*/
int DigestInitialize(Tcl_Interp *interp, DigestState *statePtr, Tcl_Obj *digestObj,
	Tcl_Obj *cipherObj, Tcl_Obj *keyObj, Tcl_Obj *macObj) {
    int res = 0, type = statePtr->format & 0xFF0;
    const EVP_MD *md = NULL;
    const EVP_CIPHER *cipher = NULL;
    const void *key = NULL, *iv = NULL, *salt = NULL;
    Tcl_Size key_len = 0;
    (void *) macObj;

    dprintf("Called");

    /* Get digest */
    md = Util_GetDigest(interp, digestObj, type != TYPE_CMAC);
    if (md == NULL && type != TYPE_CMAC) {

    case TYPE_CMAC:
	statePtr->cctx = CMAC_CTX_new();
	res = (statePtr->cctx != NULL);
	break;
    }

    if (!res) {
	Tcl_AppendResult(interp, "Create context failed", (char *) NULL);
	return TCL_ERROR;
    }

    /* Initialize cryptography function */
    switch(type) {
    case TYPE_MD:
	res = EVP_DigestInit_ex(statePtr->ctx, md, NULL);
	break;
    case TYPE_HMAC:
	res = HMAC_Init_ex(statePtr->hctx, key, (int) key_len, md, NULL);
	break;
    case TYPE_CMAC:
	res = CMAC_Init(statePtr->cctx, key, (int) key_len, cipher, NULL);
	break;
    }

    if (!res) {
	Tcl_AppendResult(interp, "Initialize failed: ", REASON(), (char *) NULL);
	return TCL_ERROR;
    }
    return TCL_OK;
}

/*
 *-------------------------------------------------------------------

 *	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, Tcl_Size read, int do_result) {
    int res = 0;

    dprintf("Called");

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

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

/*
 *-------------------------------------------------------------------

	res = CMAC_Final(statePtr->cctx, md_buf, &size);
	md_len = (int) size;
	break;
    }

    if (!res) {
	if (resultObj == NULL) {
	    Tcl_AppendResult(interp, "Finalize failed: ", REASON(), (char *) NULL);
	}
	return TCL_ERROR;
    }

    /* Return message digest as either a binary or hex string */
    if (statePtr->format & BIN_FORMAT) {
	if (resultObj == NULL) {
	    Tcl_SetObjResult(interp, Tcl_NewByteArrayObj(md_buf, (Tcl_Size) md_len));
	} else {
	    *resultObj = Tcl_NewByteArrayObj(md_buf, (Tcl_Size) md_len);
	    Tcl_IncrRefCount(*resultObj);
	}

    } else {
	Tcl_Obj *newObj = Tcl_NewObj();
	unsigned char *ptr = Tcl_SetByteArrayLength(newObj, (Tcl_Size) md_len*2);

	for (int i = 0; i < md_len; i++) {
	    *ptr++ = hex[(md_buf[i] >> 4) & 0x0F];
	    *ptr++ = hex[md_buf[i] & 0x0F];
	}

	if (resultObj == NULL) {

	statePtr->timer = (Tcl_TimerToken) NULL;
    }

    /* Output message digest if not already done */
    if (!(statePtr->flags & CHAN_EOF)) {
	Tcl_Channel parent = Tcl_GetStackedChannel(statePtr->self);
	Tcl_Obj *resultObj;
	Tcl_Size written, toWrite;

	if (DigestFinalize(statePtr->interp, statePtr, &resultObj) == TCL_OK) {
	    unsigned char *data = Tcl_GetByteArrayFromObj(resultObj, &toWrite);
	    written = Tcl_WriteRaw(parent, data, toWrite);
	    Tcl_DecrRefCount(resultObj);
	}
	statePtr->flags |= CHAN_EOF;
    }

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

 *	Read data from transform and write to buf
 *
 *----------------------------------------------------------------------
 */
int DigestInputProc(ClientData clientData, char *buf, int toRead, int *errorCodePtr) {
    DigestState *statePtr = (DigestState *) clientData;
    Tcl_Channel parent;
    Tcl_Size read;
    *errorCodePtr = 0;

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

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

    /* Update hash function */
    if (read > 0) {
	/* Have data */
	if (DigestUpdate(statePtr, buf, 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;

    } else if (read < 0) {
	/* Error */
	*errorCodePtr = Tcl_GetErrno();

    } else if (!(statePtr->flags & CHAN_EOF)) {
	/* EOF */
	Tcl_Obj *resultObj;
	if (DigestFinalize(statePtr->interp, statePtr, &resultObj) == TCL_OK) {
	    unsigned char *data = Tcl_GetByteArrayFromObj(resultObj, &read);
	    memcpy(buf, data, (int) read);
	    Tcl_DecrRefCount(resultObj);

	} else {
	    Tcl_SetChannelError(statePtr->self, Tcl_ObjPrintf("Finalize failed: %s", REASON()));
	    *errorCodePtr = EINVAL;
	    read = 0;
	}
	statePtr->flags |= CHAN_EOF;
    }
    return (int) read;
}

/*
 *----------------------------------------------------------------------
 *
 * DigestOutputProc --
 *

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

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

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

    /* Get channel */
    chan = Tcl_GetChannel(interp, Tcl_GetStringFromObj(objv[1], (Tcl_Size *) NULL), &mode);
    if (chan == (Tcl_Channel) NULL) {
	return TCL_ERROR;
    }

    /* Make sure to operate on the topmost channel */
    chan = Tcl_GetTopChannel(chan);

 * Side effects:
 *	Adds data to hash or returns message digest
 *
 *-------------------------------------------------------------------
 */
int DigestInstanceObjCmd(ClientData clientData, Tcl_Interp *interp, int objc, Tcl_Obj *const objv[]) {
    DigestState *statePtr = (DigestState *) clientData;
    int fn;
    Tcl_Size data_len = 0;
    char *data = NULL;
    static const char *instance_fns [] = { "finalize", "update", NULL };

    dprintf("Called");

    /* Validate arg count */
    if (objc < 2 || objc > 3) {

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

	/* Update hash function */
	if (DigestUpdate(statePtr, data, data_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;

 *	Creates command or error message
 *
 *-------------------------------------------------------------------
 */
int DigestCommandHandler(Tcl_Interp *interp, Tcl_Obj *cmdObj, Tcl_Obj *digestObj,
	Tcl_Obj *cipherObj, int format, Tcl_Obj *keyObj, Tcl_Obj *macObj) {
    DigestState *statePtr;
    char *cmdName = Tcl_GetStringFromObj(cmdObj, (Tcl_Size *) NULL);

    dprintf("Called");

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

 *	Sets result to message digest or error message
 *
 *-------------------------------------------------------------------
 */
int DigestDataHandler(Tcl_Interp *interp, Tcl_Obj *dataObj, Tcl_Obj *digestObj,
	Tcl_Obj *cipherObj, int format, Tcl_Obj *keyObj, Tcl_Obj *macObj) {
    char *data;
    Tcl_Size 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 */
    if (DigestInitialize(interp, statePtr, digestObj, cipherObj, keyObj, macObj) != TCL_OK ||
	DigestUpdate(statePtr, data, data_len, 1) != TCL_OK ||
	DigestFinalize(interp, statePtr, NULL) != TCL_OK) {
	DigestStateFree(statePtr);
	return TCL_ERROR;
    }

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

 *-------------------------------------------------------------------
 */
int DigestFileHandler(Tcl_Interp *interp, Tcl_Obj *inFileObj, Tcl_Obj *digestObj,
	Tcl_Obj *cipherObj, int format, Tcl_Obj *keyObj, Tcl_Obj *macObj) {
    DigestState *statePtr;
    Tcl_Channel chan = NULL;
    unsigned char buf[BUFFER_SIZE];
    int res = TCL_OK;

    dprintf("Called");

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

    /* Initialize hash function */
    if ((res = DigestInitialize(interp, statePtr, digestObj, cipherObj, keyObj, macObj)) != TCL_OK) {
	goto done;
    }

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

    /* Finalize hash function and calculate message digest */
    res = DigestFinalize(interp, statePtr, NULL);

 *
 * Side effects:
 *	Sets result to message digest or error message
 *
 *-------------------------------------------------------------------
 */
static int DigestMain(int type, Tcl_Interp *interp, int objc, Tcl_Obj *const objv[]) {
    int start = 1, format = HEX_FORMAT, res = TCL_OK;
    Tcl_Size fn;
    Tcl_Obj *cipherObj = NULL, *cmdObj = NULL, *dataObj = NULL, *digestObj = NULL;
    Tcl_Obj *fileObj = NULL, *keyObj = NULL, *macObj = NULL;
    const char *channel = NULL, *opt;

    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]");
	return TCL_ERROR;
    }

    /* Special case of first arg is digest, cipher, or mac */
    opt = Tcl_GetStringFromObj(objv[start], (Tcl_Size *) NULL);
    if (opt[0] != '-') {
	switch(type) {
	case TYPE_MD:
	case TYPE_HMAC:
	    digestObj = objv[start++];
	    break;
	case TYPE_CMAC:
	    cipherObj = objv[start++];
	    break;
	case TYPE_MAC:
	    macObj = objv[start++];
	    break;
	}
    }

    /* Get options */
    for (int idx = start; idx < objc; idx++) {
	/* Special case for when last arg is data */
	if (idx == objc - 1) {
	    opt = Tcl_GetStringFromObj(objv[idx], (Tcl_Size *) NULL);
	    if (opt[0] != '-' && dataObj == NULL) {
		dataObj = objv[idx];
		break;
	    }
	}

	/* Get option */

	} else if (keyObj != NULL) {
	    type = TYPE_HMAC;
	}
    }

    if (type == TYPE_MAC) {
	if (macObj != NULL) {
	    char *macName = Tcl_GetStringFromObj(macObj, (Tcl_Size *) NULL);
	    if (strcmp(macName,"cmac") == 0) {
		type = TYPE_CMAC;
	    } else if (strcmp(macName,"hmac") == 0) {
		type = TYPE_HMAC;
	    } else {
		Tcl_AppendResult(interp, "invalid MAC \"", macName, "\"", (char *) NULL);
		return TCL_ERROR;
	    }
	} else {
	    Tcl_AppendResult(interp, "no MAC", (char *) NULL);
	    return TCL_ERROR;
	}
    }

    /* Calc digest on file, stacked channel, using instance command, or data blob */
    if (fileObj != NULL) {
	res = DigestFileHandler(interp, fileObj, digestObj, cipherObj, format | type, keyObj, macObj);
    } else if (channel != NULL) {
	res = DigestChannelHandler(interp, channel, digestObj, cipherObj, format | type, keyObj, macObj);
    } else if (cmdObj != NULL) {
	res = DigestCommandHandler(interp, cmdObj, digestObj, cipherObj, format | type, keyObj, macObj);
    } else if (dataObj != NULL) {
	res = DigestDataHandler(interp, dataObj, digestObj, cipherObj, format | type, keyObj, macObj);
    } else {
	Tcl_AppendResult(interp, "No operation: Use -channel, -command, -data, or -file option", (char *) NULL);
	res = TCL_ERROR;
    }
    return res;
}

/*
 *-------------------------------------------------------------------