#define TYPE_CMAC	0x040
#define TYPE_MAC	0x080
#define TYPE_ENCRYPT	0x100
#define TYPE_DECRYPT	0x200
#define TYPE_SIGN	0x400
#define TYPE_VERIFY	0x800

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

/*
 * This structure defines the per-instance state of a encrypt operation.
 */
typedef struct EncryptState {
	int type;		/* Operation type */

	Tcl_Interp *interp;	/* Current interpreter */
	EVP_CIPHER_CTX *ctx;	/* Cipher Context */
	Tcl_Command token;	/* Command token */
} EncryptState;


/*
 *-------------------------------------------------------------------
 *
 * EncryptStateNew --
 *
 *	This function creates a per-instance state data structure
 *
 * Returns:
 *	State structure pointer
 *
 * Side effects:
 *	Creates structure
 *
 *-------------------------------------------------------------------
 */
EncryptState *EncryptStateNew(Tcl_Interp *interp, int type) {
    EncryptState *statePtr = (EncryptState *) ckalloc((unsigned) sizeof(EncryptState));

    if (statePtr != NULL) {
	memset(statePtr, 0, sizeof(EncryptState));
	statePtr->type = type;		/* Operation type */
	statePtr->interp = interp;	/* Current interpreter */
	statePtr->ctx = NULL;		/* Cipher Context */
	statePtr->token = NULL;		/* Command token */
    }
    return statePtr;
}

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

    /* Free context structures */
    if (statePtr->ctx != (EVP_CIPHER_CTX *) NULL) {
	EVP_CIPHER_CTX_free(statePtr->ctx);
    }
    ckfree(statePtr);
}

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

/*
 *-------------------------------------------------------------------
 *
 * EncryptInitialize --

}

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

/*
 *-------------------------------------------------------------------
 *
 * EncryptInstanceObjCmd --
 *
 *	Handler for encrypt/decrypt command instances. Used to update
 *	and finalize data for encrypt/decrypt function.
 *
 * Returns:
 *	TCL_OK or TCL_ERROR
 *
 * Side effects:
 *	Adds data to encrypt/decrypt function
 *
 *-------------------------------------------------------------------
 */
int EncryptInstanceObjCmd(ClientData clientData, Tcl_Interp *interp, int objc, Tcl_Obj *const objv[]) {
    EncryptState *statePtr = (EncryptState *) clientData;
    int fn, data_len = 0, out_len;
    char *data = NULL;
    Tcl_Obj *resultObj;
    unsigned char *outbuf;
    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;
    }

    /* Get function */
    if (Tcl_GetIndexFromObj(interp, objv[1], instance_fns, "function", 0, &fn) != TCL_OK) {
	return TCL_ERROR;
    }

    /* Allocate storage for result. Size should be data size + block size. */
    resultObj = Tcl_NewObj();
    outbuf = Tcl_SetByteArrayLength(resultObj, data_len+EVP_MAX_BLOCK_LENGTH);
    if (resultObj == NULL || outbuf == NULL) {
	Tcl_AppendResult(interp, "Memory allocation error", (char *) NULL);
	Tcl_DecrRefCount(resultObj);
	return TCL_ERROR;
    }

    /* Do function */
    if (fn) {
	/* Get data or return error if none */
	if (objc == 3) {
	    data = Tcl_GetByteArrayFromObj(objv[2], &data_len);
	} else {
	    Tcl_WrongNumArgs(interp, 1, objv, "update data");
	    Tcl_DecrRefCount(resultObj);
	    return TCL_ERROR;
	}

	/* Update function */
	if (EncryptUpdate(interp, statePtr->type, statePtr->ctx, outbuf, &out_len, data, data_len) == TCL_OK) {
	    outbuf = Tcl_SetByteArrayLength(resultObj, out_len);
	    Tcl_SetObjResult(interp, resultObj);
	} else {
	    Tcl_DecrRefCount(resultObj);
	    return TCL_ERROR;
	}

    } else {
	/* Finalize function */
	if (EncryptFinalize(interp, statePtr->type, statePtr->ctx, outbuf, &out_len) == TCL_OK) {
	    outbuf = Tcl_SetByteArrayLength(resultObj, out_len);
	    Tcl_SetObjResult(interp, resultObj);
	} else {
	    Tcl_DecrRefCount(resultObj);
	    return TCL_ERROR;
	}

	/* Clean-up */
	Tcl_DeleteCommandFromToken(interp, statePtr->token);
    }
    return TCL_OK;
}

/*
 *-------------------------------------------------------------------
 *
 * EncryptCommandDeleteHandler --
 *
 *	 Callback to clean-up when encrypt/decrypt command is deleted.
 *
 * Returns:
 *	Nothing
 *
 * Side effects:
 *	Destroys state info structure
 *
 *-------------------------------------------------------------------
 */
void EncryptCommandDeleteHandler(ClientData clientData) {
    EncryptState *statePtr = (EncryptState *) clientData;

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

/*
 *-------------------------------------------------------------------
 *
 * EncryptCommandHandler --
 *
 *	 Create command to add data to encrypt/decrypt function.
 *
 * Returns:
 *	TCL_OK or TCL_ERROR
 *
 * Side effects:
 *	Creates command or error message
 *
 *-------------------------------------------------------------------
 */
int EncryptCommandHandler(Tcl_Interp *interp, int type, Tcl_Obj *cmdObj,
	Tcl_Obj *cipherObj, Tcl_Obj *digestObj, Tcl_Obj *keyObj, Tcl_Obj *ivObj) {
    EncryptState *statePtr;
    char *cmdName = Tcl_GetStringFromObj(cmdObj, NULL);

    dprintf("Called");

    if ((statePtr = EncryptStateNew(interp, type)) == NULL) {
	Tcl_AppendResult(interp, "Memory allocation error", (char *) NULL);
	return TCL_ERROR;
    }

    /* Initialize function */
    if (EncryptInitialize(interp, type, &statePtr->ctx, cipherObj, keyObj, ivObj) != TCL_OK) {
	EncryptStateFree(statePtr);
	return TCL_ERROR;
    }

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

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

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

/*
 *-------------------------------------------------------------------
 *
 * EncryptDataHandler --
 *
 *	Perform encryption function on a block of data and return result.
 *
 * Returns:
 *	TCL_OK or TCL_ERROR
 *

    if (dataObj != NULL) {
	data = Tcl_GetByteArrayFromObj(dataObj, &data_len);
    } else {
	Tcl_AppendResult(interp, "No data", NULL);
	return TCL_ERROR;
    }

    /* Allocate storage for result. Size should be data size + block size. */
    resultObj = Tcl_NewObj();
    outbuf = Tcl_SetByteArrayLength(resultObj, data_len+EVP_MAX_BLOCK_LENGTH);
    if (resultObj == NULL || outbuf == NULL) {
	Tcl_AppendResult(interp, "Memory allocation error", (char *) NULL);
	return TCL_ERROR;
    }

    /* Perform operation */
    if (EncryptInitialize(interp, type, &ctx, cipherObj, keyObj, ivObj) != TCL_OK ||

 */
int EncryptFileHandler(Tcl_Interp *interp, int type, Tcl_Obj *inFileObj, Tcl_Obj *outFileObj,
	Tcl_Obj *cipherObj, Tcl_Obj *digestObj, Tcl_Obj *keyObj, Tcl_Obj *ivObj) {
    EVP_CIPHER_CTX *ctx = NULL;
    int total = 0, res, out_len = 0, len;
    Tcl_Channel in = NULL, out = NULL;
    unsigned char in_buf[BUFFER_SIZE];
    unsigned char out_buf[BUFFER_SIZE+EVP_MAX_BLOCK_LENGTH];

    dprintf("Called");

    /* Open input file */
    if ((in = Tcl_FSOpenFileChannel(interp, inFileObj, "rb", 0444)) == (Tcl_Channel) NULL) {
	return TCL_ERROR;
    }

    dprintf("Called");

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

    /* Validate arg count */
    if (objc < 3 || objc > 12) {
	Tcl_WrongNumArgs(interp, 1, objv, "-cipher name ?-digest name? -key key ?-iv string? [-command cmdName | -infile filename -outfile filename | -data data]");
	return TCL_ERROR;
    }

    /* Get options */
    for (int idx = 1; idx < objc; idx++) {
	opt = Tcl_GetStringFromObj(objv[idx], NULL);

	if (opt[0] != '-') {
	    break;
	}

	OPTOBJ("-cipher", cipherObj);
	OPTOBJ("-command", cmdObj);
	OPTOBJ("-data", dataObj);
	OPTOBJ("-digest", digestObj);
	OPTOBJ("-infile", inFileObj);
	OPTOBJ("-outfile", outFileObj);
	OPTOBJ("-key", keyObj);
	OPTOBJ("-iv", ivObj);

	OPTBAD("option", "-cipher, -command, -data, -digest, -infile, -key, -iv, -outfile");
	return TCL_ERROR;
    }

    /* Check for required options */
    if (cipherObj == NULL) {
	Tcl_AppendResult(interp, "No cipher", NULL);
    } else if (keyObj == NULL) {
	Tcl_AppendResult(interp, "No key", NULL);
	return TCL_ERROR;
    }

    /* Perform encryption function on file, stacked channel, using instance command, or data blob */
    if (inFileObj != NULL && outFileObj != NULL) {
	res = EncryptFileHandler(interp, type, inFileObj, outFileObj, cipherObj, digestObj, keyObj, ivObj);
    } else if (cmdObj != NULL) {
	res = EncryptCommandHandler(interp, type, cmdObj, cipherObj, digestObj, keyObj, ivObj);
    } else if (dataObj != NULL) {
	res = EncryptDataHandler(interp, type, dataObj, cipherObj, digestObj, keyObj, ivObj);
    } else {
	Tcl_AppendResult(interp, "No operation specified: Use -command, -data, -infile, or -outfile option", NULL);
	res = TCL_ERROR;
    }
    return res;
}

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