unicodertf.cpp

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/******************************************************************************
 *
 *  unicodertf.cpp -    SWFilter descendant to convert UTF-8 to RTF tags
 *
 * $Id: unicodertf.cpp 3081 2014-03-05 19:52:08Z chrislit $
 *
 * Copyright 2001-2013 CrossWire Bible Society (http://www.crosswire.org)
 *  CrossWire Bible Society
 *  P. O. Box 2528
 *  Tempe, AZ  85280-2528
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation version 2.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 */

#include <stdio.h>
#include <unicodertf.h>
#include <swbuf.h>

SWORD_NAMESPACE_START

UnicodeRTF::UnicodeRTF() {
}


char UnicodeRTF::processText(SWBuf &text, const SWKey *key, const SWModule *module)
{
    const unsigned char *from;
    char digit[10];
    unsigned long ch;
        signed short utf16;
    unsigned char from2[7];

    SWBuf orig = text;

    from = (const unsigned char *)orig.c_str();

    // -------------------------------
    for (text = ""; *from; from++) {
        ch = 0;
                //case: ANSI
        if ((*from & 128) != 128) {
            text += *from;
            continue;
        }
                //case: Invalid UTF-8 (illegal continuing byte in initial position)
        if ((*from & 128) && ((*from & 64) != 64)) {
            continue;
        }
                //case: 2+ byte codepoint
        from2[0] = *from;
        from2[0] <<= 1;
        int subsequent;
        for (subsequent = 1; (from2[0] & 128) && (subsequent < 7); subsequent++) {
            from2[0] <<= 1;
            from2[subsequent] = from[subsequent];
            from2[subsequent] &= 63;
            ch <<= 6;
            ch |= from2[subsequent];
        }
        subsequent--;
        from2[0] <<= 1;
        char significantFirstBits = 8 - (2+subsequent);
        
        ch |= (((short)from2[0]) << (((6*subsequent)+significantFirstBits)-8));
        from += subsequent;
                if (ch < 0x10000) {
                utf16 = (signed short)ch;
                text += '\\';
                text += 'u';
                sprintf(digit, "%d", utf16);
                text += digit;
                text += '?';
             }
            else {
                utf16 = (signed short)((ch - 0x10000) / 0x400 + 0xD800);
                text += '\\';
                text += 'u';
                sprintf(digit, "%d", utf16);
                text += digit;
                text += '?';
                utf16 = (signed short)((ch - 0x10000) % 0x400 + 0xDC00);
                text += '\\';
                text += 'u';
                sprintf(digit, "%d", utf16);
                text += digit;
                text += '?';
            }
    }
       
    return 0;
}

SWORD_NAMESPACE_END