Function decoder_update

lib_acl_cpp/src/mime/rfc2047.cpp:319–351

	  || ((x) != NULL && (y) != NULL && !strcasecmp((x), (y))))

static bool decoder_update(rfc2047_entry* entry,
	const char* fromCharset, const char* toCharset,
	acl::mime_code* pDecoder, acl::charset_conv* pConv,
	string* out, string* buf1, string* buf2)
{
	buf1->clear();
	pDecoder->decode_update(entry->pData->c_str(),
			(int) entry->pData->length(), buf1);
	if (buf1->empty()) {
		return true;
	}

	// ���Դ�ַ�����Ŀ���ַ�����ͬ�򲻽����ַ���ת��

	if (EQ(fromCharset, toCharset) || pConv == NULL) {
		out->append(buf1->c_str(), buf1->length());
		return true;
	}

	// �����ַ���ת��

	buf2->clear();

	if (!pConv->update_begin(fromCharset, toCharset)) {
		out->append(buf1->c_str(), buf1->length());
	} else if (!pConv->update(buf1->c_str(), buf1->length(), buf2)) {
		out->append(buf1->c_str(), buf1->length());
	} else if (buf2->length() > 0) {
		out->append(buf2->c_str(), buf2->length());
	}

	return true;
}

static bool decoder_finish(acl::mime_code* pDecoder, acl::charset_conv* pConv,
	string* out, string* buf1, string* buf2)