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<!-- Weave of 'Dictionaries' generated by 7 -->
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< ul class = "crumbs" > < li > < a href = "../index.html" > Home< / a > < / li > < li > < a href = "index.html" > foundation< / a > < / li > < li > < a href = "index.html#2" > Chapter 2: Memory, Streams and Collections< / a > < / li > < li > < b > Dictionaries< / b > < / li > < / ul > < p class = "purpose" > A simple implementation for a flexible-sized dictionary of key-value pairs.< / p >
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< ul class = "toc" > < li > < a href = "#SP1" > § 1. Storage< / a > < / li > < li > < a href = "#SP2" > § 2. Creation< / a > < / li > < li > < a href = "#SP3" > § 3. Logging< / a > < / li > < li > < a href = "#SP4" > § 4. Hashing< / a > < / li > < li > < a href = "#SP5" > § 5. Create, find, destroy< / a > < / li > < li > < a href = "#SP8" > § 8. Accessing entries< / a > < / li > < li > < a href = "#SP11" > § 11. Disposal< / a > < / li > < / ul > < hr class = "tocbar" >
< p class = "inwebparagraph" > < a id = "SP1" > < / a > < b > § 1. Storage. < / b > There's nothing fancy here. A "dictionary" is a hash table allowing reasonably
efficient lookup: it's a correspondence between "keys", which are texts, and
pointers to some external structure. Often these will also be texts, but
not necessarily.
< / p >
< pre class = "display" >
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< span class = "reserved" > typedef< / span > < span class = "plain" > < / span > < span class = "reserved" > struct< / span > < span class = "plain" > < / span > < span class = "reserved" > dictionary< / span > < span class = "plain" > {< / span >
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< span class = "reserved" > int< / span > < span class = "plain" > < / span > < span class = "identifier" > textual< / span > < span class = "plain" > ; < / span > < span class = "comment" > values are texts?< / span >
< span class = "reserved" > int< / span > < span class = "plain" > < / span > < span class = "identifier" > no_entries< / span > < span class = "plain" > ; < / span > < span class = "comment" > total number of key-value pairs currently stored here< / span >
< span class = "reserved" > int< / span > < span class = "plain" > < / span > < span class = "identifier" > hash_table_size< / span > < span class = "plain" > ; < / span > < span class = "comment" > size of array...< / span >
< span class = "reserved" > struct< / span > < span class = "plain" > < / span > < span class = "reserved" > dict_entry< / span > < span class = "plain" > *< / span > < span class = "identifier" > hash_table< / span > < span class = "plain" > ; < / span > < span class = "comment" > ...of linked lists of dictionary entries< / span >
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< span class = "constant" > MEMORY_MANAGEMENT< / span >
< span class = "plain" > } < / span > < span class = "reserved" > dictionary< / span > < span class = "plain" > ;< / span >
< span class = "reserved" > typedef< / span > < span class = "plain" > < / span > < span class = "reserved" > struct< / span > < span class = "plain" > < / span > < span class = "reserved" > dict_entry< / span > < span class = "plain" > {< / span >
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< span class = "reserved" > int< / span > < span class = "plain" > < / span > < span class = "identifier" > vacant< / span > < span class = "plain" > ; < / span > < span class = "comment" > a "vacant" entry is not currently used to store a k-v pair< / span >
< span class = "reserved" > struct< / span > < span class = "plain" > < / span > < span class = "reserved" > text_stream< / span > < span class = "plain" > *< / span > < span class = "identifier" > key< / span > < span class = "plain" > ; < / span > < span class = "comment" > for non-vacant entries only: the key text< / span >
< span class = "reserved" > void< / span > < span class = "plain" > *< / span > < span class = "identifier" > value< / span > < span class = "plain" > ; < / span > < span class = "comment" > for non-vacant entries only: the value, some kind of pointer< / span >
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< span class = "reserved" > struct< / span > < span class = "plain" > < / span > < span class = "reserved" > dict_entry< / span > < span class = "plain" > *< / span > < span class = "identifier" > next_in_entry< / span > < span class = "plain" > ;< / span >
< span class = "plain" > } < / span > < span class = "reserved" > dict_entry< / span > < span class = "plain" > ;< / span >
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< / pre >
< p class = "inwebparagraph" > < / p >
< p class = "endnote" > The structure dictionary is private to this section.< / p >
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< p class = "endnote" > The structure dict_entry is accessed in 5/ee, 8/bdfw and here.< / p >
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< p class = "inwebparagraph" > < a id = "SP2" > < / a > < b > § 2. Creation. < / b > Dictionaries can have arbitrary size, in that they expand as needed, but for
efficiency's sake the caller can set them up with an initial size of her choice.
< / p >
< pre class = "display" >
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< span class = "reserved" > dictionary< / span > < span class = "plain" > *< / span > < span class = "functiontext" > Dictionaries::new< button class = "popup" onclick = "togglePopup('usagePopup131')" > ...< span class = "popuptext" id = "usagePopup131" > Usage of < b > Dictionaries::new< / b > :< br > < a href = "#SP7_2" > § 7.2< / a > , Command Line Arguments - < a href = "3-cla.html#SP5" > § 5< / a > < br > String Manipulation - < a href = "4-sm.html#SP26_1" > § 26.1< / a > < / span > < / button > < / span > < span class = "plain" > (< / span > < span class = "reserved" > int< / span > < span class = "plain" > < / span > < span class = "identifier" > S< / span > < span class = "plain" > , < / span > < span class = "reserved" > int< / span > < span class = "plain" > < / span > < span class = "identifier" > textual< / span > < span class = "plain" > ) {< / span >
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< span class = "reserved" > if< / span > < span class = "plain" > (< / span > < span class = "identifier" > S< / span > < span class = "plain" > < < / span > < span class = "constant" > 2< / span > < span class = "plain" > ) < / span > < span class = "identifier" > internal_error< / span > < span class = "plain" > (< / span > < span class = "string" > "dictionary too small"< / span > < span class = "plain" > );< / span >
< span class = "reserved" > dictionary< / span > < span class = "plain" > *< / span > < span class = "identifier" > D< / span > < span class = "plain" > = < / span > < span class = "identifier" > CREATE< / span > < span class = "plain" > (< / span > < span class = "reserved" > dictionary< / span > < span class = "plain" > );< / span >
< span class = "identifier" > D< / span > < span class = "plain" > -> < / span > < span class = "element" > textual< / span > < span class = "plain" > = < / span > < span class = "identifier" > textual< / span > < span class = "plain" > ;< / span >
< span class = "identifier" > D< / span > < span class = "plain" > -> < / span > < span class = "element" > hash_table_size< / span > < span class = "plain" > = < / span > < span class = "identifier" > S< / span > < span class = "plain" > ;< / span >
< span class = "identifier" > D< / span > < span class = "plain" > -> < / span > < span class = "element" > no_entries< / span > < span class = "plain" > = < / span > < span class = "constant" > 0< / span > < span class = "plain" > ;< / span >
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< span class = "identifier" > D< / span > < span class = "plain" > -> < / span > < span class = "element" > hash_table< / span > < span class = "plain" > = < / span > < span class = "functiontext" > < a href = "2-mmr.html#SP25" > Memory::I7_calloc< / a > < / span > < span class = "plain" > (< / span > < span class = "identifier" > S< / span > < span class = "plain" > , < / span > < span class = "reserved" > sizeof< / span > < span class = "plain" > (< / span > < span class = "reserved" > dict_entry< / span > < span class = "plain" > ), < / span > < span class = "constant" > DICTIONARY_MREASON< / span > < span class = "plain" > );< / span >
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< span class = "reserved" > for< / span > < span class = "plain" > (< / span > < span class = "reserved" > int< / span > < span class = "plain" > < / span > < span class = "identifier" > i< / span > < span class = "plain" > =0; < / span > < span class = "identifier" > i< / span > < span class = "plain" > < < / span > < span class = "identifier" > S< / span > < span class = "plain" > ; < / span > < span class = "identifier" > i< / span > < span class = "plain" > ++) {< / span >
< span class = "identifier" > D< / span > < span class = "plain" > -> < / span > < span class = "element" > hash_table< / span > < span class = "plain" > [< / span > < span class = "identifier" > i< / span > < span class = "plain" > ].< / span > < span class = "element" > vacant< / span > < span class = "plain" > = < / span > < span class = "constant" > TRUE< / span > < span class = "plain" > ;< / span >
< span class = "identifier" > D< / span > < span class = "plain" > -> < / span > < span class = "element" > hash_table< / span > < span class = "plain" > [< / span > < span class = "identifier" > i< / span > < span class = "plain" > ].< / span > < span class = "element" > value< / span > < span class = "plain" > = < / span > < span class = "identifier" > NULL< / span > < span class = "plain" > ;< / span >
< span class = "identifier" > D< / span > < span class = "plain" > -> < / span > < span class = "element" > hash_table< / span > < span class = "plain" > [< / span > < span class = "identifier" > i< / span > < span class = "plain" > ].< / span > < span class = "element" > next_in_entry< / span > < span class = "plain" > = < / span > < span class = "identifier" > NULL< / span > < span class = "plain" > ;< / span >
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< span class = "plain" > }< / span >
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< span class = "reserved" > return< / span > < span class = "plain" > < / span > < span class = "identifier" > D< / span > < span class = "plain" > ;< / span >
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< span class = "plain" > }< / span >
< / pre >
< p class = "inwebparagraph" > < / p >
< p class = "inwebparagraph" > < a id = "SP3" > < / a > < b > § 3. Logging. < / b > < / p >
< pre class = "display" >
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< span class = "reserved" > void< / span > < span class = "plain" > < / span > < span class = "functiontext" > Dictionaries::log< button class = "popup" onclick = "togglePopup('usagePopup132')" > ...< span class = "popuptext" id = "usagePopup132" > Usage of < b > Dictionaries::log< / b > :< br > none< / span > < / button > < / span > < span class = "plain" > (< / span > < span class = "constant" > OUTPUT_STREAM< / span > < span class = "plain" > , < / span > < span class = "reserved" > dictionary< / span > < span class = "plain" > *< / span > < span class = "identifier" > D< / span > < span class = "plain" > ) {< / span >
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< span class = "identifier" > WRITE< / span > < span class = "plain" > (< / span > < span class = "string" > "Dictionary:\n"< / span > < span class = "plain" > , (< / span > < span class = "reserved" > unsigned< / span > < span class = "plain" > < / span > < span class = "reserved" > int< / span > < span class = "plain" > ) < / span > < span class = "identifier" > D< / span > < span class = "plain" > ); < / span > < span class = "constant" > INDENT< / span > < span class = "plain" > ;< / span >
< span class = "reserved" > for< / span > < span class = "plain" > (< / span > < span class = "reserved" > int< / span > < span class = "plain" > < / span > < span class = "identifier" > i< / span > < span class = "plain" > =0; < / span > < span class = "identifier" > i< / span > < span class = "plain" > < < / span > < span class = "identifier" > D< / span > < span class = "plain" > -> < / span > < span class = "element" > hash_table_size< / span > < span class = "plain" > ; < / span > < span class = "identifier" > i< / span > < span class = "plain" > ++) {< / span >
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< span class = "identifier" > WRITE< / span > < span class = "plain" > (< / span > < span class = "string" > "Slot %02d:"< / span > < span class = "plain" > , < / span > < span class = "identifier" > i< / span > < span class = "plain" > );< / span >
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< span class = "reserved" > for< / span > < span class = "plain" > (< / span > < span class = "reserved" > dict_entry< / span > < span class = "plain" > *< / span > < span class = "identifier" > E< / span > < span class = "plain" > = & (< / span > < span class = "identifier" > D< / span > < span class = "plain" > -> < / span > < span class = "element" > hash_table< / span > < span class = "plain" > [< / span > < span class = "identifier" > i< / span > < span class = "plain" > ]); < / span > < span class = "identifier" > E< / span > < span class = "plain" > ; < / span > < span class = "identifier" > E< / span > < span class = "plain" > = < / span > < span class = "identifier" > E< / span > < span class = "plain" > -> < / span > < span class = "element" > next_in_entry< / span > < span class = "plain" > )< / span >
< span class = "reserved" > if< / span > < span class = "plain" > (< / span > < span class = "identifier" > E< / span > < span class = "plain" > -> < / span > < span class = "element" > vacant< / span > < span class = "plain" > ) < / span > < span class = "identifier" > WRITE< / span > < span class = "plain" > (< / span > < span class = "string" > " vacant"< / span > < span class = "plain" > );< / span >
< span class = "reserved" > else< / span > < span class = "plain" > < / span > < span class = "reserved" > if< / span > < span class = "plain" > (< / span > < span class = "identifier" > D< / span > < span class = "plain" > -> < / span > < span class = "element" > textual< / span > < span class = "plain" > ) < / span > < span class = "identifier" > WRITE< / span > < span class = "plain" > (< / span > < span class = "string" > " %S='%S'"< / span > < span class = "plain" > , < / span > < span class = "identifier" > E< / span > < span class = "plain" > -> < / span > < span class = "element" > key< / span > < span class = "plain" > , < / span > < span class = "identifier" > E< / span > < span class = "plain" > -> < / span > < span class = "element" > value< / span > < span class = "plain" > );< / span >
< span class = "reserved" > else< / span > < span class = "plain" > < / span > < span class = "identifier" > WRITE< / span > < span class = "plain" > (< / span > < span class = "string" > " %S=%08x"< / span > < span class = "plain" > , < / span > < span class = "identifier" > E< / span > < span class = "plain" > -> < / span > < span class = "element" > key< / span > < span class = "plain" > , (< / span > < span class = "reserved" > unsigned< / span > < span class = "plain" > < / span > < span class = "reserved" > int< / span > < span class = "plain" > ) < / span > < span class = "identifier" > E< / span > < span class = "plain" > -> < / span > < span class = "element" > value< / span > < span class = "plain" > );< / span >
< span class = "identifier" > WRITE< / span > < span class = "plain" > (< / span > < span class = "string" > "\n"< / span > < span class = "plain" > );< / span >
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< span class = "plain" > }< / span >
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< span class = "constant" > OUTDENT< / span > < span class = "plain" > ;< / span >
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< span class = "plain" > }< / span >
< / pre >
< p class = "inwebparagraph" > < / p >
< p class = "inwebparagraph" > < a id = "SP4" > < / a > < b > § 4. Hashing. < / b > The whole point of a hash table is that it crudely sorts the contents by a rough
indication of the key values. This crude indication is the hash value, calculated
here. If there are < code class = "display" > < span class = "extract" > N< / span > < / code > slots in the dictionary table, this tells us which slot
(from 0 to < code class = "display" > < span class = "extract" > N-1< / span > < / code > ) a given key value belongs in.
< / p >
< pre class = "display" >
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< span class = "reserved" > int< / span > < span class = "plain" > < / span > < span class = "functiontext" > Dictionaries::hash< button class = "popup" onclick = "togglePopup('usagePopup133')" > ...< span class = "popuptext" id = "usagePopup133" > Usage of < b > Dictionaries::hash< / b > :< br > < a href = "#SP7_3" > § 7.3< / a > < / span > < / button > < / span > < span class = "plain" > (< / span > < span class = "reserved" > text_stream< / span > < span class = "plain" > *< / span > < span class = "identifier" > K< / span > < span class = "plain" > , < / span > < span class = "reserved" > int< / span > < span class = "plain" > < / span > < span class = "identifier" > N< / span > < span class = "plain" > ) {< / span >
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< span class = "reserved" > unsigned< / span > < span class = "plain" > < / span > < span class = "reserved" > int< / span > < span class = "plain" > < / span > < span class = "identifier" > hash< / span > < span class = "plain" > = < / span > < span class = "constant" > 0< / span > < span class = "plain" > ;< / span >
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< span class = "identifier" > LOOP_THROUGH_TEXT< / span > < span class = "plain" > (< / span > < span class = "identifier" > P< / span > < span class = "plain" > , < / span > < span class = "identifier" > K< / span > < span class = "plain" > )< / span >
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< span class = "identifier" > hash< / span > < span class = "plain" > = < / span > < span class = "constant" > 16339< / span > < span class = "plain" > *< / span > < span class = "identifier" > hash< / span > < span class = "plain" > + ((< / span > < span class = "reserved" > unsigned< / span > < span class = "plain" > < / span > < span class = "reserved" > int< / span > < span class = "plain" > ) < / span > < span class = "functiontext" > < a href = "4-sm.html#SP13" > Str::get< / a > < / span > < span class = "plain" > (< / span > < span class = "identifier" > P< / span > < span class = "plain" > ));< / span >
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< span class = "reserved" > return< / span > < span class = "plain" > (< / span > < span class = "reserved" > int< / span > < span class = "plain" > ) (< / span > < span class = "identifier" > hash< / span > < span class = "plain" > % ((< / span > < span class = "reserved" > unsigned< / span > < span class = "plain" > < / span > < span class = "reserved" > int< / span > < span class = "plain" > ) < / span > < span class = "identifier" > N< / span > < span class = "plain" > ));< / span >
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< span class = "plain" > }< / span >
< / pre >
< p class = "inwebparagraph" > < / p >
< p class = "inwebparagraph" > < a id = "SP5" > < / a > < b > § 5. Create, find, destroy. < / b > These three fundamental operations locate the dictionary entry structure for
a given key value, and then do something to/with it. Note that these pointers
remain valid only until somebody writes a new value into the dictionary;
so be careful if thread safety's an issue.
< / p >
< pre class = "display" >
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< span class = "reserved" > dict_entry< / span > < span class = "plain" > *< / span > < span class = "functiontext" > Dictionaries::find< button class = "popup" onclick = "togglePopup('usagePopup134')" > ...< span class = "popuptext" id = "usagePopup134" > Usage of < b > Dictionaries::find< / b > :< br > < a href = "#SP6" > § 6< / a > , < a href = "#SP8" > § 8< / a > , < a href = "#SP10" > § 10< / a > , Command Line Arguments - < a href = "3-cla.html#SP13" > § 13< / a > < / span > < / button > < / span > < span class = "plain" > (< / span > < span class = "reserved" > dictionary< / span > < span class = "plain" > *< / span > < span class = "identifier" > D< / span > < span class = "plain" > , < / span > < span class = "reserved" > text_stream< / span > < span class = "plain" > *< / span > < span class = "identifier" > K< / span > < span class = "plain" > ) {< / span >
< span class = "reserved" > return< / span > < span class = "plain" > < / span > < span class = "functiontext" > < a href = "#SP7" > Dictionaries::find_p< / a > < / span > < span class = "plain" > (< / span > < span class = "identifier" > D< / span > < span class = "plain" > , < / span > < span class = "identifier" > K< / span > < span class = "plain" > , < / span > < span class = "constant" > 0< / span > < span class = "plain" > );< / span >
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< span class = "plain" > }< / span >
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< span class = "reserved" > dict_entry< / span > < span class = "plain" > *< / span > < span class = "functiontext" > Dictionaries::create< button class = "popup" onclick = "togglePopup('usagePopup135')" > ...< span class = "popuptext" id = "usagePopup135" > Usage of < b > Dictionaries::create< / b > :< br > < a href = "#SP6" > § 6< / a > , < a href = "#SP9" > § 9< / a > , Command Line Arguments - < a href = "3-cla.html#SP5" > § 5< / a > < / span > < / button > < / span > < span class = "plain" > (< / span > < span class = "reserved" > dictionary< / span > < span class = "plain" > *< / span > < span class = "identifier" > D< / span > < span class = "plain" > , < / span > < span class = "reserved" > text_stream< / span > < span class = "plain" > *< / span > < span class = "identifier" > K< / span > < span class = "plain" > ) {< / span >
< span class = "reserved" > return< / span > < span class = "plain" > < / span > < span class = "functiontext" > < a href = "#SP7" > Dictionaries::find_p< / a > < / span > < span class = "plain" > (< / span > < span class = "identifier" > D< / span > < span class = "plain" > , < / span > < span class = "identifier" > K< / span > < span class = "plain" > , < / span > < span class = "constant" > 1< / span > < span class = "plain" > );< / span >
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< span class = "plain" > }< / span >
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< span class = "reserved" > void< / span > < span class = "plain" > < / span > < span class = "functiontext" > Dictionaries::destroy< button class = "popup" onclick = "togglePopup('usagePopup136')" > ...< span class = "popuptext" id = "usagePopup136" > Usage of < b > Dictionaries::destroy< / b > :< br > < a href = "#SP6" > § 6< / a > < / span > < / button > < / span > < span class = "plain" > (< / span > < span class = "reserved" > dictionary< / span > < span class = "plain" > *< / span > < span class = "identifier" > D< / span > < span class = "plain" > , < / span > < span class = "reserved" > text_stream< / span > < span class = "plain" > *< / span > < span class = "identifier" > K< / span > < span class = "plain" > ) {< / span >
< span class = "functiontext" > < a href = "#SP7" > Dictionaries::find_p< / a > < / span > < span class = "plain" > (< / span > < span class = "identifier" > D< / span > < span class = "plain" > , < / span > < span class = "identifier" > K< / span > < span class = "plain" > , -1);< / span >
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< span class = "plain" > }< / span >
< / pre >
< p class = "inwebparagraph" > < / p >
< p class = "inwebparagraph" > < a id = "SP6" > < / a > < b > § 6. < / b > A nuisance we have to live with is that we often want to express the key
as wide text (so that we can use literals like < code class = "display" > < span class = "extract" > L"my-key"< / span > < / code > ) instead of text
streams. So we also offer versions suffixed < code class = "display" > < span class = "extract" > _literal< / span > < / code > :
< / p >
< pre class = "display" >
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< span class = "reserved" > dict_entry< / span > < span class = "plain" > *< / span > < span class = "functiontext" > Dictionaries::find_literal< button class = "popup" onclick = "togglePopup('usagePopup137')" > ...< span class = "popuptext" id = "usagePopup137" > Usage of < b > Dictionaries::find_literal< / b > :< br > < a href = "#SP8" > § 8< / a > , < a href = "#SP10" > § 10< / a > < / span > < / button > < / span > < span class = "plain" > (< / span > < span class = "reserved" > dictionary< / span > < span class = "plain" > *< / span > < span class = "identifier" > D< / span > < span class = "plain" > , < / span > < span class = "identifier" > wchar_t< / span > < span class = "plain" > *< / span > < span class = "identifier" > lit< / span > < span class = "plain" > ) {< / span >
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< span class = "identifier" > TEMPORARY_TEXT< / span > < span class = "plain" > (< / span > < span class = "identifier" > K< / span > < span class = "plain" > );< / span >
< span class = "identifier" > WRITE_TO< / span > < span class = "plain" > (< / span > < span class = "identifier" > K< / span > < span class = "plain" > , < / span > < span class = "string" > "%w"< / span > < span class = "plain" > , < / span > < span class = "identifier" > lit< / span > < span class = "plain" > );< / span >
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< span class = "reserved" > dict_entry< / span > < span class = "plain" > *< / span > < span class = "identifier" > E< / span > < span class = "plain" > = < / span > < span class = "functiontext" > < a href = "#SP5" > Dictionaries::find< / a > < / span > < span class = "plain" > (< / span > < span class = "identifier" > D< / span > < span class = "plain" > , < / span > < span class = "identifier" > K< / span > < span class = "plain" > );< / span >
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< span class = "identifier" > DISCARD_TEXT< / span > < span class = "plain" > (< / span > < span class = "identifier" > K< / span > < span class = "plain" > );< / span >
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< span class = "reserved" > return< / span > < span class = "plain" > < / span > < span class = "identifier" > E< / span > < span class = "plain" > ;< / span >
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< span class = "plain" > }< / span >
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< span class = "reserved" > dict_entry< / span > < span class = "plain" > *< / span > < span class = "functiontext" > Dictionaries::create_literal< button class = "popup" onclick = "togglePopup('usagePopup138')" > ...< span class = "popuptext" id = "usagePopup138" > Usage of < b > Dictionaries::create_literal< / b > :< br > < a href = "#SP9" > § 9< / a > , String Manipulation - < a href = "4-sm.html#SP26_1" > § 26.1< / a > < / span > < / button > < / span > < span class = "plain" > (< / span > < span class = "reserved" > dictionary< / span > < span class = "plain" > *< / span > < span class = "identifier" > D< / span > < span class = "plain" > , < / span > < span class = "identifier" > wchar_t< / span > < span class = "plain" > *< / span > < span class = "identifier" > lit< / span > < span class = "plain" > ) {< / span >
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< span class = "identifier" > TEMPORARY_TEXT< / span > < span class = "plain" > (< / span > < span class = "identifier" > K< / span > < span class = "plain" > );< / span >
< span class = "identifier" > WRITE_TO< / span > < span class = "plain" > (< / span > < span class = "identifier" > K< / span > < span class = "plain" > , < / span > < span class = "string" > "%w"< / span > < span class = "plain" > , < / span > < span class = "identifier" > lit< / span > < span class = "plain" > );< / span >
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< span class = "reserved" > dict_entry< / span > < span class = "plain" > *< / span > < span class = "identifier" > E< / span > < span class = "plain" > = < / span > < span class = "functiontext" > < a href = "#SP5" > Dictionaries::create< / a > < / span > < span class = "plain" > (< / span > < span class = "identifier" > D< / span > < span class = "plain" > , < / span > < span class = "identifier" > K< / span > < span class = "plain" > );< / span >
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< span class = "identifier" > DISCARD_TEXT< / span > < span class = "plain" > (< / span > < span class = "identifier" > K< / span > < span class = "plain" > );< / span >
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< span class = "reserved" > return< / span > < span class = "plain" > < / span > < span class = "identifier" > E< / span > < span class = "plain" > ;< / span >
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< span class = "plain" > }< / span >
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< span class = "reserved" > void< / span > < span class = "plain" > < / span > < span class = "functiontext" > Dictionaries::destroy_literal< button class = "popup" onclick = "togglePopup('usagePopup139')" > ...< span class = "popuptext" id = "usagePopup139" > Usage of < b > Dictionaries::destroy_literal< / b > :< br > none< / span > < / button > < / span > < span class = "plain" > (< / span > < span class = "reserved" > dictionary< / span > < span class = "plain" > *< / span > < span class = "identifier" > D< / span > < span class = "plain" > , < / span > < span class = "identifier" > wchar_t< / span > < span class = "plain" > *< / span > < span class = "identifier" > lit< / span > < span class = "plain" > ) {< / span >
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< span class = "identifier" > TEMPORARY_TEXT< / span > < span class = "plain" > (< / span > < span class = "identifier" > K< / span > < span class = "plain" > );< / span >
< span class = "identifier" > WRITE_TO< / span > < span class = "plain" > (< / span > < span class = "identifier" > K< / span > < span class = "plain" > , < / span > < span class = "string" > "%w"< / span > < span class = "plain" > , < / span > < span class = "identifier" > lit< / span > < span class = "plain" > );< / span >
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< span class = "functiontext" > < a href = "#SP5" > Dictionaries::destroy< / a > < / span > < span class = "plain" > (< / span > < span class = "identifier" > D< / span > < span class = "plain" > , < / span > < span class = "identifier" > K< / span > < span class = "plain" > );< / span >
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< span class = "identifier" > DISCARD_TEXT< / span > < span class = "plain" > (< / span > < span class = "identifier" > K< / span > < span class = "plain" > );< / span >
< span class = "plain" > }< / span >
< / pre >
< p class = "inwebparagraph" > < / p >
< p class = "inwebparagraph" > < a id = "SP7" > < / a > < b > § 7. < / b > So, then, find an entry (if < code class = "display" > < span class = "extract" > change< / span > < / code > is < code class = "display" > < span class = "extract" > 0< / span > < / code > ), create it (if < code class = "display" > < span class = "extract" > +1< / span > < / code > ) or delete
it (if < code class = "display" > < span class = "extract" > -1< / span > < / code > ).
< / p >
< pre class = "display" >
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< span class = "reserved" > dict_entry< / span > < span class = "plain" > *< / span > < span class = "functiontext" > Dictionaries::find_p< button class = "popup" onclick = "togglePopup('usagePopup140')" > ...< span class = "popuptext" id = "usagePopup140" > Usage of < b > Dictionaries::find_p< / b > :< br > < a href = "#SP5" > § 5< / a > , < a href = "#SP7_2" > § 7.2< / a > < / span > < / button > < / span > < span class = "plain" > (< / span > < span class = "reserved" > dictionary< / span > < span class = "plain" > *< / span > < span class = "identifier" > D< / span > < span class = "plain" > , < / span > < span class = "reserved" > text_stream< / span > < span class = "plain" > *< / span > < span class = "identifier" > K< / span > < span class = "plain" > , < / span > < span class = "reserved" > int< / span > < span class = "plain" > < / span > < span class = "identifier" > change< / span > < span class = "plain" > ) {< / span >
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< span class = "reserved" > if< / span > < span class = "plain" > (< / span > < span class = "identifier" > D< / span > < span class = "plain" > == < / span > < span class = "identifier" > NULL< / span > < span class = "plain" > ) < / span > < < span class = "cwebmacro" > Handle the null dictionary< / span > < span class = "cwebmacronumber" > 7.1< / span > > < span class = "plain" > ;< / span >
< span class = "reserved" > if< / span > < span class = "plain" > (< / span > < span class = "identifier" > change< / span > < span class = "plain" > == < / span > < span class = "constant" > 1< / span > < span class = "plain" > ) < / span > < < span class = "cwebmacro" > Expand the dictionary if necessary< / span > < span class = "cwebmacronumber" > 7.2< / span > > < span class = "plain" > ;< / span >
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< < span class = "cwebmacro" > Work within the existing dictionary< / span > < span class = "cwebmacronumber" > 7.3< / span > > < span class = "plain" > ;< / span >
< span class = "plain" > }< / span >
< / pre >
< p class = "inwebparagraph" > < / p >
< p class = "inwebparagraph" > < a id = "SP7_1" > < / a > < b > § 7.1. < / b > It's legal to perform a find on the null dictionary: the answer's always "no".
< / p >
< p class = "macrodefinition" > < code class = "display" >
< < span class = "cwebmacrodefn" > Handle the null dictionary< / span > < span class = "cwebmacronumber" > 7.1< / span > > =
< / code > < / p >
< pre class = "displaydefn" >
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< span class = "reserved" > if< / span > < span class = "plain" > (< / span > < span class = "identifier" > change< / span > < span class = "plain" > == < / span > < span class = "constant" > 0< / span > < span class = "plain" > ) < / span > < span class = "reserved" > return< / span > < span class = "plain" > < / span > < span class = "identifier" > NULL< / span > < span class = "plain" > ;< / span >
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< span class = "identifier" > internal_error< / span > < span class = "plain" > (< / span > < span class = "string" > "tried to create or destroy in a null dictionary"< / span > < span class = "plain" > );< / span >
< / pre >
< p class = "inwebparagraph" > < / p >
< p class = "endnote" > This code is used in < a href = "#SP7" > § 7< / a > .< / p >
< p class = "inwebparagraph" > < a id = "SP7_2" > < / a > < b > § 7.2. < / b > For speed, our policy is that the hash table should have roughly the
same number of slots as there are entries in the dictionary; that way, each
slot will have an average of one or fewer entries. When we exceed this
ideal population, we double the dictionary's capacity.
< / p >
< p class = "macrodefinition" > < code class = "display" >
< < span class = "cwebmacrodefn" > Expand the dictionary if necessary< / span > < span class = "cwebmacronumber" > 7.2< / span > > =
< / code > < / p >
< pre class = "displaydefn" >
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< span class = "reserved" > if< / span > < span class = "plain" > (< / span > < span class = "identifier" > D< / span > < span class = "plain" > -> < / span > < span class = "element" > no_entries< / span > < span class = "plain" > > < / span > < span class = "identifier" > D< / span > < span class = "plain" > -> < / span > < span class = "element" > hash_table_size< / span > < span class = "plain" > ) {< / span >
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< span class = "reserved" > dictionary< / span > < span class = "plain" > *< / span > < span class = "identifier" > D2< / span > < span class = "plain" > = < / span > < span class = "functiontext" > < a href = "#SP2" > Dictionaries::new< / a > < / span > < span class = "plain" > (2*< / span > < span class = "identifier" > D< / span > < span class = "plain" > -> < / span > < span class = "element" > hash_table_size< / span > < span class = "plain" > , < / span > < span class = "identifier" > D< / span > < span class = "plain" > -> < / span > < span class = "element" > textual< / span > < span class = "plain" > );< / span >
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< span class = "reserved" > for< / span > < span class = "plain" > (< / span > < span class = "reserved" > int< / span > < span class = "plain" > < / span > < span class = "identifier" > i< / span > < span class = "plain" > =0; < / span > < span class = "identifier" > i< / span > < span class = "plain" > < < / span > < span class = "identifier" > D< / span > < span class = "plain" > -> < / span > < span class = "element" > hash_table_size< / span > < span class = "plain" > ; < / span > < span class = "identifier" > i< / span > < span class = "plain" > ++)< / span >
< span class = "reserved" > for< / span > < span class = "plain" > (< / span > < span class = "reserved" > dict_entry< / span > < span class = "plain" > *< / span > < span class = "identifier" > E< / span > < span class = "plain" > = & (< / span > < span class = "identifier" > D< / span > < span class = "plain" > -> < / span > < span class = "element" > hash_table< / span > < span class = "plain" > [< / span > < span class = "identifier" > i< / span > < span class = "plain" > ]); < / span > < span class = "identifier" > E< / span > < span class = "plain" > ; < / span > < span class = "identifier" > E< / span > < span class = "plain" > = < / span > < span class = "identifier" > E< / span > < span class = "plain" > -> < / span > < span class = "element" > next_in_entry< / span > < span class = "plain" > )< / span >
< span class = "reserved" > if< / span > < span class = "plain" > (< / span > < span class = "identifier" > E< / span > < span class = "plain" > -> < / span > < span class = "element" > vacant< / span > < span class = "plain" > == < / span > < span class = "constant" > FALSE< / span > < span class = "plain" > ) {< / span >
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< span class = "reserved" > dict_entry< / span > < span class = "plain" > *< / span > < span class = "identifier" > E2< / span > < span class = "plain" > = < / span > < span class = "functiontext" > < a href = "#SP7" > Dictionaries::find_p< / a > < / span > < span class = "plain" > (< / span > < span class = "identifier" > D2< / span > < span class = "plain" > , < / span > < span class = "identifier" > E< / span > < span class = "plain" > -> < / span > < span class = "element" > key< / span > < span class = "plain" > , < / span > < span class = "constant" > 1< / span > < span class = "plain" > );< / span >
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< span class = "identifier" > E2< / span > < span class = "plain" > -> < / span > < span class = "element" > value< / span > < span class = "plain" > = < / span > < span class = "identifier" > E< / span > < span class = "plain" > -> < / span > < span class = "element" > value< / span > < span class = "plain" > ;< / span >
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< span class = "plain" > }< / span >
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< span class = "functiontext" > < a href = "2-mmr.html#SP27" > Memory::I7_free< / a > < / span > < span class = "plain" > (< / span > < span class = "identifier" > D< / span > < span class = "plain" > -> < / span > < span class = "element" > hash_table< / span > < span class = "plain" > , < / span > < span class = "constant" > DICTIONARY_MREASON< / span > < span class = "plain" > ,< / span >
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< span class = "identifier" > D< / span > < span class = "plain" > -> < / span > < span class = "element" > hash_table_size< / span > < span class = "plain" > *((< / span > < span class = "reserved" > int< / span > < span class = "plain" > ) < / span > < span class = "reserved" > sizeof< / span > < span class = "plain" > (< / span > < span class = "reserved" > dict_entry< / span > < span class = "plain" > )));< / span >
< span class = "identifier" > D< / span > < span class = "plain" > -> < / span > < span class = "element" > hash_table_size< / span > < span class = "plain" > = < / span > < span class = "identifier" > D2< / span > < span class = "plain" > -> < / span > < span class = "element" > hash_table_size< / span > < span class = "plain" > ;< / span >
< span class = "identifier" > D< / span > < span class = "plain" > -> < / span > < span class = "element" > hash_table< / span > < span class = "plain" > = < / span > < span class = "identifier" > D2< / span > < span class = "plain" > -> < / span > < span class = "element" > hash_table< / span > < span class = "plain" > ;< / span >
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< span class = "plain" > }< / span >
< / pre >
< p class = "inwebparagraph" > < / p >
< p class = "endnote" > This code is used in < a href = "#SP7" > § 7< / a > .< / p >
< p class = "inwebparagraph" > < a id = "SP7_3" > < / a > < b > § 7.3. < / b > < code class = "display" >
< < span class = "cwebmacrodefn" > Work within the existing dictionary< / span > < span class = "cwebmacronumber" > 7.3< / span > > =
< / code > < / p >
< pre class = "displaydefn" >
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< span class = "reserved" > dict_entry< / span > < span class = "plain" > *< / span > < span class = "identifier" > last_E< / span > < span class = "plain" > = < / span > < span class = "identifier" > NULL< / span > < span class = "plain" > ;< / span >
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< span class = "reserved" > for< / span > < span class = "plain" > (< / span > < span class = "reserved" > dict_entry< / span > < span class = "plain" > *< / span > < span class = "identifier" > E< / span > < span class = "plain" > = & (< / span > < span class = "identifier" > D< / span > < span class = "plain" > -> < / span > < span class = "element" > hash_table< / span > < span class = "plain" > [< / span > < span class = "functiontext" > < a href = "#SP4" > Dictionaries::hash< / a > < / span > < span class = "plain" > (< / span > < span class = "identifier" > K< / span > < span class = "plain" > , < / span > < span class = "identifier" > D< / span > < span class = "plain" > -> < / span > < span class = "element" > hash_table_size< / span > < span class = "plain" > )]);< / span >
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< span class = "identifier" > E< / span > < span class = "plain" > ; < / span > < span class = "identifier" > E< / span > < span class = "plain" > = < / span > < span class = "identifier" > E< / span > < span class = "plain" > -> < / span > < span class = "identifier" > next_in_entry< / span > < span class = "plain" > ) {< / span >
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< span class = "identifier" > last_E< / span > < span class = "plain" > = < / span > < span class = "identifier" > E< / span > < span class = "plain" > ;< / span >
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< span class = "reserved" > if< / span > < span class = "plain" > (< / span > < span class = "identifier" > E< / span > < span class = "plain" > -> < / span > < span class = "element" > vacant< / span > < span class = "plain" > ) {< / span >
< span class = "reserved" > if< / span > < span class = "plain" > (< / span > < span class = "identifier" > change< / span > < span class = "plain" > == < / span > < span class = "constant" > 1< / span > < span class = "plain" > ) { < / span > < < span class = "cwebmacro" > Make E the new entry< / span > < span class = "cwebmacronumber" > 7.3.1< / span > > < span class = "plain" > ; < / span > < span class = "reserved" > return< / span > < span class = "plain" > < / span > < span class = "identifier" > E< / span > < span class = "plain" > ; }< / span >
< span class = "plain" > } < / span > < span class = "reserved" > else< / span > < span class = "plain" > {< / span >
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< span class = "reserved" > if< / span > < span class = "plain" > (< / span > < span class = "functiontext" > < a href = "4-sm.html#SP18" > Str::eq< / a > < / span > < span class = "plain" > (< / span > < span class = "identifier" > K< / span > < span class = "plain" > , < / span > < span class = "identifier" > E< / span > < span class = "plain" > -> < / span > < span class = "element" > key< / span > < span class = "plain" > )) {< / span >
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< span class = "reserved" > if< / span > < span class = "plain" > (< / span > < span class = "identifier" > change< / span > < span class = "plain" > == -1) < / span > < < span class = "cwebmacro" > Destroy the E entry< / span > < span class = "cwebmacronumber" > 7.3.2< / span > > < span class = "plain" > ;< / span >
< span class = "reserved" > return< / span > < span class = "plain" > < / span > < span class = "identifier" > E< / span > < span class = "plain" > ;< / span >
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< span class = "plain" > }< / span >
< span class = "plain" > }< / span >
< span class = "plain" > }< / span >
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< span class = "reserved" > if< / span > < span class = "plain" > (< / span > < span class = "identifier" > change< / span > < span class = "plain" > == < / span > < span class = "constant" > 1< / span > < span class = "plain" > ) {< / span >
< span class = "reserved" > dict_entry< / span > < span class = "plain" > *< / span > < span class = "identifier" > E< / span > < span class = "plain" > = < / span > < span class = "identifier" > CREATE< / span > < span class = "plain" > (< / span > < span class = "reserved" > dict_entry< / span > < span class = "plain" > );< / span >
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< < span class = "cwebmacro" > Make E the new entry< / span > < span class = "cwebmacronumber" > 7.3.1< / span > > < span class = "plain" > ;< / span >
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< span class = "identifier" > last_E< / span > < span class = "plain" > -> < / span > < span class = "element" > next_in_entry< / span > < span class = "plain" > = < / span > < span class = "identifier" > E< / span > < span class = "plain" > ;< / span >
< span class = "reserved" > return< / span > < span class = "plain" > < / span > < span class = "identifier" > E< / span > < span class = "plain" > ;< / span >
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< span class = "plain" > }< / span >
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< span class = "reserved" > return< / span > < span class = "plain" > < / span > < span class = "identifier" > NULL< / span > < span class = "plain" > ;< / span >
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< / pre >
< p class = "inwebparagraph" > < / p >
< p class = "endnote" > This code is used in < a href = "#SP7" > § 7< / a > .< / p >
< p class = "inwebparagraph" > < a id = "SP7_3_1" > < / a > < b > § 7.3.1. < / b > When creating text values, we want them to be empty strings rather than null
strings, so that printing to them will work.
< / p >
< p class = "macrodefinition" > < code class = "display" >
< < span class = "cwebmacrodefn" > Make E the new entry< / span > < span class = "cwebmacronumber" > 7.3.1< / span > > =
< / code > < / p >
< pre class = "displaydefn" >
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< span class = "identifier" > E< / span > < span class = "plain" > -> < / span > < span class = "element" > vacant< / span > < span class = "plain" > = < / span > < span class = "constant" > FALSE< / span > < span class = "plain" > ;< / span >
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< span class = "reserved" > if< / span > < span class = "plain" > (< / span > < span class = "identifier" > D< / span > < span class = "plain" > -> < / span > < span class = "element" > textual< / span > < span class = "plain" > ) < / span > < span class = "identifier" > E< / span > < span class = "plain" > -> < / span > < span class = "element" > value< / span > < span class = "plain" > = < / span > < span class = "functiontext" > < a href = "4-sm.html#SP2" > Str::new< / a > < / span > < span class = "plain" > (); < / span > < span class = "reserved" > else< / span > < span class = "plain" > < / span > < span class = "identifier" > E< / span > < span class = "plain" > -> < / span > < span class = "element" > value< / span > < span class = "plain" > = < / span > < span class = "identifier" > NULL< / span > < span class = "plain" > ;< / span >
< span class = "identifier" > E< / span > < span class = "plain" > -> < / span > < span class = "element" > key< / span > < span class = "plain" > = < / span > < span class = "functiontext" > < a href = "4-sm.html#SP3" > Str::duplicate< / a > < / span > < span class = "plain" > (< / span > < span class = "identifier" > K< / span > < span class = "plain" > );< / span >
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< span class = "identifier" > D< / span > < span class = "plain" > -> < / span > < span class = "element" > no_entries< / span > < span class = "plain" > ++;< / span >
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< / pre >
< p class = "inwebparagraph" > < / p >
< p class = "endnote" > This code is used in < a href = "#SP7_3" > § 7.3< / a > (twice).< / p >
< p class = "inwebparagraph" > < a id = "SP7_3_2" > < / a > < b > § 7.3.2. < / b > When deleting text values, we close them first, to give back the memory.
Careful: it would not be thread-safe to allow different threads to use the
same dictionary if deletions are a possibility.
< / p >
< p class = "macrodefinition" > < code class = "display" >
< < span class = "cwebmacrodefn" > Destroy the E entry< / span > < span class = "cwebmacronumber" > 7.3.2< / span > > =
< / code > < / p >
< pre class = "displaydefn" >
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< span class = "identifier" > E< / span > < span class = "plain" > -> < / span > < span class = "element" > vacant< / span > < span class = "plain" > = < / span > < span class = "constant" > TRUE< / span > < span class = "plain" > ; < / span > < span class = "identifier" > D< / span > < span class = "plain" > -> < / span > < span class = "element" > no_entries< / span > < span class = "plain" > --;< / span >
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< span class = "reserved" > if< / span > < span class = "plain" > ((< / span > < span class = "identifier" > D< / span > < span class = "plain" > -> < / span > < span class = "element" > textual< / span > < span class = "plain" > ) & & (< / span > < span class = "identifier" > E< / span > < span class = "plain" > -> < / span > < span class = "element" > value< / span > < span class = "plain" > )) < / span > < span class = "functiontext" > < a href = "4-sm.html#SP2" > Str::dispose_of< / a > < / span > < span class = "plain" > (< / span > < span class = "identifier" > E< / span > < span class = "plain" > -> < / span > < span class = "element" > value< / span > < span class = "plain" > );< / span >
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< span class = "identifier" > E< / span > < span class = "plain" > -> < / span > < span class = "element" > value< / span > < span class = "plain" > = < / span > < span class = "identifier" > NULL< / span > < span class = "plain" > ;< / span >
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< / pre >
< p class = "inwebparagraph" > < / p >
< p class = "endnote" > This code is used in < a href = "#SP7_3" > § 7.3< / a > .< / p >
< p class = "inwebparagraph" > < a id = "SP8" > < / a > < b > § 8. Accessing entries. < / b > Eventually we're going to want the value. In principle we could be storing
values which are arbitrary pointers, so we have to use void pointers:
< / p >
< pre class = "display" >
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< span class = "reserved" > void< / span > < span class = "plain" > *< / span > < span class = "functiontext" > Dictionaries::read_value< button class = "popup" onclick = "togglePopup('usagePopup141')" > ...< span class = "popuptext" id = "usagePopup141" > Usage of < b > Dictionaries::read_value< / b > :< br > Command Line Arguments - < a href = "3-cla.html#SP13" > § 13< / a > < / span > < / button > < / span > < span class = "plain" > (< / span > < span class = "reserved" > dictionary< / span > < span class = "plain" > *< / span > < span class = "identifier" > D< / span > < span class = "plain" > , < / span > < span class = "reserved" > text_stream< / span > < span class = "plain" > *< / span > < span class = "identifier" > key< / span > < span class = "plain" > ) {< / span >
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< span class = "reserved" > if< / span > < span class = "plain" > (< / span > < span class = "identifier" > D< / span > < span class = "plain" > == < / span > < span class = "identifier" > NULL< / span > < span class = "plain" > ) < / span > < span class = "reserved" > return< / span > < span class = "plain" > < / span > < span class = "identifier" > NULL< / span > < span class = "plain" > ;< / span >
< span class = "reserved" > if< / span > < span class = "plain" > (< / span > < span class = "identifier" > D< / span > < span class = "plain" > -> < / span > < span class = "element" > textual< / span > < span class = "plain" > ) < / span > < span class = "identifier" > internal_error< / span > < span class = "plain" > (< / span > < span class = "string" > "textual dictionary accessed as pointy"< / span > < span class = "plain" > );< / span >
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< span class = "reserved" > dict_entry< / span > < span class = "plain" > *< / span > < span class = "identifier" > E< / span > < span class = "plain" > = < / span > < span class = "functiontext" > < a href = "#SP5" > Dictionaries::find< / a > < / span > < span class = "plain" > (< / span > < span class = "identifier" > D< / span > < span class = "plain" > , < / span > < span class = "identifier" > key< / span > < span class = "plain" > );< / span >
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< span class = "reserved" > if< / span > < span class = "plain" > (< / span > < span class = "identifier" > E< / span > < span class = "plain" > == < / span > < span class = "identifier" > NULL< / span > < span class = "plain" > ) < / span > < span class = "identifier" > internal_error< / span > < span class = "plain" > (< / span > < span class = "string" > "read null dictionary entry"< / span > < span class = "plain" > );< / span >
< span class = "reserved" > if< / span > < span class = "plain" > (< / span > < span class = "identifier" > E< / span > < span class = "plain" > -> < / span > < span class = "element" > vacant< / span > < span class = "plain" > ) < / span > < span class = "identifier" > internal_error< / span > < span class = "plain" > (< / span > < span class = "string" > "read vacant dictionary entry"< / span > < span class = "plain" > );< / span >
< span class = "reserved" > return< / span > < span class = "plain" > < / span > < span class = "identifier" > E< / span > < span class = "plain" > -> < / span > < span class = "identifier" > value< / span > < span class = "plain" > ;< / span >
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< span class = "plain" > }< / span >
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< span class = "reserved" > void< / span > < span class = "plain" > *< / span > < span class = "functiontext" > Dictionaries::read_value_literal< button class = "popup" onclick = "togglePopup('usagePopup142')" > ...< span class = "popuptext" id = "usagePopup142" > Usage of < b > Dictionaries::read_value_literal< / b > :< br > none< / span > < / button > < / span > < span class = "plain" > (< / span > < span class = "reserved" > dictionary< / span > < span class = "plain" > *< / span > < span class = "identifier" > D< / span > < span class = "plain" > , < / span > < span class = "identifier" > wchar_t< / span > < span class = "plain" > *< / span > < span class = "identifier" > key< / span > < span class = "plain" > ) {< / span >
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< span class = "reserved" > if< / span > < span class = "plain" > (< / span > < span class = "identifier" > D< / span > < span class = "plain" > == < / span > < span class = "identifier" > NULL< / span > < span class = "plain" > ) < / span > < span class = "reserved" > return< / span > < span class = "plain" > < / span > < span class = "identifier" > NULL< / span > < span class = "plain" > ;< / span >
< span class = "reserved" > if< / span > < span class = "plain" > (< / span > < span class = "identifier" > D< / span > < span class = "plain" > -> < / span > < span class = "element" > textual< / span > < span class = "plain" > ) < / span > < span class = "identifier" > internal_error< / span > < span class = "plain" > (< / span > < span class = "string" > "textual dictionary accessed as pointy"< / span > < span class = "plain" > );< / span >
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< span class = "reserved" > dict_entry< / span > < span class = "plain" > *< / span > < span class = "identifier" > E< / span > < span class = "plain" > = < / span > < span class = "functiontext" > < a href = "#SP6" > Dictionaries::find_literal< / a > < / span > < span class = "plain" > (< / span > < span class = "identifier" > D< / span > < span class = "plain" > , < / span > < span class = "identifier" > key< / span > < span class = "plain" > );< / span >
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< span class = "reserved" > if< / span > < span class = "plain" > (< / span > < span class = "identifier" > E< / span > < span class = "plain" > == < / span > < span class = "identifier" > NULL< / span > < span class = "plain" > ) < / span > < span class = "identifier" > internal_error< / span > < span class = "plain" > (< / span > < span class = "string" > "read null dictionary entry"< / span > < span class = "plain" > );< / span >
< span class = "reserved" > if< / span > < span class = "plain" > (< / span > < span class = "identifier" > E< / span > < span class = "plain" > -> < / span > < span class = "element" > vacant< / span > < span class = "plain" > ) < / span > < span class = "identifier" > internal_error< / span > < span class = "plain" > (< / span > < span class = "string" > "read vacant dictionary entry"< / span > < span class = "plain" > );< / span >
< span class = "reserved" > return< / span > < span class = "plain" > < / span > < span class = "identifier" > E< / span > < span class = "plain" > -> < / span > < span class = "identifier" > value< / span > < span class = "plain" > ;< / span >
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< span class = "plain" > }< / span >
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< span class = "reserved" > void< / span > < span class = "plain" > < / span > < span class = "functiontext" > Dictionaries::write_value< button class = "popup" onclick = "togglePopup('usagePopup143')" > ...< span class = "popuptext" id = "usagePopup143" > Usage of < b > Dictionaries::write_value< / b > :< br > Command Line Arguments - < a href = "3-cla.html#SP5" > § 5< / a > < / span > < / button > < / span > < span class = "plain" > (< / span > < span class = "reserved" > dictionary< / span > < span class = "plain" > *< / span > < span class = "identifier" > D< / span > < span class = "plain" > , < / span > < span class = "reserved" > text_stream< / span > < span class = "plain" > *< / span > < span class = "identifier" > key< / span > < span class = "plain" > , < / span > < span class = "reserved" > void< / span > < span class = "plain" > *< / span > < span class = "identifier" > val< / span > < span class = "plain" > ) {< / span >
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< span class = "reserved" > if< / span > < span class = "plain" > (< / span > < span class = "identifier" > D< / span > < span class = "plain" > == < / span > < span class = "identifier" > NULL< / span > < span class = "plain" > ) < / span > < span class = "identifier" > internal_error< / span > < span class = "plain" > (< / span > < span class = "string" > "wrote to null dictionary"< / span > < span class = "plain" > );< / span >
< span class = "reserved" > if< / span > < span class = "plain" > (< / span > < span class = "identifier" > D< / span > < span class = "plain" > -> < / span > < span class = "element" > textual< / span > < span class = "plain" > ) < / span > < span class = "identifier" > internal_error< / span > < span class = "plain" > (< / span > < span class = "string" > "textual dictionary accessed as pointy"< / span > < span class = "plain" > );< / span >
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< span class = "reserved" > dict_entry< / span > < span class = "plain" > *< / span > < span class = "identifier" > E< / span > < span class = "plain" > = < / span > < span class = "functiontext" > < a href = "#SP5" > Dictionaries::find< / a > < / span > < span class = "plain" > (< / span > < span class = "identifier" > D< / span > < span class = "plain" > , < / span > < span class = "identifier" > key< / span > < span class = "plain" > );< / span >
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< span class = "reserved" > if< / span > < span class = "plain" > (< / span > < span class = "identifier" > E< / span > < span class = "plain" > == < / span > < span class = "identifier" > NULL< / span > < span class = "plain" > ) < / span > < span class = "identifier" > internal_error< / span > < span class = "plain" > (< / span > < span class = "string" > "wrote null dictionary entry"< / span > < span class = "plain" > );< / span >
< span class = "reserved" > if< / span > < span class = "plain" > (< / span > < span class = "identifier" > E< / span > < span class = "plain" > -> < / span > < span class = "element" > vacant< / span > < span class = "plain" > ) < / span > < span class = "identifier" > internal_error< / span > < span class = "plain" > (< / span > < span class = "string" > "wrote vacant dictionary entry"< / span > < span class = "plain" > );< / span >
< span class = "identifier" > E< / span > < span class = "plain" > -> < / span > < span class = "element" > value< / span > < span class = "plain" > = < / span > < span class = "identifier" > val< / span > < span class = "plain" > ;< / span >
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< span class = "plain" > }< / span >
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< span class = "reserved" > void< / span > < span class = "plain" > < / span > < span class = "functiontext" > Dictionaries::write_value_literal< button class = "popup" onclick = "togglePopup('usagePopup144')" > ...< span class = "popuptext" id = "usagePopup144" > Usage of < b > Dictionaries::write_value_literal< / b > :< br > none< / span > < / button > < / span > < span class = "plain" > (< / span > < span class = "reserved" > dictionary< / span > < span class = "plain" > *< / span > < span class = "identifier" > D< / span > < span class = "plain" > , < / span > < span class = "identifier" > wchar_t< / span > < span class = "plain" > *< / span > < span class = "identifier" > key< / span > < span class = "plain" > , < / span > < span class = "reserved" > void< / span > < span class = "plain" > *< / span > < span class = "identifier" > val< / span > < span class = "plain" > ) {< / span >
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< span class = "reserved" > if< / span > < span class = "plain" > (< / span > < span class = "identifier" > D< / span > < span class = "plain" > == < / span > < span class = "identifier" > NULL< / span > < span class = "plain" > ) < / span > < span class = "identifier" > internal_error< / span > < span class = "plain" > (< / span > < span class = "string" > "wrote to null dictionary"< / span > < span class = "plain" > );< / span >
< span class = "reserved" > if< / span > < span class = "plain" > (< / span > < span class = "identifier" > D< / span > < span class = "plain" > -> < / span > < span class = "element" > textual< / span > < span class = "plain" > ) < / span > < span class = "identifier" > internal_error< / span > < span class = "plain" > (< / span > < span class = "string" > "textual dictionary accessed as pointy"< / span > < span class = "plain" > );< / span >
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< span class = "reserved" > dict_entry< / span > < span class = "plain" > *< / span > < span class = "identifier" > E< / span > < span class = "plain" > = < / span > < span class = "functiontext" > < a href = "#SP6" > Dictionaries::find_literal< / a > < / span > < span class = "plain" > (< / span > < span class = "identifier" > D< / span > < span class = "plain" > , < / span > < span class = "identifier" > key< / span > < span class = "plain" > );< / span >
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< span class = "reserved" > if< / span > < span class = "plain" > (< / span > < span class = "identifier" > E< / span > < span class = "plain" > == < / span > < span class = "identifier" > NULL< / span > < span class = "plain" > ) < / span > < span class = "identifier" > internal_error< / span > < span class = "plain" > (< / span > < span class = "string" > "wrote null dictionary entry"< / span > < span class = "plain" > );< / span >
< span class = "reserved" > if< / span > < span class = "plain" > (< / span > < span class = "identifier" > E< / span > < span class = "plain" > -> < / span > < span class = "element" > vacant< / span > < span class = "plain" > ) < / span > < span class = "identifier" > internal_error< / span > < span class = "plain" > (< / span > < span class = "string" > "wrote vacant dictionary entry"< / span > < span class = "plain" > );< / span >
< span class = "identifier" > E< / span > < span class = "plain" > -> < / span > < span class = "element" > value< / span > < span class = "plain" > = < / span > < span class = "identifier" > val< / span > < span class = "plain" > ;< / span >
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< span class = "plain" > }< / span >
< / pre >
< p class = "inwebparagraph" > < / p >
< p class = "inwebparagraph" > < a id = "SP9" > < / a > < b > § 9. < / b > But the commonest use case is that the dictionary stores texts as values,
so we provide convenient wrappers with the correct C types.
< / p >
< pre class = "display" >
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< span class = "reserved" > text_stream< / span > < span class = "plain" > *< / span > < span class = "functiontext" > Dictionaries::create_text< button class = "popup" onclick = "togglePopup('usagePopup145')" > ...< span class = "popuptext" id = "usagePopup145" > Usage of < b > Dictionaries::create_text< / b > :< br > none< / span > < / button > < / span > < span class = "plain" > (< / span > < span class = "reserved" > dictionary< / span > < span class = "plain" > *< / span > < span class = "identifier" > D< / span > < span class = "plain" > , < / span > < span class = "reserved" > text_stream< / span > < span class = "plain" > *< / span > < span class = "identifier" > key< / span > < span class = "plain" > ) {< / span >
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< span class = "reserved" > if< / span > < span class = "plain" > (< / span > < span class = "identifier" > D< / span > < span class = "plain" > == < / span > < span class = "identifier" > NULL< / span > < span class = "plain" > ) < / span > < span class = "identifier" > internal_error< / span > < span class = "plain" > (< / span > < span class = "string" > "wrote to null dictionary"< / span > < span class = "plain" > );< / span >
< span class = "reserved" > if< / span > < span class = "plain" > (< / span > < span class = "identifier" > D< / span > < span class = "plain" > -> < / span > < span class = "element" > textual< / span > < span class = "plain" > == < / span > < span class = "constant" > FALSE< / span > < span class = "plain" > ) < / span > < span class = "identifier" > internal_error< / span > < span class = "plain" > (< / span > < span class = "string" > "pointy dictionary accessed as textual"< / span > < span class = "plain" > );< / span >
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< span class = "reserved" > dict_entry< / span > < span class = "plain" > *< / span > < span class = "identifier" > E< / span > < span class = "plain" > = < / span > < span class = "functiontext" > < a href = "#SP5" > Dictionaries::create< / a > < / span > < span class = "plain" > (< / span > < span class = "identifier" > D< / span > < span class = "plain" > , < / span > < span class = "identifier" > key< / span > < span class = "plain" > );< / span >
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< span class = "reserved" > return< / span > < span class = "plain" > (< / span > < span class = "reserved" > text_stream< / span > < span class = "plain" > *) < / span > < span class = "identifier" > E< / span > < span class = "plain" > -> < / span > < span class = "element" > value< / span > < span class = "plain" > ;< / span >
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< span class = "plain" > }< / span >
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< span class = "reserved" > text_stream< / span > < span class = "plain" > *< / span > < span class = "functiontext" > Dictionaries::create_text_literal< button class = "popup" onclick = "togglePopup('usagePopup146')" > ...< span class = "popuptext" id = "usagePopup146" > Usage of < b > Dictionaries::create_text_literal< / b > :< br > none< / span > < / button > < / span > < span class = "plain" > (< / span > < span class = "reserved" > dictionary< / span > < span class = "plain" > *< / span > < span class = "identifier" > D< / span > < span class = "plain" > , < / span > < span class = "identifier" > wchar_t< / span > < span class = "plain" > *< / span > < span class = "identifier" > lit< / span > < span class = "plain" > ) {< / span >
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< span class = "reserved" > if< / span > < span class = "plain" > (< / span > < span class = "identifier" > D< / span > < span class = "plain" > == < / span > < span class = "identifier" > NULL< / span > < span class = "plain" > ) < / span > < span class = "identifier" > internal_error< / span > < span class = "plain" > (< / span > < span class = "string" > "wrote to null dictionary"< / span > < span class = "plain" > );< / span >
< span class = "reserved" > if< / span > < span class = "plain" > (< / span > < span class = "identifier" > D< / span > < span class = "plain" > -> < / span > < span class = "element" > textual< / span > < span class = "plain" > == < / span > < span class = "constant" > FALSE< / span > < span class = "plain" > ) < / span > < span class = "identifier" > internal_error< / span > < span class = "plain" > (< / span > < span class = "string" > "pointy dictionary accessed as textual"< / span > < span class = "plain" > );< / span >
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< span class = "reserved" > dict_entry< / span > < span class = "plain" > *< / span > < span class = "identifier" > E< / span > < span class = "plain" > = < / span > < span class = "functiontext" > < a href = "#SP6" > Dictionaries::create_literal< / a > < / span > < span class = "plain" > (< / span > < span class = "identifier" > D< / span > < span class = "plain" > , < / span > < span class = "identifier" > lit< / span > < span class = "plain" > );< / span >
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< span class = "reserved" > return< / span > < span class = "plain" > (< / span > < span class = "reserved" > text_stream< / span > < span class = "plain" > *) < / span > < span class = "identifier" > E< / span > < span class = "plain" > -> < / span > < span class = "element" > value< / span > < span class = "plain" > ;< / span >
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< span class = "plain" > }< / span >
< / pre >
< p class = "inwebparagraph" > < / p >
< p class = "inwebparagraph" > < a id = "SP10" > < / a > < b > § 10. < / b > We only need a read operation, because the caller can write to the dictionary
entry by reading the text pointer and then using < code class = "display" > < span class = "extract" > WRITE_TO< / span > < / code > .
< / p >
< pre class = "display" >
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< span class = "reserved" > text_stream< / span > < span class = "plain" > *< / span > < span class = "functiontext" > Dictionaries::get_text< button class = "popup" onclick = "togglePopup('usagePopup147')" > ...< span class = "popuptext" id = "usagePopup147" > Usage of < b > Dictionaries::get_text< / b > :< br > none< / span > < / button > < / span > < span class = "plain" > (< / span > < span class = "reserved" > dictionary< / span > < span class = "plain" > *< / span > < span class = "identifier" > D< / span > < span class = "plain" > , < / span > < span class = "reserved" > text_stream< / span > < span class = "plain" > *< / span > < span class = "identifier" > key< / span > < span class = "plain" > ) {< / span >
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< span class = "reserved" > if< / span > < span class = "plain" > (< / span > < span class = "identifier" > D< / span > < span class = "plain" > == < / span > < span class = "identifier" > NULL< / span > < span class = "plain" > ) < / span > < span class = "reserved" > return< / span > < span class = "plain" > < / span > < span class = "identifier" > NULL< / span > < span class = "plain" > ;< / span >
< span class = "reserved" > if< / span > < span class = "plain" > (< / span > < span class = "identifier" > D< / span > < span class = "plain" > -> < / span > < span class = "element" > textual< / span > < span class = "plain" > == < / span > < span class = "constant" > FALSE< / span > < span class = "plain" > ) < / span > < span class = "identifier" > internal_error< / span > < span class = "plain" > (< / span > < span class = "string" > "pointy dictionary accessed as textual"< / span > < span class = "plain" > );< / span >
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< span class = "reserved" > dict_entry< / span > < span class = "plain" > *< / span > < span class = "identifier" > E< / span > < span class = "plain" > = < / span > < span class = "functiontext" > < a href = "#SP5" > Dictionaries::find< / a > < / span > < span class = "plain" > (< / span > < span class = "identifier" > D< / span > < span class = "plain" > , < / span > < span class = "identifier" > key< / span > < span class = "plain" > );< / span >
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< span class = "reserved" > if< / span > < span class = "plain" > (< / span > < span class = "identifier" > E< / span > < span class = "plain" > == < / span > < span class = "identifier" > NULL< / span > < span class = "plain" > ) < / span > < span class = "reserved" > return< / span > < span class = "plain" > < / span > < span class = "identifier" > NULL< / span > < span class = "plain" > ;< / span >
< span class = "reserved" > return< / span > < span class = "plain" > (< / span > < span class = "reserved" > text_stream< / span > < span class = "plain" > *) < / span > < span class = "identifier" > E< / span > < span class = "plain" > -> < / span > < span class = "element" > value< / span > < span class = "plain" > ;< / span >
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< span class = "plain" > }< / span >
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< span class = "reserved" > text_stream< / span > < span class = "plain" > *< / span > < span class = "functiontext" > Dictionaries::get_text_literal< button class = "popup" onclick = "togglePopup('usagePopup148')" > ...< span class = "popuptext" id = "usagePopup148" > Usage of < b > Dictionaries::get_text_literal< / b > :< br > String Manipulation - < a href = "4-sm.html#SP26_1" > § 26.1< / a > < / span > < / button > < / span > < span class = "plain" > (< / span > < span class = "reserved" > dictionary< / span > < span class = "plain" > *< / span > < span class = "identifier" > D< / span > < span class = "plain" > , < / span > < span class = "identifier" > wchar_t< / span > < span class = "plain" > *< / span > < span class = "identifier" > lit< / span > < span class = "plain" > ) {< / span >
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< span class = "reserved" > if< / span > < span class = "plain" > (< / span > < span class = "identifier" > D< / span > < span class = "plain" > == < / span > < span class = "identifier" > NULL< / span > < span class = "plain" > ) < / span > < span class = "reserved" > return< / span > < span class = "plain" > < / span > < span class = "identifier" > NULL< / span > < span class = "plain" > ;< / span >
< span class = "reserved" > if< / span > < span class = "plain" > (< / span > < span class = "identifier" > D< / span > < span class = "plain" > -> < / span > < span class = "element" > textual< / span > < span class = "plain" > == < / span > < span class = "constant" > FALSE< / span > < span class = "plain" > ) < / span > < span class = "identifier" > internal_error< / span > < span class = "plain" > (< / span > < span class = "string" > "pointy dictionary accessed as textual"< / span > < span class = "plain" > );< / span >
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< span class = "reserved" > dict_entry< / span > < span class = "plain" > *< / span > < span class = "identifier" > E< / span > < span class = "plain" > = < / span > < span class = "functiontext" > < a href = "#SP6" > Dictionaries::find_literal< / a > < / span > < span class = "plain" > (< / span > < span class = "identifier" > D< / span > < span class = "plain" > , < / span > < span class = "identifier" > lit< / span > < span class = "plain" > );< / span >
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< span class = "reserved" > if< / span > < span class = "plain" > (< / span > < span class = "identifier" > E< / span > < span class = "plain" > == < / span > < span class = "identifier" > NULL< / span > < span class = "plain" > ) < / span > < span class = "reserved" > return< / span > < span class = "plain" > < / span > < span class = "identifier" > NULL< / span > < span class = "plain" > ;< / span >
< span class = "reserved" > return< / span > < span class = "plain" > (< / span > < span class = "reserved" > text_stream< / span > < span class = "plain" > *) < / span > < span class = "identifier" > E< / span > < span class = "plain" > -> < / span > < span class = "element" > value< / span > < span class = "plain" > ;< / span >
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< span class = "plain" > }< / span >
< / pre >
< p class = "inwebparagraph" > < / p >
< p class = "inwebparagraph" > < a id = "SP11" > < / a > < b > § 11. Disposal. < / b > If a dictionary was only needed temporarily then we should dispose of it
and free the memory when done:
< / p >
< pre class = "display" >
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< span class = "reserved" > void< / span > < span class = "plain" > < / span > < span class = "functiontext" > Dictionaries::dispose_of< button class = "popup" onclick = "togglePopup('usagePopup149')" > ...< span class = "popuptext" id = "usagePopup149" > Usage of < b > Dictionaries::dispose_of< / b > :< br > none< / span > < / button > < / span > < span class = "plain" > (< / span > < span class = "reserved" > dictionary< / span > < span class = "plain" > *< / span > < span class = "identifier" > D< / span > < span class = "plain" > ) {< / span >
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< span class = "reserved" > if< / span > < span class = "plain" > (< / span > < span class = "identifier" > D< / span > < span class = "plain" > -> < / span > < span class = "element" > textual< / span > < span class = "plain" > )< / span >
< span class = "reserved" > for< / span > < span class = "plain" > (< / span > < span class = "reserved" > int< / span > < span class = "plain" > < / span > < span class = "identifier" > i< / span > < span class = "plain" > =0; < / span > < span class = "identifier" > i< / span > < span class = "plain" > < < / span > < span class = "identifier" > D< / span > < span class = "plain" > -> < / span > < span class = "element" > hash_table_size< / span > < span class = "plain" > ; < / span > < span class = "identifier" > i< / span > < span class = "plain" > ++)< / span >
< span class = "reserved" > for< / span > < span class = "plain" > (< / span > < span class = "reserved" > dict_entry< / span > < span class = "plain" > *< / span > < span class = "identifier" > E< / span > < span class = "plain" > = & (< / span > < span class = "identifier" > D< / span > < span class = "plain" > -> < / span > < span class = "element" > hash_table< / span > < span class = "plain" > [< / span > < span class = "identifier" > i< / span > < span class = "plain" > ]); < / span > < span class = "identifier" > E< / span > < span class = "plain" > ; < / span > < span class = "identifier" > E< / span > < span class = "plain" > = < / span > < span class = "identifier" > E< / span > < span class = "plain" > -> < / span > < span class = "element" > next_in_entry< / span > < span class = "plain" > )< / span >
< span class = "reserved" > if< / span > < span class = "plain" > (< / span > < span class = "identifier" > E< / span > < span class = "plain" > -> < / span > < span class = "element" > vacant< / span > < span class = "plain" > == < / span > < span class = "constant" > FALSE< / span > < span class = "plain" > )< / span >
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< span class = "functiontext" > < a href = "4-sm.html#SP2" > Str::dispose_of< / a > < / span > < span class = "plain" > (< / span > < span class = "identifier" > E< / span > < span class = "plain" > -> < / span > < span class = "element" > value< / span > < span class = "plain" > );< / span >
< span class = "functiontext" > < a href = "2-mmr.html#SP27" > Memory::I7_free< / a > < / span > < span class = "plain" > (< / span > < span class = "identifier" > D< / span > < span class = "plain" > -> < / span > < span class = "element" > hash_table< / span > < span class = "plain" > , < / span > < span class = "constant" > DICTIONARY_MREASON< / span > < span class = "plain" > , < / span > < span class = "identifier" > D< / span > < span class = "plain" > -> < / span > < span class = "element" > hash_table_size< / span > < span class = "plain" > *((< / span > < span class = "reserved" > int< / span > < span class = "plain" > ) < / span > < span class = "reserved" > sizeof< / span > < span class = "plain" > (< / span > < span class = "reserved" > dict_entry< / span > < span class = "plain" > )));< / span >
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< span class = "identifier" > D< / span > < span class = "plain" > -> < / span > < span class = "element" > hash_table< / span > < span class = "plain" > = < / span > < span class = "identifier" > NULL< / span > < span class = "plain" > ;< / span >
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< span class = "plain" > }< / span >
< / pre >
< p class = "inwebparagraph" > < / p >
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< hr class = "tocbar" >
< ul class = "toc" > < li > < a href = "2-llas.html" > Back to 'Linked Lists and Stacks'< / a > < / li > < li > < i > (This section ends Chapter 2: Memory, Streams and Collections.)< / i > < / li > < / ul > < hr class = "tocbar" >
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<!-- End of weave -->
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< script >
function togglePopup(material_id) {
var popup = document.getElementById(material_id);
popup.classList.toggle("show");
}
< / script >
< link href = "Popups.css" rel = "stylesheet" rev = "stylesheet" type = "text/css" >
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< / main >
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< / body >
< / html >