CMAC_CTX *cctx;		/* CMAC Context */
	Tcl_Command token;	/* Command token */
} DigestState;

/*
 *-------------------------------------------------------------------
 *
 * DigestStateNew --
 *
 *	This function creates a per-instance state data structure
 *
 * Returns:
 *	Digest structure pointer
 *
 * Side effects:
 *	Creates structure
 *
 *-------------------------------------------------------------------
 */
DigestState *DigestStateNew(Tcl_Interp *interp, int format) {
    DigestState *statePtr;

    statePtr = (DigestState *) ckalloc((unsigned) sizeof(DigestState));
    if (statePtr != NULL) {
	memset(statePtr, 0, sizeof(DigestState));
	statePtr->self	= NULL;		/* This socket channel */
	statePtr->timer = NULL;		/* Timer to flush data */

    }
    return statePtr;
}

/*
 *-------------------------------------------------------------------
 *
 * DigestStateFree --
 *
 *	This function deletes a digest state structure
 *
 * Returns:
 *	Nothing
 *
 * Side effects:
 *	Removes structure
 *
 *-------------------------------------------------------------------
 */
void DigestStateFree(DigestState *statePtr) {
    if (statePtr == (DigestState *) NULL) {
	return;
    }

    /* Remove pending timer */
    if (statePtr->timer != (Tcl_TimerToken) NULL) {
	Tcl_DeleteTimerHandler(statePtr->timer);

}

/*******************************************************************/

/*
 *-------------------------------------------------------------------
 *
 * DigestInitialize --
 *
 *	Initialize a hash function
 *
 * Returns:
 *	TCL_OK if successful or TCL_ERROR for failure with result set
 *	to error message.
 *
 * Side effects:
 *	No result or error message
 *
 *-------------------------------------------------------------------
 */
int DigestInitialize(Tcl_Interp *interp, DigestState *statePtr, const EVP_MD *md,
	const EVP_CIPHER *cipher, Tcl_Obj *keyObj) {
    int key_len = 0, res = 0;
    const unsigned char *key = NULL;

    /* Create message digest context */
    if (statePtr->format & TYPE_MD) {
	statePtr->ctx = EVP_MD_CTX_new();

    }
    return TCL_OK;
}

/*
 *-------------------------------------------------------------------
 *
 * DigestUpdate --
 *
 *	Update a hash function with data
 *
 * Returns:
 *	1 if successful or 0 for failure
 *
 * 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;

    if (statePtr->format & TYPE_MD) {
	res = EVP_DigestUpdate(statePtr->ctx, buf, read);
    } else if (statePtr->format & TYPE_HMAC) {
	res = HMAC_Update(statePtr->hctx, buf, read);
    } else if (statePtr->format & TYPE_CMAC) {
	res = CMAC_Update(statePtr->cctx, buf, read);
    }
    if (!res && do_result) {
	Tcl_AppendResult(statePtr->interp, "Update failed: ", REASON(), NULL);
	return TCL_ERROR;
    }
    return res;
}

/*
 *-------------------------------------------------------------------
 *
 * DigestFinalize --
 *
 *	Finalize a hash function and return the message digest
 *
 * Returns:
 *	TCL_OK if successful or TCL_ERROR for failure with result set
 *	to error message.
 *
 * Side effects:
 *	Sets result to message digest or an error message.
 *
 *-------------------------------------------------------------------
 */
int DigestFinalize(Tcl_Interp *interp, DigestState *statePtr, Tcl_Obj **resultObj) {
    unsigned char md_buf[EVP_MAX_MD_SIZE];
    unsigned int md_len;
    int res = 0;

    /* Finalize hash function and calculate message digest */
    if (statePtr->format & TYPE_MD) {
	if (!(statePtr->format & IS_XOF)) {

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

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

    /* Clean-up */
    DigestStateFree(statePtr);
    return 0;
}

/*
 * Same as DigestCloseProc but with individual read and write close control
 */
static int DigestClose2Proc(ClientData instanceData, Tcl_Interp *interp, int flags) {

    /* 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)) {
	    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, read);
	    Tcl_DecrRefCount(resultObj);

	} else {
	    Tcl_SetChannelError(statePtr->self, Tcl_ObjPrintf("Finalize failed: %s", REASON()));
	    *errorCodePtr = EINVAL;

    /* 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)) {
	Tcl_SetChannelError(statePtr->self, Tcl_ObjPrintf("Update failed: %s", REASON()));
	*errorCodePtr = EINVAL;
	return 0;
    }
    return toWrite;
}

    NULL,			/* Thread action */
    NULL			/* Truncate */
};

/*
 *----------------------------------------------------------------------
 *
 * DigestChannelHandler --
 *
 *	Create a stacked channel for a message digest transformation.
 *
 * Returns:
 *	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,
	const EVP_CIPHER *cipher, int format, Tcl_Obj *keyObj) {
    int mode; /* OR-ed combination of TCL_READABLE and TCL_WRITABLE */
    Tcl_Channel chan;
    DigestState *statePtr;

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

    /* Get channel Id */
    chan = Tcl_GetChannel(interp, channel, &mode);
    if (chan == (Tcl_Channel) NULL) {
	return TCL_ERROR;
    }

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

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

    /* Initialize hash function */
    if (DigestInitialize(interp, statePtr, md, cipher, keyObj) != TCL_OK) {
	return TCL_ERROR;
    }

    /* Configure channel */
    Tcl_SetChannelOption(interp, chan, "-translation", "binary");
    if (Tcl_GetChannelBufferSize(chan) < EVP_MAX_MD_SIZE * 2) {
	Tcl_SetChannelBufferSize(chan, EVP_MAX_MD_SIZE * 2);
    }

    /* Stack channel, abort for error */
    statePtr->self = Tcl_StackChannel(interp, &digestChannelType, (ClientData) statePtr, mode, chan);
    if (statePtr->self == (Tcl_Channel) NULL) {
	DigestStateFree(statePtr);
	return TCL_ERROR;
    }

    /* Set result to channel Id */
    Tcl_SetResult(interp, (char *) Tcl_GetChannelName(chan), TCL_VOLATILE);
    return TCL_OK;
}

 *
 * 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[]) {
    Tcl_Channel chan;
    int mode; /* OR-ed combination of TCL_READABLE and TCL_WRITABLE  */

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

/*******************************************************************/

static const char *instance_fns [] = { "finalize", "update", NULL };

/*
 *-------------------------------------------------------------------
 *
 * DigestInstanceObjCmd --
 *
 *	Handler for digest command instances. Used to add data to hash
 *	function or retrieve message digest.
 *
 * Returns:
 *	TCL_OK or TCL_ERROR
 *
 * 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, len = 0;
    char *buf = NULL;

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

	    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)) {
	    return TCL_ERROR;
	}

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

	Tcl_DeleteCommandFromToken(interp, statePtr->token);
    }
    return TCL_OK;
}

/*
 *-------------------------------------------------------------------
 *
 * DigestCommandDeleteHandler --
 *
 *	 Callback to clean-up when digest instance command is deleted.
 *
 * Returns:
 *	Nothing
 *
 * Side effects:
 *	Destroys state info structure
 *
 *-------------------------------------------------------------------
 */
void DigestCommandDeleteHandler(ClientData clientData) {
    DigestState *statePtr = (DigestState *) clientData;

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

/*
 *-------------------------------------------------------------------
 *
 * DigestCommandHandler --
 *
 *	 Create command to allow user to add data to hash function.
 *
 * Returns:
 *	TCL_OK or TCL_ERROR
 *
 * Side effects:
 *	Creates command or error message
 *
 *-------------------------------------------------------------------
 */
int DigestCommandHandler(Tcl_Interp *interp, Tcl_Obj *cmdObj, const EVP_MD *md,
	const EVP_CIPHER *cipher, int format, Tcl_Obj *keyObj) {
    DigestState *statePtr;
    char *cmdName = Tcl_GetStringFromObj(cmdObj, NULL);

    /* 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 (DigestInitialize(interp, statePtr, md, cipher, keyObj) != TCL_OK) {
	return TCL_ERROR;
    }

    /* Create instance command */
    statePtr->token = Tcl_CreateObjCommand(interp, cmdName, DigestInstanceObjCmd,
	(ClientData) statePtr, DigestCommandDeleteHandler);

    /* Return command name */
    Tcl_SetObjResult(interp, cmdObj);
    return TCL_OK;
}


/*******************************************************************/

/*
 *-------------------------------------------------------------------
 *
 * DigestDataHandler --
 *
 *	Return message digest for data using user specified hash function.
 *
 * Returns:
 *	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,
	const EVP_CIPHER *cipher, int format, Tcl_Obj *keyObj) {
    char *data;
    int data_len;
    DigestState *statePtr;

    /* Get data */
    data = Tcl_GetByteArrayFromObj(dataObj, &data_len);
    if (data == NULL || data_len == 0) {
	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) != TCL_OK ||
	DigestUpdate(statePtr, data, (size_t) data_len, 1) == 0 ||
	DigestFinalize(interp, statePtr, NULL) != TCL_OK) {
	DigestStateFree(statePtr);
	return TCL_ERROR;
    }

    /* Clean-up */
    DigestStateFree(statePtr);
    return TCL_OK;
}

/*******************************************************************/

/*
 *-------------------------------------------------------------------
 *
 * DigestFileHandler --
 *
 *	Return message digest for file using user specified hash function.
 *
 * Returns:
 *	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,
	const EVP_CIPHER *cipher, int format, Tcl_Obj *keyObj) {
    DigestState *statePtr;
    Tcl_Channel chan = NULL;
    unsigned char buf[BUFFER_SIZE];
    int res = TCL_OK, len;

    /* 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);
    if (chan == (Tcl_Channel) NULL) {
	DigestStateFree(statePtr);
	return TCL_ERROR;
    }

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

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

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

done:
    /* Close channel */
    if (Tcl_Close(interp, chan) == TCL_ERROR) {
	res = TCL_ERROR;
    }

    /* Clean-up */
    DigestStateFree(statePtr);
    return res;
}

/*******************************************************************/

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

	return TCL_ERROR;
    }

    /* Optimal case for a digest and blob of data */
    if (objc == 3 && type == TYPE_MD) {
	digestName = Tcl_GetStringFromObj(objv[1],NULL);
	if ((md = EVP_get_digestbyname(digestName)) != NULL) {
	    return DigestDataHandler(interp, objv[2], md, NULL, HEX_FORMAT | TYPE_MD, NULL);
	} else {
	    Tcl_AppendResult(interp, "Invalid digest \"", digestName, "\"", NULL);
	    return TCL_ERROR;
	}
    }

    /* Get options */

    } else if (type != TYPE_MD) {
	Tcl_AppendResult(interp, "No key specified", NULL);
	return TCL_ERROR;
    }

    /* Calc digest on file, stacked channel, using instance command, or data blob */
    if (fileObj != NULL) {
	res = DigestFileHandler(interp, fileObj, md, cipher, format | type, keyObj);
    } else if (channel != NULL) {
	res = DigestChannelHandler(interp, channel, md, cipher, format | type, keyObj);
    } else if (cmdObj != NULL) {
	res = DigestCommandHandler(interp, cmdObj, md, cipher, format | type, keyObj);
    } else if (dataObj != NULL) {
	res = DigestDataHandler(interp, dataObj, md, cipher, format | type, keyObj);
    }
    return res;
}

/*
 *-------------------------------------------------------------------
 *
 * Message Digest and Message Authentication Code Commands --
 *
 *	Return Message Digest (MD) or Message Authentication Code (MAC).
 *
 * Returns:
 *	TCL_OK or TCL_ERROR
 *
 * Side effects:
 *	Sets result to message digest or error message
 *
 *-------------------------------------------------------------------
 */
static int MdObjCmd(ClientData clientData, Tcl_Interp *interp, int objc, Tcl_Obj *const objv[]) {
    return DigestMain(TYPE_MD, interp, objc, objv);
}

static int CMACObjCmd(ClientData clientData, Tcl_Interp *interp, int objc, Tcl_Obj *const objv[]) {
    return DigestMain(TYPE_CMAC, interp, objc, objv);
}

 #define validate_argc(objc, objv) { \
    if (objc != 2) { \
	Tcl_WrongNumArgs(interp, 1, objv, "data"); \
	return TCL_ERROR; \
    } \
}
 
int MD4ObjCmd(ClientData clientData, Tcl_Interp *interp, int objc, Tcl_Obj *const objv[]) {
    validate_argc(objc, objv);
    return DigestDataHandler(interp, objv[1], EVP_md4(), NULL, HEX_FORMAT | TYPE_MD, NULL);
}

int MD5ObjCmd(ClientData clientData, Tcl_Interp *interp, int objc, Tcl_Obj *const objv[]) {
    validate_argc(objc, objv);
    return DigestDataHandler(interp, objv[1], EVP_md5(), NULL, HEX_FORMAT | TYPE_MD, NULL);
}

int SHA1ObjCmd(ClientData clientData, Tcl_Interp *interp, int objc, Tcl_Obj *const objv[]) {
    validate_argc(objc, objv);
    return DigestDataHandler(interp, objv[1], EVP_sha1(), NULL, HEX_FORMAT | TYPE_MD, NULL);
}

int SHA256ObjCmd(ClientData clientData, Tcl_Interp *interp, int objc, Tcl_Obj *const objv[]) {
    validate_argc(objc, objv);
    return DigestDataHandler(interp, objv[1], EVP_sha256(), NULL, HEX_FORMAT | TYPE_MD, NULL);
}

int SHA512ObjCmd(ClientData clientData, Tcl_Interp *interp, int objc, Tcl_Obj *const objv[]) {
    validate_argc(objc, objv);
    return DigestDataHandler(interp, objv[1], EVP_sha512(), NULL, HEX_FORMAT | TYPE_MD, NULL);
}

/*
 *-------------------------------------------------------------------
 *
 * Tls_DigestCommands --
 *
 *	Create digest commands
 *
 * Returns:
 *	TCL_OK or TCL_ERROR
 *
 * Side effects:
 *	Creates commands
 *
 *-------------------------------------------------------------------
 */
int Tls_DigestCommands(Tcl_Interp *interp) {
    Tcl_CreateObjCommand(interp, "tls::digest", MdObjCmd, (ClientData) 0, (Tcl_CmdDeleteProc *) NULL);
    Tcl_CreateObjCommand(interp, "tls::md", MdObjCmd, (ClientData) 0, (Tcl_CmdDeleteProc *) NULL);
    Tcl_CreateObjCommand(interp, "tls::cmac", CMACObjCmd, (ClientData) 0, (Tcl_CmdDeleteProc *) NULL);
    Tcl_CreateObjCommand(interp, "tls::hmac", HMACObjCmd, (ClientData) 0, (Tcl_CmdDeleteProc *) NULL);
    Tcl_CreateObjCommand(interp, "tls::md4", MD4ObjCmd, (ClientData) 0, (Tcl_CmdDeleteProc *) NULL);
    Tcl_CreateObjCommand(interp, "tls::md5", MD5ObjCmd, (ClientData) 0, (Tcl_CmdDeleteProc *) NULL);
    Tcl_CreateObjCommand(interp, "tls::sha1", SHA1ObjCmd, (ClientData) 0, (Tcl_CmdDeleteProc *) NULL);
    Tcl_CreateObjCommand(interp, "tls::sha256", SHA256ObjCmd, (ClientData) 0, (Tcl_CmdDeleteProc *) NULL);
    Tcl_CreateObjCommand(interp, "tls::sha512", SHA512ObjCmd, (ClientData) 0, (Tcl_CmdDeleteProc *) NULL);
    Tcl_CreateObjCommand(interp, "tls::unstack", DigestUnstackObjCmd, (ClientData) 0, (Tcl_CmdDeleteProc *) NULL);
    return TCL_OK;
}