evolution/libversit

NOTE: If you used the earlier APIs released by Versit

then you will want to look at the document "migrate.doc"

included with this package. It contains a discussion of

the differences between the old API and this one.



----------------------------------------------------------------



The vCard/vCalendar C interface is implemented in the set 

of files as follows:



vcc.y, yacc source, and vcc.c, the yacc output you will use

implements the core parser



vobject.c implements an API that insulates the caller from

the parser and changes in the vCard/vCalendar BNF



port.h defines compilation environment dependent stuff



vcc.h and vobject.h are header files for their .c counterparts



vcaltmp.h and vcaltmp.c implement vCalendar "macro" functions

which you may find useful.



test.c is a standalone test driver that exercises some of

the features of the APIs provided. Invoke test.exe on a

VCARD/VCALENDAR input text file and you will see the pretty

print output of the internal representation (this pretty print

output should give you a good idea of how the internal 

representation looks like -- there is one such output in the 

following too). Also, a file with the .out suffix is generated 

to show that the internal representation can be written back 

in the original text format.



-----------------------------------------------------------------

			

			  

				VObject for VCard/VCalendar



Table of Contents

=================

1. VObject

2. Internal Representations of VCard/VCalendar

3. Iterating Through VObject's Properties or Values

4. Pretty Printing a VObject Tree

5. Building A VObject Representation of A VCard/VCalendar

6. Converting A VObject Representation Into Its Textual Representation

7. Miscellaneous Notes On VObject APIs usages

8. Brief descriptions of each APIs

9. Additional Programming Notes.



This document is mainly about the VObject and its APIs. The main

use of a VObject is to represent a VCard or a VCalendar inside

a program. However, its use is not limited to aforemention as it

can represent an arbitrary information that makes up of a tree or

forest of properties/values.



1. VObject

   =======

A VObject can have a name (id) and a list of associated properties and

a value. Each property is itself a VObject.



2. Internal Representations of VCard/VCalendar

   ===========================================

A list of VCard or a VCalendar is represented by a list of VObjects.

The name (id) of the VObjects in the list is either VCCardProp or

VCCalProp. Each of these VObjects can have a list of properties.

Since a property is represented as a VObject, each of these properties

can have a name, a list of properties, and a value.



For example, the input file "vobject.vcf":

	

BEGIN:VCARD

N:Alden;Roland

FN:Roland H. Alden

ORG:AT&T;Versit Project Office

TITLE:Consultant

EMAIL;WORK;PREF;INTERNET:sf!rincon!ralden@alden.attmail.com

EMAIL;INTERNET:ralden@sfgate.com

EMAIL;MCIMail:242-2200

LABEL;DOM;POSTAL;PARCEL;HOME;WORK;QUOTED-PRINTABLE:Roland H. Alden=0A=

Suite 2208=0A=

One Pine Street=0A=

San Francisco, CA 94111

LABEL;POSTAL;PARCEL;HOME;WORK;QUOTED-PRINTABLE:Roland H. Alden=0A=

Suite 2208=0A=

One Pine Street=0A=

San Francisco, CA 94111=0A=

U.S.A.

TEL;WORK;PREF;MSG:+1 415 296 9106

TEL;WORK;FAX:+1 415 296 9016

TEL;MSG;CELL:+1 415 608 5981

ADR:;Suite 2208;One Pine Street;San Francisco;CA;94111;U.S.A.

SOUND:ROW-LAND H ALL-DIN

LOGO;GIF;BASE64:

    R0lGODdhpgBOAMQAAP///+/v797e3s7Ozr29va2trZycnIyMjHt7e2NjY1JSUkJC

    QjExMSEhIRAQEO///87v9973/73n95zW71K13jGl1nvG50Kt3iGc1gCMzq3e94zO

    7xCU1nO952O15wAAACwAAAAApgBOAAAF/yAgjmRpnmiqrmzrvnAsz3Rt33iu73zv

    /8CgcEj8QTaeywWTyWCUno2kSK0KI5tLc8vtNi+WiHVMlj0mFK96nalsxOW4fPSw

    cNj4tQc+7xcjGh4WExJTJYUTFkp3eU0eEH6RkpOUlTARhRoWm5ydFpCWoS0QEqAu

    ARKaHRcVjV0borEoFl0cSre4Sq67FA+yvwAeTU8XHZ7HmxS6u2wVfMCVpAE3pJoW

    ylrMptDcOqSF4OHg3eQ5pInInb7lcc86mNbLzBXsZbRfUOn6ucyNHvVWJHCpQFDf

    MWwEEzLqx2YCQCqF3OnItClJNmYcJD7cSAKTuI/gtnEcOQKkyVIk6/+ds5CkFcMM

    61LiENikwi1jBnNyuvUSjwWZOS5uIZarqNFcNl32XMMB6I06GgoJ+bZp1ZKeDl8E

    +MC1K1cBIhZ4HUu2LAsCZdOWRQDt20lxIlccSHsgrNq7Xc/ixcsWmNu34WKyYJCW

    gQjCe9XqTZy2L4pv04gg2sSKSc8OLgTcBSuWsdkVaD2TdXyiQxebFyjo1Gnx6tJm

    LuaqrdtZtNfFtruSNmF5IKujwIsmJbjwtRqNJhrcNVw79wcRAgogmE4ArIjQzj/s

    JvHAGCFDQR4UqigPK4sBe62XwO51OwADiMcqUG+iOdcFAL+hW20BfAoEexlwAnu6

    mZDAXQ1EVh//WfhxJB5gIbHgwFgOTOiVAgOuVQKAfKFg3weGwSBYFZMp4hpDGKyA

    3lgJKECWgiMQyBVpW+0V4oJjNfhCNkR1IgWEb21QlRK9GdfFCgeOZYBsXgm4noYj

    GEBhAQHYh0J8XenoQnFGdrkUciJY6FUAK15ogozakcBhliKsyZWHDMZQ0wWC/Aim

    DB6h01KRr/lXQgFxAqDcWDACgCZpUnrVQJtjwTnWjS6MWAYqqfDnSaEkJOlVXQBo

    2pWTMUJ53WgAuPncCR9q6VQMAYjZlXWJmknCoSUM2p4BC+SaKwG88hoZlvfFMM4f

    hQh5TXkv+RklWYtC91mopJIAKFkJlDAW/wF25ShnLbeo5gmQ+1FGkJdrKCuCi2OR

    BuwHBcwqKgABrMtVAgpem61XkLbAJ7n8uiIpvGVhO4KpH1QLbbpqLheZvQCkGoNL

    thSzSTg2UGVBBzbtaxwKsYrmgLvRAlCmWgwMAADD66rKAgR3XlGspcdkZYK8ibU7

    asgEl+XAyB8I7PCqMWiWncGGimpfAgO4ypXSPpOVLwsRCDJxRD2AoyeRRv5kApO5

    fXwzwvfOKLKtaTWtbQxccmGLTZy8xYlVSvXbhbk0M2YzrYfJJ0K8m+V9NgxpyC04

    UycI/aiuiH9Y8NftDUwWp1Wm5UABnAUKwwRsPFGBt4Oc9PZvGvNLwf8JOZt8Arpe

    eY23yDovwIDiBX74NAsPVLDJj3Hh4JEExsKcjrlKf9DsCVx3ZfLqAKBuG1s/A90C

    z2KjYHjjyPOdG1spz6BBUr+BcUxUb1nDCTa/VZD2Uv+YkLPAKJC9dNEh7628WgqI

    ybzlaA+ufxMa6bxC6ciLUQLcx5UGIAAsAkDA6wQkOxrcY39yo4cQMNWCAPTKV1R4

    wPkgaBxzOc8FtMiF1NoGoXBRJjgoPApmPsjCFlbMdzCM4TFy50IXxI2DPcHAv2rY

    gghsEIeu8CAPW6ABIPYEFkOsAeaMyIz0JfGJUExBBGRIRX0IMYovWCIT1eBELNpA

    i1vcgta8iANPCIQOghzQABl30J0tXqBla4wjFLFQxZzAUY42CIAd5OYBCuKxB2c4

    I0b28EcrQKADgmSKB9RYyDhA4BqCxIBqrtjIMTwoFeCjYSU3KZMQAAA7



BEGIN:VCALENDAR

DCREATED:19960523T100522

PRODID:-//Alden Roland/Hand Crafted In North Carolina//NONSGML Made By Hand//EN

VERSION:0.3

BEGIN:VEVENT

START:19960523T120000

END:19960523T130000

SUBTYPE:PHONE CALL

SUMMARY:VERSIT PDI PR Teleconference/Interview

DESCRIPTION:VERSIT PDI PR Teleconference/Interview With Tom Streeter and Alden Roland

END:VEVENT

BEGIN:VEVENT

START:19960523T113000

END:19960523T115500

SUBTYPE:LUNCH

SUMMARY:Eat in the cafeteria today

END:VEVENT

END:VCALENDAR



END:VCARD





will conceptually be be represented as

    vcard

	VCNameProp

	    VCFamilyNameProp=Alden

	    VCGivenNameProp=Roland

	VCFullNameProp=Roland H.Alden

	....

	

note that

    EMAIL;WORK;PREF;INTERNET:sf!rincon!ralden@alden.attmail.com

will be represented as:

	VCEmailAddress=sf!rincon!ralden@alden.attmail.com

	    VCWork

	    VCPreferred

	    VCInternet

where the lower level properties are properties of the property

VCEmailAddress.



Groupings are flattened out in the VObject representation such

that:

	a.b:blah

	a.c:blahblah

are represented as:

	b=blah

	    VCGrouping=a

	c=blahblah

	    VCGrouping=a

i.e. one can read the above as:

	 the property "b" has value "blah" and property "VCGrouping"

		with the value "a".

	 the property "c" has value "blahblah" and property "VCGrouping"

		with the value "a".

likewise, multi-level groupings are flatten similarly. e.g.

	a.b.c:blah

	a.b.e:blahblah

-->

	c=blah

	    VCGrouping=b

		VCGrouping=a

	e=blahblah

	    VCGrouping=b

		VCGrouping=a

which read:

	 the property "c" has value "blah" and property "VCGrouping"

		with the value "b" which has property "VCGrouping"

		with value "a".

	 the property "e" has value "blahblah" and property "VCGrouping"

		with the value "b" which has property "VCGrouping"

		with value "a".



3. Iterating Through VObject's Properties or Values

   ================================================

The following is a skeletal form of iterating through

all properties of a vobject, o:



    // assume the object of interest, o, is of type VObject

    VObjectIterator i;

    initPropIterator(&i,o);

    while (moreIteration(&i)) {

	VObject *each = nextVObject(&i);

	// ... do something with "each" property 

	}



Use the API vObjectName() to access a VObject's name.

Use the API vObjectValueType() to determine if a VObject has

	a value. For VCard/VCalendar application, you

	should not need this function as practically

	all values are either of type VCVT_USTRINGZ or

	VCVT_RAW (i.e set by setVObjectUStringZValue and

	setVObjectAnyValue APIs respectively), and the

	value returned by calls to vObjectUStringZValue

	and vObjectAnyValue are 0 if a VObject has no

	value. (There is a minor exception where VObject with

	VCDataSizeProp has value that is set by

	setVObjectLongValue).

Use the APIs vObject???Value() to access a VObject's value.

	where ??? is the expected type.

Use the APIs setvObject???Value() to set or modify a VObject's value.

	where ??? is the expected type.

Use the API isAPropertyOf() to query if a name match the name of

	a property of a VObject. Since isAPropertyOf() return

	the matching property, we can use that to retrieve

	a property and subsequently the value of the property.



4. Pretty Printing a VObject Tree

   ==============================

VObject tree can be pretty printed with the printVObject() function.

The output of pretty printing a VObject representation of the input

test file "vobject.vcf" is shown below. Note that the indentation

indicates the tree hirerarchy where the immediate children nodes

of a parent node is all at the same indentation level and the

immediate children nodes are the immediate properties of the

associated parent nodes.  In the following, {N,FN,ORG,TITLE,...}

are immediate properties of VCARD. {F and G} are properties of N

with value {"Alden" and "Roland"} respectively; FN has no property

but has the value "Roland H. Alden"; EMAIL has value and

the properties WORK, PREF, and INTERNET.





VCARD

    N

        F="Alden"

        G="Roland"

    FN="Roland H. Alden"

    ORG

        ORGNAME="AT&T"

        OUN="Versit Project Office"

    TITLE="Consultant"

    EMAIL="sf!rincon!ralden@alden.attmail.com"

        WORK

        PREF

        INTERNET

    EMAIL="ralden@sfgate.com"

        INTERNET

    EMAIL="242-2200"

        MCIMail

    LABEL="Roland H. Alden

            Suite 2208

            One Pine Street

            San Francisco, CA 94111"

        DOM

        POSTAL

        PARCEL

        HOME

        WORK

        QP

    LABEL="Roland H. Alden

            Suite 2208

            One Pine Street

            San Francisco, CA 94111

            U.S.A."

        POSTAL

        PARCEL

        HOME

        WORK

        QP

    TEL="+1 415 296 9106"

        WORK

        PREF

        MSG

    TEL="+1 415 296 9016"

        WORK

        FAX

    TEL="+1 415 608 5981"

        MSG

        CELL

    ADR

        EXT ADD="Suite 2208"

        STREET="One Pine Street"

        L="San Francisco"

        R="CA"

        PC="94111"

        C="U.S.A."

    SOUND="ROW-LAND H ALL-DIN"

    LOGO=[raw data]

        GIF

        BASE64

        DataSize=1482

VCALENDAR

    DCREATED="19960523T100522"

    PRODID="-//Alden Roland/Hand Crafted In North Carolina//NONSGML Made By Hand//EN"

    VERSION="0.3"

    VEVENT

        START="19960523T120000"

        END="19960523T130000"

        SUBTYPE="PHONE CALL"

        SUMMARY="VERSIT PDI PR Teleconference/Interview"

        DESCRIPTION="VERSIT PDI PR Teleconference/Interview With Tom Streeter and Alden Roland"

    VEVENT

        START="19960523T113000"

        END="19960523T115500"

        SUBTYPE="LUNCH"

        SUMMARY="Eat in the cafeteria today"



5. Building A VObject Representation of A VCard/VCalendar

   ======================================================

The parser in vcc.y converts an input file with one or more

VCard/VCalendar that is in their textual representation

into their corresponding VObject representation.



VObject representation of a VCard/VCalendar can also be built

directly with calls to the VObject building APIs. e.g.



	VObject *prop;

	VObject *vcard = newVObject(VCCardProp);

	prop = addProp(vcard,VCNameProp);

		addPropValue(prop,VCFamilyNameProp,"Alden");

		addPropValue(prop,VCGivenNameProp,"Roland");

	addPropValue(vcard,VCFullNameProp,"Roland H. Alden");

	....



6. Converting A VObject Representation Into Its Textual Representation

   ===================================================================

The VObject representation can be converted back to its textual

representation via the call to writeVObject() or writeMemVObject()

API. e.g.

   a. to write to a file:

	// assume vcard is of type VObject

	FILE *fp = fopen("alden.vcf","w");

	writeVObject(fp,vcard);

   a. to write to memory, and let the API allocate the required memory.

	char* clipboard = writeVObject(0,0,vcard);

	... do something to clipboard

	free(clipboard);

   b. to write to a user allocated buffer:

	char clipboard[16384];

	int len = 16384;

	char *buf  = writeVObject(clipboard,&len,vcard);

	... buf will be equal to clipboard if the write

	is successful otherwise 0.



In the case of writing to memory, the memory buffer can be either

allocated by the API or the user. If the user allocate the

memory for the buffer, then the length of the buffer needs to be

communicated to the API via a variable. The variable passed as

the length argument will be overwritten with the actual size

of the text output. A 0 return value from writeMemVObject()

indicates an error which could be caused by overflowing the

size of the buffer or lack of heap memory.



7. Miscellaneous Notes On VObject APIs usages

   ==========================================

a. vcc.h -- contains basic interfaces to the parser:

    VObject* Parse_MIME(const char *input, unsigned long len);

    VObject* Parse_MIME_FromFile(FILE *file);

	-- both of this return a null-terminated list of

	   VObject that is either a VCARD or VCALENDAR.

	   To iterate through this list, do

		VObject *t, *v;

		v = Parse_Mime_FromFile(fp);

		while (v) {

		    // ... do something to v.

		    t = v;

		    v = nextVObjectInList(v);

		    cleanVObject(t);

		    }

	    note that call to cleanVObject will release

	    resource used to represent the VObject.



b. vobject.h -- contains basic interfaces to the VObject APIs.

	see the header for more details.

	The structure of VObject is purposely (hiddened) not exposed

	to the user. Every access has to be done via

	the APIs. This way, if we need to change the

	structure or implementation, the client need not

	recompile as long as the interfaces remain the

	same.



c. values of a property is determined by the property definition

	itself. The vobject APIs does not attempt to enforce

	any of such definition. It is the consumer responsibility

	to know what value is expected from a property. e.g

	most properties have unicode string value, so to access

	the value of these type of properties, you will use

	the vObjectUStringZValue() to read the value and

	setVObjectUStringZValue() to set or modify the value.

	Refer to the VCard and VCalendar specifications for

	the definition of each property.



d. properties name (id) are case incensitive.



8. Brief descriptions of each APIs

   ===============================

   * the predefined properties' names (id) are listed under vobject.h

	each is of the form VC*Prop. e.g.

		#define VC7bitProp		"7BIT"

		#define VCAAlarmProp	"AALARM"

		....



   * consumer of a VObject can only define pointers to VObject.



   * a variable of type VObjectIterator, say "i", can be used to iterate

	through a VObject's properties, say "o". The APIs related to

	VObjectIterator are:

		void initPropIterator(VObjectIterator *i, VObject *o);

			-- e.g. usage

				initPropIterator(&i,o);

		int moreIteration(VObjectIterator *i);

			-- e.g. usage

				while (moreIteration(&i)) { ... }

		VObject* nextVObject(VObjectIterator *i);

			-- e.g. usage

				while (moreIteration(&i)) {

				    VObject *each = nextVObject(&i);

				    }



    * VObject can be chained together to form a list. e.g. of such

	use is in the parser where the return value of the parser is

	a link list of VObject. A link list of VObject can be

	built by:

		void addList(VObject **o, VObject *p);

	and iterated by

		VObject* nextVObjectInList(VObject *o);

			-- next VObjectInList return 0 if the list

				is exhausted.



    * the following APIs are mainly used to construct a VObject tree:

	VObject* newVObject(const char *id);

	    -- used extensively internally by VObject APIs but when

		used externally, its use is mainly limited to the

		construction of top level object (e.g. an object

		with VCCardProp or VCCalendarProp id).

	

	void deleteVObject(VObject *p);

	    -- to deallocate single VObject, for most user, use

		cleanVObject(VObject *o) instead for freeing all

		resources associated with the VObject.



	char* dupStr(const char *s, unsigned int size);

	    -- duplicate a string s. If size is 0, the string is

		assume to be a null-terminated. 



	void deleteStr(const char *p);

	    -- used to deallocate a string allocated by dupStr();



	void setVObjectName(VObject *o, const char* id);

	    -- set the id of VObject o. This function is not

		normally used by the user. The setting of id

		is normally done as part of other APIs (e.g.

		addProp()).



	void setVObjectStringZValue(VObject *o, const char *s);

	    -- set a string value of a VObject.



	void setVObjectUStringZValue(VObject *o, const wchar_t *s);

	    -- set a Unicode string value of a VObject.



	void setVObjectIntegerValue(VObject *o, unsigned int i);

	    -- set an integer value of a VObject.



	void setVObjectLongValue(VObject *o, unsigned long l);

	    -- set an long integer value of a VObject.



	void setVObjectAnyValue(VObject *o, void *t);

	    -- set any value of a VObject. The value type is

		unspecified.



	VObject* setValueWithSize(VObject *prop, void *val, unsigned int size);

	    -- set a raw data (stream of bytes) value of a VObject

		whose size is size. The internal VObject representation

		is

			this object = val

			    VCDataSizeProp=size

		i.e. the value val will be attached to the VObject prop

		and a property of VCDataSize whose value is size

		is also added to the object.

		

	void setVObjectVObjectValue(VObject *o, VObject *p);

	    -- set a VObject as the value of another VObject.



	const char* vObjectName(VObject *o);

	    -- retrieve the VObject's Name (i.e. id).



	const char* vObjectStringZValue(VObject *o);

	    -- retrieve the VObject's value interpreted as

		null-terminated string.



	const wchar_t* vObjectUStringZValue(VObject *o);

	    -- retrieve the VObject's value interpreted as

		null-terminated unicode string.



	unsigned int vObjectIntegerValue(VObject *o);

	    -- retrieve the VObject's value interpreted as

		integer.



	unsigned long vObjectLongValue(VObject *o);

	    -- retrieve the VObject's value interpreted as

		long integer.



	void* vObjectAnyValue(VObject *o);

	    -- retrieve the VObject's value interpreted as

		any value.



	VObject* vObjectVObjectValue(VObject *o);

	    -- retrieve the VObject's value interpreted as

		a VObject.



	VObject* addVObjectProp(VObject *o, VObject *p);

	    -- add a VObject p as a property of VObject o.

		(not normally used externally for building a

		VObject).



	VObject* addProp(VObject *o, const char *id);

	    -- add a property whose name is id to VObject o.



	VObject* addPropValue(VObject *o, const char *id, const char *v);

	    -- add a property whose name is id and whose value

		is a null-terminated string to VObject o.



	VObject* addPropSizedValue(VObject *o, const char *id,

			const char *v, unsigned int size);

	    -- add a property whose name is id and whose value

		is a stream of bytes of size size, to VObject o.



	VObject* addGroup(VObject *o, const char *g);

	    -- add a group g to VObject o.

		e.g. if g is a.b.c, you will have

		    o

			c

			   VCGroupingProp=b

			       VCGroupingProp=a

		and the object c is returned.

		

	VObject* isAPropertyOf(VObject *o, const char *id);

	     -- query if a property by the name id is in o and

		return the VObject that represent that property.



	void printVObject(VObject *o);

	     -- pretty print VObject o to stdout (for debugging use).



	void writeVObject(FILE *fp, VObject *o);

	     -- convert VObject o to its textual representation and

		write it to file.



	char* writeMemVObject(char *s, int *len, VObject *o);

	     -- convert VObject o to its textual representation and

		write it to memory. If s is 0, then memory required

		to hold the textual representation will be allocated

		by this API. If a variable len is passed, len will

		be overwriten with the byte size of the textual

		representation. If s is non-zero, then s has to

		be a user allocated buffer whose size has be passed

		in len as a variable. Memory allocated by the API

		has to be freed with call to free. The return value

		of this API is either the user supplied buffer,

		the memory allocated by the API, or 0 (in case of

		failure).



	void cleanStrTbl();

		-- this function has to be called when all

		VObject has been destroyed.



	void cleanVObject(VObject *o);

		-- release all resources used by VObject o.



	wchar_t* fakeUnicode(const char *ps, int *bytes);

		-- convert char* to wchar_t*.



	extern int uStrLen(const wchar_t *u);

		-- length of unicode u.



	char *fakeCString(const wchar_t *u);

		-- convert wchar_t to CString (blindly assumes that

		this could be done).



9. Additional Programming Notes

   ============================

In the following notes, please refers to the listing

of Example.vcf and its VObject Representation

(shown at the end of this section).



* Handling the Return Value of the VCard/VCalendar Parser

    The example input text file contains two root VObjects

    (a VCalendar and a VCard). The output of the VCard/VCalendar

    parser is a null-terminated list of VObjects. For this

    particular input file, the list will have two VObjects.

    The following shows a template for iterating through the

    output of the Parser:



	VObject *t, *v;

	v = Parse_Mime_fromFileName("example.vcf");

	while (v) {

	    // currently, v will either be a VCard or a VCalendar

	    //	do whatever your application need to do to

	    //  v here ...

	    t = v;

	    v = nextVObjectInList(v);

	    cleanVObject(t);

	    }



* Iterating Through a VCard/VCalendar VObject

    From the VObject APIs point of view, a VCard VObject

    is the same as a VCalendar VObject. However, the application

    needs to know what are in a VCard or a VCalendar.

    For example, A VCalendar VObject can have VCDCreatedProp,

    a VCGEOLocationProp, etc, and one or more VCEventProp and

    or VCTodoProp. The VCEventProp and VCTodoProp can have

    many properties of their own, which in turn could have

    more properties (e.g. VCDAlarmProp can be a VCEventProp

    VObject's property, and VCRunTimeProp can be a

    VCDAlarmProp VObject's property. Because a VObject tree

    can be arbitrarily complex, in general, to process all

    properties and values of a VObject tree, a recursive walk

    is desirable. An example recursive VObject tree walk

    can be found in the vobject.c source lines for printVObject*

    and writeVObject* APIs. Depending on what the application need

    to do with a VCard or a VCalendar, a recursive walk

    of the VObject tree may or may not be desirable. An example

    template of a non-recursive walk is shown below:

	

    void processVCardVCalendar(char *inputFile)

    {

	VObject *t, *v;

	v = Parse_Mime_fromFileName(inputFile);

	while (v) {

	    char *n = vObjectName(v);

	    if (strcmp(n,VCCardProp) == 0) {

		do_VCard(v);

		}

	    else if (strcmp(n,VCCalendarProp) == 0) {

		do_VCalendar(v);

		}

	    else {

		// don't know how to handle anything else!

		}

	    t = v;

	    v = nextVObjectInList(v);

	    cleanVObject(t);

	    }

    }



    void  do_VCard(VObject *vcard)

    {

	VObjectIterator t;

	initPropIterator(&t,vcard);

	while (moreIteration(&t)) {

	    VObject *eachProp = nextVObject(&t);

	    //	The primarly purpose of this example is to

	    //  show how to iterate through a VCard VObject,

	    //	it is not meant to be efficient at all.

	    char *n = vObjectName(eachProp);

	    if (strcmp(n,VCNameProp)==0) {

		do_name(eachProp);

		}

	    else if (strcmp(n,VCEmailProp)==0) {

		do_email(eachProp);

		}

	    else if (strcmp(n,VCLabelProp)==0) {

		do_label(eachProp);

		}

	    else if ....

	    }

    }



    void  do_VCalendar(VObject *vcal)

    {

	VObjectIterator t;

	initPropIterator(&t,vcard);

	while (moreIteration(&t)) {

	    VObject *eachProp = nextVObject(&t);

	    //	The primarly purpose of this example is to

	    //  show how to iterate through a VCalendar VObject,

	    //	it is not meant to be efficient at all.

	    char *n = vObjectName(eachProp);

	    if (strcmp(n,VCDCreatedProp)==0) {

		do_DCreated(eachProp);

		}

	    else if (strcmp(n,VCVersionProp)==0) {

		do_Version(eachProp);

		}

	    else if (strcmp(n,VCTodoProp)==0) {

		do_Todo(eachProp);

		}

	    else if (strcmp(n,VCEventProp)==0) {

		do_Event(eachProp);

		}

	    else if ....

	    }

    }



    void do_Todo(VObject *vtodo) { ... }



    void do_Event(VObject *vevent) { ... }



    ...

    

* Property's Values and Properties

    The VObject APIs do not attempt to check for the

    correctness of the values of a property. Nor do they

    will prevent the user from attaching a non-VCard/VCalendar

    standard property to a VCard/VCalendar property. Take

    the example of line [11] of the example, "O.K" is not

    a valid value of VCStatusProp.  It is up to the application

    to accept or reject the value of a property.

    

* Output of printVObject

    PrintVObject pretty prints a VObject tree in human

    readable form. See the listing at the end of the file

    for an example output of printVObject on the example

    input file "Example.vcf".



    Note that binary data are not shown in the output of

    printVObject. Instead, a note is made ([raw data]) to

    indicate that there exists such a binary data.



* Note on Binary Data

    When the value of a property is a binary data, it is only

    useful to know the size of the binary data.



    In the case of the VCard/VCalendar parser, it chooses

    to represent the size information as a separate property

    called VCDataSizeProp whose value is the size of the binary

    data. The APIs sequence to construct the VObject subtree

    of line [44] of Example.vcf is



	    // VObject *vcard;

	    VObject *p1 = addProp(vcard,VCLogoProp);

	    (void) addProp(p1,VCGIFProp);

	    (void) addProp(p1,VCBASE64Prop);

	    VObject *p2 = addProp(p1,VCDataSizeProp);

	    (void) setVObjectLongValue(p2,1482);

	    setVObjectAnyValue(vcard,...pointer to binary data);

	

    Note the presence of VCBase64Prop will cause the

    writeVObject API to output the binary data as BASE64 text.

    For VCard/VCalendar application, having the VCBase64Prop

    property is pratically always neccessary for property with

    binary data as its value.

	

* Note on Quoted-Printable String

    String value with embedded newline are written out as

    quoted-prinatable string. It is therefore important

    to mark a property with a string value that has

    one or more embedded newlines, with the VCQutedPrintableProp

    property. e.g.

			

	// VObject *root;

	char *msg="To be\nor\nnot to be";

	VObject *p = addPropValue(root,VCDescriptionProp,msg);

	    // the following is how you mark a property with

	    //	a property. In this case, the marker is

	    //  VCQuotedPrintableProp

	    addProp(p,VCQuotedPrintableProp);



* Note on Unicode

    Although, the current parser takes ASCII text file only,

    string values are all stored as Unicode in the VObject tree.

    For now, when using the VObject APIs to construct a

    VObject tree, one should always convert ASCII string value

    to a Unicode string value:



	// VObject *root;

	VObject *p = addProp(root,VCSomeProp);

	setVObjectUStringZValue(p,fakeUnicode(someASCIIStringZvalue));



    An API is provided to simplify the above process:



	addPropValue(root,VCSomeProp,someASCIIStringZValue);



    Note that someASCIISTringZValue is automatically converted to

    Unicode by addPropValue API, where as, the former code

    sequence do an explicit call to fakeUnicode.



    To read back the value, one should use the vObjectUStringZValue

    API not vObjectStringZValue API. The value returned by the

    vObjectUStringZValue API is a Unicode string. If the application

    do not know how to handle Unicode string, it can use the

    fakeCString API to convert it back to ASCII string (as long

    as the conversion is meaningful).



    Note that fakeCString return a heap allocated memory. It is

    important to call deleteStr on fakeCString return value if

    it is not longer required (or there will be memory leak).



    NOTE: Unfortunately, at the point when this document is written,

    there is still no consensus on how Unicode is to be handled

    in the textual representation of VCard/VCalendar. So, there

    is no version of writeVObject and the parser to output and

    input Unicode textual representation of VCard/VCalendar.

   



Example.vcf

-----------

line

number Input Text (example.vcf)

------ ----------

1      BEGIN:VCALENDAR

2      DCREATED:19961102T100522

3      GEO:0,0

4      VERSION:1.0

5      BEGIN:VEVENT

6      DTSTART:19961103T000000

7      DTEND:20000101T000000

8      DESCRIPTION;QUOTED-PRINTABLE:To be =0A=

9      or =0A=

10     not to be

11     STATUS:O.K.

12     X-ACTION:No action required

13     DALARM:19961103T114500;5;3;Enjoy

14     MALARM:19970101T120000;;;johny@nowhere.com;Call Mom.

15     END:VEVENT

16

17     BEGIN:VTODO

18     DUE:19960614T0173000

19     DESCRIPTION:Relex.

20     END:VTODO

21

22     END:VCALENDAR

23

24     BEGIN:VCARD

25     N:Alden;Roland

26     FN:Roland H. Alden

27     ORG:AT&T;Versit Project Office

28     TITLE:Consultant

29     EMAIL;WORK;PREF;INTERNET:ralden@ralden.com

30     LABEL;DOM;POSTAL;PARCEL;HOME;WORK;QUOTED-PRINTABLE:Roland H. Alden=0A=

31     Suite 2208=0A=

32     One Pine Street=0A=

33     San Francisco, CA 94111

34     LABEL;POSTAL;PARCEL;HOME;WORK;QUOTED-PRINTABLE:Roland H. Alden=0A=

35     Suite 2208=0A=

36     One Pine Street=0A=

37     San Francisco, CA 94111=0A=

38     U.S.A.

39     TEL;WORK;PREF;MSG:+1 415 296 9106

40     TEL;WORK;FAX:+1 415 296 9016

41     TEL;MSG;CELL:+1 415 608 5981

42     ADR:;Suite 2208;One Pine Street;San Francisco;CA;94111;U.S.A.

43     SOUND:ROW-LAND H ALL-DIN

44     LOGO;GIF;BASE64:

45         R0lGODdhpgBOAMQAAP///+/v797e3s7Ozr29va2trZycnIyMjHt7e2NjY1JSUkJC

    ... 30 lines of BASE64 data not shown here.

76     END:VCARD





VObject Representation of Example.vcf:

-------------------------------------

line

in

text

file  VObject Tree as Printed by printVObject API

----  -------------------------------------------

1     VCALENDAR

2         DCREATED="19961102T100522"

3         GEO="0,0"

4         VERSION="1.0"

5         VEVENT

6             DTSTART="19961103T000000"

7             DTEND="20000101T000000"

8             DESCRIPTION="To be

9                     or

10                    not to be"

8                 QUOTED-PRINTABLE

11            STATUS="O.K."

12            X-ACTION="No action required"

13            DALARM

13                RUNTIME="19961103T114500"

13                SNOOZETIME="5"

13                REPEATCOUNT="3"

13                DISPLAYSTRING="Enjoy"

14            MALARM

14                RUNTIME="19970101T120000"

14                EMAIL="johny@nowhere.com"

14                NOTE="Call Mom"

17        VTODO

18            DUE="19960614T0173000"

19            DESCRIPTION="Relex."

24    VCARD

25        N

25            F="Alden"

25            G="Roland"

26        FN="Roland H. Alden"

27        ORG

27            ORGNAME="AT&T"

27            OUN="Versit Project Office"

28        TITLE="Consultant"

29        EMAIL="ralden@alden.com"

29            WORK

29            PREF

29            INTERNET

30        LABEL="Roland H. Alden

31                Suite 2208

32                One Pine Street

33                San Francisco, CA 94111"

30            DOM

30            POSTAL

30            PARCEL

30            HOME

30            WORK

30            QUOTED-PRINTABLE

34        LABEL="Roland H. Alden

35                Suite 2208

36                One Pine Street

37                San Francisco, CA 94111

38                U.S.A."

34            POSTAL

34            PARCEL

34            HOME

34            WORK

34            QUOTED-PRINTABLE

39        TEL="+1 415 296 9106"

39            WORK

39            PREF

39            MSG

40        TEL="+1 415 296 9016"

40            WORK

40            FAX

41        TEL="+1 415 608 5981"

41            MSG

41            CELL

42        ADR

42            EXT ADD="Suite 2208"

42            STREET="One Pine Street"

42            L="San Francisco"

42            R="CA"

42            PC="94111"

42            C="U.S.A."

43        SOUND="ROW-LAND H ALL-DIN"

44        LOGO=[raw data]

44            GIF

44            BASE64

44            DATASIZE=1482