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diff --git a/libical/doc/UsingLibical.sgml b/libical/doc/UsingLibical.sgml deleted file mode 100644 index d967bd860c..0000000000 --- a/libical/doc/UsingLibical.sgml +++ /dev/null @@ -1,318 +0,0 @@ -<!doctype linuxdoc system> - -<!-- LinuxDoc file was created by LyX 1.0 (C) 1995-1999 by <eric> Wed Jan 5 22:30:06 2000 - --> - <article> - <title> -Using Libical - </title> - <author> -Eric Busboom (eric@softwarestudio.org) - </author> - <date> -January 2000 - </date> - <sect> -Introduction - <p> -Libical is an Open Source implementation of the iCalendar protocols and - protocol data units. The iCalendar specification describes how calendar clients - can communicate with calendar servers for users can store their calendar data - and arrange meetings with other users. - </p> - <p> -Libical implements the following specifications and protocols - </p> - <p> -iCal Core -2445 -iTIP -2446 -iMIP -2447 -iRIP -draft -CAP -draft - </p> - <p> -(The current version, 0.14, does not implement iRip or CAP. ) - </p> - <p> -This code is under active development. If you would like to contribute - to the project, you can contact me, Eric Busboom, at eric@softwarestudio.org. - The project has a webpage at - </p> - <p> - <quote> -http://softwarestudio.org/libical/index.html - </quote> -</p> <p> -and a mailing list that you can join by sending the following mail: - </p> - <p> - <code> ------------- -To: minimalist@softwarestudio.org -Subject: subscribe libical ------------- - </code> -</p> <p> -$Id: UsingLibical.lyx,v 1.3 2000/01/06 06:20:06 eric Exp eric $ - </p> - <sect1> -License - <p> -The code and datafiles in this distribution are licensed under the Mozilla - Public License. See http://www.mozilla.org/NPL/MPL-1.0.html for a copy of the - license. Alternately, you may use libical under the terms of the GNU Library - General Public License. See http://www.fsf.org/copyleft/lesser.html for a copy - of the LGPL. - </p> - <p> -This dual license ensures that the library can be incorporated into both - proprietary code and GPL'd programs, and will benefit from improvements made - by programmers in both realms. I will only accept changes into my version of - the library if they are similarly dual-licensed. - </p> - <sect1> -Purpose & Goals - <sect> -Building the Library - <sect> -Structure - <p> -The iCal calendar model is based on four types of objects: components, - properties, values and parameters. - </p> - <p> -Components are the fundamental grouping of calendar information - </p> - <p> -Properties are the fundamental unit of information. Each property is composed - of a type, a value and collection of parameters. - </p> - <sect1> -Components - <p> -Components are named clusters of properties - </p> - <sect1> -Properties - <sect1> -Values - <sect1> -Parameters - <sect1> -Storage - <sect2> -Cluster - <sect2> -Store - <sect2> -Calendar - <sect1> -Other bits - <p> -Restrictions - </p> - <p> -Types - </p> - <sect> -Differences From RFCs - <p> -Although libical has been design to follow the standards as closely as - possible, there are a few areas where the specifications are irregular, and - following them exactly would result in an unfriendly interface. - </p> - <sect1> -Pseudo Components - <p> -Libical defines pseudo components for groups of properties that look and - act like components, but are not defined as components in the specification. - XDAYLIGHT and XSTANDARD are notable examples. These pseudo components group - properties within the VTIMEZONE components. XDAYLIGHT starts with "BEGIN:DAYLIGHT" - and ends with "END:DAYLIGHT, just like other components, but is not defined - as a component in RFC2445. ( See RFC2445, page 61 ) In Libical, it is a component. - - </p> - <p> -There are also pseudo componentsthat are conceptually derived classess - of VALARM. RFC2446 defines what properties may be included in each component, - and for VALARM, the set of properties it may have depends on the value of the - ACTION property. - </p> - <p> -For instance, if a VALARM component has an ACTION property with the value - of "AUDIO," the component must also have an "ATTACH" property. However, if the - ACTION value is "DISPLAY," the component must have a DESCRIPTION property. - </p> - <p> -To handle these various, complex restrictions, libical has pseudo components - for each type of alarm: XAUDIOALARM, XDISPLAYALARM, XEMAILALARM and XPROCEDUREALARM. - - </p> - <sect1> -Combined Values - <p> -Many values can take more than one type. TRIGGER, for instance, can have - a value type of with DURATION or of DATE-TIME. It is natural to have interfaces - that would return the value of a property, but it is cumbersone for a single - routine to return multiple types. So, in libical, properties that can have - multiple types are given a single type that is the union of their RFC2445 types. - In libical, the value of the TRIGGER property resolves to - </p> - <p> -struct icaltriggertype - </p> - <p> -This type is a union of a DURATION and a DATE-TIME. - </p> - <sect1> -Multi-Valued Properties - <p> -Some properties, such as CATEGORIES, have a single value type, but may - have multiple values in a single instance. This also results in a cumbersome - interface -- CATEGORIES accessors would have to return a list which all other - accessors returned a single value. In libical, all properties have a single - value, and multi-valued properties are broken down into multiple single valued - properties during parsing. The is, - </p> - <p> - <code> -CATEGORIES: work, home - </code> -</p> <p> -becomes in libical's internal representation - </p> - <p> - <code> -CATEGORIES: work -CATEGORIES: home - </code> -</p> <p> -Oddly, RFC2445 allows some multi-valued properties ( like FREEBUSY ) to - exist as both a multi-values property and as multiple single value properties, - while others ( like CATEGORIES ) can only exist as single multi-valued properties. - This makes the internal representation for CATEGORIES illegal. However when - you convert a component to a string, the library will collect all of the CATEGORIES - properties into one. - </p> - <sect> -Implementation Limitations - <sect> -Using libical - <sect1> -Creating Components - <sect2> -Constructor interfaces - <sect2> -vaargs Constructors - <sect2> -Parsing Text Files - <sect1> -Accessing Components - <sect2> -Finding Components - <sect2> -Removing Components - <p> -Removing an element from a list while iterating through the list can cause - problems, since you will probably be removing the element that the internal - iterator points to. This will result in the iteration loop terminating immediately - after removing the element. To avoid the problem, you will need to step the - iterator ahead of the element you are going to remove, like this: - </p> - <p> - <code> -for(c = icalcomponent_get_first_component(s); - c != 0; - c = next) -{ - next = icalcomponent_get_next_component(s); - icalcomponent_remove_component(s,c); -} - </code> -</p> <sect2> -Finding Properties - <sect2> -Removing Properties - <sect2> -Getting Values - <sect2> -Setting Values - <sect2> -Getting Parameters - <sect2> -Setting Parameters - <sect2> -Removing Parameters - <sect1> -Storing Objects - <p> -When you store a component to the database with icalstore_add_component, - you give the library takes the memory, so the caller does not own the component - anymore. If you want to keep ownership, use clone to make a copy. ( See "Memory - Management" and "Naming Starndard for more about routines with "add" in the name. - ) - </p> - <sect1> -Memory Management - <p> -Here are the memory rules for the C library: - </p> - <p> - <descrip> - <tag> -1)</tag>If the function name has "new" in it, the caller gets - control of the memory. ( such as icalcomponent_new(), or icalproperty_new_clone() - ) - <tag> -2)</tag>If you got the memory from a routine with new in it, you must - call the corresponding *_free routine to free the memory. ( Use icalcomponent_free() - to free objects created with icalcomponent_new()) - <tag> -3)</tag>If the function name has "add" in it, the caller is - transfering control of the memory to the routine. ( icalproperty_add_parameter() - ) - <tag> -4)</tag>If the function name has "remove" in it, the caller - passes in a pointer to an object and after the call returns, the caller owns - the object. So, before you call icalcomponent_remove_property(comp,foo), you - do not own "foo" and after the call returns, you do. - <tag> -5)</tag>If the routine returns a string, libical owns the memory and will - put it on a ring buffer to reclaim later. You'd better strdup it if you want - to keep it, and you don't have to delete it. - </descrip> -</p> <sect1> -Error Handling - <sect2> -Return values - <sect2> -icalerrno - <sect2> -Component errors - <sect1> -Naming Standard - <p> -Structures that you access with the "struct" keyword, such as "struct icaltimetype" - are things that you are allowed to see inside and poke at. - </p> - <p> -Structures that you access though a typedef, such as "icalcomponent" are - things where all of the data is hidden. - </p> - <p> -Component names that start with "V" are part of RFC 2445 or another iCal - standard. Component names that start with "X" are also part of the spec, but - they are not actually components in the spec. However, they look and act like - components, so they are components in libical. Names that start with "XLIC" or - "X-LIC" are not part of any iCal spec. They are used internally by libical. - </p> - <sect> -Hacks and Bugs - - - </article> |