* Side effects:
 *	No result or error message
 *
 *-------------------------------------------------------------------
 */
int Tls_DigestInit(Tcl_Interp *interp, DigestState *statePtr, const EVP_MD *md,
	const EVP_CIPHER *cipher, Tcl_Obj *keyObj) {
    int key_len, res = 0;
    const unsigned char *key;

    /* Create message digest context */
    if (statePtr->format & TYPE_MD) {
	statePtr->ctx = EVP_MD_CTX_new();
	res = (statePtr->ctx != NULL);
    } else if (statePtr->format & TYPE_HMAC) {
	statePtr->hctx = HMAC_CTX_new();
	res = (statePtr->hctx != NULL);
    } else if (statePtr->format & TYPE_CMAC) {
	statePtr->cctx = CMAC_CTX_new();
	res = (statePtr->cctx != NULL);
    }
    if (!res) {
	Tcl_AppendResult(interp, "Create digest context failed: ", REASON(), NULL);
	return TCL_ERROR;
    }

    /* Initialize hash function */
    if (statePtr->format & TYPE_MD) {
	res = EVP_DigestInit_ex(statePtr->ctx, md, NULL);
    } else if (statePtr->format & TYPE_HMAC) {
	key = Tcl_GetByteArrayFromObj(keyObj, &key_len);
	res = HMAC_Init_ex(statePtr->hctx, (const void *) key, key_len, md, NULL);
    } else if (statePtr->format & TYPE_CMAC) {
	key = Tcl_GetByteArrayFromObj(keyObj, &key_len);
	res = CMAC_Init(statePtr->cctx, (const void *) key, key_len, cipher, NULL);
    }
    if (!res) {
	Tcl_AppendResult(interp, "Initialize digest failed: ", REASON(), NULL);
	return TCL_ERROR;
    }
    return TCL_OK;
}

/*
 *-------------------------------------------------------------------
 *
 * Tls_DigestUpdate --
 *
 *	Update a hash function
 *
 * Returns:
 *	1 if successful or 0 for failure
 *
 * Side effects:
 *	Adds buf to hash function
 *
 *-------------------------------------------------------------------
 */
int Tls_DigestUpdate(DigestState *statePtr, char *buf, size_t read) {
    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);




    }
    return res;
}

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

	res = HMAC_Final(statePtr->hctx, md_buf, &md_len);
    } else if (statePtr->format & TYPE_CMAC) {
	size_t len;
	res = CMAC_Final(statePtr->cctx, md_buf, &len);
	md_len = (unsigned int) len;
    }
    if (!res) {
	Tcl_AppendResult(interp, "Finalize digest failed: ", REASON(), NULL);
	return TCL_ERROR;
    }

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

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

    /* Create state data struct */
    if ((statePtr = Tls_DigestNew(interp, format)) == NULL) {

	res = TCL_ERROR;
	goto done;
    }

    /* Initialize hash function */
    if ((res = Tls_DigestInit(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 (!Tls_DigestUpdate(statePtr, &buf[0], (size_t) len)) {
		Tcl_AppendResult(interp, "Update digest failed: ", REASON(), NULL);
		res = TCL_ERROR;
		goto done;
	    }
	}
    }

    /* Finalize hash function and calculate message digest */

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

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

	    res = HMAC_Final(statePtr->hctx, md_buf, &md_len);
	} else if (statePtr->format & TYPE_CMAC) {
	    size_t len;
	    res = CMAC_Final(statePtr->cctx, md_buf, &len);
	    md_len = (unsigned int) len;
	}
	if (!res) {
	    Tcl_SetChannelError(statePtr->self, Tcl_ObjPrintf("Digest finalize failed: %s", REASON()));
	    *errorCodePtr = EINVAL;

	/* Write message digest to output channel as byte array or hex string */
	} else if (md_len > 0) {
	    if ((statePtr->format & BIN_FORMAT) && toRead >= (int) md_len) {
		read = md_len;
		memcpy(buf, md_buf, read);

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

    /* Update hash function */
    if (toWrite > 0 && !Tls_DigestUpdate(statePtr, buf, (size_t) toWrite)) {
	Tcl_SetChannelError(statePtr->self, Tcl_ObjPrintf("Digest update failed: %s", REASON()));
	*errorCodePtr = EINVAL;
	return -1;
    }
    return toWrite;
}

/*

    }

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

    /* Create state data struct */
    if ((statePtr = Tls_DigestNew(interp, format)) == NULL) {
	Tcl_AppendResult(interp, "Initialize digest error: memory allocation failure", (char *) NULL);
	return TCL_ERROR;
    }
    statePtr->self = chan;
    statePtr->mode = mode;

    /* Initialize hash function */
    if (Tls_DigestInit(interp, statePtr, md, cipher, keyObj) != TCL_OK) {

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

	/* Update hash function */
	if (!Tls_DigestUpdate(statePtr, buf, (size_t) len)) {
	    Tcl_SetObjResult(interp, Tcl_ObjPrintf("Digest update failed: %s", REASON()));
	    return TCL_ERROR;
	}

    } else {
	/* Finalize hash function and calculate message digest */
	if (Tls_DigestFinialize(interp, statePtr) != TCL_OK) {
	    Tcl_SetObjResult(interp, Tcl_ObjPrintf("Digest finalize failed: %s", REASON()));
	    return TCL_ERROR;
	}

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

int Tls_DigestInstance(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 struct */
    if ((statePtr = Tls_DigestNew(interp, format)) == NULL) {
	Tcl_AppendResult(interp, "Initialize digest error: memory allocation failure", (char *) NULL);
	return TCL_ERROR;
    }

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

	DigestState *statePtr;

	if ((statePtr = Tls_DigestNew(interp, format)) == NULL) {
	    Tcl_AppendResult(interp, "Memory allocation error", (char *) NULL);
	    return TCL_ERROR;
	}
	if (Tls_DigestInit(interp, statePtr, md, cipher, keyObj) != TCL_OK ||
	    Tls_DigestUpdate(statePtr, data, (size_t) len) == 0 ||
	    Tls_DigestFinialize(interp, statePtr) != TCL_OK) {
	    Tls_DigestFree(statePtr);
	    return TCL_ERROR;
	}
	Tls_DigestFree(statePtr);
	return TCL_OK;
    }

    /* Subject identifies the entity associated with the public key stored in
	the subject public key field. RFC 5280 section 4.1.2.6 */
    len = BIO_to_Buffer(X509_NAME_print_ex(bio, X509_get_subject_name(cert), 0, flags), bio, buffer, BUFSIZ);
    LAPPEND_STR(interp, certPtr, "subject", buffer, len);

    /* SHA1 Digest (Fingerprint) of cert - DER representation */
    if (X509_digest(cert, EVP_sha1(), md, &len)) {
    len = String_to_Hex(md, len, buffer, BUFSIZ);
	LAPPEND_STR(interp, certPtr, "sha1_hash", buffer, len);
    }

    /* SHA256 Digest (Fingerprint) of cert - DER representation */
    if (X509_digest(cert, EVP_sha256(), md, &len)) {
    len = String_to_Hex(md, len, buffer, BUFSIZ);
	LAPPEND_STR(interp, certPtr, "sha256_hash", buffer, len);
    }

    /* Subject Public Key Info specifies the public key and identifies the
	algorithm with which the key is used. RFC 5280 section 4.1.2.7 */
    if (X509_get_signature_info(cert, &mdnid, &pknid, &bits, &xflags)) {
	ASN1_BIT_STRING *key;

    LAPPEND_STR(interp, certPtr, "purpose", Tls_x509Purpose(cert), -1);
    LAPPEND_OBJ(interp, certPtr, "certificatePurpose", Tls_x509Purposes(interp, cert));

    /* Get extensions flags */
    xflags = X509_get_extension_flags(cert);
    LAPPEND_INT(interp, certPtr, "extFlags", xflags);

	/* Check if cert was issued by CA cert issuer or self signed */
    LAPPEND_BOOL(interp, certPtr, "selfIssued", xflags & EXFLAG_SI);
    LAPPEND_BOOL(interp, certPtr, "selfSigned", xflags & EXFLAG_SS);
    LAPPEND_BOOL(interp, certPtr, "isProxyCert", xflags & EXFLAG_PROXY);
    LAPPEND_BOOL(interp, certPtr, "extInvalid", xflags & EXFLAG_INVALID);
    LAPPEND_BOOL(interp, certPtr, "isCACert", X509_check_ca(cert));

    /* The Unique Ids are used to handle the possibility of reuse of subject
	and/or issuer names over time. RFC 5280 section 4.1.2.8 */
    {
	const ASN1_BIT_STRING *iuid, *suid;
        X509_get0_uids(cert, &iuid, &suid);

	Tcl_ListObjAppendElement(interp, certPtr, Tcl_NewStringObj("issuerUniqueId", -1));
	if (iuid != NULL) {
	    Tcl_ListObjAppendElement(interp, certPtr, Tcl_NewByteArrayObj((char *)iuid->data, iuid->length));
	} else {
	    Tcl_ListObjAppendElement(interp, certPtr, Tcl_NewStringObj("", -1));
	}

    LAPPEND_INT(interp, certPtr, "extCount", X509_get_ext_count(cert));
    LAPPEND_OBJ(interp, certPtr, "extensions", Tls_x509Extensions(interp, cert));

    /* Authority Key Identifier (AKI) is the Subject Key Identifier (SKI) of
	its signer (the CA). RFC 5280 section 4.2.1.1, NID_authority_key_identifier */
    LAPPEND_OBJ(interp, certPtr, "authorityKeyIdentifier",
	Tls_x509Identifier(X509_get0_authority_key_id(cert)));

    /* Subject Key Identifier (SKI) is used to identify certificates that contain
	a particular public key. RFC 5280 section 4.2.1.2, NID_subject_key_identifier */
    LAPPEND_OBJ(interp, certPtr, "subjectKeyIdentifier",
	Tls_x509Identifier(X509_get0_subject_key_id(cert)));

    /* Key usage extension defines the purpose (e.g., encipherment, signature, certificate
	signing) of the key in the certificate. RFC 5280 section 4.2.1.3, NID_key_usage */