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Annotation of libwww/Library/src/HTList.html, revision 2.21

2.6       timbl       1: <HTML>
                      2: <HEAD>
2.15      frystyk     3: <TITLE>Linked List Class</TITLE>
2.21    ! frystyk     4: <!-- Changed by: Henrik Frystyk Nielsen, 15-Nov-1995 -->
2.6       timbl       5: <NEXTID N="z3">
                      6: </HEAD>
                      7: <BODY>
2.7       frystyk     8: 
                      9: <H1>List object</H1>
                     10: 
                     11: <PRE>
                     12: /*
2.13      frystyk    13: **     (c) COPYRIGHT MIT 1995.
2.7       frystyk    14: **     Please first read the full copyright statement in the file COPYRIGH.
                     15: */
                     16: </PRE>
                     17: 
                     18: The list object is a generic container for storing collections of
                     19: things in order.  In principle it could be implemented in many ways,
                     20: but in practice knowing that it is a linked list is important for
2.19      frystyk    21: speed.<P>
2.7       frystyk    22: 
                     23: This module is implemented by <A HREF="HTList.c">HTList.c</A>, and it
2.19      frystyk    24: is a part of the <A HREF="http://www.w3.org/pub/WWW/Library/"> W3C
                     25: Reference Library</A>.
2.7       frystyk    26: 
2.1       timbl      27: <PRE>
                     28: #ifndef HTLIST_H
                     29: #define HTLIST_H
                     30: 
                     31: typedef struct _HTList HTList;
                     32: 
                     33: struct _HTList {
                     34:   void * object;
                     35:   HTList * next;
                     36: };
2.19      frystyk    37: </PRE>
                     38: 
                     39: <H2>Creation and Deletion Methods</H2>
                     40: 
                     41: These two functions create and deletes a list
2.1       timbl      42: 
2.19      frystyk    43: <PRE>
                     44: extern HTList *        HTList_new      (void);
2.20      frystyk    45: extern BOOL    HTList_delete   (HTList *me);
2.12      frystyk    46: </PRE>
2.1       timbl      47: 
2.19      frystyk    48: <H2>Add an Element to List</H2>
                     49: 
                     50: A new list element is added to the beginning of the list so that it is
                     51: first element just after the head element.
2.12      frystyk    52: 
2.6       timbl      53: <PRE>
2.19      frystyk    54: extern BOOL    HTList_addObject (HTList *me, void *newObject);
2.21    ! frystyk    55: </PRE>
        !            56: 
        !            57: You can also append an element to the end of the list (the end is the
        !            58: first entered object) by using the following function:
        !            59: 
        !            60: <PRE>
        !            61: extern BOOL HTList_appendObject (HTList * me, void * newObject);
2.19      frystyk    62: </PRE>
                     63: 
                     64: <H2>Remove List Elements</H2>
                     65: 
                     66: <PRE>
                     67: extern BOOL    HTList_removeObject             (HTList *me, void *oldObject);
                     68: extern void *  HTList_removeLastObject         (HTList *me);
                     69: extern void *  HTList_removeFirstObject        (HTList *me);
                     70: </PRE>
                     71: 
                     72: <H2>Size of a List</H2>
                     73: 
                     74: Two small function to ask for the size
                     75: 
                     76: <PRE>
                     77: #define        HTList_isEmpty(me)              (me ? me->next == NULL : YES)
                     78: extern int     HTList_count                    (HTList *me);
                     79: </PRE>
                     80: 
                     81: <H2>Reference List Elements By Index</H2>
                     82: 
                     83: In some situations is is required to use an index in order to refer to
                     84: a list element. This is for example the case if an element can be
                     85: registered multiple times.
                     86: 
                     87: <PRE>
                     88: extern int     HTList_indexOf  (HTList *me, void *object);
                     89: extern void *  HTList_objectAt (HTList *me, int position);
                     90: </PRE>
                     91: 
                     92: <H2>Find Last Element Added</H2>
                     93: 
                     94: <PRE>
                     95: #define                HTList_lastObject(me) \
2.16      frystyk    96:                ((me) &amp;&amp; (me)->next ? (me)->next->object : NULL)
2.12      frystyk    97: </PRE>
                     98: 
2.19      frystyk    99: <H2>Traverse list</H2>
2.12      frystyk   100: 
                    101: Fast macro to traverse the list.  Call it first with copy of list
                    102: header: it returns the first object and increments the passed list
                    103: pointer.  Call it with the same variable until it returns NULL.
2.1       timbl     104: 
2.19      frystyk   105: <PRE>
                    106: #define                HTList_nextObject(me) \
                    107:                ((me) &amp;&amp; ((me) = (me)->next) ? (me)->object : NULL)
2.12      frystyk   108: </PRE>
2.6       timbl     109: 
2.19      frystyk   110: <H2>Free list</H2>
2.12      frystyk   111: 
                    112: <PRE>
                    113: #define HTList_free(x)  FREE(x)
2.1       timbl     114: 
                    115: #endif /* HTLIST_H */
2.6       timbl     116: 
                    117: </PRE>end</A></BODY>
                    118: </HTML>
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