103 lines
2.9 KiB
C
103 lines
2.9 KiB
C
/* This file is part of the Project Athena Zephyr Notification System.
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* It is one of the source files comprising zwgc, the Zephyr WindowGram
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* client.
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*
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* Created by: Marc Horowitz <marc@athena.mit.edu>
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*
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* $Id$
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*
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* Copyright (c) 1989 by the Massachusetts Institute of Technology.
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* For copying and distribution information, see the file
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* "mit-copyright.h".
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*/
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#if (!defined(lint) && !defined(SABER))
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static const char rcsid_string_dictionary_aux_c[] = "$Id$";
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#endif
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/*
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* string_dictionary_aux - a module implementing convenience routines for use
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* with string_dictionarys
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*
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* Overview:
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*
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* This module implements Fetch and Set operations on
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* string_dictionaries which take the place of Define and Lookup for
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* most uses. The importance difference between them and Define and
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* Lookup is that they maintain the invariant that all the value strings
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* in a string_dictionary are on the heap. In particular, they do
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* free's and string_Copy's whenever needed. Also implemented is
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* SafeDestroy which does a Destroy after freeing all the value strings
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* in a string_dictionary.
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*/
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#include <sysdep.h>
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#include "new_memory.h"
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#include "string_dictionary.h"
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#include "string_dictionary_aux.h"
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/*
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* void string_dictionary_Set(string_dictionary d, string key,string value):
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* Modifies: d
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* Effects: Binds key to value in d. Automatically free's the
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* previous value of key, if any. Value is copied on the
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* heap.
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*/
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void
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string__dictionary_Set(string_dictionary d,
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string key,
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string value)
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{
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string_dictionary_binding *binding;
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int already_exists;
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binding = string_dictionary_Define(d, key, &already_exists);
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if (already_exists)
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free(binding->value);
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binding->value = string_Copy(value);
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}
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/*
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* char *string_dictionary_Fetch(string_dictionary d, string key)
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* Effects: If key is not bound in d, returns 0. Otherwise,
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* returns the value that key is bound to.
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* Note that the returned string if any should not be
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* freed or modified in any way. Note also that it may
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* disappear later if key is rebound.
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*/
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char *
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string_dictionary_Fetch(string_dictionary d,
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string key)
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{
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string_dictionary_binding *binding;
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binding = string_dictionary_Lookup(d, key);
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if (!binding)
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return(0);
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return(binding->value);
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}
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/*
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* void string_dictionary_SafeDestroy(string_dictionary d)
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* Modifies: d
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* Effects: Like string_dictionary_Destroy except first frees
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* all value's in the dictionary.
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*/
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static void
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free_value_of_binding(string_dictionary_binding *b)
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{
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free(b->value);
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}
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void
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string_dictionary_SafeDestroy(string_dictionary d)
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{
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string_dictionary_Enumerate(d, free_value_of_binding);
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string_dictionary_Destroy(d);
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}
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