LIST.CPP
资源名称:commutil.zip [点击查看]
上传用户:xr_qian
上传日期:2007-01-05
资源大小:443k
文件大小:7k
源码类别:
通讯/手机编程
开发平台:
DOS
- // ******************************************************************** //
- // //
- // LIST.CPP //
- // Copyright (c) 1993, Michael Holmes and Bob Flanders //
- // C++ Communication Utilities //
- // //
- // This file contains the definition and interface for //
- // the List class. The List class implements a simple //
- // double-linked list with a single string item stored //
- // in the object. //
- // //
- // ******************************************************************** //
- /* ******************************************************************** *
- *
- * List class definition
- *
- * ******************************************************************** */
- class List
- {
- public:
- List(void); // build a list header
- List(char *s, // create a single entry
- char *d); // ..with string and data
- List(List *l, // add to end of list
- char *s, // ..string name
- char *d); // ..and data
- List(char *s, // put at the head of list
- char *d, // ..string and data
- List *l); // ..list to chain to
- char *Find(char *s); // find string name
- ~List(); // destructor
- private:
- void EntryInit(char *s, // initialize a entry
- char *d); // ..with string and data
- char *string_name, // string name
- *data; // ..and data
- List *prev, // pervious item pointer
- *next; // next item pointer
- };
- /* ******************************************************************** *
- *
- * List -- build list header
- *
- * ******************************************************************** */
- List::List(void)
- {
- EntryInit("", ""); // initialize new instance
- }
- /* ******************************************************************** *
- *
- * List -- build a single list entry
- *
- * ******************************************************************** */
- List::List(char *s, // string name
- char *d) // ..and data
- {
- EntryInit(s, d); // initialize new instance
- }
- /* ******************************************************************** *
- *
- * List -- add an entry to the end of the list
- *
- * ******************************************************************** */
- List::List(List *l, // list to chain to
- char *s, // string name
- char *d) // ..and data
- {
- EntryInit(s, d); // build base instance
- while (l->next) // loop thru..
- l = l->next; // ..to the end of the list
- l->next = this; // put this at the end
- this->prev = l; // ..and backward chain
- }
- /* ******************************************************************** *
- *
- * List -- put an entry at the head of the list
- *
- * ******************************************************************** */
- List::List(char *s, // string name
- char *d, // ..and data
- List *l) // list to chain into
- {
- EntryInit(s, d); // build base instance
- this->prev = l; // set up backward link
- this->next = l->next; // ..and forward link
- l->next = this; // update list anchor
- if (this->next) // q. any more after us?
- (this->next)->prev = this; // a. yes .. set up link
- }
- /* ******************************************************************** *
- *
- * EntryInit -- initialize list entry instance
- *
- * ******************************************************************** */
- void List::EntryInit(char *s, // string name
- char *d) // ..and data
- {
- string_name = data = (char *) 0; // init string pointers
- prev = next = 0; // ..and list pointers
- if (*s) // q. string name given?
- {
- string_name = new char[strlen(s) + 1]; // a. yes .. get memory and
- strcpy(string_name, s); // ..copy for this instance
- }
- if (*d) // q. data given
- {
- data = new char[strlen(d) + 1]; // a. yes .. get memory and
- strcpy(data, d); // ..copy for this instance
- }
- }
- /* ******************************************************************** *
- *
- * Find -- find a list entry by the string name
- *
- * ******************************************************************** */
- char *List::Find(char *s) // string name to search on
- {
- List *l = this; // work pointer
- for (;;) // loop thru the list
- {
- if (l->string_name && // q. string available?
- NOT stricmp(s, l->string_name)) // ..and find the entry?
- return(l->data); // a. yes .. quit here
- if ((l = l->next) == 0) // q. end of list?
- break; // a. yes .. exit loop
- }
- return(0); // else return empty-handed
- }
- /* ******************************************************************** *
- *
- * ~List -- object destructor
- *
- * ******************************************************************** */
- List::~List()
- {
- if (string_name) // q. string name given?
- delete string_name; // a. yes .. de-alloc space
- if (data) // q. data string available?
- delete data; // a. yes .. de-alloc space
- if (this->next) // q. anything after this?
- (this->next)->prev = this->prev; // a. yes .. de-chain prev
- if (this->prev) // q. anything before this?
- (this->prev)->next = this->next; // a. yes .. de-chain next
- }