432 lines
64 KiB
HTML
432 lines
64 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
|
<html>
|
|
<head>
|
|
<title>Dictionaries</title>
|
|
<meta name="viewport" content="width=device-width initial-scale=1">
|
|
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
|
|
<meta http-equiv="Content-Language" content="en-gb">
|
|
<link href="../inweb.css" rel="stylesheet" rev="stylesheet" type="text/css">
|
|
|
|
</head>
|
|
<body>
|
|
<nav role="navigation">
|
|
<h1><a href="../webs.html">Inweb Source</a></h1>
|
|
<ul>
|
|
<li><a href="../inweb/index.html">inweb</a></li>
|
|
</ul>
|
|
<h2>Foundation</h2>
|
|
<ul>
|
|
<li><a href="../foundation-module/index.html">foundation-module</a></li>
|
|
<li><a href="../foundation-test/index.html">foundation-test</a></li>
|
|
</ul>
|
|
<h2>Example Webs</h2>
|
|
<ul>
|
|
<li><a href="../goldbach/index.html">goldbach</a></li>
|
|
<li><a href="../twinprimes/twinprimes.html">twinprimes</a></li>
|
|
</ul>
|
|
|
|
|
|
</nav>
|
|
<main role="main">
|
|
|
|
<!--Weave of 'Dictionaries' generated by 7-->
|
|
<ul class="crumbs"><li><a href="../webs.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>
|
|
|
|
<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">
|
|
<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>
|
|
<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>
|
|
<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>
|
|
<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>
|
|
<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>
|
|
</pre>
|
|
|
|
<p class="inwebparagraph"></p>
|
|
|
|
<p class="endnote">The structure dictionary is private to this section.</p>
|
|
|
|
<p class="endnote">The structure dict_entry is accessed in 5/ee, 8/bdfw and here.</p>
|
|
|
|
<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">
|
|
<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>
|
|
<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>
|
|
<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>
|
|
<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>
|
|
<span class="plain">}</span>
|
|
<span class="reserved">return</span><span class="plain"> </span><span class="identifier">D</span><span class="plain">;</span>
|
|
<span class="plain">}</span>
|
|
</pre>
|
|
|
|
<p class="inwebparagraph"></p>
|
|
|
|
<p class="inwebparagraph"><a id="SP3"></a><b>§3. Logging. </b></p>
|
|
|
|
<pre class="display">
|
|
<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>
|
|
<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>
|
|
<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>
|
|
<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>
|
|
<span class="plain">}</span>
|
|
<span class="constant">OUTDENT</span><span class="plain">;</span>
|
|
<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">
|
|
<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>
|
|
<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>
|
|
<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>
|
|
<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>
|
|
<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>
|
|
<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">
|
|
<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>
|
|
<span class="plain">}</span>
|
|
<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>
|
|
<span class="plain">}</span>
|
|
<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>
|
|
<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">
|
|
<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>
|
|
<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>
|
|
<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>
|
|
<span class="identifier">DISCARD_TEXT</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="identifier">E</span><span class="plain">;</span>
|
|
<span class="plain">}</span>
|
|
<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>
|
|
<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>
|
|
<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>
|
|
<span class="identifier">DISCARD_TEXT</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="identifier">E</span><span class="plain">;</span>
|
|
<span class="plain">}</span>
|
|
<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>
|
|
<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>
|
|
<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>
|
|
<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">
|
|
<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>
|
|
<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>
|
|
<<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">
|
|
<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>
|
|
<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">
|
|
<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>
|
|
<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>
|
|
<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>
|
|
<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>
|
|
<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>
|
|
<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>
|
|
<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>
|
|
<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">
|
|
<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>
|
|
<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>
|
|
<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>
|
|
<span class="identifier">last_E</span><span class="plain"> = </span><span class="identifier">E</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="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>
|
|
<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>
|
|
<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>
|
|
<span class="plain">}</span>
|
|
<span class="plain">}</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="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>
|
|
<<span class="cwebmacro">Make E the new entry</span> <span class="cwebmacronumber">7.3.1</span>><span class="plain">;</span>
|
|
<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>
|
|
<span class="plain">}</span>
|
|
<span class="reserved">return</span><span class="plain"> </span><span class="identifier">NULL</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_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">
|
|
<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>
|
|
<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>
|
|
<span class="identifier">D</span><span class="plain">-></span><span class="element">no_entries</span><span class="plain">++;</span>
|
|
</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">
|
|
<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>
|
|
<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>
|
|
<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>
|
|
</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">
|
|
<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>
|
|
<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>
|
|
<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>
|
|
<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>
|
|
<span class="plain">}</span>
|
|
<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>
|
|
<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>
|
|
<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>
|
|
<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>
|
|
<span class="plain">}</span>
|
|
|
|
<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>
|
|
<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>
|
|
<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>
|
|
<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>
|
|
<span class="plain">}</span>
|
|
<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>
|
|
<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>
|
|
<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>
|
|
<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>
|
|
<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">
|
|
<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>
|
|
<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>
|
|
<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>
|
|
<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>
|
|
<span class="plain">}</span>
|
|
<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>
|
|
<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>
|
|
<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>
|
|
<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>
|
|
<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">
|
|
<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>
|
|
<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>
|
|
<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>
|
|
<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>
|
|
<span class="plain">}</span>
|
|
|
|
<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>
|
|
<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>
|
|
<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>
|
|
<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>
|
|
<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">
|
|
<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>
|
|
<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>
|
|
<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>
|
|
<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>
|
|
<span class="plain">}</span>
|
|
</pre>
|
|
|
|
<p class="inwebparagraph"></p>
|
|
|
|
<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">
|
|
<!--End of weave-->
|
|
<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">
|
|
</main>
|
|
</body>
|
|
</html>
|
|
|