#include <errno.h>
#include <string.h>
#include <iconv.h>
#include "conv.h"

#ifndef __BYTE_ORDER__
#error __BYTE_ORDER__ not defined!
#endif	//	__BYTE_ORDER__

#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
#define _UTF_16			"UTF-16LE//"
#define _UTF_32			"UTF-32LE//"
#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
#define _UTF_16			"UTF-16BE//"
#define _UTF_32			"UTF-32BE//"
#else	//	__BYTE_ORDER__
#error Invalid Byte Order!
#endif	//	__BYTE_ORDER__

/////////////////////////////////////////////////////////////////////////////////////////////////////////////

static size_t _Conv(iconv_t cd, char **pszIn, size_t nCbIn, char **pszOut, size_t nCbOut, size_t *pnTruncated)
{
    size_t nRet = nCbOut;
    iconv(cd, pszIn, &nCbIn, pszOut, &nCbOut);
    if(pnTruncated)
        *pnTruncated = nCbIn;
    return nRet - nCbOut;
}

/////////////////////////////////////////////////////////////////////////////////////////////////////////////

size_t wcs16len(const char16_t *psz)
{
	const char16_t *p = psz;
	while(*p)
		p++;
	return (size_t)(p - psz);
}

size_t wcs32len(const char32_t *psz)
{
	const char32_t *p = psz;
	while(*p)
		p++;
	return (size_t)(p - psz);
}

/////////////////////////////////////////////////////////////////////////////////////////////////////////////

size_t EncToUtf8(const char *pszEncIn, const void *pszIn, size_t nCbIn, char *pszOut, size_t nCbOut)
{
	if(pszEncIn && pszIn && pszOut && nCbOut && nCbIn != (size_t)-1)
	{
	    iconv_t desc = iconv_open("UTF-8//", pszEncIn);

		if(desc != (iconv_t)-1)
		{
			size_t nRet;
			size_t nTrunc;
			char *pIn = (char*)pszIn;
			memset(pszOut, 0, nCbOut);
			nRet = _Conv(desc, &pIn, nCbIn, &pszOut, nCbOut - 1, &nTrunc);
			iconv_close(desc);
			return nRet;
		}
	}
	
	return 0;
}

/////////////////////////////////////////////////////////////////////////////////////////////////////////////

size_t Utf8ToLatin1(const char *pszIn, size_t nCbIn, char *pszOut, size_t nCbOut)
{
	if(pszIn && pszOut && nCbOut)
	{
	    iconv_t desc = iconv_open("LATIN1//", "UTF-8//");

		if(desc != (iconv_t)-1)
		{
			size_t nRet;
			size_t nTrunc;
			char *pIn = (char*)pszIn;
			if(nCbIn == (size_t)-1)
				nCbIn = strlen(pszIn);
			memset(pszOut, 0, nCbOut);
			nRet = _Conv(desc, &pIn, nCbIn, &pszOut, nCbOut - 1, &nTrunc);
			iconv_close(desc);
			return nRet;
		}
	}
	
	return 0;
}

size_t Latin1ToUtf8(const char *pszIn, size_t nCbIn, char *pszOut, size_t nCbOut)
{
	if(pszIn && pszOut && nCbOut)
	{
	    iconv_t desc = iconv_open("UTF-8//", "LATIN1//");

		if(desc != (iconv_t)-1)
		{
			size_t nRet;
			size_t nTrunc;
			char *pIn = (char*)pszIn;
			if(nCbIn == (size_t)-1)
				nCbIn = strlen(pszIn);
			memset(pszOut, 0, nCbOut);
			nRet = _Conv(desc, &pIn, nCbIn, &pszOut, nCbOut - 1, &nTrunc);
			iconv_close(desc);
			return nRet;
		}
	}
	
	return 0;
}

/////////////////////////////////////////////////////////////////////////////////////////////////////////////

size_t Utf8ToUtf16(const char *pszIn, size_t nCbIn, char16_t *pszOut, size_t nCChOut)
{
	if(pszIn && pszOut && nCChOut)
	{
        iconv_t desc = iconv_open(_UTF_16, "UTF-8//");

		if(desc != (iconv_t)-1)
		{
			size_t nRet;
			size_t nTrunc;
			char *pIn = (char*)pszIn;
			if(nCbIn == (size_t)-1)
				nCbIn = strlen(pszIn);
			memset(pszOut, 0, nCChOut * sizeof(char16_t));
			nRet = _Conv(desc, &pIn, nCbIn, (char**)&pszOut, (nCChOut - 1) * sizeof(char16_t), &nTrunc);
			iconv_close(desc);
			return nRet;
		}
	}
	
	return 0;
}

size_t Utf16ToUtf8(const char16_t *pszIn, size_t nCChIn, char *pszOut, size_t nCbOut)
{
	if(pszIn && pszOut && nCbOut)
	{
	    iconv_t desc = iconv_open("UTF-8//", _UTF_16);

		if(desc != (iconv_t)-1)
		{
			size_t nRet;
			size_t nTrunc;
			char *pIn = (char*)pszIn;
			if(nCChIn == (size_t)-1)
				nCChIn = wcs16len(pszIn);
			memset(pszOut, 0, nCbOut);
			nRet = _Conv(desc, &pIn, nCChIn * sizeof(char16_t), &pszOut, nCbOut - 1, &nTrunc);
			iconv_close(desc);
			return nRet;
		}
	}
	
	return 0;
}

/////////////////////////////////////////////////////////////////////////////////////////////////////////////

size_t Utf8ToUtf32(const char *pszIn, size_t nCbIn, char32_t *pszOut, size_t nCChOut)
{
	if(pszIn && pszOut && nCChOut)
	{
	    iconv_t desc = iconv_open(_UTF_32, "UTF-8//");

		if(desc != (iconv_t)-1)
		{
			size_t nRet;
			size_t nTrunc;
			char *pIn = (char*)pszIn;
			if(nCbIn == (size_t)-1)
				nCbIn = strlen(pszIn);
			memset(pszOut, 0, nCChOut * sizeof(char32_t));
			nRet = _Conv(desc, &pIn, nCbIn, (char**)&pszOut, (nCChOut - 1) * sizeof(char32_t), &nTrunc);
			iconv_close(desc);
			return nRet;
		}
	}
	
	return 0;
}

size_t Utf32ToUtf8(const char32_t *pszIn, size_t nCChIn, char *pszOut, size_t nCbOut)
{
	if(pszIn && pszOut && nCbOut)
	{
	    iconv_t desc = iconv_open("UTF-8//", _UTF_32);

		if(desc != (iconv_t)-1)
		{
			size_t nRet;
			size_t nTrunc;
			char *pIn = (char*)pszIn;
			if(nCChIn == (size_t)-1)
				nCChIn = wcs32len(pszIn);
			memset(pszOut, 0, nCbOut);
			nRet = _Conv(desc, &pIn, nCChIn * sizeof(char32_t), &pszOut, nCbOut - 1, &nTrunc);
			iconv_close(desc);
			return nRet;
		}
	}
	
	return 0;
}

/////////////////////////////////////////////////////////////////////////////////////////////////////////////

size_t Utf8ToWcs(const char *pszIn, size_t nCbIn, wchar_t *pszOut, size_t nCChOut)
{
	if(pszIn && pszOut && nCChOut)
	{
	    iconv_t desc = iconv_open("WCHAR_T//", "UTF-8//");

		if(desc != (iconv_t)-1)
		{
			size_t nRet;
			size_t nTrunc;
			char *pIn = (char*)pszIn;
			if(nCbIn == (size_t)-1)
				nCbIn = strlen(pszIn);
			memset(pszOut, 0, nCChOut * sizeof(wchar_t));
			nRet = _Conv(desc, &pIn, nCbIn, (char**)&pszOut, (nCChOut - 1) * sizeof(wchar_t), &nTrunc);
			iconv_close(desc);
			return nRet;
		}
	}
	
	return 0;
}

size_t WcsToUtf8(const wchar_t *pszIn, size_t nCChIn, char *pszOut, size_t nCbOut)
{
	if(pszIn && pszOut && nCbOut)
	{
	    iconv_t desc = iconv_open("UTF-8//", "WCHAR_T//");

		if(desc != (iconv_t)-1)
		{
			size_t nRet;
			size_t nTrunc;
			char *pIn = (char*)pszIn;
			if(nCChIn == (size_t)-1)
				nCChIn = wcslen(pszIn);
			memset(pszOut, 0, nCbOut);
			nRet = _Conv(desc, &pIn, nCChIn * sizeof(wchar_t), &pszOut, nCbOut - 1, &nTrunc);
			iconv_close(desc);
			return nRet;
		}
	}
	
	return 0;
}