encoding.c

xml开源解析代码.版本为libxml2-2.6.29,可支持GB3212.网络消息发送XML时很有用.

    xmlNewCharEncodingHandler("UTF-8", UTF8ToUTF8, UTF8ToUTF8);
#ifdef LIBXML_OUTPUT_ENABLED
    xmlUTF16LEHandler = 
          xmlNewCharEncodingHandler("UTF-16LE", UTF16LEToUTF8, UTF8ToUTF16LE);
    xmlUTF16BEHandler = 
          xmlNewCharEncodingHandler("UTF-16BE", UTF16BEToUTF8, UTF8ToUTF16BE);
    xmlNewCharEncodingHandler("UTF-16", UTF16LEToUTF8, UTF8ToUTF16);
    xmlNewCharEncodingHandler("ISO-8859-1", isolat1ToUTF8, UTF8Toisolat1);
    xmlNewCharEncodingHandler("ASCII", asciiToUTF8, UTF8Toascii);
    xmlNewCharEncodingHandler("US-ASCII", asciiToUTF8, UTF8Toascii);
#ifdef LIBXML_HTML_ENABLED
    xmlNewCharEncodingHandler("HTML", NULL, UTF8ToHtml);
#endif
#else
    xmlUTF16LEHandler = 
          xmlNewCharEncodingHandler("UTF-16LE", UTF16LEToUTF8, NULL);
    xmlUTF16BEHandler = 
          xmlNewCharEncodingHandler("UTF-16BE", UTF16BEToUTF8, NULL);
    xmlNewCharEncodingHandler("UTF-16", UTF16LEToUTF8, NULL);
    xmlNewCharEncodingHandler("ISO-8859-1", isolat1ToUTF8, NULL);
    xmlNewCharEncodingHandler("ASCII", asciiToUTF8, NULL);
    xmlNewCharEncodingHandler("US-ASCII", asciiToUTF8, NULL);
#endif /* LIBXML_OUTPUT_ENABLED */
#ifndef LIBXML_ICONV_ENABLED
#ifdef LIBXML_ISO8859X_ENABLED
    xmlRegisterCharEncodingHandlersISO8859x ();
#endif
#endif

}

/**
 * xmlCleanupCharEncodingHandlers:
 *
 * Cleanup the memory allocated for the char encoding support, it
 * unregisters all the encoding handlers and the aliases.
 */
void
xmlCleanupCharEncodingHandlers(void) {
    xmlCleanupEncodingAliases();

    if (handlers == NULL) return;

    for (;nbCharEncodingHandler > 0;) {
        nbCharEncodingHandler--;
	if (handlers[nbCharEncodingHandler] != NULL) {
	    if (handlers[nbCharEncodingHandler]->name != NULL)
		xmlFree(handlers[nbCharEncodingHandler]->name);
	    xmlFree(handlers[nbCharEncodingHandler]);
	}
    }
    xmlFree(handlers);
    handlers = NULL;
    nbCharEncodingHandler = 0;
    xmlDefaultCharEncodingHandler = NULL;
}

/**
 * xmlRegisterCharEncodingHandler:
 * @handler:  the xmlCharEncodingHandlerPtr handler block
 *
 * Register the char encoding handler, surprising, isn't it ?
 */
void
xmlRegisterCharEncodingHandler(xmlCharEncodingHandlerPtr handler) {
    if (handlers == NULL) xmlInitCharEncodingHandlers();
    if (handler == NULL) {
        xmlEncodingErr(XML_I18N_NO_HANDLER,
		"xmlRegisterCharEncodingHandler: NULL handler !\n", NULL);
	return;
    }

    if (nbCharEncodingHandler >= MAX_ENCODING_HANDLERS) {
        xmlEncodingErr(XML_I18N_EXCESS_HANDLER,
	"xmlRegisterCharEncodingHandler: Too many handler registered, see %s\n",
	               "MAX_ENCODING_HANDLERS");
	return;
    }
    handlers[nbCharEncodingHandler++] = handler;
}

/**
 * xmlGetCharEncodingHandler:
 * @enc:  an xmlCharEncoding value.
 *
 * Search in the registered set the handler able to read/write that encoding.
 *
 * Returns the handler or NULL if not found
 */
xmlCharEncodingHandlerPtr
xmlGetCharEncodingHandler(xmlCharEncoding enc) {
    xmlCharEncodingHandlerPtr handler;

    if (handlers == NULL) xmlInitCharEncodingHandlers();
    switch (enc) {
        case XML_CHAR_ENCODING_ERROR:
	    return(NULL);
        case XML_CHAR_ENCODING_NONE:
	    return(NULL);
        case XML_CHAR_ENCODING_UTF8:
	    return(NULL);
        case XML_CHAR_ENCODING_UTF16LE:
	    return(xmlUTF16LEHandler);
        case XML_CHAR_ENCODING_UTF16BE:
	    return(xmlUTF16BEHandler);
        case XML_CHAR_ENCODING_EBCDIC:
            handler = xmlFindCharEncodingHandler("EBCDIC");
            if (handler != NULL) return(handler);
            handler = xmlFindCharEncodingHandler("ebcdic");
            if (handler != NULL) return(handler);
	    break;
        case XML_CHAR_ENCODING_UCS4BE:
            handler = xmlFindCharEncodingHandler("ISO-10646-UCS-4");
            if (handler != NULL) return(handler);
            handler = xmlFindCharEncodingHandler("UCS-4");
            if (handler != NULL) return(handler);
            handler = xmlFindCharEncodingHandler("UCS4");
            if (handler != NULL) return(handler);
	    break;
        case XML_CHAR_ENCODING_UCS4LE:
            handler = xmlFindCharEncodingHandler("ISO-10646-UCS-4");
            if (handler != NULL) return(handler);
            handler = xmlFindCharEncodingHandler("UCS-4");
            if (handler != NULL) return(handler);
            handler = xmlFindCharEncodingHandler("UCS4");
            if (handler != NULL) return(handler);
	    break;
        case XML_CHAR_ENCODING_UCS4_2143:
	    break;
        case XML_CHAR_ENCODING_UCS4_3412:
	    break;
        case XML_CHAR_ENCODING_UCS2:
            handler = xmlFindCharEncodingHandler("ISO-10646-UCS-2");
            if (handler != NULL) return(handler);
            handler = xmlFindCharEncodingHandler("UCS-2");
            if (handler != NULL) return(handler);
            handler = xmlFindCharEncodingHandler("UCS2");
            if (handler != NULL) return(handler);
	    break;

	    /*
	     * We used to keep ISO Latin encodings native in the
	     * generated data. This led to so many problems that
	     * this has been removed. One can still change this
	     * back by registering no-ops encoders for those
	     */
        case XML_CHAR_ENCODING_8859_1:
	    handler = xmlFindCharEncodingHandler("ISO-8859-1");
	    if (handler != NULL) return(handler);
	    break;
        case XML_CHAR_ENCODING_8859_2:
	    handler = xmlFindCharEncodingHandler("ISO-8859-2");
	    if (handler != NULL) return(handler);
	    break;
        case XML_CHAR_ENCODING_8859_3:
	    handler = xmlFindCharEncodingHandler("ISO-8859-3");
	    if (handler != NULL) return(handler);
	    break;
        case XML_CHAR_ENCODING_8859_4:
	    handler = xmlFindCharEncodingHandler("ISO-8859-4");
	    if (handler != NULL) return(handler);
	    break;
        case XML_CHAR_ENCODING_8859_5:
	    handler = xmlFindCharEncodingHandler("ISO-8859-5");
	    if (handler != NULL) return(handler);
	    break;
        case XML_CHAR_ENCODING_8859_6:
	    handler = xmlFindCharEncodingHandler("ISO-8859-6");
	    if (handler != NULL) return(handler);
	    break;
        case XML_CHAR_ENCODING_8859_7:
	    handler = xmlFindCharEncodingHandler("ISO-8859-7");
	    if (handler != NULL) return(handler);
	    break;
        case XML_CHAR_ENCODING_8859_8:
	    handler = xmlFindCharEncodingHandler("ISO-8859-8");
	    if (handler != NULL) return(handler);
	    break;
        case XML_CHAR_ENCODING_8859_9:
	    handler = xmlFindCharEncodingHandler("ISO-8859-9");
	    if (handler != NULL) return(handler);
	    break;


        case XML_CHAR_ENCODING_2022_JP:
            handler = xmlFindCharEncodingHandler("ISO-2022-JP");
            if (handler != NULL) return(handler);
	    break;
        case XML_CHAR_ENCODING_SHIFT_JIS:
            handler = xmlFindCharEncodingHandler("SHIFT-JIS");
            if (handler != NULL) return(handler);
            handler = xmlFindCharEncodingHandler("SHIFT_JIS");
            if (handler != NULL) return(handler);
            handler = xmlFindCharEncodingHandler("Shift_JIS");
            if (handler != NULL) return(handler);
	    break;
        case XML_CHAR_ENCODING_EUC_JP:
            handler = xmlFindCharEncodingHandler("EUC-JP");
            if (handler != NULL) return(handler);
	    break;
	default: 
	    break;
    }
    
#ifdef DEBUG_ENCODING
    xmlGenericError(xmlGenericErrorContext,
	    "No handler found for encoding %d\n", enc);
#endif
    return(NULL);
}

/**
 * xmlFindCharEncodingHandler:
 * @name:  a string describing the char encoding.
 *
 * Search in the registered set the handler able to read/write that encoding.
 *
 * Returns the handler or NULL if not found
 */
xmlCharEncodingHandlerPtr
xmlFindCharEncodingHandler(const char *name) {
    const char *nalias;
    const char *norig;
    xmlCharEncoding alias;
#ifdef LIBXML_ICONV_ENABLED
    xmlCharEncodingHandlerPtr enc;
    iconv_t icv_in, icv_out;
#endif /* LIBXML_ICONV_ENABLED */
    char upper[100];
    int i;

    if (handlers == NULL) xmlInitCharEncodingHandlers();
    if (name == NULL) return(xmlDefaultCharEncodingHandler);
    if (name[0] == 0) return(xmlDefaultCharEncodingHandler);

    /*
     * Do the alias resolution
     */
    norig = name;
    nalias = xmlGetEncodingAlias(name);
    if (nalias != NULL)
	name = nalias;

    /*
     * Check first for directly registered encoding names
     */
    for (i = 0;i < 99;i++) {
        upper[i] = toupper(name[i]);
	if (upper[i] == 0) break;
    }
    upper[i] = 0;

    for (i = 0;i < nbCharEncodingHandler; i++)
        if (!strcmp(upper, handlers[i]->name)) {
#ifdef DEBUG_ENCODING
            xmlGenericError(xmlGenericErrorContext,
		    "Found registered handler for encoding %s\n", name);
#endif
	    return(handlers[i]);
	}

#ifdef LIBXML_ICONV_ENABLED
    /* check whether iconv can handle this */
    icv_in = iconv_open("UTF-8", name);
    icv_out = iconv_open(name, "UTF-8");
    if (icv_in == (iconv_t) -1) {
        icv_in = iconv_open("UTF-8", upper);
    }
    if (icv_out == (iconv_t) -1) {
	icv_out = iconv_open(upper, "UTF-8");
    }
    if ((icv_in != (iconv_t) -1) && (icv_out != (iconv_t) -1)) {
	    enc = (xmlCharEncodingHandlerPtr)
	          xmlMalloc(sizeof(xmlCharEncodingHandler));
	    if (enc == NULL) {
	        iconv_close(icv_in);
	        iconv_close(icv_out);
		return(NULL);
	    }
	    enc->name = xmlMemStrdup(name);
	    enc->input = NULL;
	    enc->output = NULL;
	    enc->iconv_in = icv_in;
	    enc->iconv_out = icv_out;
#ifdef DEBUG_ENCODING
            xmlGenericError(xmlGenericErrorContext,
		    "Found iconv handler for encoding %s\n", name);
#endif
	    return enc;
    } else if ((icv_in != (iconv_t) -1) || icv_out != (iconv_t) -1) {
	    xmlEncodingErr(XML_ERR_INTERNAL_ERROR,
		    "iconv : problems with filters for '%s'\n", name);
    }
#endif /* LIBXML_ICONV_ENABLED */

#ifdef DEBUG_ENCODING
    xmlGenericError(xmlGenericErrorContext,
	    "No handler found for encoding %s\n", name);
#endif

    /*
     * Fallback using the canonical names
     */
    alias = xmlParseCharEncoding(norig);
    if (alias != XML_CHAR_ENCODING_ERROR) {
        const char* canon;
        canon = xmlGetCharEncodingName(alias);
        if ((canon != NULL) && (strcmp(name, canon))) {
	    return(xmlFindCharEncodingHandler(canon));
        }
    }

    /* If "none of the above", give up */
    return(NULL);
}

/************************************************************************
 *									*
 *		ICONV based generic conversion functions		*
 *									*
 ************************************************************************/

#ifdef LIBXML_ICONV_ENABLED
/**
 * xmlIconvWrapper:
 * @cd:		iconv converter data structure
 * @out:  a pointer to an array of bytes to store the result
 * @outlen:  the length of @out
 * @in:  a pointer to an array of ISO Latin 1 chars
 * @inlen:  the length of @in
 *
 * Returns 0 if success, or 
 *     -1 by lack of space, or
 *     -2 if the transcoding fails (for *in is not valid utf8 string or
 *        the result of transformation can't fit into the encoding we want), or
 *     -3 if there the last byte can't form a single output char.
 *     
 * The value of @inlen after return is the number of octets consumed
 *     as the return value is positive, else unpredictable.
 * The value of @outlen after return is the number of ocetes consumed.
 */
static int
xmlIconvWrapper(iconv_t cd, unsigned char *out, int *outlen,
                const unsigned char *in, int *inlen) {
    size_t icv_inlen, icv_outlen;
    const char *icv_in = (const char *) in;
    char *icv_out = (char *) out;
    int ret;

    if ((out == NULL) || (outlen == NULL) || (inlen == NULL) || (in == NULL)) {
        if (outlen != NULL) *outlen = 0;
        return(-1);
    }
    icv_inlen = *inlen;
    icv_outlen = *outlen;
    ret = iconv(cd, (char **) &icv_in, &icv_inlen, &icv_out, &icv_outlen);
    *inlen -= icv_inlen;
    *outlen -= icv_outlen;
    if ((icv_inlen != 0) || (ret == -1)) {
#ifdef EILSEQ
        if (errno == EILSEQ) {
            return -2;
        } else
#endif
#ifdef E2BIG
        if (errno == E2BIG) {
            return -1;
        } else
#endif
#ifdef EINVAL
        if (errno == EINVAL) {
            return -3;
        } else
#endif
        {
            return -3;
        }
    }
    return 0;
}
#endif /* LIBXML_ICONV_ENABLED */

/************************************************************************
 *									*
 *		The real API used by libxml for on-the-fly conversion	*
 *									*
 ************************************************************************/

/**
 * xmlCharEncFirstLine:
 * @handler:	char enconding transformation data structure
 * @out:  an xmlBuffer for the output.
 * @in:  an xmlBuffer for the input
 *     
 * Front-end for the encoding handler input function, but handle only
 * the very first line, i.e. limit itself to 45 chars.
 *     
 * Returns the number of byte written if success, or 
 *     -1 general error
 *     -2 if the transcoding fails (for *in is not valid utf8 string or
 *        the result of transformation can't fit into the encoding we want), or
 */
int
xmlCharEncFirstLine(xmlCharEncodingHandler *handler, xmlBufferPtr out,
                 xmlBufferPtr in) {
    int ret = -2;
    int written;
    int toconv;

    if (handler == NULL) return(-1);
    if (out == NULL) return(-1);
    if (in == NULL) return(-1);

    /* calculate space available */
    written = out->size - out->use;
    toconv = in->use;
    /*
     * echo '<?xml version="1.0" encoding="UCS4"?>' | wc -c => 38
     * 45 chars should be sufficient to reach the end of the encoding
     * declaration without going too far inside the document content.
     */
    if (toconv > 45)
	toconv  = 45;
    if (toconv * 2 >= written) {
        xmlBufferGrow(out, toconv);
	written = out->size - out->use - 1;
    }

    if (handler->input != NULL) {
	ret = handler->input(&out->content[out->use], &written,
	                     in->content, &toconv);
	xmlBufferShrink(in, toconv);
	out->use += written;
	out->content[out->use] = 0;
    }
#ifdef LIBXML_ICONV_ENABLED
    else if (handler->iconv_in != NULL) {
	ret = xmlIconvWrapper(handler->iconv_in, &out->content[out->use],
	                      &written, in->content, &toconv);
	xmlBufferShrink(in, toconv);
	out->use += written;
	out->content[out->use] = 0;
	if (ret == -1) ret = -3;
    }
#endif /* LIBXML_ICONV_ENABLED */
#ifdef DEBUG_ENCODING
    switch (ret) {
        case 0:
	    xmlGenericError(xmlGenericErrorContext,
		    "converted %d bytes to %d bytes of input\n",