*
 *-------------------------------------------------------------------
 */
int DigestInitialize(Tcl_Interp *interp, DigestState *statePtr, const EVP_MD *md,
	const EVP_CIPHER *cipher, Tcl_Obj *keyObj, EVP_MAC *mac) {
    int key_len = 0, res = 0;
    const unsigned char *key = NULL;

    dprintf("Called");

    /* Create contexts */
    switch(statePtr->format & 0xFF0) {
    case TYPE_MD:
	statePtr->ctx = EVP_MD_CTX_new();
	res = (statePtr->ctx != NULL);
	break;

 *-------------------------------------------------------------------
 *
 * DigestUpdate --
 *
 *	Update a hash function with data
 *
 * Returns:
 *	1 if successful or 0 for failure
 *	TCL_OK if successful or TCL_ERROR for failure with result set
 *	to error message if do_result is true.
 *
 * Side effects:
 *	Adds buf data to hash function or sets result to error message
 *
 *-------------------------------------------------------------------
 */
int DigestUpdate(DigestState *statePtr, char *buf, size_t read, int do_result) {
    int res = 0;

    dprintf("Called");

    switch(statePtr->format & 0xFF0) {
    case TYPE_MD:
        res = EVP_DigestUpdate(statePtr->ctx, buf, read);
	break;
    case TYPE_HMAC:
        res = HMAC_Update(statePtr->hctx, buf, read);
	break;
    case TYPE_CMAC:
        res = CMAC_Update(statePtr->cctx, buf, read);
	break;
    }

    if (!res && do_result) {
	Tcl_AppendResult(statePtr->interp, "Update failed: ", REASON(), NULL);
	return TCL_ERROR;
    }
    return res;
    return TCL_OK;
}

/*
 *-------------------------------------------------------------------
 *
 * DigestFinalize --
 *

 *
 *-------------------------------------------------------------------
 */
int DigestFinalize(Tcl_Interp *interp, DigestState *statePtr, Tcl_Obj **resultObj) {
    unsigned char md_buf[EVP_MAX_MD_SIZE];
    unsigned int ulen;
    int res = 0, md_len = 0;

    dprintf("Called");

    /* Finalize cryptography function and get result */
    switch(statePtr->format & 0xFF0) {
    case TYPE_MD:
	if (!(statePtr->format & IS_XOF)) {
	    res = EVP_DigestFinal_ex(statePtr->ctx, md_buf, &ulen);
	    md_len = (int) ulen;

    /* Get bytes from underlying channel */
    parent = Tcl_GetStackedChannel(statePtr->self);
    read = Tcl_ReadRaw(parent, buf, toRead);

    /* Update hash function */
    if (read > 0) {
	/* Have data */
	if (!DigestUpdate(statePtr, buf, (size_t) read, 0)) {
	if (DigestUpdate(statePtr, buf, (size_t) read, 0) != TCL_OK) {
	    Tcl_SetChannelError(statePtr->self, Tcl_ObjPrintf("Update failed: %s", REASON()));
	    *errorCodePtr = EINVAL;
	    return 0;
	}
	/* This is correct */
	read = -1;
	*errorCodePtr = EAGAIN;

    /* Abort if nothing to process */
    if (toWrite <= 0 || statePtr->self == (Tcl_Channel) NULL) {
	return 0;
    }

    /* Update hash function */
    if (toWrite > 0 && !DigestUpdate(statePtr, buf, (size_t) toWrite, 0)) {
    if (toWrite > 0 && DigestUpdate(statePtr, buf, (size_t) toWrite, 0) != TCL_OK) {
	Tcl_SetChannelError(statePtr->self, Tcl_ObjPrintf("Update failed: %s", REASON()));
	*errorCodePtr = EINVAL;
	return 0;
    }
    return toWrite;
}

 *	TCL_OK or TCL_ERROR
 *
 * Side effects:
 *	Adds transform to channel and sets result to channel id or error message.
 *
 *----------------------------------------------------------------------
 */
static int
DigestChannelHandler(Tcl_Interp *interp, const char *channel, const EVP_MD *md,
static int DigestChannelHandler(Tcl_Interp *interp, const char *channel, const EVP_MD *md,
	const EVP_CIPHER *cipher, int format, Tcl_Obj *keyObj, EVP_MAC *mac) {
    int mode; /* OR-ed combination of TCL_READABLE and TCL_WRITABLE */
    Tcl_Channel chan;
    DigestState *statePtr;

    dprintf("Called");

    /* Validate args */
    if (channel == (const char *) NULL) {
	return TCL_ERROR;
    }

    /* Get channel Id */

 *	TCL_OK or TCL_ERROR
 *
 * Side effects:
 *	Removes transform from channel or sets result to error message.
 *
 *----------------------------------------------------------------------
 */
static int
DigestUnstackObjCmd(ClientData clientData, Tcl_Interp *interp, int objc, Tcl_Obj *const objv[]) {
static int DigestUnstackObjCmd(ClientData clientData, Tcl_Interp *interp, int objc, Tcl_Obj *const objv[]) {
    Tcl_Channel chan;
    int mode; /* OR-ed combination of TCL_READABLE and TCL_WRITABLE  */

    dprintf("Called");

    /* Validate arg count */
    if (objc != 2) {
	Tcl_WrongNumArgs(interp, 1, objv, "channelId");
	return TCL_ERROR;
    }

 *-------------------------------------------------------------------
 */
int DigestInstanceObjCmd(ClientData clientData, Tcl_Interp *interp, int objc, Tcl_Obj *const objv[]) {
    DigestState *statePtr = (DigestState *) clientData;
    int fn, len = 0;
    char *buf = NULL;
    static const char *instance_fns [] = { "finalize", "update", NULL };

    dprintf("Called");

    /* Validate arg count */
    if (objc < 2 || objc > 3) {
	Tcl_WrongNumArgs(interp, 1, objv, "function ?data?");
	return TCL_ERROR;
    }

	    buf = Tcl_GetByteArrayFromObj(objv[2], &len);
	} else {
	    Tcl_WrongNumArgs(interp, 1, objv, "update data");
	    return TCL_ERROR;
	}

	/* Update hash function */
	if (!DigestUpdate(statePtr, buf, (size_t) len, 1)) {
	if (DigestUpdate(statePtr, buf, (size_t) len, 1) != TCL_OK) {
	    return TCL_ERROR;
	}

    } else {
	/* Finalize hash function and calculate message digest */
	if (DigestFinalize(interp, statePtr, NULL) != TCL_OK) {
	    return TCL_ERROR;

 *
 *-------------------------------------------------------------------
 */
int DigestCommandHandler(Tcl_Interp *interp, Tcl_Obj *cmdObj, const EVP_MD *md,
	const EVP_CIPHER *cipher, int format, Tcl_Obj *keyObj, EVP_MAC *mac) {
    DigestState *statePtr;
    char *cmdName = Tcl_GetStringFromObj(cmdObj, NULL);

    dprintf("Called");

    /* Create state data structure */
    if ((statePtr = DigestStateNew(interp, format)) == NULL) {
	Tcl_AppendResult(interp, "Memory allocation error", (char *) NULL);
	return TCL_ERROR;
    }

 *	TCL_OK or TCL_ERROR
 *
 * Side effects:
 *	Sets result to message digest or error message
 *
 *-------------------------------------------------------------------
 */
int
DigestDataHandler(Tcl_Interp *interp, Tcl_Obj *dataObj, const EVP_MD *md,
int DigestDataHandler(Tcl_Interp *interp, Tcl_Obj *dataObj, const EVP_MD *md,
	const EVP_CIPHER *cipher, int format, Tcl_Obj *keyObj, EVP_MAC *mac) {
    char *data;
    int data_len;
    DigestState *statePtr;

    dprintf("Called");

    /* Get data */
    data = Tcl_GetByteArrayFromObj(dataObj, &data_len);
    if (data == NULL) {
	Tcl_SetResult(interp, "No data", NULL);
	return TCL_ERROR;
    }

    /* Create state data structure */
    if ((statePtr = DigestStateNew(interp, format)) == NULL) {
	Tcl_AppendResult(interp, "Memory allocation error", (char *) NULL);
	return TCL_ERROR;
    }

    /* Calc Digest, abort for error */
    if (DigestInitialize(interp, statePtr, md, cipher, keyObj, mac) != TCL_OK ||
	DigestUpdate(statePtr, data, (size_t) data_len, 1) == 0 ||
	DigestUpdate(statePtr, data, (size_t) data_len, 1) != TCL_OK ||
	DigestFinalize(interp, statePtr, NULL) != TCL_OK) {
	DigestStateFree(statePtr);
	return TCL_ERROR;
    }

    /* Clean-up */
    DigestStateFree(statePtr);

 *	TCL_OK or TCL_ERROR
 *
 * Side effects:
 *	Result is message digest or error message
 *
 *-------------------------------------------------------------------
 */
int DigestFileHandler(Tcl_Interp *interp, Tcl_Obj *filename, const EVP_MD *md,
int DigestFileHandler(Tcl_Interp *interp, Tcl_Obj *inFileObj, const EVP_MD *md,
	const EVP_CIPHER *cipher, int format, Tcl_Obj *keyObj, EVP_MAC *mac) {
    DigestState *statePtr;
    Tcl_Channel chan = NULL;
    unsigned char buf[BUFFER_SIZE];
    int res = TCL_OK, len;

    dprintf("Called");

    /* Create state data structure */
    if ((statePtr = DigestStateNew(interp, format)) == NULL) {
	Tcl_AppendResult(interp, "Memory allocation error", (char *) NULL);
	return TCL_ERROR;
    }

    /* Open file channel, abort for error */
    chan = Tcl_FSOpenFileChannel(interp, filename, "rb", 0444);
    chan = Tcl_FSOpenFileChannel(interp, inFileObj, "rb", 0444);
    if (chan == (Tcl_Channel) NULL) {
	DigestStateFree(statePtr);
	return TCL_ERROR;
    }

    /* Configure channel */
    if ((res = Tcl_SetChannelOption(interp, chan, "-translation", "binary")) == TCL_ERROR) {
    if ((res = Tcl_SetChannelOption(interp, chan, "-translation", "binary")) != TCL_OK) {
	goto done;
    }
    Tcl_SetChannelBufferSize(chan, BUFFER_SIZE);

    /* Initialize hash function */
    if ((res = DigestInitialize(interp, statePtr, md, cipher, keyObj, mac)) != TCL_OK) {
	goto done;
    }

    /* Read file data and update hash function */
    while (!Tcl_Eof(chan)) {
	len = Tcl_ReadRaw(chan, (char *) buf, BUFFER_SIZE);
	if (len > 0) {
	    if (!DigestUpdate(statePtr, &buf[0], (size_t) len, 1)) {
	    if (DigestUpdate(statePtr, &buf[0], (size_t) len, 1) != TCL_OK) {
		res = TCL_ERROR;
		goto done;
	    }
	}
    }

    /* Finalize hash function and calculate message digest */

    int idx, start = 1, format = HEX_FORMAT, res = TCL_OK;
    Tcl_Obj *cipherObj = NULL, *cmdObj = NULL, *dataObj = NULL, *digestObj = NULL;
    Tcl_Obj *fileObj = NULL, *keyObj = NULL, *macObj = NULL;
    const char *channel = NULL, *opt;
    const EVP_MD *md = NULL;
    const EVP_CIPHER *cipher = NULL;
    EVP_MAC *mac = NULL;

    dprintf("Called");

    /* Clear interp result */
    Tcl_ResetResult(interp);

    /* Validate arg count */
    if (objc < 3 || objc > 12) {
	Tcl_WrongNumArgs(interp, 1, objv, "?-bin|-hex? ?-cipher name? ?-digest name? ?-key key? ?-mac name? [-channel chan | -command cmdName | -file filename | ?-data? data]");