src/stdlib/SDL_iconv.c

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2006 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library 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
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga
    slouken@libsdl.org
*/
#include "SDL_config.h"

/* This file contains portable iconv functions for SDL */

#include "SDL_stdinc.h"
#include "SDL_endian.h"

#ifdef HAVE_ICONV

#include <errno.h>

size_t
SDL_iconv(SDL_iconv_t cd,
          char **inbuf, size_t * inbytesleft,
          char **outbuf, size_t * outbytesleft)
{
    size_t retCode = iconv(cd, inbuf, inbytesleft, outbuf, outbytesleft);
    if (retCode == (size_t) - 1) {
        switch (errno) {
        case E2BIG:
            return SDL_ICONV_E2BIG;
        case EILSEQ:
            return SDL_ICONV_EILSEQ;
        case EINVAL:
            return SDL_ICONV_EINVAL;
        default:
            return SDL_ICONV_ERROR;
        }
    }
    return retCode;
}

#else

/* Lots of useful information on Unicode at:
	http://www.cl.cam.ac.uk/~mgk25/unicode.html
*/

#define UNICODE_BOM	0xFEFF

#define UNKNOWN_ASCII	'?'
#define UNKNOWN_UNICODE	0xFFFD

enum
{
    ENCODING_UNKNOWN,
    ENCODING_ASCII,
    ENCODING_LATIN1,
    ENCODING_UTF8,
    ENCODING_UTF16,             /* Needs byte order marker */
    ENCODING_UTF16BE,
    ENCODING_UTF16LE,
    ENCODING_UTF32,             /* Needs byte order marker */
    ENCODING_UTF32BE,
    ENCODING_UTF32LE,
    ENCODING_UCS2,              /* Native byte order assumed */
    ENCODING_UCS4,              /* Native byte order assumed */
};
#if SDL_BYTEORDER == SDL_BIG_ENDIAN
#define ENCODING_UTF16NATIVE	ENCODING_UTF16BE
#define ENCODING_UTF32NATIVE	ENCODING_UTF32BE
#else
#define ENCODING_UTF16NATIVE	ENCODING_UTF16LE
#define ENCODING_UTF32NATIVE	ENCODING_UTF32LE
#endif

struct _SDL_iconv_t
{
    int src_fmt;
    int dst_fmt;
};

static struct
{
    const char *name;
    int format;
} encodings[] = {
    {
    "ASCII", ENCODING_ASCII}, {
    "US-ASCII", ENCODING_ASCII}, {
    "LATIN1", ENCODING_LATIN1}, {
    "ISO-8859-1", ENCODING_LATIN1}, {
    "UTF8", ENCODING_UTF8}, {
    "UTF-8", ENCODING_UTF8}, {
    "UTF16", ENCODING_UTF16}, {
    "UTF-16", ENCODING_UTF16}, {
    "UTF16BE", ENCODING_UTF16BE}, {
    "UTF-16BE", ENCODING_UTF16BE}, {
    "UTF16LE", ENCODING_UTF16LE}, {
    "UTF-16LE", ENCODING_UTF16LE}, {
    "UTF32", ENCODING_UTF32}, {
    "UTF-32", ENCODING_UTF32}, {
    "UTF32BE", ENCODING_UTF32BE}, {
    "UTF-32BE", ENCODING_UTF32BE}, {
    "UTF32LE", ENCODING_UTF32LE}, {
    "UTF-32LE", ENCODING_UTF32LE}, {
    "UCS2", ENCODING_UCS2}, {
    "UCS-2", ENCODING_UCS2}, {
    "UCS4", ENCODING_UCS4}, {
"UCS-4", ENCODING_UCS4},};

SDL_iconv_t
SDL_iconv_open(const char *tocode, const char *fromcode)
{
    int src_fmt = ENCODING_UNKNOWN;
    int dst_fmt = ENCODING_UNKNOWN;
    int i;

    for (i = 0; i < SDL_arraysize(encodings); ++i) {
        if (SDL_strcasecmp(fromcode, encodings[i].name) == 0) {
            src_fmt = encodings[i].format;
            if (dst_fmt != ENCODING_UNKNOWN) {
                break;
            }
        }
        if (SDL_strcasecmp(tocode, encodings[i].name) == 0) {
            dst_fmt = encodings[i].format;
            if (src_fmt != ENCODING_UNKNOWN) {
                break;
            }
        }
    }
    if (src_fmt != ENCODING_UNKNOWN && dst_fmt != ENCODING_UNKNOWN) {
        SDL_iconv_t cd = (SDL_iconv_t) SDL_malloc(sizeof(*cd));
        if (cd) {
            cd->src_fmt = src_fmt;
            cd->dst_fmt = dst_fmt;
            return cd;
        }
    }
    return (SDL_iconv_t) - 1;
}

size_t
SDL_iconv(SDL_iconv_t cd,
          char **inbuf, size_t * inbytesleft,
          char **outbuf, size_t * outbytesleft)
{
    /* For simplicity, we'll convert everything to and from UCS-4 */
    char *src, *dst;
    size_t srclen, dstlen;
    Uint32 ch;
    size_t total;

    if (!inbuf || !*inbuf) {
        /* Reset the context */
        return 0;
    }
    if (!outbuf || !*outbuf || !outbytesleft || !*outbytesleft) {
        return SDL_ICONV_E2BIG;
    }
    src = *inbuf;
    srclen = (inbytesleft ? *inbytesleft : 0);
    dst = *outbuf;
    dstlen = *outbytesleft;

    switch (cd->src_fmt) {
    case ENCODING_UTF16:
        /* Scan for a byte order marker */
        {
            Uint8 *p = (Uint8 *) src;
            size_t n = srclen / 2;
            while (n) {
                if (p[0] == 0xFF && p[1] == 0xFE) {
                    cd->src_fmt = ENCODING_UTF16BE;
                    break;
                } else if (p[0] == 0xFE && p[1] == 0xFF) {
                    cd->src_fmt = ENCODING_UTF16LE;
                    break;
                }
                p += 2;
                --n;
            }
            if (n == 0) {
                /* We can't tell, default to host order */
                cd->src_fmt = ENCODING_UTF16NATIVE;
            }
        }
        break;
    case ENCODING_UTF32:
        /* Scan for a byte order marker */
        {
            Uint8 *p = (Uint8 *) src;
            size_t n = srclen / 4;
            while (n) {
                if (p[0] == 0xFF && p[1] == 0xFE &&
                    p[2] == 0x00 && p[3] == 0x00) {
                    cd->src_fmt = ENCODING_UTF32BE;
                    break;
                } else if (p[0] == 0x00 && p[1] == 0x00 &&
                           p[2] == 0xFE && p[3] == 0xFF) {
                    cd->src_fmt = ENCODING_UTF32LE;
                    break;
                }
                p += 4;
                --n;
            }
            if (n == 0) {
                /* We can't tell, default to host order */
                cd->src_fmt = ENCODING_UTF32NATIVE;
            }
        }
        break;
    }

    switch (cd->dst_fmt) {
    case ENCODING_UTF16:
        /* Default to host order, need to add byte order marker */
        if (dstlen < 2) {
            return SDL_ICONV_E2BIG;
        }
        *(Uint16 *) dst = UNICODE_BOM;
        dst += 2;
        dstlen -= 2;
        cd->dst_fmt = ENCODING_UTF16NATIVE;
        break;
    case ENCODING_UTF32:
        /* Default to host order, need to add byte order marker */
        if (dstlen < 4) {
            return SDL_ICONV_E2BIG;
        }
        *(Uint32 *) dst = UNICODE_BOM;
        dst += 4;
        dstlen -= 4;
        cd->dst_fmt = ENCODING_UTF32NATIVE;
        break;
    }

    total = 0;
    while (srclen > 0) {
        /* Decode a character */
        switch (cd->src_fmt) {
        case ENCODING_ASCII:
            {
                Uint8 *p = (Uint8 *) src;
                ch = (Uint32) (p[0] & 0x7F);
                ++src;
                --srclen;
            }
            break;
        case ENCODING_LATIN1:
            {
                Uint8 *p = (Uint8 *) src;
                ch = (Uint32) p[0];
                ++src;
                --srclen;
            }
            break;
        case ENCODING_UTF8:    /* RFC 3629 */
            {
                Uint8 *p = (Uint8 *) src;
                size_t left = 0;
                SDL_bool overlong = SDL_FALSE;
                if (p[0] >= 0xFC) {
                    if ((p[0] & 0xFE) != 0xFC) {
                        /* Skip illegal sequences
                           return SDL_ICONV_EILSEQ;
                         */
                        ch = UNKNOWN_UNICODE;
                    } else {
                        if (p[0] == 0xFC) {
                            overlong = SDL_TRUE;
                        }
                        ch = (Uint32) (p[0] & 0x01);
                        left = 5;
                    }
                } else if (p[0] >= 0xF8) {
                    if ((p[0] & 0xFC) != 0xF8) {
                        /* Skip illegal sequences
                           return SDL_ICONV_EILSEQ;
                         */
                        ch = UNKNOWN_UNICODE;
                    } else {
                        if (p[0] == 0xF8) {
                            overlong = SDL_TRUE;
                        }
                        ch = (Uint32) (p[0] & 0x03);
                        left = 4;
                    }
                } else if (p[0] >= 0xF0) {
                    if ((p[0] & 0xF8) != 0xF0) {
                        /* Skip illegal sequences
                           return SDL_ICONV_EILSEQ;
                         */
                        ch = UNKNOWN_UNICODE;
                    } else {
                        if (p[0] == 0xF0) {
                            overlong = SDL_TRUE;
                        }
                        ch = (Uint32) (p[0] & 0x07);
                        left = 3;
                    }
                } else if (p[0] >= 0xE0) {
                    if ((p[0] & 0xF0) != 0xE0) {
                        /* Skip illegal sequences
                           return SDL_ICONV_EILSEQ;
                         */
                        ch = UNKNOWN_UNICODE;
                    } else {
                        if (p[0] == 0xE0) {
                            overlong = SDL_TRUE;
                        }
                        ch = (Uint32) (p[0] & 0x0F);
                        left = 2;
                    }
                } else if (p[0] >= 0xC0) {
                    if ((p[0] & 0xE0) != 0xC0) {
                        /* Skip illegal sequences
                           return SDL_ICONV_EILSEQ;
                         */
                        ch = UNKNOWN_UNICODE;
                    } else {
                        if ((p[0] & 0xCE) == 0xC0) {
                            overlong = SDL_TRUE;
                        }
                        ch = (Uint32) (p[0] & 0x1F);
                        left = 1;
                    }
                } else {
                    if ((p[0] & 0x80) != 0x00) {
                        /* Skip illegal sequences
                           return SDL_ICONV_EILSEQ;
                         */
                        ch = UNKNOWN_UNICODE;
                    } else {
                        ch = (Uint32) p[0];
                    }
                }
                ++src;
                --srclen;
                if (srclen < left) {
                    return SDL_ICONV_EINVAL;
                }
                while (left--) {
                    ++p;
                    if ((p[0] & 0xC0) != 0x80) {
                        /* Skip illegal sequences
                           return SDL_ICONV_EILSEQ;
                         */
                        ch = UNKNOWN_UNICODE;
                        break;
                    }
                    ch <<= 6;
                    ch |= (p[0] & 0x3F);
                    ++src;
                    --srclen;
                }
                if (overlong) {
                    /* Potential security risk
                       return SDL_ICONV_EILSEQ;
                     */
                    ch = UNKNOWN_UNICODE;
                }
                if ((ch >= 0xD800 && ch <= 0xDFFF) ||
                    (ch == 0xFFFE || ch == 0xFFFF) || ch > 0x10FFFF) {
                    /* Skip illegal sequences
                       return SDL_ICONV_EILSEQ;
                     */
                    ch = UNKNOWN_UNICODE;
                }
            }
            break;
        case ENCODING_UTF16BE: /* RFC 2781 */
            {
                Uint8 *p = (Uint8 *) src;
                Uint16 W1, W2;
                if (srclen < 2) {
                    return SDL_ICONV_EINVAL;
                }
                W1 = ((Uint16) p[0] << 8) | (Uint16) p[1];
                src += 2;
                srclen -= 2;
                if (W1 < 0xD800 || W1 > 0xDFFF) {
                    ch = (Uint32) W1;
                    break;
                }
                if (W1 > 0xDBFF) {
                    /* Skip illegal sequences
                       return SDL_ICONV_EILSEQ;
                     */
                    ch = UNKNOWN_UNICODE;
                    break;
                }
                if (srclen < 2) {
                    return SDL_ICONV_EINVAL;
                }
                p = (Uint8 *) src;
                W2 = ((Uint16) p[0] << 8) | (Uint16) p[1];
                src += 2;
                srclen -= 2;
                if (W2 < 0xDC00 || W2 > 0xDFFF) {
                    /* Skip illegal sequences
                       return SDL_ICONV_EILSEQ;
                     */
                    ch = UNKNOWN_UNICODE;
                    break;
                }
                ch = (((Uint32) (W1 & 0x3FF) << 10) |
                      (Uint32) (W2 & 0x3FF)) + 0x10000;
            }
            break;
        case ENCODING_UTF16LE: /* RFC 2781 */
            {
                Uint8 *p = (Uint8 *) src;
                Uint16 W1, W2;
                if (srclen < 2) {
                    return SDL_ICONV_EINVAL;
                }
                W1 = ((Uint16) p[1] << 8) | (Uint16) p[0];
                src += 2;
                srclen -= 2;
                if (W1 < 0xD800 || W1 > 0xDFFF) {
                    ch = (Uint32) W1;
                    break;
                }
                if (W1 > 0xDBFF) {
                    /* Skip illegal sequences
                       return SDL_ICONV_EILSEQ;
                     */
                    ch = UNKNOWN_UNICODE;
                    break;
                }
                if (srclen < 2) {
                    return SDL_ICONV_EINVAL;
                }
                p = (Uint8 *) src;
                W2 = ((Uint16) p[1] << 8) | (Uint16) p[0];
                src += 2;
                srclen -= 2;
                if (W2 < 0xDC00 || W2 > 0xDFFF) {
                    /* Skip illegal sequences
                       return SDL_ICONV_EILSEQ;
                     */
                    ch = UNKNOWN_UNICODE;
                    break;
                }
                ch = (((Uint32) (W1 & 0x3FF) << 10) |
                      (Uint32) (W2 & 0x3FF)) + 0x10000;
            }
            break;
        case ENCODING_UTF32BE:
            {
                Uint8 *p = (Uint8 *) src;
                if (srclen < 4) {
                    return SDL_ICONV_EINVAL;
                }
                ch = ((Uint32) p[0] << 24) |
                    ((Uint32) p[1] << 16) |
                    ((Uint32) p[2] << 8) | (Uint32) p[3];
                src += 4;
                srclen -= 4;
            }
            break;
        case ENCODING_UTF32LE:
            {
                Uint8 *p = (Uint8 *) src;
                if (srclen < 4) {
                    return SDL_ICONV_EINVAL;
                }
                ch = ((Uint32) p[3] << 24) |
                    ((Uint32) p[2] << 16) |
                    ((Uint32) p[1] << 8) | (Uint32) p[0];
                src += 4;
                srclen -= 4;
            }
            break;
        case ENCODING_UCS2:
            {
                Uint16 *p = (Uint16 *) src;
                if (srclen < 2) {
                    return SDL_ICONV_EINVAL;
                }
                ch = *p;
                src += 2;
                srclen -= 2;
            }
            break;
        case ENCODING_UCS4:
            {
                Uint32 *p = (Uint32 *) src;
                if (srclen < 4) {
                    return SDL_ICONV_EINVAL;
                }
                ch = *p;
                src += 4;
                srclen -= 4;
            }
            break;
        }

        /* Encode a character */
        switch (cd->dst_fmt) {
        case ENCODING_ASCII:
            {
                Uint8 *p = (Uint8 *) dst;
                if (dstlen < 1) {
                    return SDL_ICONV_E2BIG;
                }
                if (ch > 0x7F) {
                    *p = UNKNOWN_ASCII;
                } else {
                    *p = (Uint8) ch;
                }
                ++dst;
                --dstlen;
            }
            break;
        case ENCODING_LATIN1:
            {
                Uint8 *p = (Uint8 *) dst;
                if (dstlen < 1) {
                    return SDL_ICONV_E2BIG;
                }
                if (ch > 0xFF) {
                    *p = UNKNOWN_ASCII;
                } else {
                    *p = (Uint8) ch;
                }
                ++dst;
                --dstlen;
            }
            break;
        case ENCODING_UTF8:    /* RFC 3629 */
            {
                Uint8 *p = (Uint8 *) dst;
                if (ch > 0x10FFFF) {
                    ch = UNKNOWN_UNICODE;
                }
                if (ch <= 0x7F) {
                    if (dstlen < 1) {
                        return SDL_ICONV_E2BIG;
                    }
                    *p = (Uint8) ch;
                    ++dst;
                    --dstlen;
                } else if (ch <= 0x7FF) {
                    if (dstlen < 2) {
                        return SDL_ICONV_E2BIG;
                    }
                    p[0] = 0xC0 | (Uint8) ((ch >> 6) & 0x1F);
                    p[1] = 0x80 | (Uint8) (ch & 0x3F);
                    dst += 2;
                    dstlen -= 2;
                } else if (ch <= 0xFFFF) {
                    if (dstlen < 3) {
                        return SDL_ICONV_E2BIG;
                    }
                    p[0] = 0xE0 | (Uint8) ((ch >> 12) & 0x0F);
                    p[1] = 0x80 | (Uint8) ((ch >> 6) & 0x3F);
                    p[2] = 0x80 | (Uint8) (ch & 0x3F);
                    dst += 3;
                    dstlen -= 3;
                } else if (ch <= 0x1FFFFF) {
                    if (dstlen < 4) {
                        return SDL_ICONV_E2BIG;
                    }
                    p[0] = 0xF0 | (Uint8) ((ch >> 18) & 0x07);
                    p[1] = 0x80 | (Uint8) ((ch >> 12) & 0x3F);
                    p[2] = 0x80 | (Uint8) ((ch >> 6) & 0x3F);
                    p[3] = 0x80 | (Uint8) (ch & 0x3F);
                    dst += 4;
                    dstlen -= 4;
                } else if (ch <= 0x3FFFFFF) {
                    if (dstlen < 5) {
                        return SDL_ICONV_E2BIG;
                    }
                    p[0] = 0xF8 | (Uint8) ((ch >> 24) & 0x03);
                    p[1] = 0x80 | (Uint8) ((ch >> 18) & 0x3F);
                    p[2] = 0x80 | (Uint8) ((ch >> 12) & 0x3F);
                    p[3] = 0x80 | (Uint8) ((ch >> 6) & 0x3F);
                    p[4] = 0x80 | (Uint8) (ch & 0x3F);
                    dst += 5;
                    dstlen -= 5;
                } else {
                    if (dstlen < 6) {
                        return SDL_ICONV_E2BIG;
                    }
                    p[0] = 0xFC | (Uint8) ((ch >> 30) & 0x01);
                    p[1] = 0x80 | (Uint8) ((ch >> 24) & 0x3F);
                    p[2] = 0x80 | (Uint8) ((ch >> 18) & 0x3F);
                    p[3] = 0x80 | (Uint8) ((ch >> 12) & 0x3F);
                    p[4] = 0x80 | (Uint8) ((ch >> 6) & 0x3F);
                    p[5] = 0x80 | (Uint8) (ch & 0x3F);
                    dst += 6;
                    dstlen -= 6;
                }
            }
            break;
        case ENCODING_UTF16BE: /* RFC 2781 */
            {
                Uint8 *p = (Uint8 *) dst;
                if (ch > 0x10FFFF) {
                    ch = UNKNOWN_UNICODE;
                }
                if (ch < 0x10000) {
                    if (dstlen < 2) {
                        return SDL_ICONV_E2BIG;
                    }
                    p[0] = (Uint8) (ch >> 8);
                    p[1] = (Uint8) ch;
                    dst += 2;
                    dstlen -= 2;
                } else {
                    Uint16 W1, W2;
                    if (dstlen < 4) {
                        return SDL_ICONV_E2BIG;
                    }
                    ch = ch - 0x10000;
                    W1 = 0xD800 | (Uint16) ((ch >> 10) & 0x3FF);
                    W2 = 0xDC00 | (Uint16) (ch & 0x3FF);
                    p[0] = (Uint8) (W1 >> 8);
                    p[1] = (Uint8) W1;
                    p[2] = (Uint8) (W2 >> 8);
                    p[3] = (Uint8) W2;
                    dst += 4;
                    dstlen -= 4;
                }
            }
            break;
        case ENCODING_UTF16LE: /* RFC 2781 */
            {
                Uint8 *p = (Uint8 *) dst;
                if (ch > 0x10FFFF) {
                    ch = UNKNOWN_UNICODE;
                }
                if (ch < 0x10000) {
                    if (dstlen < 2) {
                        return SDL_ICONV_E2BIG;
                    }
                    p[1] = (Uint8) (ch >> 8);
                    p[0] = (Uint8) ch;
                    dst += 2;
                    dstlen -= 2;
                } else {
                    Uint16 W1, W2;
                    if (dstlen < 4) {
                        return SDL_ICONV_E2BIG;
                    }
                    ch = ch - 0x10000;
                    W1 = 0xD800 | (Uint16) ((ch >> 10) & 0x3FF);
                    W2 = 0xDC00 | (Uint16) (ch & 0x3FF);
                    p[1] = (Uint8) (W1 >> 8);
                    p[0] = (Uint8) W1;
                    p[3] = (Uint8) (W2 >> 8);
                    p[2] = (Uint8) W2;
                    dst += 4;
                    dstlen -= 4;
                }
            }
            break;
        case ENCODING_UTF32BE:
            {
                Uint8 *p = (Uint8 *) dst;
                if (ch > 0x10FFFF) {
                    ch = UNKNOWN_UNICODE;
                }
                if (dstlen < 4) {
                    return SDL_ICONV_E2BIG;
                }
                p[0] = (Uint8) (ch >> 24);
                p[1] = (Uint8) (ch >> 16);
                p[2] = (Uint8) (ch >> 8);
                p[3] = (Uint8) ch;
                dst += 4;
                dstlen -= 4;
            }
            break;
        case ENCODING_UTF32LE:
            {
                Uint8 *p = (Uint8 *) dst;
                if (ch > 0x10FFFF) {
                    ch = UNKNOWN_UNICODE;
                }
                if (dstlen < 4) {
                    return SDL_ICONV_E2BIG;
                }
                p[3] = (Uint8) (ch >> 24);
                p[2] = (Uint8) (ch >> 16);
                p[1] = (Uint8) (ch >> 8);
                p[0] = (Uint8) ch;
                dst += 4;
                dstlen -= 4;
            }
            break;
        case ENCODING_UCS2:
            {
                Uint16 *p = (Uint16 *) dst;
                if (ch > 0xFFFF) {
                    ch = UNKNOWN_UNICODE;
                }
                if (dstlen < 2) {
                    return SDL_ICONV_E2BIG;
                }
                *p = (Uint16) ch;
                dst += 2;
                dstlen -= 2;
            }
            break;
        case ENCODING_UCS4:
            {
                Uint32 *p = (Uint32 *) dst;
                if (ch > 0x7FFFFFFF) {
                    ch = UNKNOWN_UNICODE;
                }
                if (dstlen < 4) {
                    return SDL_ICONV_E2BIG;
                }
                *p = ch;
                dst += 4;
                dstlen -= 4;
            }
            break;
        }

        /* Update state */
        *inbuf = src;
        *inbytesleft = srclen;
        *outbuf = dst;
        *outbytesleft = dstlen;
        ++total;
    }
    return total;
}

int
SDL_iconv_close(SDL_iconv_t cd)
{
    if (cd && cd != (SDL_iconv_t) - 1) {
        SDL_free(cd);
    }
    return 0;
}

#endif /* !HAVE_ICONV */

char *
SDL_iconv_string(const char *tocode, const char *fromcode, char *inbuf,
                 size_t inbytesleft)
{
    SDL_iconv_t cd;
    char *string;
    size_t stringsize;
    char *outbuf;
    size_t outbytesleft;
    size_t retCode = 0;

    cd = SDL_iconv_open(tocode, fromcode);
    if (cd == (SDL_iconv_t) - 1) {
        return NULL;
    }

    stringsize = inbytesleft > 4 ? inbytesleft : 4;
    string = SDL_malloc(stringsize);
    if (!string) {
        SDL_iconv_close(cd);
        return NULL;
    }
    outbuf = string;
    outbytesleft = stringsize;
    SDL_memset(outbuf, 0, 4);

    while (inbytesleft > 0) {
        retCode = SDL_iconv(cd, &inbuf, &inbytesleft, &outbuf, &outbytesleft);
        switch (retCode) {
        case SDL_ICONV_E2BIG:
            {
                char *oldstring = string;
                stringsize *= 2;
                string = SDL_realloc(string, stringsize);
                if (!string) {
                    SDL_iconv_close(cd);
                    return NULL;
                }
                outbuf = string + (outbuf - oldstring);
                outbytesleft = stringsize - (outbuf - string);
                SDL_memset(outbuf, 0, 4);
            }
            break;
        case SDL_ICONV_EILSEQ:
            /* Try skipping some input data - not perfect, but... */
            ++inbuf;
            --inbytesleft;
            break;
        case SDL_ICONV_EINVAL:
        case SDL_ICONV_ERROR:
            /* We can't continue... */
            inbytesleft = 0;
            break;
        }
    }
    SDL_iconv_close(cd);

    return string;
}

/* vi: set ts=4 sw=4 expandtab: */