/*
 * Copyright (c) 2004, Nate Nielsen
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *     * Redistributions of source code must retain the above
 *       copyright notice, this list of conditions and the
 *       following disclaimer.
 *     * Redistributions in binary form must reproduce the
 *       above copyright notice, this list of conditions and
 *       the following disclaimer in the documentation and/or
 *       other materials provided with the distribution.
 *     * The names of contributors to this software may not be
 *       used to endorse or promote products derived from this
 *       software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 *
 *
 * CONTRIBUTORS
 *  Nate Nielsen <nielsen@memberwebs.com>
 *
 */

#include <wchar.h>
#include "usuals.h"

bool transcode16to8(wchar_t ch, string& ret)
{
    ret.reserve(ret.length() + 3);

    if(ch <= 0x007F)
    {
        ret.append(1, (char)ch);
    }
    else if(ch <= 0x07FF)
    {
        ret.append(1, (char)(192 | (ch >> 6)));
        ret.append(1, (char)(128 | (ch & 63)));
    }
    else
    {
        ret.append(1, (char)(224 | (ch >> 12)));
        ret.append(1, (char)(128 | ((ch >> 6) & 63)));
        ret.append(1, (char)(128 | (ch & 63)));
    }

    return true;
}

bool transcode16to8(const wstring& data, string& ret)
{
	ret.reserve(ret.length() + data.length() + (data.length() / 2));

	// basic_string.c_str doesn't work properly everywhere
	// most notably not in the g++ std library

	const wchar_t* c = data.length() ? data.data() : L"";
	const wchar_t* e = c + data.length();

	for( ; c < e; c++)
	{
		if(*c <= 0x007F)
		{
			ret.append(1, (char)*c);
		}
		else if(*c <= 0x07FF)
		{
			ret.append(1, (char)(192 | (*c >> 6)));
			ret.append(1, (char)(128 | (*c & 63)));
		}
		else
		{
			ret.append(1, (char)(224 | (*c >> 12)));
			ret.append(1, (char)(128 | ((*c >> 6) & 63)));
			ret.append(1, (char)(128 | (*c & 63)) );
		}
	}

	return true;
}

bool transcode8to16(const string& data, wstring& ret)
{
	ret.reserve(data.length());

	// basic_string.c_str doesn't work properly everywhere
	// most notably not in the g++ std library

	const char* c = data.length() ? data.data() : "";
	const char* e = c + data.length();

	for( ; c < e; c++)
	{
		// First 4 bits set
		if((c[0] & 0xF8) == 0xF0 &&
		   (c[1] & 0xC0) == 0x80 &&
		   (c[2] & 0xC0) == 0x80 &&
		   (c[3] & 0xC0) == 0x80)
		{
			ret.append(1, (wchar_t)(((wchar_t)c[0] & 7) << 18 |
				       ((wchar_t)c[1] & 63) << 12 |
					   ((wchar_t)c[2] & 63) << 6 |
					   ((wchar_t)c[3] & 63)));
			c += 3;
		}

		// First 3 bits set
		else if((c[0] & 0xF0) == 0xE0 &&
		        (c[1] & 0xC0) == 0x80 &&
				(c[2] & 0xC0) == 0x80)
		{
			ret.append(1, (wchar_t)(((wchar_t)c[0] & 15) << 12 |
				       ((wchar_t)c[1] & 63) << 6 |
					   ((wchar_t)c[2] & 63)));
			c += 2;
		}

		// First 2 bits set
		else if((c[0] & 0xE0) == 0xC0 &&
			    (c[1] & 0xC0) == 0x80)
		{
			ret.append(1, (wchar_t)(((wchar_t)c[0] & 31) << 6 |
					   ((wchar_t)c[1] & 63)));
			c += 1;
		}

		// First bit set
		else if(!(c[0] & 0x80))
		{
			ret.append(1, (wchar_t)c[0]);
		}

		else
			return false;
	}

	return true;
}