C"), LOG4CXX_STR("c")) ||
        charset == LOG4CXX_STR("646") ||
        StringHelper::equalsIgnoreCase(charset, LOG4CXX_STR("US-ASCII"), LOG4CXX_STR("us-ascii")) ||
        StringHelper::equalsIgnoreCase(charset, LOG4CXX_STR("ISO646-US"), LOG4CXX_STR("iso646-US")) ||
        StringHelper::equalsIgnoreCase(charset, LOG4CXX_STR("ANSI_X3.4-1968"), LOG4CXX_STR("ansi_x3.4-1968"))) {
        return new USASCIICharsetDecoder();
    } else if (StringHelper::equalsIgnoreCase(charset, LOG4CXX_STR("ISO-8859-1"), LOG4CXX_STR("iso-8859-1")) ||
        StringHelper::equalsIgnoreCase(charset, LOG4CXX_STR("ISO-LATIN-1"), LOG4CXX_STR("iso-latin-1"))) {
        return new ISOLatinCharsetDecoder();
    }
#if APR_HAS_XLATE
    return new APRCharsetDecoder(charset);
#else    
    throw IllegalArgumentException(charset);
#endif
}