scsuutf8.cpp

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/******************************************************************************
 *
 *  scsuutf8.cpp -  SWFilter descendant to convert a SCSU character to
 *          UTF-8
 *
 * $Id: scsuutf8.cpp 3727 2020-04-29 02:33:23Z scribe $
 *
 * Copyright 2001-2014 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.
 *
 */

/* This class is based on:
 * http://czyborra.com/scsu/scsu.c written by Roman Czyborra@dds.nl
 *
 * This is a deflator to UTF-8 output for input compressed in SCSU,
 * the (Reuters) Standard Compression Scheme for Unicode as described
 * in http://www.unicode.org/unicode/reports/tr6.html
 */

#include <scsuutf8.h>
#include <swbuf.h>
#ifdef _ICU_
#include <unicode/unistr.h>
#endif



SWORD_NAMESPACE_START


SCSUUTF8::SCSUUTF8()
#ifdef _ICU_
 : err()
#endif
{
#ifdef _ICU_
    
    // initialize SCSU converter
    scsuConv = ucnv_open("SCSU", &err);
    // initialize UTF-8 converter
    utf8Conv = ucnv_open("UTF-8", &err);    
#else
    active = 0;
    mode = 0;
#endif
}

SCSUUTF8::~SCSUUTF8() {
#ifdef _ICU_
    ucnv_close(scsuConv);
    ucnv_close(utf8Conv);
#endif
}

#ifndef _ICU_
unsigned short SCSUUTF8::start[] = {0x0000,0x0080,0x0100,0x0300,0x2000,0x2080,0x2100,0x3000};
unsigned short SCSUUTF8::slide[] = {0x0080,0x00C0,0x0400,0x0600,0x0900,0x3040,0x30A0,0xFF00};
unsigned short SCSUUTF8::win[] = {
    0x0000, 0x0080, 0x0100, 0x0180, 0x0200, 0x0280, 0x0300, 0x0380,
    0x0400, 0x0480, 0x0500, 0x0580, 0x0600, 0x0680, 0x0700, 0x0780,
    0x0800, 0x0880, 0x0900, 0x0980, 0x0A00, 0x0A80, 0x0B00, 0x0B80,
    0x0C00, 0x0C80, 0x0D00, 0x0D80, 0x0E00, 0x0E80, 0x0F00, 0x0F80,
    0x1000, 0x1080, 0x1100, 0x1180, 0x1200, 0x1280, 0x1300, 0x1380,
    0x1400, 0x1480, 0x1500, 0x1580, 0x1600, 0x1680, 0x1700, 0x1780,
    0x1800, 0x1880, 0x1900, 0x1980, 0x1A00, 0x1A80, 0x1B00, 0x1B80,
    0x1C00, 0x1C80, 0x1D00, 0x1D80, 0x1E00, 0x1E80, 0x1F00, 0x1F80,
    0x2000, 0x2080, 0x2100, 0x2180, 0x2200, 0x2280, 0x2300, 0x2380,
    0x2400, 0x2480, 0x2500, 0x2580, 0x2600, 0x2680, 0x2700, 0x2780,
    0x2800, 0x2880, 0x2900, 0x2980, 0x2A00, 0x2A80, 0x2B00, 0x2B80,
    0x2C00, 0x2C80, 0x2D00, 0x2D80, 0x2E00, 0x2E80, 0x2F00, 0x2F80,
    0x3000, 0x3080, 0x3100, 0x3180, 0x3200, 0x3280, 0x3300, 0x3800,
    0xE000, 0xE080, 0xE100, 0xE180, 0xE200, 0xE280, 0xE300, 0xE380,
    0xE400, 0xE480, 0xE500, 0xE580, 0xE600, 0xE680, 0xE700, 0xE780,
    0xE800, 0xE880, 0xE900, 0xE980, 0xEA00, 0xEA80, 0xEB00, 0xEB80,
    0xEC00, 0xEC80, 0xED00, 0xED80, 0xEE00, 0xEE80, 0xEF00, 0xEF80,
    0xF000, 0xF080, 0xF100, 0xF180, 0xF200, 0xF280, 0xF300, 0xF380,
    0xF400, 0xF480, 0xF500, 0xF580, 0xF600, 0xF680, 0xF700, 0xF780,
    0xF800, 0xF880, 0xF900, 0xF980, 0xFA00, 0xFA80, 0xFB00, 0xFB80,
    0xFC00, 0xFC80, 0xFD00, 0xFD80, 0xFE00, 0xFE80, 0xFF00, 0xFF80,
    0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
    0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
    0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
    0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
    0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
    0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
    0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
    0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
    0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
    0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
    0x0000, 0x00C0, 0x0250, 0x0370, 0x0530, 0x3040, 0x30A0, 0xFF60,
};

int SCSUUTF8::UTF8Output(unsigned long uchar, SWBuf* utf8Buf)
{
    // join UTF-16 surrogates without any pairing sanity checks
    if (uchar >= 0xd800 && uchar <= 0xdbff) {
        d = uchar & 0x3ff;
        return 0;
    }
    if (uchar >= 0xdc00 && uchar <= 0xdfff) {
        uchar = uchar + 0x2400 + d * 0x400;
    }
    
    // output one character as UTF-8 multibyte sequence
    
    if (uchar < 0x80) {
        utf8Buf += uchar;
    }
    else if (uchar < 0x800) {
        utf8Buf += (0xc0 | (uchar>>6));
        utf8Buf += (0x80 | (uchar & 0x3f));
    }
    else if (uchar < 0x10000) {
        utf8Buf += (0xe0 | (uchar>>12));
        utf8Buf += (0x80 | (uchar>>6 & 0x3f));
        utf8Buf += (0x80 | (uchar & 0x3f));
    }
    else if (uchar < 0x200000) {
        utf8Buf += (0xf0 | (uchar>>18));
        utf8Buf += (0x80 | (uchar>>12 & 0x3f));
        utf8Buf += (0x80 | (uchar>>6 & 0x3f));
        utf8Buf += (0x80 | (uchar & 0x3f));
    }
    
    return 0;
}
#endif

char SCSUUTF8::processText(SWBuf &text, const SWKey *key, const SWModule *module) {
    if ((unsigned long)key < 2) // hack, we're en(1)/de(0)ciphering
        return -1;
    
#ifdef _ICU_
    // Try decoding with ICU if possible
    err = U_ZERO_ERROR;
    icu::UnicodeString utf16Text(text.getRawData(), text.length(), scsuConv, err);
    err = U_ZERO_ERROR;
    int32_t len = utf16Text.extract(text.getRawData(), text.size(), utf8Conv, err);
    if (len > (int32_t)text.size()+1) {
        text.setSize(len+1);
        utf16Text.extract(text.getRawData(), text.size(), utf8Conv, err);
    }
#else
    // If ICU is unavailable, decode using Czyborra's decoder
    SWBuf utf8Buf = "";
    int len = text.length();
    const char* scsuString = text.c_str();

    for (int i = 0; i < len;) {
        
        if (i >= len) break;
        c = scsuString[i++];
        
        if (c >= 0x80)
        {
            UTF8Output(c - 0x80 + slide[active], &utf8Buf);
        }
        else if (c >= 0x20 && c <= 0x7F)
        {
            UTF8Output(c, &utf8Buf);
        }
        else if (c == 0x0 || c == 0x9 || c == 0xA || c == 0xC || c == 0xD)
        {
            UTF8Output(c, &utf8Buf);
        }
        else if (c >= 0x1 && c <= 0x8) // SQn
        {
            if (i >= len) break;
            d = scsuString[i++]; // single quote
            
            UTF8Output(d < 0x80 ? d + start[c - 0x1] :
                    d - 0x80 + slide[c - 0x1], &utf8Buf);
        }
        else if (c >= 0x10 && c <= 0x17) // SCn
        {
            active = c - 0x10; // change window
        }
        else if (c >= 0x18 && c <= 0x1F) // SDn
        {
            active = c - 0x18;  // define window
            if (i >= len) break;
            slide[active] = win[(unsigned char)scsuString[i++]];
        }
        else if (c == 0xB) // SDX
        {
            if (i >= len) break;
            c = scsuString[i++];
            
            if (i >= len) break;
            d = scsuString[i++];
            
            slide[active = c>>5] = 0x10000 + (((c & 0x1F) << 8 | d) << 7);
        }
        else if (c == 0xE) // SQU
        {
            if (i >= len) break;
            c = scsuString[i++]; // SQU
            
            if (i >= len) break;
            UTF8Output(c << 8 | scsuString[i++], &utf8Buf);
        }
        else if (c == 0xF) // SCU
        {
            mode = 1; // change to Unicode mode
            
            while (mode)
            {
                if (i >= len) break;
                c = scsuString[i++];
                
                if (c <= 0xDF || c >= 0xF3)
                {
                    if (i >= len) break;
                    UTF8Output(c << 8 | scsuString[i++], &utf8Buf);
                }
                else if (c == 0xF0) // UQU
                {
                    if (i >= len) break;
                    c = scsuString[i++];
                    
                    if (i >= len) break;
                    UTF8Output(c << 8 | scsuString[i++], &utf8Buf);
                }
                else if (c >= 0xE0 && c <= 0xE7) // UCn
                {
                    active = c - 0xE0;
                    mode = 0;
                }
                else if (c >= 0xE8 && c <= 0xEF) // UDn
                {
                    if (i >= len) break;
                    slide[active=c-0xE8] = win[(unsigned char)scsuString[i++]];
                    mode = 0;
                }
                else if (c == 0xF1) // UDX
                {
                    if (i >= len) break;
                    c = scsuString[i++];
                    
                    if (i >= len) break;
                    d = scsuString[i++];
                    
                    slide[active = c>>5] =
                        0x10000 + (((c & 0x1F) << 8 | d) << 7);
                    mode = 0;
                }
            }
        }
    }
#endif
    
    return 0;
}


SWORD_NAMESPACE_END