// **********************************************************************
//
// Copyright (c) 2006 ZeroC, Inc. All rights reserved.
//
// **********************************************************************

#include <Ice/Ice.h>

#include <algorithm>

#include <iconv.h>
#include <pthread.h>

//
// Converts charT encoded with internalCode to and from UTF-8 byte sequences
//
// The implementation allocates a pair of iconv_t on each thread, to avoid
// opening / closing iconv_t objects all the time.
//
//
template<typename charT>
class IconvStringConverter : public Ice::BasicStringConverter<charT>
{
public:

    IconvStringConverter(const char* internalCode);

    virtual ~IconvStringConverter();

    virtual Ice::Byte* toUTF8(const charT* sourceStart, const charT* sourceEnd, Ice::UTF8Buffer& buf) const;
    
    virtual void fromUTF8(const Ice::Byte* sourceStart, const Ice::Byte* sourceEnd,
			  std::basic_string<charT>& target) const;
    
private:

    std::pair<iconv_t, iconv_t> createDescriptors() const;
    std::pair<iconv_t, iconv_t> getDescriptors() const;

    static void cleanupKey(void*);
    static void close(std::pair<iconv_t, iconv_t>);
    
    mutable pthread_key_t _key;

    const char* _internalCode;
};



template<typename charT>
IconvStringConverter<charT>::IconvStringConverter(const char* internalCode) :
    _internalCode(internalCode)
{
    //
    // Verify that iconv supports conversion to/from internalCode
    //
    try
    {
	close(createDescriptors());

    }
    catch(const Ice::StringConversionException& sce)
    {
	throw Ice::InitializationException(
	    __FILE__, __LINE__, sce.reason);
    }

    //
    // Create thread-specific key
    //
    int rs = pthread_key_create(&_key, &cleanupKey);

    if(rs != 0)
    {
	throw IceUtil::ThreadSyscallException(__FILE__, __LINE__, rs);
    }
}

template<typename charT>
IconvStringConverter<charT>::~IconvStringConverter()
{
    void* val = pthread_getspecific(_key);
    if(val != 0)
    {
	cleanupKey(val);
    }
    int rs = pthread_key_delete(_key);
    assert(rs == 0);
}

template<typename charT> std::pair<iconv_t, iconv_t>
IconvStringConverter<charT>::createDescriptors() const
{
    std::pair<iconv_t, iconv_t> cdp;

    const char* externalCode = "UTF-8";

    cdp.first = iconv_open(_internalCode, externalCode);
    if(cdp.first == iconv_t(-1))
    {
	throw Ice::StringConversionException(
	    __FILE__, __LINE__,
	    std::string("iconv can convert from ") 
	    + externalCode + " to " + _internalCode);
					   
    }
    
    cdp.second = iconv_open(externalCode, _internalCode);
    if(cdp.second == iconv_t(-1))
    {
	iconv_close(cdp.first);

	throw Ice::StringConversionException(
	    __FILE__, __LINE__,
	    std::string("iconv can convert from ") 
	    + _internalCode + " to " + externalCode);
					   
    }
    return cdp;
}

template<typename charT> std::pair<iconv_t, iconv_t>
IconvStringConverter<charT>::getDescriptors() const
{
    void* val = pthread_getspecific(_key);
    if(val != 0)
    {
	return *static_cast<std::pair<iconv_t, iconv_t>*>(val);
    }
    else
    {
	std::pair<iconv_t, iconv_t> cdp = createDescriptors();
	
	int rs = pthread_setspecific(_key, new std::pair<iconv_t, iconv_t>(cdp));

	if(rs != 0)
	{
	    throw IceUtil::ThreadSyscallException(__FILE__, __LINE__, rs);
	}
	return cdp;
    }
}

template<typename charT> /*static*/ void
IconvStringConverter<charT>::cleanupKey(void* val)
{
    std::pair<iconv_t, iconv_t>* cdp = static_cast<std::pair<iconv_t, iconv_t>*>(val);

    close(*cdp);
    delete cdp;
}

template<typename charT> /*static*/ void
IconvStringConverter<charT>::close(std::pair<iconv_t, iconv_t> cdp)
{
    int rs = iconv_close(cdp.first);
    assert(rs == 0);

    rs = iconv_close(cdp.second);
    assert(rs == 0);
}
 

template<typename charT> Ice::Byte* 
IconvStringConverter<charT>::toUTF8(const charT* sourceStart, const charT* sourceEnd, Ice::UTF8Buffer& buf) const
{ 
    iconv_t cd = getDescriptors().second;
    
    //
    // Reset cd
    //
    int rs = iconv(cd, 0, 0, 0, 0);
    assert(rs == 0);

    char* inbuf = reinterpret_cast<char*>(const_cast<charT*>(sourceStart));
    size_t inbytesleft = (sourceEnd - sourceStart) * sizeof(charT);
    Ice::Byte* outbuf  = 0;
  
    size_t count = 0; 

    //
    // Loop while we need more buffer space
    //
    do
    {
	size_t howMany = std::max(inbytesleft, size_t(4));
	outbuf = buf.getMoreBytes(howMany, outbuf);
	count = iconv(cd, &inbuf, &inbytesleft, reinterpret_cast<char**>(&outbuf), &howMany);
    } while(count == size_t(-1) && errno == E2BIG);
      
    if(count == size_t(-1))
    {
	throw Ice::StringConversionException(__FILE__, __LINE__);
    }
    return outbuf;
}

  
template<typename charT> void
IconvStringConverter<charT>::fromUTF8(const Ice::Byte* sourceStart, const Ice::Byte* sourceEnd,
				      std::basic_string<charT>& target) const
{
    iconv_t cd = getDescriptors().first;
    
    //
    // Reset cd
    //
    int rs = iconv(cd, 0, 0, 0, 0);
    assert(rs == 0);


    char* inbuf = reinterpret_cast<char*>(const_cast<Ice::Byte*>(sourceStart));
    size_t inbytesleft = sourceEnd - sourceStart;

    //
    // Result buffer
    //
    char* buf = 0;
    size_t bufsize = 0;

    char* outbuf = 0;
    size_t outbytesleft = 0;

    size_t count = 0;

    //
    // Loop while we need more buffer space
    //
    do
    {
	size_t increment = std::max(inbytesleft * sizeof(wchar_t), size_t(8));
	bufsize += increment;	
				    
	char* newbuf = static_cast<char*>(realloc(buf, bufsize));

	if(newbuf == 0)
	{
	    free(buf);
	    throw Ice::StringConversionException(
		__FILE__, __LINE__, "Out of memory");
	}

	outbuf = newbuf + (outbuf - buf);
	outbytesleft += increment;

        buf = newbuf;
	
	count = iconv(cd, &inbuf, &inbytesleft, &outbuf, &outbytesleft);
    } while(count == size_t(-1) && errno == E2BIG);

    if(count == size_t(-1))
    {
	free(buf);
	throw Ice::StringConversionException(__FILE__, __LINE__);
    }
    
    size_t length = (bufsize - outbytesleft) / sizeof(charT);
    
    std::basic_string<charT> result(reinterpret_cast<charT*>(buf), length);
    target.swap(result);
    free(buf);
};