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<li><a class="reference internal" href="#">1.x vs 2.x</a><ul>
<li><a class="reference internal" href="#allocation">Allocation</a></li>
<li><a class="reference internal" href="#strings-and-names">Strings And Names</a></li>
<li><a class="reference internal" href="#cleanups">Cleanups</a></li>
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<div class="section" id="x-vs-2-x">
<h1>1.x vs 2.x<a class="headerlink" href="#x-vs-2-x" title="Permalink to this headline">¶</a></h1>
<div class="section" id="allocation">
<h2>Allocation<a class="headerlink" href="#allocation" title="Permalink to this headline">¶</a></h2>
<p>Allocation mechanisms has been revised. All objects are still allocated from a private storage (called heap),
but now the heap serves properly aligned memory chunks. Implementation of the heap is (hopefully) platform
independent, so all <code class="docutils literal notranslate"><span class="pre">ARM_COMPLIANT</span></code> checks has been removed. Some details work differently on 32/64-bit
machines, this distinction seems inevitable. Allocation related code has been moved to <code class="docutils literal notranslate"><span class="pre">util/utilmem*.c</span></code> files.</p>
<p>[There are actually 3 different allocators - <strong>heap</strong>, <strong>stock</strong>, and <strong>pool</strong> - each of which has 4 variants
for 1, 2, 4 and 8 bytes alignment. So far <code class="docutils literal notranslate"><span class="pre">pplib</span></code> uses only the <strong>heap</strong>, but I want to have this part
in a single place for a while. More notes about allocators in <code class="docutils literal notranslate"><span class="pre">utilmemallc.h</span></code>.]</p>
<p><code class="docutils literal notranslate"><span class="pre">pplib</span></code> uses two heaps:</p>
<ul class="simple">
<li>bytes heap - providing 2-bytes aligned memory chunks for byte data</li>
<li>structures heap - providing 8-bytes aligned chunks for all structures</li>
</ul>
<p>2-bytes alignment of byte data is caused by implementation details / limits, <code class="docutils literal notranslate"><span class="pre">pplib</span></code> doesn’t make a use of it
(could be unaligned as well). All the structures are stored in 8-bytes aligned chunks on both 32 and 64-bit machines
(in some structures we use <code class="docutils literal notranslate"><span class="pre">double</span></code> and <code class="docutils literal notranslate"><span class="pre">int64_t</span></code>, which generally needs 8-bytes).</p>
</div>
<div class="section" id="strings-and-names">
<h2>Strings And Names<a class="headerlink" href="#strings-and-names" title="Permalink to this headline">¶</a></h2>
<p>So far, both <code class="docutils literal notranslate"><span class="pre">ppname</span></code> and <code class="docutils literal notranslate"><span class="pre">ppstring</span></code> were aliases to <code class="docutils literal notranslate"><span class="pre">char</span> <span class="pre">*</span></code> with an extra structure hidden just below
the data address. The idea was to make a string or name usable whenever chars array can, at the cost of some
pointers trickery. Both names and strings keep an information about pdf-encoded data, as well as plain bytes data.
I implemented this feature once <code class="docutils literal notranslate"><span class="pre">pplib</span> <span class="pre">1.0</span></code> was almost done, and to avoid a revolution, I made that with yet
another trick. This all was dirty and caused lots of alignment issues.</p>
<p>Now <code class="docutils literal notranslate"><span class="pre">ppstring</span></code> and <code class="docutils literal notranslate"><span class="pre">ppname</span></code> are <strong>structures</strong>, keeping data and size members, pretty much like <code class="docutils literal notranslate"><span class="pre">pparray</span></code>:</p>
<div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="n">struct</span> <span class="n">ppname</span> <span class="p">{</span>
<span class="n">ppbyte</span> <span class="o">*</span><span class="n">data</span><span class="p">;</span>
<span class="n">size_t</span> <span class="n">size</span><span class="p">;</span>
<span class="n">ppname</span> <span class="o">*</span><span class="n">alterego</span><span class="p">;</span>
<span class="nb">int</span> <span class="n">flags</span><span class="p">;</span>
<span class="p">};</span>
<span class="n">struct</span> <span class="n">ppstring</span> <span class="p">{</span>
<span class="n">ppbyte</span> <span class="o">*</span><span class="n">data</span><span class="p">;</span>
<span class="n">size_t</span> <span class="n">size</span><span class="p">;</span>
<span class="n">ppstring</span> <span class="o">*</span><span class="n">alterego</span><span class="p">;</span>
<span class="nb">int</span> <span class="n">flags</span><span class="p">;</span>
<span class="p">};</span>
</pre></div>
</div>
<p>Data member is a pointer to (2-bytes aligned) bytes array – <code class="docutils literal notranslate"><span class="pre">ppbyte</span> <span class="pre">*</span></code>. <code class="docutils literal notranslate"><span class="pre">ppbyte</span></code> is an alias to <code class="docutils literal notranslate"><span class="pre">char</span></code>.
<code class="docutils literal notranslate"><span class="pre">pplib</span></code> makes no assumptions about <code class="docutils literal notranslate"><span class="pre">ppbyte</span></code> signedness. [I’d prefer to have <code class="docutils literal notranslate"><span class="pre">uint8_t</span></code>, but better
keep that in sync with <code class="docutils literal notranslate"><span class="pre">ppdict_get_*</span></code> suite, which accepts <code class="docutils literal notranslate"><span class="pre">char</span> <span class="pre">*</span></code>. Using <code class="docutils literal notranslate"><span class="pre">"string</span> <span class="pre">literals"</span></code>
with <code class="docutils literal notranslate"><span class="pre">ppdict_get</span></code> function is the most common case, I guess.]</p>
<p><code class="docutils literal notranslate"><span class="pre">ppname_size()</span></code> and <code class="docutils literal notranslate"><span class="pre">ppstring_size()</span> <span class="pre">``</span> <span class="pre">now</span> <span class="pre">have</span>
<span class="pre">trivial</span> <span class="pre">``ppname_data()</span></code> and <code class="docutils literal notranslate"><span class="pre">ppstring_data()</span></code> counterparts:</p>
<div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="c1">#define ppname_size(name) ((name)->size)</span>
<span class="c1">#define ppname_data(name) ((name)->data)</span>
<span class="c1">#define ppstring_size(string) ((string)->size)</span>
<span class="c1">#define ppstring_data(string) ((string)->data)</span>
</pre></div>
</div>
<p>Switching between encoded / decoded variants is made via explicit <code class="docutils literal notranslate"><span class="pre">alterego</span></code> member. If encoded and decoded forms
are identical, then <code class="docutils literal notranslate"><span class="pre">self->alfterego</span> <span class="pre">==</span> <span class="pre">self</span></code> (never NULL). Helper functions for that:</p>
<div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="n">PPAPI</span> <span class="n">ppname</span> <span class="o">*</span> <span class="n">ppname_decoded</span> <span class="p">(</span><span class="n">ppname</span> <span class="o">*</span><span class="n">name</span><span class="p">);</span>
<span class="n">PPAPI</span> <span class="n">ppname</span> <span class="o">*</span> <span class="n">ppname_encoded</span> <span class="p">(</span><span class="n">ppname</span> <span class="o">*</span><span class="n">name</span><span class="p">);</span>
<span class="n">PPAPI</span> <span class="n">ppbyte</span> <span class="o">*</span> <span class="n">ppname_decoded_data</span> <span class="p">(</span><span class="n">ppname</span> <span class="o">*</span><span class="n">name</span><span class="p">);</span>
<span class="n">PPAPI</span> <span class="n">ppbyte</span> <span class="o">*</span> <span class="n">ppname_encoded_data</span> <span class="p">(</span><span class="n">ppname</span> <span class="o">*</span><span class="n">name</span><span class="p">);</span>
<span class="n">PPAPI</span> <span class="n">ppstring</span> <span class="o">*</span> <span class="n">ppstring_decoded</span> <span class="p">(</span><span class="n">ppstring</span> <span class="o">*</span><span class="n">string</span><span class="p">);</span>
<span class="n">PPAPI</span> <span class="n">ppstring</span> <span class="o">*</span> <span class="n">ppstring_encoded</span> <span class="p">(</span><span class="n">ppstring</span> <span class="o">*</span><span class="n">string</span><span class="p">);</span>
<span class="n">PPAPI</span> <span class="n">ppbyte</span> <span class="o">*</span> <span class="n">ppstring_decoded_data</span> <span class="p">(</span><span class="n">ppstring</span> <span class="o">*</span><span class="n">string</span><span class="p">);</span>
<span class="n">PPAPI</span> <span class="n">ppbyte</span> <span class="o">*</span> <span class="n">ppstring_encoded_data</span> <span class="p">(</span><span class="n">ppstring</span> <span class="o">*</span><span class="n">string</span><span class="p">);</span>
</pre></div>
</div>
<p>Since <code class="docutils literal notranslate"><span class="pre">ppname</span></code> and <code class="docutils literal notranslate"><span class="pre">ppstring</span></code> are now structures, all API functions returning name/string or taking name/string
as an argument, now take <strong>a pointer to name/string</strong>. Watch out for <code class="docutils literal notranslate"><span class="pre">ppdict_get_*</span></code> functions suite. They still accept
<code class="docutils literal notranslate"><span class="pre">const</span> <span class="pre">char</span> <span class="pre">*</span></code> key as an argument, but <code class="docutils literal notranslate"><span class="pre">ppname</span></code> type can no longer be used there:</p>
<div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="n">ppname</span> <span class="n">key</span><span class="p">;</span>
<span class="n">ppdict_get_something</span><span class="p">(</span><span class="nb">dict</span><span class="p">,</span> <span class="n">key</span><span class="p">);</span> <span class="o">//</span> <span class="n">wrong</span>
<span class="n">ppdict_get_something</span><span class="p">(</span><span class="nb">dict</span><span class="p">,</span> <span class="n">key</span><span class="o">.</span><span class="n">data</span><span class="p">);</span> <span class="o">//</span> <span class="n">ok</span>
<span class="n">ppname</span> <span class="o">*</span><span class="n">pkey</span><span class="p">;</span>
<span class="n">ppdict_get_something</span><span class="p">(</span><span class="nb">dict</span><span class="p">,</span> <span class="p">(</span><span class="n">const</span> <span class="n">char</span> <span class="o">*</span><span class="p">)</span><span class="n">pkey</span><span class="p">);</span> <span class="o">//</span> <span class="n">wrong</span>
<span class="n">ppdict_get_something</span><span class="p">(</span><span class="nb">dict</span><span class="p">,</span> <span class="n">pkey</span><span class="o">-></span><span class="n">data</span><span class="p">);</span> <span class="o">//</span> <span class="n">ok</span>
</pre></div>
</div>
<p>Consequently, functions / macros that used pointer to <code class="docutils literal notranslate"><span class="pre">ppname</span></code> (<code class="docutils literal notranslate"><span class="pre">ppdict_first()</span></code> / <code class="docutils literal notranslate"><span class="pre">ppdict_next()</span></code>),
now needs <code class="docutils literal notranslate"><span class="pre">ppname</span> <span class="pre">**pname</span></code>.</p>
</div>
<div class="section" id="cleanups">
<h2>Cleanups<a class="headerlink" href="#cleanups" title="Permalink to this headline">¶</a></h2>
<p>Some of unused utils were removed. There is still some code in utils part that is not used by the library,
but I need this tollbox in many other places and don’t want to maintain two versions.</p>
<p>Some unification in integer types; <code class="docutils literal notranslate"><span class="pre">size_t</span></code> seems to be the best choice for and integer representing machine
word (<code class="docutils literal notranslate"><span class="pre">unsigned</span> <span class="pre">long</span></code> is not long enough on windows), less utils dependencies, less compiler warnings.</p>
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