| <!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta name="generator" content="rustdoc"><meta name="description" content="Source of the Rust file `/root/.cargo/registry/src/github.com-1ecc6299db9ec823/jpeg-decoder-0.1.22/src/decoder.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>decoder.rs - source</title><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceSerif4-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../FiraSans-Regular.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../FiraSans-Medium.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceCodePro-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceSerif4-Bold.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceCodePro-Semibold.ttf.woff2"><link rel="stylesheet" href="../../normalize.css"><link rel="stylesheet" href="../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" href="../../ayu.css" disabled><link rel="stylesheet" href="../../dark.css" disabled><link rel="stylesheet" href="../../light.css" id="themeStyle"><script id="default-settings" ></script><script src="../../storage.js"></script><script defer src="../../source-script.js"></script><script defer src="../../source-files.js"></script><script defer src="../../main.js"></script><noscript><link rel="stylesheet" href="../../noscript.css"></noscript><link rel="alternate icon" type="image/png" href="../../favicon-16x16.png"><link rel="alternate icon" type="image/png" href="../../favicon-32x32.png"><link rel="icon" type="image/svg+xml" href="../../favicon.svg"></head><body class="rustdoc source"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><a class="sidebar-logo" href="../../jpeg_decoder/index.html"><div class="logo-container"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></div></a></nav><main><div class="width-limiter"><nav class="sub"><a class="sub-logo-container" href="../../jpeg_decoder/index.html"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></a><form class="search-form"><div class="search-container"><span></span><input class="search-input" name="search" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><div id="help-button" title="help" tabindex="-1"><a href="../../help.html">?</a></div><div id="settings-menu" tabindex="-1"><a href="../../settings.html" title="settings"><img width="22" height="22" alt="Change settings" src="../../wheel.svg"></a></div></div></form></nav><section id="main-content" class="content"><div class="example-wrap"><pre class="src-line-numbers"><span id="1">1</span> |
| <span id="2">2</span> |
| <span id="3">3</span> |
| <span id="4">4</span> |
| <span id="5">5</span> |
| <span id="6">6</span> |
| <span id="7">7</span> |
| <span id="8">8</span> |
| <span id="9">9</span> |
| <span id="10">10</span> |
| <span id="11">11</span> |
| <span id="12">12</span> |
| <span id="13">13</span> |
| <span id="14">14</span> |
| <span id="15">15</span> |
| <span id="16">16</span> |
| <span id="17">17</span> |
| <span id="18">18</span> |
| <span id="19">19</span> |
| <span id="20">20</span> |
| <span id="21">21</span> |
| <span id="22">22</span> |
| <span id="23">23</span> |
| <span id="24">24</span> |
| <span id="25">25</span> |
| <span id="26">26</span> |
| <span id="27">27</span> |
| <span id="28">28</span> |
| <span id="29">29</span> |
| <span id="30">30</span> |
| <span id="31">31</span> |
| <span id="32">32</span> |
| <span id="33">33</span> |
| <span id="34">34</span> |
| <span id="35">35</span> |
| <span id="36">36</span> |
| <span id="37">37</span> |
| <span id="38">38</span> |
| <span id="39">39</span> |
| <span id="40">40</span> |
| <span id="41">41</span> |
| <span id="42">42</span> |
| <span id="43">43</span> |
| <span id="44">44</span> |
| <span id="45">45</span> |
| <span id="46">46</span> |
| <span id="47">47</span> |
| <span id="48">48</span> |
| <span id="49">49</span> |
| <span id="50">50</span> |
| <span id="51">51</span> |
| <span id="52">52</span> |
| <span id="53">53</span> |
| <span id="54">54</span> |
| <span id="55">55</span> |
| <span id="56">56</span> |
| <span id="57">57</span> |
| <span id="58">58</span> |
| <span id="59">59</span> |
| <span id="60">60</span> |
| <span id="61">61</span> |
| <span id="62">62</span> |
| <span id="63">63</span> |
| <span id="64">64</span> |
| <span id="65">65</span> |
| <span id="66">66</span> |
| <span id="67">67</span> |
| <span id="68">68</span> |
| <span id="69">69</span> |
| <span id="70">70</span> |
| <span id="71">71</span> |
| <span id="72">72</span> |
| <span id="73">73</span> |
| <span id="74">74</span> |
| <span id="75">75</span> |
| <span id="76">76</span> |
| <span id="77">77</span> |
| <span id="78">78</span> |
| <span id="79">79</span> |
| <span id="80">80</span> |
| <span id="81">81</span> |
| <span id="82">82</span> |
| <span id="83">83</span> |
| <span id="84">84</span> |
| <span id="85">85</span> |
| <span id="86">86</span> |
| <span id="87">87</span> |
| <span id="88">88</span> |
| <span id="89">89</span> |
| <span id="90">90</span> |
| <span id="91">91</span> |
| <span id="92">92</span> |
| <span id="93">93</span> |
| <span id="94">94</span> |
| <span id="95">95</span> |
| <span id="96">96</span> |
| <span id="97">97</span> |
| <span id="98">98</span> |
| <span id="99">99</span> |
| <span id="100">100</span> |
| <span id="101">101</span> |
| <span id="102">102</span> |
| <span id="103">103</span> |
| <span id="104">104</span> |
| <span id="105">105</span> |
| <span id="106">106</span> |
| <span id="107">107</span> |
| <span id="108">108</span> |
| <span id="109">109</span> |
| <span id="110">110</span> |
| <span id="111">111</span> |
| <span id="112">112</span> |
| <span id="113">113</span> |
| <span id="114">114</span> |
| <span id="115">115</span> |
| <span id="116">116</span> |
| <span id="117">117</span> |
| <span id="118">118</span> |
| <span id="119">119</span> |
| <span id="120">120</span> |
| <span id="121">121</span> |
| <span id="122">122</span> |
| <span id="123">123</span> |
| <span id="124">124</span> |
| <span id="125">125</span> |
| <span id="126">126</span> |
| <span id="127">127</span> |
| <span id="128">128</span> |
| <span id="129">129</span> |
| <span id="130">130</span> |
| <span id="131">131</span> |
| <span id="132">132</span> |
| <span id="133">133</span> |
| <span id="134">134</span> |
| <span id="135">135</span> |
| <span id="136">136</span> |
| <span id="137">137</span> |
| <span id="138">138</span> |
| <span id="139">139</span> |
| <span id="140">140</span> |
| <span id="141">141</span> |
| <span id="142">142</span> |
| <span id="143">143</span> |
| <span id="144">144</span> |
| <span id="145">145</span> |
| <span id="146">146</span> |
| <span id="147">147</span> |
| <span id="148">148</span> |
| <span id="149">149</span> |
| <span id="150">150</span> |
| <span id="151">151</span> |
| <span id="152">152</span> |
| <span id="153">153</span> |
| <span id="154">154</span> |
| <span id="155">155</span> |
| <span id="156">156</span> |
| <span id="157">157</span> |
| <span id="158">158</span> |
| <span id="159">159</span> |
| <span id="160">160</span> |
| <span id="161">161</span> |
| <span id="162">162</span> |
| <span id="163">163</span> |
| <span id="164">164</span> |
| <span id="165">165</span> |
| <span id="166">166</span> |
| <span id="167">167</span> |
| <span id="168">168</span> |
| <span id="169">169</span> |
| <span id="170">170</span> |
| <span id="171">171</span> |
| <span id="172">172</span> |
| <span id="173">173</span> |
| <span id="174">174</span> |
| <span id="175">175</span> |
| <span id="176">176</span> |
| <span id="177">177</span> |
| <span id="178">178</span> |
| <span id="179">179</span> |
| <span id="180">180</span> |
| <span id="181">181</span> |
| <span id="182">182</span> |
| <span id="183">183</span> |
| <span id="184">184</span> |
| <span id="185">185</span> |
| <span id="186">186</span> |
| <span id="187">187</span> |
| <span id="188">188</span> |
| <span id="189">189</span> |
| <span id="190">190</span> |
| <span id="191">191</span> |
| <span id="192">192</span> |
| <span id="193">193</span> |
| <span id="194">194</span> |
| <span id="195">195</span> |
| <span id="196">196</span> |
| <span id="197">197</span> |
| <span id="198">198</span> |
| <span id="199">199</span> |
| <span id="200">200</span> |
| <span id="201">201</span> |
| <span id="202">202</span> |
| <span id="203">203</span> |
| <span id="204">204</span> |
| <span id="205">205</span> |
| <span id="206">206</span> |
| <span id="207">207</span> |
| <span id="208">208</span> |
| <span id="209">209</span> |
| <span id="210">210</span> |
| <span id="211">211</span> |
| <span id="212">212</span> |
| <span id="213">213</span> |
| <span id="214">214</span> |
| <span id="215">215</span> |
| <span id="216">216</span> |
| <span id="217">217</span> |
| <span id="218">218</span> |
| <span id="219">219</span> |
| <span id="220">220</span> |
| <span id="221">221</span> |
| <span id="222">222</span> |
| <span id="223">223</span> |
| <span id="224">224</span> |
| <span id="225">225</span> |
| <span id="226">226</span> |
| <span id="227">227</span> |
| <span id="228">228</span> |
| <span id="229">229</span> |
| <span id="230">230</span> |
| <span id="231">231</span> |
| <span id="232">232</span> |
| <span id="233">233</span> |
| <span id="234">234</span> |
| <span id="235">235</span> |
| <span id="236">236</span> |
| <span id="237">237</span> |
| <span id="238">238</span> |
| <span id="239">239</span> |
| <span id="240">240</span> |
| <span id="241">241</span> |
| <span id="242">242</span> |
| <span id="243">243</span> |
| <span id="244">244</span> |
| <span id="245">245</span> |
| <span id="246">246</span> |
| <span id="247">247</span> |
| <span id="248">248</span> |
| <span id="249">249</span> |
| <span id="250">250</span> |
| <span id="251">251</span> |
| <span id="252">252</span> |
| <span id="253">253</span> |
| <span id="254">254</span> |
| <span id="255">255</span> |
| <span id="256">256</span> |
| <span id="257">257</span> |
| <span id="258">258</span> |
| <span id="259">259</span> |
| <span id="260">260</span> |
| <span id="261">261</span> |
| <span id="262">262</span> |
| <span id="263">263</span> |
| <span id="264">264</span> |
| <span id="265">265</span> |
| <span id="266">266</span> |
| <span id="267">267</span> |
| <span id="268">268</span> |
| <span id="269">269</span> |
| <span id="270">270</span> |
| <span id="271">271</span> |
| <span id="272">272</span> |
| <span id="273">273</span> |
| <span id="274">274</span> |
| <span id="275">275</span> |
| <span id="276">276</span> |
| <span id="277">277</span> |
| <span id="278">278</span> |
| <span id="279">279</span> |
| <span id="280">280</span> |
| <span id="281">281</span> |
| <span id="282">282</span> |
| <span id="283">283</span> |
| <span id="284">284</span> |
| <span id="285">285</span> |
| <span id="286">286</span> |
| <span id="287">287</span> |
| <span id="288">288</span> |
| <span id="289">289</span> |
| <span id="290">290</span> |
| <span id="291">291</span> |
| <span id="292">292</span> |
| <span id="293">293</span> |
| <span id="294">294</span> |
| <span id="295">295</span> |
| <span id="296">296</span> |
| <span id="297">297</span> |
| <span id="298">298</span> |
| <span id="299">299</span> |
| <span id="300">300</span> |
| <span id="301">301</span> |
| <span id="302">302</span> |
| <span id="303">303</span> |
| <span id="304">304</span> |
| <span id="305">305</span> |
| <span id="306">306</span> |
| <span id="307">307</span> |
| <span id="308">308</span> |
| <span id="309">309</span> |
| <span id="310">310</span> |
| <span id="311">311</span> |
| <span id="312">312</span> |
| <span id="313">313</span> |
| <span id="314">314</span> |
| <span id="315">315</span> |
| <span id="316">316</span> |
| <span id="317">317</span> |
| <span id="318">318</span> |
| <span id="319">319</span> |
| <span id="320">320</span> |
| <span id="321">321</span> |
| <span id="322">322</span> |
| <span id="323">323</span> |
| <span id="324">324</span> |
| <span id="325">325</span> |
| <span id="326">326</span> |
| <span id="327">327</span> |
| <span id="328">328</span> |
| <span id="329">329</span> |
| <span id="330">330</span> |
| <span id="331">331</span> |
| <span id="332">332</span> |
| <span id="333">333</span> |
| <span id="334">334</span> |
| <span id="335">335</span> |
| <span id="336">336</span> |
| <span id="337">337</span> |
| <span id="338">338</span> |
| <span id="339">339</span> |
| <span id="340">340</span> |
| <span id="341">341</span> |
| <span id="342">342</span> |
| <span id="343">343</span> |
| <span id="344">344</span> |
| <span id="345">345</span> |
| <span id="346">346</span> |
| <span id="347">347</span> |
| <span id="348">348</span> |
| <span id="349">349</span> |
| <span id="350">350</span> |
| <span id="351">351</span> |
| <span id="352">352</span> |
| <span id="353">353</span> |
| <span id="354">354</span> |
| <span id="355">355</span> |
| <span id="356">356</span> |
| <span id="357">357</span> |
| <span id="358">358</span> |
| <span id="359">359</span> |
| <span id="360">360</span> |
| <span id="361">361</span> |
| <span id="362">362</span> |
| <span id="363">363</span> |
| <span id="364">364</span> |
| <span id="365">365</span> |
| <span id="366">366</span> |
| <span id="367">367</span> |
| <span id="368">368</span> |
| <span id="369">369</span> |
| <span id="370">370</span> |
| <span id="371">371</span> |
| <span id="372">372</span> |
| <span id="373">373</span> |
| <span id="374">374</span> |
| <span id="375">375</span> |
| <span id="376">376</span> |
| <span id="377">377</span> |
| <span id="378">378</span> |
| <span id="379">379</span> |
| <span id="380">380</span> |
| <span id="381">381</span> |
| <span id="382">382</span> |
| <span id="383">383</span> |
| <span id="384">384</span> |
| <span id="385">385</span> |
| <span id="386">386</span> |
| <span id="387">387</span> |
| <span id="388">388</span> |
| <span id="389">389</span> |
| <span id="390">390</span> |
| <span id="391">391</span> |
| <span id="392">392</span> |
| <span id="393">393</span> |
| <span id="394">394</span> |
| <span id="395">395</span> |
| <span id="396">396</span> |
| <span id="397">397</span> |
| <span id="398">398</span> |
| <span id="399">399</span> |
| <span id="400">400</span> |
| <span id="401">401</span> |
| <span id="402">402</span> |
| <span id="403">403</span> |
| <span id="404">404</span> |
| <span id="405">405</span> |
| <span id="406">406</span> |
| <span id="407">407</span> |
| <span id="408">408</span> |
| <span id="409">409</span> |
| <span id="410">410</span> |
| <span id="411">411</span> |
| <span id="412">412</span> |
| <span id="413">413</span> |
| <span id="414">414</span> |
| <span id="415">415</span> |
| <span id="416">416</span> |
| <span id="417">417</span> |
| <span id="418">418</span> |
| <span id="419">419</span> |
| <span id="420">420</span> |
| <span id="421">421</span> |
| <span id="422">422</span> |
| <span id="423">423</span> |
| <span id="424">424</span> |
| <span id="425">425</span> |
| <span id="426">426</span> |
| <span id="427">427</span> |
| <span id="428">428</span> |
| <span id="429">429</span> |
| <span id="430">430</span> |
| <span id="431">431</span> |
| <span id="432">432</span> |
| <span id="433">433</span> |
| <span id="434">434</span> |
| <span id="435">435</span> |
| <span id="436">436</span> |
| <span id="437">437</span> |
| <span id="438">438</span> |
| <span id="439">439</span> |
| <span id="440">440</span> |
| <span id="441">441</span> |
| <span id="442">442</span> |
| <span id="443">443</span> |
| <span id="444">444</span> |
| <span id="445">445</span> |
| <span id="446">446</span> |
| <span id="447">447</span> |
| <span id="448">448</span> |
| <span id="449">449</span> |
| <span id="450">450</span> |
| <span id="451">451</span> |
| <span id="452">452</span> |
| <span id="453">453</span> |
| <span id="454">454</span> |
| <span id="455">455</span> |
| <span id="456">456</span> |
| <span id="457">457</span> |
| <span id="458">458</span> |
| <span id="459">459</span> |
| <span id="460">460</span> |
| <span id="461">461</span> |
| <span id="462">462</span> |
| <span id="463">463</span> |
| <span id="464">464</span> |
| <span id="465">465</span> |
| <span id="466">466</span> |
| <span id="467">467</span> |
| <span id="468">468</span> |
| <span id="469">469</span> |
| <span id="470">470</span> |
| <span id="471">471</span> |
| <span id="472">472</span> |
| <span id="473">473</span> |
| <span id="474">474</span> |
| <span id="475">475</span> |
| <span id="476">476</span> |
| <span id="477">477</span> |
| <span id="478">478</span> |
| <span id="479">479</span> |
| <span id="480">480</span> |
| <span id="481">481</span> |
| <span id="482">482</span> |
| <span id="483">483</span> |
| <span id="484">484</span> |
| <span id="485">485</span> |
| <span id="486">486</span> |
| <span id="487">487</span> |
| <span id="488">488</span> |
| <span id="489">489</span> |
| <span id="490">490</span> |
| <span id="491">491</span> |
| <span id="492">492</span> |
| <span id="493">493</span> |
| <span id="494">494</span> |
| <span id="495">495</span> |
| <span id="496">496</span> |
| <span id="497">497</span> |
| <span id="498">498</span> |
| <span id="499">499</span> |
| <span id="500">500</span> |
| <span id="501">501</span> |
| <span id="502">502</span> |
| <span id="503">503</span> |
| <span id="504">504</span> |
| <span id="505">505</span> |
| <span id="506">506</span> |
| <span id="507">507</span> |
| <span id="508">508</span> |
| <span id="509">509</span> |
| <span id="510">510</span> |
| <span id="511">511</span> |
| <span id="512">512</span> |
| <span id="513">513</span> |
| <span id="514">514</span> |
| <span id="515">515</span> |
| <span id="516">516</span> |
| <span id="517">517</span> |
| <span id="518">518</span> |
| <span id="519">519</span> |
| <span id="520">520</span> |
| <span id="521">521</span> |
| <span id="522">522</span> |
| <span id="523">523</span> |
| <span id="524">524</span> |
| <span id="525">525</span> |
| <span id="526">526</span> |
| <span id="527">527</span> |
| <span id="528">528</span> |
| <span id="529">529</span> |
| <span id="530">530</span> |
| <span id="531">531</span> |
| <span id="532">532</span> |
| <span id="533">533</span> |
| <span id="534">534</span> |
| <span id="535">535</span> |
| <span id="536">536</span> |
| <span id="537">537</span> |
| <span id="538">538</span> |
| <span id="539">539</span> |
| <span id="540">540</span> |
| <span id="541">541</span> |
| <span id="542">542</span> |
| <span id="543">543</span> |
| <span id="544">544</span> |
| <span id="545">545</span> |
| <span id="546">546</span> |
| <span id="547">547</span> |
| <span id="548">548</span> |
| <span id="549">549</span> |
| <span id="550">550</span> |
| <span id="551">551</span> |
| <span id="552">552</span> |
| <span id="553">553</span> |
| <span id="554">554</span> |
| <span id="555">555</span> |
| <span id="556">556</span> |
| <span id="557">557</span> |
| <span id="558">558</span> |
| <span id="559">559</span> |
| <span id="560">560</span> |
| <span id="561">561</span> |
| <span id="562">562</span> |
| <span id="563">563</span> |
| <span id="564">564</span> |
| <span id="565">565</span> |
| <span id="566">566</span> |
| <span id="567">567</span> |
| <span id="568">568</span> |
| <span id="569">569</span> |
| <span id="570">570</span> |
| <span id="571">571</span> |
| <span id="572">572</span> |
| <span id="573">573</span> |
| <span id="574">574</span> |
| <span id="575">575</span> |
| <span id="576">576</span> |
| <span id="577">577</span> |
| <span id="578">578</span> |
| <span id="579">579</span> |
| <span id="580">580</span> |
| <span id="581">581</span> |
| <span id="582">582</span> |
| <span id="583">583</span> |
| <span id="584">584</span> |
| <span id="585">585</span> |
| <span id="586">586</span> |
| <span id="587">587</span> |
| <span id="588">588</span> |
| <span id="589">589</span> |
| <span id="590">590</span> |
| <span id="591">591</span> |
| <span id="592">592</span> |
| <span id="593">593</span> |
| <span id="594">594</span> |
| <span id="595">595</span> |
| <span id="596">596</span> |
| <span id="597">597</span> |
| <span id="598">598</span> |
| <span id="599">599</span> |
| <span id="600">600</span> |
| <span id="601">601</span> |
| <span id="602">602</span> |
| <span id="603">603</span> |
| <span id="604">604</span> |
| <span id="605">605</span> |
| <span id="606">606</span> |
| <span id="607">607</span> |
| <span id="608">608</span> |
| <span id="609">609</span> |
| <span id="610">610</span> |
| <span id="611">611</span> |
| <span id="612">612</span> |
| <span id="613">613</span> |
| <span id="614">614</span> |
| <span id="615">615</span> |
| <span id="616">616</span> |
| <span id="617">617</span> |
| <span id="618">618</span> |
| <span id="619">619</span> |
| <span id="620">620</span> |
| <span id="621">621</span> |
| <span id="622">622</span> |
| <span id="623">623</span> |
| <span id="624">624</span> |
| <span id="625">625</span> |
| <span id="626">626</span> |
| <span id="627">627</span> |
| <span id="628">628</span> |
| <span id="629">629</span> |
| <span id="630">630</span> |
| <span id="631">631</span> |
| <span id="632">632</span> |
| <span id="633">633</span> |
| <span id="634">634</span> |
| <span id="635">635</span> |
| <span id="636">636</span> |
| <span id="637">637</span> |
| <span id="638">638</span> |
| <span id="639">639</span> |
| <span id="640">640</span> |
| <span id="641">641</span> |
| <span id="642">642</span> |
| <span id="643">643</span> |
| <span id="644">644</span> |
| <span id="645">645</span> |
| <span id="646">646</span> |
| <span id="647">647</span> |
| <span id="648">648</span> |
| <span id="649">649</span> |
| <span id="650">650</span> |
| <span id="651">651</span> |
| <span id="652">652</span> |
| <span id="653">653</span> |
| <span id="654">654</span> |
| <span id="655">655</span> |
| <span id="656">656</span> |
| <span id="657">657</span> |
| <span id="658">658</span> |
| <span id="659">659</span> |
| <span id="660">660</span> |
| <span id="661">661</span> |
| <span id="662">662</span> |
| <span id="663">663</span> |
| <span id="664">664</span> |
| <span id="665">665</span> |
| <span id="666">666</span> |
| <span id="667">667</span> |
| <span id="668">668</span> |
| <span id="669">669</span> |
| <span id="670">670</span> |
| <span id="671">671</span> |
| <span id="672">672</span> |
| <span id="673">673</span> |
| <span id="674">674</span> |
| <span id="675">675</span> |
| <span id="676">676</span> |
| <span id="677">677</span> |
| <span id="678">678</span> |
| <span id="679">679</span> |
| <span id="680">680</span> |
| <span id="681">681</span> |
| <span id="682">682</span> |
| <span id="683">683</span> |
| <span id="684">684</span> |
| <span id="685">685</span> |
| <span id="686">686</span> |
| <span id="687">687</span> |
| <span id="688">688</span> |
| <span id="689">689</span> |
| <span id="690">690</span> |
| <span id="691">691</span> |
| <span id="692">692</span> |
| <span id="693">693</span> |
| <span id="694">694</span> |
| <span id="695">695</span> |
| <span id="696">696</span> |
| <span id="697">697</span> |
| <span id="698">698</span> |
| <span id="699">699</span> |
| <span id="700">700</span> |
| <span id="701">701</span> |
| <span id="702">702</span> |
| <span id="703">703</span> |
| <span id="704">704</span> |
| <span id="705">705</span> |
| <span id="706">706</span> |
| <span id="707">707</span> |
| <span id="708">708</span> |
| <span id="709">709</span> |
| <span id="710">710</span> |
| <span id="711">711</span> |
| <span id="712">712</span> |
| <span id="713">713</span> |
| <span id="714">714</span> |
| <span id="715">715</span> |
| <span id="716">716</span> |
| <span id="717">717</span> |
| <span id="718">718</span> |
| <span id="719">719</span> |
| <span id="720">720</span> |
| <span id="721">721</span> |
| <span id="722">722</span> |
| <span id="723">723</span> |
| <span id="724">724</span> |
| <span id="725">725</span> |
| <span id="726">726</span> |
| <span id="727">727</span> |
| <span id="728">728</span> |
| <span id="729">729</span> |
| <span id="730">730</span> |
| <span id="731">731</span> |
| <span id="732">732</span> |
| <span id="733">733</span> |
| <span id="734">734</span> |
| <span id="735">735</span> |
| <span id="736">736</span> |
| <span id="737">737</span> |
| <span id="738">738</span> |
| <span id="739">739</span> |
| <span id="740">740</span> |
| <span id="741">741</span> |
| <span id="742">742</span> |
| <span id="743">743</span> |
| <span id="744">744</span> |
| <span id="745">745</span> |
| <span id="746">746</span> |
| <span id="747">747</span> |
| <span id="748">748</span> |
| <span id="749">749</span> |
| <span id="750">750</span> |
| <span id="751">751</span> |
| <span id="752">752</span> |
| <span id="753">753</span> |
| <span id="754">754</span> |
| <span id="755">755</span> |
| <span id="756">756</span> |
| <span id="757">757</span> |
| <span id="758">758</span> |
| <span id="759">759</span> |
| <span id="760">760</span> |
| <span id="761">761</span> |
| <span id="762">762</span> |
| <span id="763">763</span> |
| <span id="764">764</span> |
| <span id="765">765</span> |
| <span id="766">766</span> |
| <span id="767">767</span> |
| <span id="768">768</span> |
| <span id="769">769</span> |
| <span id="770">770</span> |
| <span id="771">771</span> |
| <span id="772">772</span> |
| <span id="773">773</span> |
| <span id="774">774</span> |
| <span id="775">775</span> |
| <span id="776">776</span> |
| <span id="777">777</span> |
| <span id="778">778</span> |
| <span id="779">779</span> |
| <span id="780">780</span> |
| <span id="781">781</span> |
| <span id="782">782</span> |
| <span id="783">783</span> |
| <span id="784">784</span> |
| <span id="785">785</span> |
| <span id="786">786</span> |
| <span id="787">787</span> |
| <span id="788">788</span> |
| <span id="789">789</span> |
| <span id="790">790</span> |
| <span id="791">791</span> |
| <span id="792">792</span> |
| <span id="793">793</span> |
| <span id="794">794</span> |
| <span id="795">795</span> |
| <span id="796">796</span> |
| <span id="797">797</span> |
| <span id="798">798</span> |
| <span id="799">799</span> |
| <span id="800">800</span> |
| <span id="801">801</span> |
| <span id="802">802</span> |
| <span id="803">803</span> |
| <span id="804">804</span> |
| <span id="805">805</span> |
| <span id="806">806</span> |
| <span id="807">807</span> |
| <span id="808">808</span> |
| <span id="809">809</span> |
| <span id="810">810</span> |
| <span id="811">811</span> |
| <span id="812">812</span> |
| <span id="813">813</span> |
| <span id="814">814</span> |
| <span id="815">815</span> |
| <span id="816">816</span> |
| <span id="817">817</span> |
| <span id="818">818</span> |
| <span id="819">819</span> |
| <span id="820">820</span> |
| <span id="821">821</span> |
| <span id="822">822</span> |
| <span id="823">823</span> |
| <span id="824">824</span> |
| <span id="825">825</span> |
| <span id="826">826</span> |
| <span id="827">827</span> |
| <span id="828">828</span> |
| <span id="829">829</span> |
| <span id="830">830</span> |
| <span id="831">831</span> |
| <span id="832">832</span> |
| <span id="833">833</span> |
| <span id="834">834</span> |
| <span id="835">835</span> |
| <span id="836">836</span> |
| <span id="837">837</span> |
| <span id="838">838</span> |
| <span id="839">839</span> |
| <span id="840">840</span> |
| <span id="841">841</span> |
| <span id="842">842</span> |
| <span id="843">843</span> |
| <span id="844">844</span> |
| <span id="845">845</span> |
| <span id="846">846</span> |
| <span id="847">847</span> |
| <span id="848">848</span> |
| <span id="849">849</span> |
| <span id="850">850</span> |
| <span id="851">851</span> |
| <span id="852">852</span> |
| <span id="853">853</span> |
| <span id="854">854</span> |
| <span id="855">855</span> |
| <span id="856">856</span> |
| <span id="857">857</span> |
| <span id="858">858</span> |
| <span id="859">859</span> |
| <span id="860">860</span> |
| <span id="861">861</span> |
| <span id="862">862</span> |
| <span id="863">863</span> |
| <span id="864">864</span> |
| <span id="865">865</span> |
| <span id="866">866</span> |
| <span id="867">867</span> |
| <span id="868">868</span> |
| <span id="869">869</span> |
| <span id="870">870</span> |
| <span id="871">871</span> |
| <span id="872">872</span> |
| <span id="873">873</span> |
| <span id="874">874</span> |
| <span id="875">875</span> |
| <span id="876">876</span> |
| <span id="877">877</span> |
| <span id="878">878</span> |
| <span id="879">879</span> |
| <span id="880">880</span> |
| <span id="881">881</span> |
| <span id="882">882</span> |
| <span id="883">883</span> |
| <span id="884">884</span> |
| <span id="885">885</span> |
| <span id="886">886</span> |
| <span id="887">887</span> |
| <span id="888">888</span> |
| <span id="889">889</span> |
| <span id="890">890</span> |
| <span id="891">891</span> |
| <span id="892">892</span> |
| <span id="893">893</span> |
| <span id="894">894</span> |
| <span id="895">895</span> |
| <span id="896">896</span> |
| <span id="897">897</span> |
| <span id="898">898</span> |
| <span id="899">899</span> |
| <span id="900">900</span> |
| <span id="901">901</span> |
| <span id="902">902</span> |
| <span id="903">903</span> |
| <span id="904">904</span> |
| <span id="905">905</span> |
| <span id="906">906</span> |
| <span id="907">907</span> |
| <span id="908">908</span> |
| <span id="909">909</span> |
| <span id="910">910</span> |
| <span id="911">911</span> |
| <span id="912">912</span> |
| <span id="913">913</span> |
| <span id="914">914</span> |
| <span id="915">915</span> |
| <span id="916">916</span> |
| <span id="917">917</span> |
| <span id="918">918</span> |
| <span id="919">919</span> |
| <span id="920">920</span> |
| <span id="921">921</span> |
| <span id="922">922</span> |
| <span id="923">923</span> |
| <span id="924">924</span> |
| <span id="925">925</span> |
| <span id="926">926</span> |
| <span id="927">927</span> |
| <span id="928">928</span> |
| <span id="929">929</span> |
| <span id="930">930</span> |
| <span id="931">931</span> |
| <span id="932">932</span> |
| <span id="933">933</span> |
| <span id="934">934</span> |
| <span id="935">935</span> |
| <span id="936">936</span> |
| <span id="937">937</span> |
| <span id="938">938</span> |
| <span id="939">939</span> |
| <span id="940">940</span> |
| <span id="941">941</span> |
| <span id="942">942</span> |
| <span id="943">943</span> |
| <span id="944">944</span> |
| <span id="945">945</span> |
| <span id="946">946</span> |
| <span id="947">947</span> |
| <span id="948">948</span> |
| <span id="949">949</span> |
| <span id="950">950</span> |
| <span id="951">951</span> |
| <span id="952">952</span> |
| <span id="953">953</span> |
| <span id="954">954</span> |
| <span id="955">955</span> |
| <span id="956">956</span> |
| <span id="957">957</span> |
| <span id="958">958</span> |
| <span id="959">959</span> |
| <span id="960">960</span> |
| <span id="961">961</span> |
| <span id="962">962</span> |
| <span id="963">963</span> |
| <span id="964">964</span> |
| <span id="965">965</span> |
| <span id="966">966</span> |
| <span id="967">967</span> |
| <span id="968">968</span> |
| <span id="969">969</span> |
| <span id="970">970</span> |
| <span id="971">971</span> |
| <span id="972">972</span> |
| <span id="973">973</span> |
| <span id="974">974</span> |
| <span id="975">975</span> |
| <span id="976">976</span> |
| <span id="977">977</span> |
| <span id="978">978</span> |
| <span id="979">979</span> |
| <span id="980">980</span> |
| <span id="981">981</span> |
| <span id="982">982</span> |
| <span id="983">983</span> |
| <span id="984">984</span> |
| <span id="985">985</span> |
| <span id="986">986</span> |
| <span id="987">987</span> |
| <span id="988">988</span> |
| <span id="989">989</span> |
| <span id="990">990</span> |
| <span id="991">991</span> |
| <span id="992">992</span> |
| <span id="993">993</span> |
| <span id="994">994</span> |
| <span id="995">995</span> |
| <span id="996">996</span> |
| <span id="997">997</span> |
| <span id="998">998</span> |
| <span id="999">999</span> |
| <span id="1000">1000</span> |
| <span id="1001">1001</span> |
| <span id="1002">1002</span> |
| <span id="1003">1003</span> |
| <span id="1004">1004</span> |
| <span id="1005">1005</span> |
| <span id="1006">1006</span> |
| <span id="1007">1007</span> |
| <span id="1008">1008</span> |
| <span id="1009">1009</span> |
| <span id="1010">1010</span> |
| <span id="1011">1011</span> |
| <span id="1012">1012</span> |
| <span id="1013">1013</span> |
| <span id="1014">1014</span> |
| <span id="1015">1015</span> |
| <span id="1016">1016</span> |
| <span id="1017">1017</span> |
| <span id="1018">1018</span> |
| <span id="1019">1019</span> |
| <span id="1020">1020</span> |
| <span id="1021">1021</span> |
| <span id="1022">1022</span> |
| <span id="1023">1023</span> |
| <span id="1024">1024</span> |
| <span id="1025">1025</span> |
| <span id="1026">1026</span> |
| <span id="1027">1027</span> |
| <span id="1028">1028</span> |
| <span id="1029">1029</span> |
| <span id="1030">1030</span> |
| <span id="1031">1031</span> |
| <span id="1032">1032</span> |
| <span id="1033">1033</span> |
| <span id="1034">1034</span> |
| <span id="1035">1035</span> |
| <span id="1036">1036</span> |
| <span id="1037">1037</span> |
| <span id="1038">1038</span> |
| <span id="1039">1039</span> |
| <span id="1040">1040</span> |
| <span id="1041">1041</span> |
| <span id="1042">1042</span> |
| <span id="1043">1043</span> |
| <span id="1044">1044</span> |
| <span id="1045">1045</span> |
| <span id="1046">1046</span> |
| <span id="1047">1047</span> |
| <span id="1048">1048</span> |
| <span id="1049">1049</span> |
| <span id="1050">1050</span> |
| <span id="1051">1051</span> |
| <span id="1052">1052</span> |
| <span id="1053">1053</span> |
| <span id="1054">1054</span> |
| <span id="1055">1055</span> |
| <span id="1056">1056</span> |
| <span id="1057">1057</span> |
| <span id="1058">1058</span> |
| <span id="1059">1059</span> |
| <span id="1060">1060</span> |
| <span id="1061">1061</span> |
| <span id="1062">1062</span> |
| <span id="1063">1063</span> |
| <span id="1064">1064</span> |
| <span id="1065">1065</span> |
| <span id="1066">1066</span> |
| <span id="1067">1067</span> |
| <span id="1068">1068</span> |
| <span id="1069">1069</span> |
| <span id="1070">1070</span> |
| <span id="1071">1071</span> |
| <span id="1072">1072</span> |
| <span id="1073">1073</span> |
| <span id="1074">1074</span> |
| <span id="1075">1075</span> |
| <span id="1076">1076</span> |
| <span id="1077">1077</span> |
| <span id="1078">1078</span> |
| <span id="1079">1079</span> |
| <span id="1080">1080</span> |
| <span id="1081">1081</span> |
| <span id="1082">1082</span> |
| <span id="1083">1083</span> |
| <span id="1084">1084</span> |
| </pre><pre class="rust"><code><span class="kw">use </span><span class="kw">crate</span>::read_u8; |
| <span class="kw">use </span>error::{Error, <span class="prelude-ty">Result</span>, UnsupportedFeature}; |
| <span class="kw">use </span>huffman::{fill_default_mjpeg_tables, HuffmanDecoder, HuffmanTable}; |
| <span class="kw">use </span>marker::Marker; |
| <span class="kw">use </span>parser::{AdobeColorTransform, AppData, CodingProcess, Component, Dimensions, EntropyCoding, FrameInfo, |
| parse_app, parse_com, parse_dht, parse_dqt, parse_dri, parse_sof, parse_sos, IccChunk, |
| ScanInfo}; |
| <span class="kw">use </span>upsampler::Upsampler; |
| <span class="kw">use </span>std::cmp; |
| <span class="kw">use </span>std::io::Read; |
| <span class="kw">use </span>std::mem; |
| <span class="kw">use </span>std::ops::Range; |
| <span class="kw">use </span>std::sync::Arc; |
| <span class="kw">use </span>worker::{RowData, PlatformWorker, Worker}; |
| |
| <span class="kw">pub const </span>MAX_COMPONENTS: usize = <span class="number">4</span>; |
| |
| <span class="kw">static </span>UNZIGZAG: [u8; <span class="number">64</span>] = [ |
| <span class="number">0</span>, <span class="number">1</span>, <span class="number">8</span>, <span class="number">16</span>, <span class="number">9</span>, <span class="number">2</span>, <span class="number">3</span>, <span class="number">10</span>, |
| <span class="number">17</span>, <span class="number">24</span>, <span class="number">32</span>, <span class="number">25</span>, <span class="number">18</span>, <span class="number">11</span>, <span class="number">4</span>, <span class="number">5</span>, |
| <span class="number">12</span>, <span class="number">19</span>, <span class="number">26</span>, <span class="number">33</span>, <span class="number">40</span>, <span class="number">48</span>, <span class="number">41</span>, <span class="number">34</span>, |
| <span class="number">27</span>, <span class="number">20</span>, <span class="number">13</span>, <span class="number">6</span>, <span class="number">7</span>, <span class="number">14</span>, <span class="number">21</span>, <span class="number">28</span>, |
| <span class="number">35</span>, <span class="number">42</span>, <span class="number">49</span>, <span class="number">56</span>, <span class="number">57</span>, <span class="number">50</span>, <span class="number">43</span>, <span class="number">36</span>, |
| <span class="number">29</span>, <span class="number">22</span>, <span class="number">15</span>, <span class="number">23</span>, <span class="number">30</span>, <span class="number">37</span>, <span class="number">44</span>, <span class="number">51</span>, |
| <span class="number">58</span>, <span class="number">59</span>, <span class="number">52</span>, <span class="number">45</span>, <span class="number">38</span>, <span class="number">31</span>, <span class="number">39</span>, <span class="number">46</span>, |
| <span class="number">53</span>, <span class="number">60</span>, <span class="number">61</span>, <span class="number">54</span>, <span class="number">47</span>, <span class="number">55</span>, <span class="number">62</span>, <span class="number">63</span>, |
| ]; |
| |
| <span class="doccomment">/// An enumeration over combinations of color spaces and bit depths a pixel can have. |
| </span><span class="attribute">#[derive(Clone, Copy, Debug, PartialEq)] |
| </span><span class="kw">pub enum </span>PixelFormat { |
| <span class="doccomment">/// Luminance (grayscale), 8 bits |
| </span>L8, |
| <span class="doccomment">/// RGB, 8 bits per channel |
| </span>RGB24, |
| <span class="doccomment">/// CMYK, 8 bits per channel |
| </span>CMYK32, |
| } |
| |
| <span class="kw">impl </span>PixelFormat { |
| <span class="doccomment">/// Determine the size in bytes of each pixel in this format |
| </span><span class="kw">pub fn </span>pixel_bytes(<span class="kw-2">&</span><span class="self">self</span>) -> usize { |
| <span class="kw">match </span><span class="self">self </span>{ |
| PixelFormat::L8 => <span class="number">1</span>, |
| PixelFormat::RGB24 => <span class="number">3</span>, |
| PixelFormat::CMYK32 => <span class="number">4</span>, |
| } |
| } |
| } |
| |
| <span class="doccomment">/// Represents metadata of an image. |
| </span><span class="attribute">#[derive(Clone, Copy, Debug, PartialEq)] |
| </span><span class="kw">pub struct </span>ImageInfo { |
| <span class="doccomment">/// The width of the image, in pixels. |
| </span><span class="kw">pub </span>width: u16, |
| <span class="doccomment">/// The height of the image, in pixels. |
| </span><span class="kw">pub </span>height: u16, |
| <span class="doccomment">/// The pixel format of the image. |
| </span><span class="kw">pub </span>pixel_format: PixelFormat, |
| } |
| |
| <span class="doccomment">/// JPEG decoder |
| </span><span class="kw">pub struct </span>Decoder<R> { |
| reader: R, |
| |
| frame: <span class="prelude-ty">Option</span><FrameInfo>, |
| dc_huffman_tables: Vec<<span class="prelude-ty">Option</span><HuffmanTable>>, |
| ac_huffman_tables: Vec<<span class="prelude-ty">Option</span><HuffmanTable>>, |
| quantization_tables: [<span class="prelude-ty">Option</span><Arc<[u16; <span class="number">64</span>]>>; <span class="number">4</span>], |
| |
| restart_interval: u16, |
| color_transform: <span class="prelude-ty">Option</span><AdobeColorTransform>, |
| is_jfif: bool, |
| is_mjpeg: bool, |
| |
| icc_markers: Vec<IccChunk>, |
| |
| <span class="comment">// Used for progressive JPEGs. |
| </span>coefficients: Vec<Vec<i16>>, |
| <span class="comment">// Bitmask of which coefficients has been completely decoded. |
| </span>coefficients_finished: [u64; MAX_COMPONENTS], |
| } |
| |
| <span class="kw">impl</span><R: Read> Decoder<R> { |
| <span class="doccomment">/// Creates a new `Decoder` using the reader `reader`. |
| </span><span class="kw">pub fn </span>new(reader: R) -> Decoder<R> { |
| Decoder { |
| reader: reader, |
| frame: <span class="prelude-val">None</span>, |
| dc_huffman_tables: <span class="macro">vec!</span>[<span class="prelude-val">None</span>, <span class="prelude-val">None</span>, <span class="prelude-val">None</span>, <span class="prelude-val">None</span>], |
| ac_huffman_tables: <span class="macro">vec!</span>[<span class="prelude-val">None</span>, <span class="prelude-val">None</span>, <span class="prelude-val">None</span>, <span class="prelude-val">None</span>], |
| quantization_tables: [<span class="prelude-val">None</span>, <span class="prelude-val">None</span>, <span class="prelude-val">None</span>, <span class="prelude-val">None</span>], |
| restart_interval: <span class="number">0</span>, |
| color_transform: <span class="prelude-val">None</span>, |
| is_jfif: <span class="bool-val">false</span>, |
| is_mjpeg: <span class="bool-val">false</span>, |
| icc_markers: Vec::new(), |
| coefficients: Vec::new(), |
| coefficients_finished: [<span class="number">0</span>; MAX_COMPONENTS], |
| } |
| } |
| |
| <span class="doccomment">/// Returns metadata about the image. |
| /// |
| /// The returned value will be `None` until a call to either `read_info` or `decode` has |
| /// returned `Ok`. |
| </span><span class="kw">pub fn </span>info(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="prelude-ty">Option</span><ImageInfo> { |
| <span class="kw">match </span><span class="self">self</span>.frame { |
| <span class="prelude-val">Some</span>(<span class="kw-2">ref </span>frame) => { |
| <span class="kw">let </span>pixel_format = <span class="kw">match </span>frame.components.len() { |
| <span class="number">1 </span>=> PixelFormat::L8, |
| <span class="number">3 </span>=> PixelFormat::RGB24, |
| <span class="number">4 </span>=> PixelFormat::CMYK32, |
| <span class="kw">_ </span>=> <span class="macro">panic!</span>(), |
| }; |
| |
| <span class="prelude-val">Some</span>(ImageInfo { |
| width: frame.output_size.width, |
| height: frame.output_size.height, |
| pixel_format: pixel_format, |
| }) |
| }, |
| <span class="prelude-val">None </span>=> <span class="prelude-val">None</span>, |
| } |
| } |
| |
| <span class="doccomment">/// Returns the embeded icc profile if the image contains one. |
| </span><span class="kw">pub fn </span>icc_profile(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="prelude-ty">Option</span><Vec<u8>> { |
| <span class="kw">let </span><span class="kw-2">mut </span>marker_present: [<span class="prelude-ty">Option</span><<span class="kw-2">&</span>IccChunk>; <span class="number">256</span>] = [<span class="prelude-val">None</span>; <span class="number">256</span>]; |
| <span class="kw">let </span>num_markers = <span class="self">self</span>.icc_markers.len(); |
| <span class="kw">if </span>num_markers == <span class="number">0 </span>&& num_markers < <span class="number">256 </span>{ |
| <span class="kw">return </span><span class="prelude-val">None</span>; |
| } |
| <span class="comment">// check the validity of the markers |
| </span><span class="kw">for </span>chunk <span class="kw">in </span><span class="kw-2">&</span><span class="self">self</span>.icc_markers { |
| <span class="kw">if </span>usize::from(chunk.num_markers) != num_markers { |
| <span class="comment">// all the lengths must match |
| </span><span class="kw">return </span><span class="prelude-val">None</span>; |
| } |
| <span class="kw">if </span>chunk.seq_no == <span class="number">0 </span>{ |
| <span class="kw">return </span><span class="prelude-val">None</span>; |
| } |
| <span class="kw">if </span>marker_present[usize::from(chunk.seq_no)].is_some() { |
| <span class="comment">// duplicate seq_no |
| </span><span class="kw">return </span><span class="prelude-val">None</span>; |
| } <span class="kw">else </span>{ |
| marker_present[usize::from(chunk.seq_no)] = <span class="prelude-val">Some</span>(chunk); |
| } |
| } |
| |
| <span class="comment">// assemble them together by seq_no failing if any are missing |
| </span><span class="kw">let </span><span class="kw-2">mut </span>data = Vec::new(); |
| <span class="comment">// seq_no's start at 1 |
| </span><span class="kw">for </span><span class="kw-2">&</span>chunk <span class="kw">in </span>marker_present.get(<span class="number">1</span>..=num_markers)<span class="question-mark">? </span>{ |
| data.extend_from_slice(<span class="kw-2">&</span>chunk<span class="question-mark">?</span>.data); |
| } |
| <span class="prelude-val">Some</span>(data) |
| } |
| |
| <span class="doccomment">/// Tries to read metadata from the image without decoding it. |
| /// |
| /// If successful, the metadata can be obtained using the `info` method. |
| </span><span class="kw">pub fn </span>read_info(<span class="kw-2">&mut </span><span class="self">self</span>) -> <span class="prelude-ty">Result</span><()> { |
| <span class="self">self</span>.decode_internal(<span class="bool-val">true</span>).map(|<span class="kw">_</span>| ()) |
| } |
| |
| <span class="doccomment">/// Configure the decoder to scale the image during decoding. |
| /// |
| /// This efficiently scales the image by the smallest supported scale |
| /// factor that produces an image larger than or equal to the requested |
| /// size in at least one axis. The currently implemented scale factors |
| /// are 1/8, 1/4, 1/2 and 1. |
| /// |
| /// To generate a thumbnail of an exact size, pass the desired size and |
| /// then scale to the final size using a traditional resampling algorithm. |
| </span><span class="kw">pub fn </span>scale(<span class="kw-2">&mut </span><span class="self">self</span>, requested_width: u16, requested_height: u16) -> <span class="prelude-ty">Result</span><(u16, u16)> { |
| <span class="self">self</span>.read_info()<span class="question-mark">?</span>; |
| <span class="kw">let </span>frame = <span class="self">self</span>.frame.as_mut().unwrap(); |
| <span class="kw">let </span>idct_size = <span class="kw">crate</span>::idct::choose_idct_size(frame.image_size, Dimensions{ width: requested_width, height: requested_height }); |
| frame.update_idct_size(idct_size)<span class="question-mark">?</span>; |
| <span class="prelude-val">Ok</span>((frame.output_size.width, frame.output_size.height)) |
| } |
| |
| <span class="doccomment">/// Decodes the image and returns the decoded pixels if successful. |
| </span><span class="kw">pub fn </span>decode(<span class="kw-2">&mut </span><span class="self">self</span>) -> <span class="prelude-ty">Result</span><Vec<u8>> { |
| <span class="self">self</span>.decode_internal(<span class="bool-val">false</span>) |
| } |
| |
| <span class="kw">fn </span>decode_internal(<span class="kw-2">&mut </span><span class="self">self</span>, stop_after_metadata: bool) -> <span class="prelude-ty">Result</span><Vec<u8>> { |
| <span class="kw">if </span>stop_after_metadata && <span class="self">self</span>.frame.is_some() { |
| <span class="comment">// The metadata has already been read. |
| </span><span class="kw">return </span><span class="prelude-val">Ok</span>(Vec::new()); |
| } |
| <span class="kw">else if </span><span class="self">self</span>.frame.is_none() && (read_u8(<span class="kw-2">&mut </span><span class="self">self</span>.reader)<span class="question-mark">? </span>!= <span class="number">0xFF </span>|| Marker::from_u8(read_u8(<span class="kw-2">&mut </span><span class="self">self</span>.reader)<span class="question-mark">?</span>) != <span class="prelude-val">Some</span>(Marker::SOI)) { |
| <span class="kw">return </span><span class="prelude-val">Err</span>(Error::Format(<span class="string">"first two bytes are not an SOI marker"</span>.to_owned())); |
| } |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>previous_marker = Marker::SOI; |
| <span class="kw">let </span><span class="kw-2">mut </span>pending_marker = <span class="prelude-val">None</span>; |
| <span class="kw">let </span><span class="kw-2">mut </span>worker = <span class="prelude-val">None</span>; |
| <span class="kw">let </span><span class="kw-2">mut </span>scans_processed = <span class="number">0</span>; |
| <span class="kw">let </span><span class="kw-2">mut </span>planes = <span class="macro">vec!</span>[Vec::new(); <span class="self">self</span>.frame.as_ref().map_or(<span class="number">0</span>, |frame| frame.components.len())]; |
| |
| <span class="kw">loop </span>{ |
| <span class="kw">let </span>marker = <span class="kw">match </span>pending_marker.take() { |
| <span class="prelude-val">Some</span>(m) => m, |
| <span class="prelude-val">None </span>=> <span class="self">self</span>.read_marker()<span class="question-mark">?</span>, |
| }; |
| |
| <span class="kw">match </span>marker { |
| <span class="comment">// Frame header |
| </span>Marker::SOF(..) => { |
| <span class="comment">// Section 4.10 |
| // "An image contains only one frame in the cases of sequential and |
| // progressive coding processes; an image contains multiple frames for the |
| // hierarchical mode." |
| </span><span class="kw">if </span><span class="self">self</span>.frame.is_some() { |
| <span class="kw">return </span><span class="prelude-val">Err</span>(Error::Unsupported(UnsupportedFeature::Hierarchical)); |
| } |
| |
| <span class="kw">let </span>frame = parse_sof(<span class="kw-2">&mut </span><span class="self">self</span>.reader, marker)<span class="question-mark">?</span>; |
| <span class="kw">let </span>component_count = frame.components.len(); |
| |
| <span class="kw">if </span>frame.is_differential { |
| <span class="kw">return </span><span class="prelude-val">Err</span>(Error::Unsupported(UnsupportedFeature::Hierarchical)); |
| } |
| <span class="kw">if </span>frame.coding_process == CodingProcess::Lossless { |
| <span class="kw">return </span><span class="prelude-val">Err</span>(Error::Unsupported(UnsupportedFeature::Lossless)); |
| } |
| <span class="kw">if </span>frame.entropy_coding == EntropyCoding::Arithmetic { |
| <span class="kw">return </span><span class="prelude-val">Err</span>(Error::Unsupported(UnsupportedFeature::ArithmeticEntropyCoding)); |
| } |
| <span class="kw">if </span>frame.precision != <span class="number">8 </span>{ |
| <span class="kw">return </span><span class="prelude-val">Err</span>(Error::Unsupported(UnsupportedFeature::SamplePrecision(frame.precision))); |
| } |
| <span class="kw">if </span>component_count != <span class="number">1 </span>&& component_count != <span class="number">3 </span>&& component_count != <span class="number">4 </span>{ |
| <span class="kw">return </span><span class="prelude-val">Err</span>(Error::Unsupported(UnsupportedFeature::ComponentCount(component_count <span class="kw">as </span>u8))); |
| } |
| |
| <span class="comment">// Make sure we support the subsampling ratios used. |
| </span><span class="kw">let _ </span>= Upsampler::new(<span class="kw-2">&</span>frame.components, frame.image_size.width, frame.image_size.height)<span class="question-mark">?</span>; |
| |
| <span class="self">self</span>.frame = <span class="prelude-val">Some</span>(frame); |
| |
| <span class="kw">if </span>stop_after_metadata { |
| <span class="kw">return </span><span class="prelude-val">Ok</span>(Vec::new()); |
| } |
| |
| planes = <span class="macro">vec!</span>[Vec::new(); component_count]; |
| }, |
| |
| <span class="comment">// Scan header |
| </span>Marker::SOS => { |
| <span class="kw">if </span><span class="self">self</span>.frame.is_none() { |
| <span class="kw">return </span><span class="prelude-val">Err</span>(Error::Format(<span class="string">"scan encountered before frame"</span>.to_owned())); |
| } |
| <span class="kw">if </span>worker.is_none() { |
| worker = <span class="prelude-val">Some</span>(PlatformWorker::new()<span class="question-mark">?</span>); |
| } |
| |
| <span class="kw">let </span>frame = <span class="self">self</span>.frame.clone().unwrap(); |
| <span class="kw">let </span>scan = parse_sos(<span class="kw-2">&mut </span><span class="self">self</span>.reader, <span class="kw-2">&</span>frame)<span class="question-mark">?</span>; |
| |
| <span class="kw">if </span>frame.coding_process == CodingProcess::DctProgressive && <span class="self">self</span>.coefficients.is_empty() { |
| <span class="self">self</span>.coefficients = frame.components.iter().map(|c| { |
| <span class="kw">let </span>block_count = c.block_size.width <span class="kw">as </span>usize * c.block_size.height <span class="kw">as </span>usize; |
| <span class="macro">vec!</span>[<span class="number">0</span>; block_count * <span class="number">64</span>] |
| }).collect(); |
| } |
| |
| <span class="comment">// This was previously buggy, so let's explain the log here a bit. When a |
| // progressive frame is encoded then the coefficients (DC, AC) of each |
| // component (=color plane) can be split amongst scans. In particular it can |
| // happen or at least occurs in the wild that a scan contains coefficient 0 of |
| // all components. If now one but not all components had all other coefficients |
| // delivered in previous scans then such a scan contains all components but |
| // completes only some of them! (This is technically NOT permitted for all |
| // other coefficients as the standard dictates that scans with coefficients |
| // other than the 0th must only contain ONE component so we would either |
| // complete it or not. We may want to detect and error in case more component |
| // are part of a scan than allowed.) What a weird edge case. |
| // |
| // But this means we track precisely which components get completed here. |
| </span><span class="kw">let </span><span class="kw-2">mut </span>finished = [<span class="bool-val">false</span>; MAX_COMPONENTS]; |
| |
| <span class="kw">if </span>scan.successive_approximation_low == <span class="number">0 </span>{ |
| <span class="kw">for </span>(<span class="kw-2">&</span>i, component_finished) <span class="kw">in </span>scan.component_indices.iter().zip(<span class="kw-2">&mut </span>finished) { |
| <span class="kw">if </span><span class="self">self</span>.coefficients_finished[i] == !<span class="number">0 </span>{ |
| <span class="kw">continue</span>; |
| } |
| <span class="kw">for </span>j <span class="kw">in </span>scan.spectral_selection.clone() { |
| <span class="self">self</span>.coefficients_finished[i] |= <span class="number">1 </span><< j; |
| } |
| <span class="kw">if </span><span class="self">self</span>.coefficients_finished[i] == !<span class="number">0 </span>{ |
| <span class="kw-2">*</span>component_finished = <span class="bool-val">true</span>; |
| } |
| } |
| } |
| |
| <span class="kw">let </span>(marker, data) = <span class="self">self</span>.decode_scan(<span class="kw-2">&</span>frame, <span class="kw-2">&</span>scan, worker.as_mut().unwrap(), <span class="kw-2">&</span>finished)<span class="question-mark">?</span>; |
| |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(data) = data { |
| <span class="kw">for </span>(i, plane) <span class="kw">in </span>data.into_iter().enumerate().filter(|<span class="kw-2">&</span>(<span class="kw">_</span>, <span class="kw-2">ref </span>plane)| !plane.is_empty()) { |
| <span class="kw">if </span><span class="self">self</span>.coefficients_finished[i] == !<span class="number">0 </span>{ |
| planes[i] = plane; |
| } |
| } |
| } |
| |
| pending_marker = marker; |
| scans_processed += <span class="number">1</span>; |
| }, |
| |
| <span class="comment">// Table-specification and miscellaneous markers |
| // Quantization table-specification |
| </span>Marker::DQT => { |
| <span class="kw">let </span>tables = parse_dqt(<span class="kw-2">&mut </span><span class="self">self</span>.reader)<span class="question-mark">?</span>; |
| |
| <span class="kw">for </span>(i, <span class="kw-2">&</span>table) <span class="kw">in </span>tables.iter().enumerate() { |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(table) = table { |
| <span class="kw">let </span><span class="kw-2">mut </span>unzigzagged_table = [<span class="number">0u16</span>; <span class="number">64</span>]; |
| |
| <span class="kw">for </span>j <span class="kw">in </span><span class="number">0 </span>.. <span class="number">64 </span>{ |
| unzigzagged_table[UNZIGZAG[j] <span class="kw">as </span>usize] = table[j]; |
| } |
| |
| <span class="self">self</span>.quantization_tables[i] = <span class="prelude-val">Some</span>(Arc::new(unzigzagged_table)); |
| } |
| } |
| }, |
| <span class="comment">// Huffman table-specification |
| </span>Marker::DHT => { |
| <span class="kw">let </span>is_baseline = <span class="self">self</span>.frame.as_ref().map(|frame| frame.is_baseline); |
| <span class="kw">let </span>(dc_tables, ac_tables) = parse_dht(<span class="kw-2">&mut </span><span class="self">self</span>.reader, is_baseline)<span class="question-mark">?</span>; |
| |
| <span class="kw">let </span>current_dc_tables = mem::replace(<span class="kw-2">&mut </span><span class="self">self</span>.dc_huffman_tables, <span class="macro">vec!</span>[]); |
| <span class="self">self</span>.dc_huffman_tables = dc_tables.into_iter() |
| .zip(current_dc_tables.into_iter()) |
| .map(|(a, b)| a.or(b)) |
| .collect(); |
| |
| <span class="kw">let </span>current_ac_tables = mem::replace(<span class="kw-2">&mut </span><span class="self">self</span>.ac_huffman_tables, <span class="macro">vec!</span>[]); |
| <span class="self">self</span>.ac_huffman_tables = ac_tables.into_iter() |
| .zip(current_ac_tables.into_iter()) |
| .map(|(a, b)| a.or(b)) |
| .collect(); |
| }, |
| <span class="comment">// Arithmetic conditioning table-specification |
| </span>Marker::DAC => <span class="kw">return </span><span class="prelude-val">Err</span>(Error::Unsupported(UnsupportedFeature::ArithmeticEntropyCoding)), |
| <span class="comment">// Restart interval definition |
| </span>Marker::DRI => <span class="self">self</span>.restart_interval = parse_dri(<span class="kw-2">&mut </span><span class="self">self</span>.reader)<span class="question-mark">?</span>, |
| <span class="comment">// Comment |
| </span>Marker::COM => { |
| <span class="kw">let </span>_comment = parse_com(<span class="kw-2">&mut </span><span class="self">self</span>.reader)<span class="question-mark">?</span>; |
| }, |
| <span class="comment">// Application data |
| </span>Marker::APP(..) => { |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(data) = parse_app(<span class="kw-2">&mut </span><span class="self">self</span>.reader, marker)<span class="question-mark">? </span>{ |
| <span class="kw">match </span>data { |
| AppData::Adobe(color_transform) => <span class="self">self</span>.color_transform = <span class="prelude-val">Some</span>(color_transform), |
| AppData::Jfif => { |
| <span class="comment">// From the JFIF spec: |
| // "The APP0 marker is used to identify a JPEG FIF file. |
| // The JPEG FIF APP0 marker is mandatory right after the SOI marker." |
| // Some JPEGs in the wild does not follow this though, so we allow |
| // JFIF headers anywhere APP0 markers are allowed. |
| /* |
| if previous_marker != Marker::SOI { |
| return Err(Error::Format("the JFIF APP0 marker must come right after the SOI marker".to_owned())); |
| } |
| */ |
| |
| </span><span class="self">self</span>.is_jfif = <span class="bool-val">true</span>; |
| }, |
| AppData::Avi1 => <span class="self">self</span>.is_mjpeg = <span class="bool-val">true</span>, |
| AppData::Icc(icc) => <span class="self">self</span>.icc_markers.push(icc), |
| } |
| } |
| }, |
| <span class="comment">// Restart |
| </span>Marker::RST(..) => { |
| <span class="comment">// Some encoders emit a final RST marker after entropy-coded data, which |
| // decode_scan does not take care of. So if we encounter one, we ignore it. |
| </span><span class="kw">if </span>previous_marker != Marker::SOS { |
| <span class="kw">return </span><span class="prelude-val">Err</span>(Error::Format(<span class="string">"RST found outside of entropy-coded data"</span>.to_owned())); |
| } |
| }, |
| |
| <span class="comment">// Define number of lines |
| </span>Marker::DNL => { |
| <span class="comment">// Section B.2.1 |
| // "If a DNL segment (see B.2.5) is present, it shall immediately follow the first scan." |
| </span><span class="kw">if </span>previous_marker != Marker::SOS || scans_processed != <span class="number">1 </span>{ |
| <span class="kw">return </span><span class="prelude-val">Err</span>(Error::Format(<span class="string">"DNL is only allowed immediately after the first scan"</span>.to_owned())); |
| } |
| |
| <span class="kw">return </span><span class="prelude-val">Err</span>(Error::Unsupported(UnsupportedFeature::DNL)); |
| }, |
| |
| <span class="comment">// Hierarchical mode markers |
| </span>Marker::DHP | Marker::EXP => <span class="kw">return </span><span class="prelude-val">Err</span>(Error::Unsupported(UnsupportedFeature::Hierarchical)), |
| |
| <span class="comment">// End of image |
| </span>Marker::EOI => <span class="kw">break</span>, |
| |
| <span class="kw">_ </span>=> <span class="kw">return </span><span class="prelude-val">Err</span>(Error::Format(<span class="macro">format!</span>(<span class="string">"{:?} marker found where not allowed"</span>, marker))), |
| } |
| |
| previous_marker = marker; |
| } |
| |
| <span class="kw">if </span><span class="self">self</span>.frame.is_none() { |
| <span class="kw">return </span><span class="prelude-val">Err</span>(Error::Format(<span class="string">"end of image encountered before frame"</span>.to_owned())); |
| } |
| |
| <span class="kw">let </span>frame = <span class="self">self</span>.frame.as_ref().unwrap(); |
| |
| <span class="comment">// If we're decoding a progressive jpeg and a component is unfinished, render what we've got |
| </span><span class="kw">if </span>frame.coding_process == CodingProcess::DctProgressive && <span class="self">self</span>.coefficients.len() == frame.components.len() { |
| <span class="kw">for </span>(i, component) <span class="kw">in </span>frame.components.iter().enumerate() { |
| <span class="comment">// Only dealing with unfinished components |
| </span><span class="kw">if </span><span class="self">self</span>.coefficients_finished[i] == !<span class="number">0 </span>{ |
| <span class="kw">continue</span>; |
| } |
| |
| <span class="kw">let </span>quantization_table = <span class="kw">match </span><span class="self">self</span>.quantization_tables[component.quantization_table_index].clone() { |
| <span class="prelude-val">Some</span>(quantization_table) => quantization_table, |
| <span class="prelude-val">None </span>=> <span class="kw">continue</span>, |
| }; |
| |
| <span class="comment">// Get the worker prepared |
| </span><span class="kw">if </span>worker.is_none() { |
| worker = <span class="prelude-val">Some</span>(PlatformWorker::new()<span class="question-mark">?</span>); |
| } |
| <span class="kw">let </span>worker = worker.as_mut().unwrap(); |
| <span class="kw">let </span>row_data = RowData { |
| index: i, |
| component: component.clone(), |
| quantization_table, |
| }; |
| worker.start(row_data)<span class="question-mark">?</span>; |
| |
| <span class="comment">// Send the rows over to the worker and collect the result |
| </span><span class="kw">let </span>coefficients_per_mcu_row = usize::from(component.block_size.width) * usize::from(component.vertical_sampling_factor) * <span class="number">64</span>; |
| <span class="kw">for </span>mcu_y <span class="kw">in </span><span class="number">0</span>..frame.mcu_size.height { |
| <span class="kw">let </span>row_coefficients = { |
| <span class="kw">let </span>offset = usize::from(mcu_y) * coefficients_per_mcu_row; |
| <span class="self">self</span>.coefficients[i][offset .. offset + coefficients_per_mcu_row].to_vec() |
| }; |
| |
| worker.append_row((i, row_coefficients))<span class="question-mark">?</span>; |
| } |
| planes[i] = worker.get_result(i)<span class="question-mark">?</span>; |
| } |
| } |
| |
| compute_image(<span class="kw-2">&</span>frame.components, planes, frame.output_size, <span class="self">self</span>.is_jfif, <span class="self">self</span>.color_transform) |
| } |
| |
| <span class="kw">fn </span>read_marker(<span class="kw-2">&mut </span><span class="self">self</span>) -> <span class="prelude-ty">Result</span><Marker> { |
| <span class="kw">loop </span>{ |
| <span class="comment">// This should be an error as the JPEG spec doesn't allow extraneous data between marker segments. |
| // libjpeg allows this though and there are images in the wild utilising it, so we are |
| // forced to support this behavior. |
| // Sony Ericsson P990i is an example of a device which produce this sort of JPEGs. |
| </span><span class="kw">while </span>read_u8(<span class="kw-2">&mut </span><span class="self">self</span>.reader)<span class="question-mark">? </span>!= <span class="number">0xFF </span>{} |
| |
| <span class="comment">// Section B.1.1.2 |
| // All markers are assigned two-byte codes: an X’FF’ byte followed by a |
| // byte which is not equal to 0 or X’FF’ (see Table B.1). Any marker may |
| // optionally be preceded by any number of fill bytes, which are bytes |
| // assigned code X’FF’. |
| </span><span class="kw">let </span><span class="kw-2">mut </span>byte = read_u8(<span class="kw-2">&mut </span><span class="self">self</span>.reader)<span class="question-mark">?</span>; |
| |
| <span class="comment">// Section B.1.1.2 |
| // "Any marker may optionally be preceded by any number of fill bytes, which are bytes assigned code X’FF’." |
| </span><span class="kw">while </span>byte == <span class="number">0xFF </span>{ |
| byte = read_u8(<span class="kw-2">&mut </span><span class="self">self</span>.reader)<span class="question-mark">?</span>; |
| } |
| |
| <span class="kw">if </span>byte != <span class="number">0x00 </span>&& byte != <span class="number">0xFF </span>{ |
| <span class="kw">return </span><span class="prelude-val">Ok</span>(Marker::from_u8(byte).unwrap()); |
| } |
| } |
| } |
| |
| <span class="kw">fn </span>decode_scan(<span class="kw-2">&mut </span><span class="self">self</span>, |
| frame: <span class="kw-2">&</span>FrameInfo, |
| scan: <span class="kw-2">&</span>ScanInfo, |
| worker: <span class="kw-2">&mut </span>PlatformWorker, |
| finished: <span class="kw-2">&</span>[bool; MAX_COMPONENTS]) |
| -> <span class="prelude-ty">Result</span><(<span class="prelude-ty">Option</span><Marker>, <span class="prelude-ty">Option</span><Vec<Vec<u8>>>)> { |
| <span class="macro">assert!</span>(scan.component_indices.len() <= MAX_COMPONENTS); |
| |
| <span class="kw">let </span>components: Vec<Component> = scan.component_indices.iter() |
| .map(|<span class="kw-2">&</span>i| frame.components[i].clone()) |
| .collect(); |
| |
| <span class="comment">// Verify that all required quantization tables has been set. |
| </span><span class="kw">if </span>components.iter().any(|component| <span class="self">self</span>.quantization_tables[component.quantization_table_index].is_none()) { |
| <span class="kw">return </span><span class="prelude-val">Err</span>(Error::Format(<span class="string">"use of unset quantization table"</span>.to_owned())); |
| } |
| |
| <span class="kw">if </span><span class="self">self</span>.is_mjpeg { |
| fill_default_mjpeg_tables(scan, <span class="kw-2">&mut </span><span class="self">self</span>.dc_huffman_tables, <span class="kw-2">&mut </span><span class="self">self</span>.ac_huffman_tables); |
| } |
| |
| <span class="comment">// Verify that all required huffman tables has been set. |
| </span><span class="kw">if </span>scan.spectral_selection.start == <span class="number">0 </span>&& |
| scan.dc_table_indices.iter().any(|<span class="kw-2">&</span>i| <span class="self">self</span>.dc_huffman_tables[i].is_none()) { |
| <span class="kw">return </span><span class="prelude-val">Err</span>(Error::Format(<span class="string">"scan makes use of unset dc huffman table"</span>.to_owned())); |
| } |
| <span class="kw">if </span>scan.spectral_selection.end > <span class="number">1 </span>&& |
| scan.ac_table_indices.iter().any(|<span class="kw-2">&</span>i| <span class="self">self</span>.ac_huffman_tables[i].is_none()) { |
| <span class="kw">return </span><span class="prelude-val">Err</span>(Error::Format(<span class="string">"scan makes use of unset ac huffman table"</span>.to_owned())); |
| } |
| |
| <span class="comment">// Prepare the worker thread for the work to come. |
| </span><span class="kw">for </span>(i, component) <span class="kw">in </span>components.iter().enumerate() { |
| <span class="kw">if </span>finished[i] { |
| <span class="kw">let </span>row_data = RowData { |
| index: i, |
| component: component.clone(), |
| quantization_table: <span class="self">self</span>.quantization_tables[component.quantization_table_index].clone().unwrap(), |
| }; |
| |
| worker.start(row_data)<span class="question-mark">?</span>; |
| } |
| } |
| |
| <span class="kw">let </span>is_progressive = frame.coding_process == CodingProcess::DctProgressive; |
| <span class="kw">let </span>is_interleaved = components.len() > <span class="number">1</span>; |
| <span class="kw">let </span><span class="kw-2">mut </span>dummy_block = [<span class="number">0i16</span>; <span class="number">64</span>]; |
| <span class="kw">let </span><span class="kw-2">mut </span>huffman = HuffmanDecoder::new(); |
| <span class="kw">let </span><span class="kw-2">mut </span>dc_predictors = [<span class="number">0i16</span>; MAX_COMPONENTS]; |
| <span class="kw">let </span><span class="kw-2">mut </span>mcus_left_until_restart = <span class="self">self</span>.restart_interval; |
| <span class="kw">let </span><span class="kw-2">mut </span>expected_rst_num = <span class="number">0</span>; |
| <span class="kw">let </span><span class="kw-2">mut </span>eob_run = <span class="number">0</span>; |
| <span class="kw">let </span><span class="kw-2">mut </span>mcu_row_coefficients = Vec::with_capacity(components.len()); |
| |
| <span class="kw">if </span>!is_progressive { |
| <span class="kw">for </span>(<span class="kw">_</span>, component) <span class="kw">in </span>components.iter().enumerate().filter(|<span class="kw-2">&</span>(i, <span class="kw">_</span>)| finished[i]) { |
| <span class="kw">let </span>coefficients_per_mcu_row = component.block_size.width <span class="kw">as </span>usize * component.vertical_sampling_factor <span class="kw">as </span>usize * <span class="number">64</span>; |
| mcu_row_coefficients.push(<span class="macro">vec!</span>[<span class="number">0i16</span>; coefficients_per_mcu_row]); |
| } |
| } |
| |
| <span class="comment">// 4.8.2 |
| // When reading from the stream, if the data is non-interleaved then an MCU consists of |
| // exactly one block (effectively a 1x1 sample). |
| </span><span class="kw">let </span>(mcu_horizontal_samples, mcu_vertical_samples) = <span class="kw">if </span>is_interleaved { |
| <span class="kw">let </span>horizontal = components.iter().map(|component| component.horizontal_sampling_factor <span class="kw">as </span>u16).collect::<Vec<<span class="kw">_</span>>>(); |
| <span class="kw">let </span>vertical = components.iter().map(|component| component.vertical_sampling_factor <span class="kw">as </span>u16).collect::<Vec<<span class="kw">_</span>>>(); |
| (horizontal, vertical) |
| } <span class="kw">else </span>{ |
| (<span class="macro">vec!</span>[<span class="number">1</span>], <span class="macro">vec!</span>[<span class="number">1</span>]) |
| }; |
| |
| <span class="comment">// This also affects how many MCU values we read from stream. If it's a non-interleaved stream, |
| // the MCUs will be exactly the block count. |
| </span><span class="kw">let </span>(max_mcu_x, max_mcu_y) = <span class="kw">if </span>is_interleaved { |
| (frame.mcu_size.width, frame.mcu_size.height) |
| } <span class="kw">else </span>{ |
| (components[<span class="number">0</span>].block_size.width, components[<span class="number">0</span>].block_size.height) |
| }; |
| |
| <span class="kw">for </span>mcu_y <span class="kw">in </span><span class="number">0</span>..max_mcu_y { |
| <span class="kw">if </span>mcu_y * <span class="number">8 </span>>= frame.image_size.height { |
| <span class="kw">break</span>; |
| } |
| |
| <span class="kw">for </span>mcu_x <span class="kw">in </span><span class="number">0</span>..max_mcu_x { |
| <span class="kw">if </span>mcu_x * <span class="number">8 </span>>= frame.image_size.width { |
| <span class="kw">break</span>; |
| } |
| |
| <span class="kw">if </span><span class="self">self</span>.restart_interval > <span class="number">0 </span>{ |
| <span class="kw">if </span>mcus_left_until_restart == <span class="number">0 </span>{ |
| <span class="kw">match </span>huffman.take_marker(<span class="kw-2">&mut </span><span class="self">self</span>.reader)<span class="question-mark">? </span>{ |
| <span class="prelude-val">Some</span>(Marker::RST(n)) => { |
| <span class="kw">if </span>n != expected_rst_num { |
| <span class="kw">return </span><span class="prelude-val">Err</span>(Error::Format(<span class="macro">format!</span>(<span class="string">"found RST{} where RST{} was expected"</span>, n, expected_rst_num))); |
| } |
| |
| huffman.reset(); |
| <span class="comment">// Section F.2.1.3.1 |
| </span>dc_predictors = [<span class="number">0i16</span>; MAX_COMPONENTS]; |
| <span class="comment">// Section G.1.2.2 |
| </span>eob_run = <span class="number">0</span>; |
| |
| expected_rst_num = (expected_rst_num + <span class="number">1</span>) % <span class="number">8</span>; |
| mcus_left_until_restart = <span class="self">self</span>.restart_interval; |
| }, |
| <span class="prelude-val">Some</span>(marker) => <span class="kw">return </span><span class="prelude-val">Err</span>(Error::Format(<span class="macro">format!</span>(<span class="string">"found marker {:?} inside scan where RST{} was expected"</span>, marker, expected_rst_num))), |
| <span class="prelude-val">None </span>=> <span class="kw">return </span><span class="prelude-val">Err</span>(Error::Format(<span class="macro">format!</span>(<span class="string">"no marker found where RST{} was expected"</span>, expected_rst_num))), |
| } |
| } |
| |
| mcus_left_until_restart -= <span class="number">1</span>; |
| } |
| |
| <span class="kw">for </span>(i, component) <span class="kw">in </span>components.iter().enumerate() { |
| <span class="kw">for </span>v_pos <span class="kw">in </span><span class="number">0</span>..mcu_vertical_samples[i] { |
| <span class="kw">for </span>h_pos <span class="kw">in </span><span class="number">0</span>..mcu_horizontal_samples[i] { |
| <span class="kw">let </span>coefficients = <span class="kw">if </span>is_progressive { |
| <span class="kw">let </span>block_y = (mcu_y * mcu_vertical_samples[i] + v_pos) <span class="kw">as </span>usize; |
| <span class="kw">let </span>block_x = (mcu_x * mcu_horizontal_samples[i] + h_pos) <span class="kw">as </span>usize; |
| <span class="kw">let </span>block_offset = (block_y * component.block_size.width <span class="kw">as </span>usize + block_x) * <span class="number">64</span>; |
| <span class="kw-2">&mut </span><span class="self">self</span>.coefficients[scan.component_indices[i]][block_offset..block_offset + <span class="number">64</span>] |
| } <span class="kw">else if </span>finished[i] { |
| <span class="comment">// Because the worker thread operates in batches as if we were always interleaved, we |
| // need to distinguish between a single-shot buffer and one that's currently in process |
| // (for a non-interleaved) stream |
| </span><span class="kw">let </span>mcu_batch_current_row = <span class="kw">if </span>is_interleaved { |
| <span class="number">0 |
| </span>} <span class="kw">else </span>{ |
| mcu_y % component.vertical_sampling_factor <span class="kw">as </span>u16 |
| }; |
| |
| <span class="kw">let </span>block_y = (mcu_batch_current_row * mcu_vertical_samples[i] + v_pos) <span class="kw">as </span>usize; |
| <span class="kw">let </span>block_x = (mcu_x * mcu_horizontal_samples[i] + h_pos) <span class="kw">as </span>usize; |
| <span class="kw">let </span>block_offset = (block_y * component.block_size.width <span class="kw">as </span>usize + block_x) * <span class="number">64</span>; |
| <span class="kw-2">&mut </span>mcu_row_coefficients[i][block_offset..block_offset + <span class="number">64</span>] |
| } <span class="kw">else </span>{ |
| <span class="kw-2">&mut </span>dummy_block[..] |
| }; |
| |
| <span class="kw">if </span>scan.successive_approximation_high == <span class="number">0 </span>{ |
| decode_block(<span class="kw-2">&mut </span><span class="self">self</span>.reader, |
| coefficients, |
| <span class="kw-2">&mut </span>huffman, |
| <span class="self">self</span>.dc_huffman_tables[scan.dc_table_indices[i]].as_ref(), |
| <span class="self">self</span>.ac_huffman_tables[scan.ac_table_indices[i]].as_ref(), |
| scan.spectral_selection.clone(), |
| scan.successive_approximation_low, |
| <span class="kw-2">&mut </span>eob_run, |
| <span class="kw-2">&mut </span>dc_predictors[i])<span class="question-mark">?</span>; |
| } |
| <span class="kw">else </span>{ |
| decode_block_successive_approximation(<span class="kw-2">&mut </span><span class="self">self</span>.reader, |
| coefficients, |
| <span class="kw-2">&mut </span>huffman, |
| <span class="self">self</span>.ac_huffman_tables[scan.ac_table_indices[i]].as_ref(), |
| scan.spectral_selection.clone(), |
| scan.successive_approximation_low, |
| <span class="kw-2">&mut </span>eob_run)<span class="question-mark">?</span>; |
| } |
| } |
| } |
| } |
| } |
| |
| <span class="comment">// Send the coefficients from this MCU row to the worker thread for dequantization and idct. |
| </span><span class="kw">for </span>(i, component) <span class="kw">in </span>components.iter().enumerate() { |
| <span class="kw">if </span>finished[i] { |
| <span class="comment">// In the event of non-interleaved streams, if we're still building the buffer out, |
| // keep going; don't send it yet. We also need to ensure we don't skip over the last |
| // row(s) of the image. |
| </span><span class="kw">if </span>!is_interleaved && (mcu_y + <span class="number">1</span>) * <span class="number">8 </span>< frame.image_size.height { |
| <span class="kw">if </span>(mcu_y + <span class="number">1</span>) % component.vertical_sampling_factor <span class="kw">as </span>u16 > <span class="number">0 </span>{ |
| <span class="kw">continue</span>; |
| } |
| } |
| |
| <span class="kw">let </span>coefficients_per_mcu_row = component.block_size.width <span class="kw">as </span>usize * component.vertical_sampling_factor <span class="kw">as </span>usize * <span class="number">64</span>; |
| |
| <span class="kw">let </span>row_coefficients = <span class="kw">if </span>is_progressive { |
| <span class="comment">// Because non-interleaved streams will have multiple MCU rows concatenated together, |
| // the row for calculating the offset is different. |
| </span><span class="kw">let </span>worker_mcu_y = <span class="kw">if </span>is_interleaved { |
| mcu_y |
| } <span class="kw">else </span>{ |
| <span class="comment">// Explicitly doing floor-division here |
| </span>mcu_y / component.vertical_sampling_factor <span class="kw">as </span>u16 |
| }; |
| |
| <span class="kw">let </span>offset = worker_mcu_y <span class="kw">as </span>usize * coefficients_per_mcu_row; |
| <span class="self">self</span>.coefficients[scan.component_indices[i]][offset .. offset + coefficients_per_mcu_row].to_vec() |
| } <span class="kw">else </span>{ |
| mem::replace(<span class="kw-2">&mut </span>mcu_row_coefficients[i], <span class="macro">vec!</span>[<span class="number">0i16</span>; coefficients_per_mcu_row]) |
| }; |
| |
| worker.append_row((i, row_coefficients))<span class="question-mark">?</span>; |
| } |
| } |
| } |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>marker = huffman.take_marker(<span class="kw-2">&mut </span><span class="self">self</span>.reader)<span class="question-mark">?</span>; |
| <span class="kw">while let </span><span class="prelude-val">Some</span>(Marker::RST(<span class="kw">_</span>)) = marker { |
| marker = <span class="self">self</span>.read_marker().ok(); |
| } |
| |
| <span class="kw">if </span>finished.iter().any(|<span class="kw-2">&</span>c| c) { |
| <span class="comment">// Retrieve all the data from the worker thread. |
| </span><span class="kw">let </span><span class="kw-2">mut </span>data = <span class="macro">vec!</span>[Vec::new(); frame.components.len()]; |
| |
| <span class="kw">for </span>(i, <span class="kw-2">&</span>component_index) <span class="kw">in </span>scan.component_indices.iter().enumerate() { |
| <span class="kw">if </span>finished[i] { |
| data[component_index] = worker.get_result(i)<span class="question-mark">?</span>; |
| } |
| } |
| |
| <span class="prelude-val">Ok</span>((marker, <span class="prelude-val">Some</span>(data))) |
| } |
| <span class="kw">else </span>{ |
| <span class="prelude-val">Ok</span>((marker, <span class="prelude-val">None</span>)) |
| } |
| } |
| } |
| |
| <span class="kw">fn </span>decode_block<R: Read>(reader: <span class="kw-2">&mut </span>R, |
| coefficients: <span class="kw-2">&mut </span>[i16], |
| huffman: <span class="kw-2">&mut </span>HuffmanDecoder, |
| dc_table: <span class="prelude-ty">Option</span><<span class="kw-2">&</span>HuffmanTable>, |
| ac_table: <span class="prelude-ty">Option</span><<span class="kw-2">&</span>HuffmanTable>, |
| spectral_selection: Range<u8>, |
| successive_approximation_low: u8, |
| eob_run: <span class="kw-2">&mut </span>u16, |
| dc_predictor: <span class="kw-2">&mut </span>i16) -> <span class="prelude-ty">Result</span><()> { |
| <span class="macro">debug_assert_eq!</span>(coefficients.len(), <span class="number">64</span>); |
| |
| <span class="kw">if </span>spectral_selection.start == <span class="number">0 </span>{ |
| <span class="comment">// Section F.2.2.1 |
| // Figure F.12 |
| </span><span class="kw">let </span>value = huffman.decode(reader, dc_table.unwrap())<span class="question-mark">?</span>; |
| <span class="kw">let </span>diff = <span class="kw">match </span>value { |
| <span class="number">0 </span>=> <span class="number">0</span>, |
| <span class="number">1</span>..=<span class="number">11 </span>=> huffman.receive_extend(reader, value)<span class="question-mark">?</span>, |
| <span class="kw">_ </span>=> { |
| <span class="comment">// Section F.1.2.1.1 |
| // Table F.1 |
| </span><span class="kw">return </span><span class="prelude-val">Err</span>(Error::Format(<span class="string">"invalid DC difference magnitude category"</span>.to_owned())); |
| }, |
| }; |
| |
| <span class="comment">// Malicious JPEG files can cause this add to overflow, therefore we use wrapping_add. |
| // One example of such a file is tests/crashtest/images/dc-predictor-overflow.jpg |
| </span><span class="kw-2">*</span>dc_predictor = dc_predictor.wrapping_add(diff); |
| coefficients[<span class="number">0</span>] = <span class="kw-2">*</span>dc_predictor << successive_approximation_low; |
| } |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>index = cmp::max(spectral_selection.start, <span class="number">1</span>); |
| |
| <span class="kw">if </span>index < spectral_selection.end && <span class="kw-2">*</span>eob_run > <span class="number">0 </span>{ |
| <span class="kw-2">*</span>eob_run -= <span class="number">1</span>; |
| <span class="kw">return </span><span class="prelude-val">Ok</span>(()); |
| } |
| |
| <span class="comment">// Section F.1.2.2.1 |
| </span><span class="kw">while </span>index < spectral_selection.end { |
| <span class="kw">if let </span><span class="prelude-val">Some</span>((value, run)) = huffman.decode_fast_ac(reader, ac_table.unwrap())<span class="question-mark">? </span>{ |
| index += run; |
| |
| <span class="kw">if </span>index >= spectral_selection.end { |
| <span class="kw">break</span>; |
| } |
| |
| coefficients[UNZIGZAG[index <span class="kw">as </span>usize] <span class="kw">as </span>usize] = value << successive_approximation_low; |
| index += <span class="number">1</span>; |
| } |
| <span class="kw">else </span>{ |
| <span class="kw">let </span>byte = huffman.decode(reader, ac_table.unwrap())<span class="question-mark">?</span>; |
| <span class="kw">let </span>r = byte >> <span class="number">4</span>; |
| <span class="kw">let </span>s = byte & <span class="number">0x0f</span>; |
| |
| <span class="kw">if </span>s == <span class="number">0 </span>{ |
| <span class="kw">match </span>r { |
| <span class="number">15 </span>=> index += <span class="number">16</span>, <span class="comment">// Run length of 16 zero coefficients. |
| </span><span class="kw">_ </span>=> { |
| <span class="kw-2">*</span>eob_run = (<span class="number">1 </span><< r) - <span class="number">1</span>; |
| |
| <span class="kw">if </span>r > <span class="number">0 </span>{ |
| <span class="kw-2">*</span>eob_run += huffman.get_bits(reader, r)<span class="question-mark">?</span>; |
| } |
| |
| <span class="kw">break</span>; |
| }, |
| } |
| } |
| <span class="kw">else </span>{ |
| index += r; |
| |
| <span class="kw">if </span>index >= spectral_selection.end { |
| <span class="kw">break</span>; |
| } |
| |
| coefficients[UNZIGZAG[index <span class="kw">as </span>usize] <span class="kw">as </span>usize] = huffman.receive_extend(reader, s)<span class="question-mark">? </span><< successive_approximation_low; |
| index += <span class="number">1</span>; |
| } |
| } |
| } |
| |
| <span class="prelude-val">Ok</span>(()) |
| } |
| |
| <span class="kw">fn </span>decode_block_successive_approximation<R: Read>(reader: <span class="kw-2">&mut </span>R, |
| coefficients: <span class="kw-2">&mut </span>[i16], |
| huffman: <span class="kw-2">&mut </span>HuffmanDecoder, |
| ac_table: <span class="prelude-ty">Option</span><<span class="kw-2">&</span>HuffmanTable>, |
| spectral_selection: Range<u8>, |
| successive_approximation_low: u8, |
| eob_run: <span class="kw-2">&mut </span>u16) -> <span class="prelude-ty">Result</span><()> { |
| <span class="macro">debug_assert_eq!</span>(coefficients.len(), <span class="number">64</span>); |
| |
| <span class="kw">let </span>bit = <span class="number">1 </span><< successive_approximation_low; |
| |
| <span class="kw">if </span>spectral_selection.start == <span class="number">0 </span>{ |
| <span class="comment">// Section G.1.2.1 |
| |
| </span><span class="kw">if </span>huffman.get_bits(reader, <span class="number">1</span>)<span class="question-mark">? </span>== <span class="number">1 </span>{ |
| coefficients[<span class="number">0</span>] |= bit; |
| } |
| } |
| <span class="kw">else </span>{ |
| <span class="comment">// Section G.1.2.3 |
| |
| </span><span class="kw">if </span><span class="kw-2">*</span>eob_run > <span class="number">0 </span>{ |
| <span class="kw-2">*</span>eob_run -= <span class="number">1</span>; |
| refine_non_zeroes(reader, coefficients, huffman, spectral_selection, <span class="number">64</span>, bit)<span class="question-mark">?</span>; |
| <span class="kw">return </span><span class="prelude-val">Ok</span>(()); |
| } |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>index = spectral_selection.start; |
| |
| <span class="kw">while </span>index < spectral_selection.end { |
| <span class="kw">let </span>byte = huffman.decode(reader, ac_table.unwrap())<span class="question-mark">?</span>; |
| <span class="kw">let </span>r = byte >> <span class="number">4</span>; |
| <span class="kw">let </span>s = byte & <span class="number">0x0f</span>; |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>zero_run_length = r; |
| <span class="kw">let </span><span class="kw-2">mut </span>value = <span class="number">0</span>; |
| |
| <span class="kw">match </span>s { |
| <span class="number">0 </span>=> { |
| <span class="kw">match </span>r { |
| <span class="number">15 </span>=> { |
| <span class="comment">// Run length of 16 zero coefficients. |
| // We don't need to do anything special here, zero_run_length is 15 |
| // and then value (which is zero) gets written, resulting in 16 |
| // zero coefficients. |
| </span>}, |
| <span class="kw">_ </span>=> { |
| <span class="kw-2">*</span>eob_run = (<span class="number">1 </span><< r) - <span class="number">1</span>; |
| |
| <span class="kw">if </span>r > <span class="number">0 </span>{ |
| <span class="kw-2">*</span>eob_run += huffman.get_bits(reader, r)<span class="question-mark">?</span>; |
| } |
| |
| <span class="comment">// Force end of block. |
| </span>zero_run_length = <span class="number">64</span>; |
| }, |
| } |
| }, |
| <span class="number">1 </span>=> { |
| <span class="kw">if </span>huffman.get_bits(reader, <span class="number">1</span>)<span class="question-mark">? </span>== <span class="number">1 </span>{ |
| value = bit; |
| } |
| <span class="kw">else </span>{ |
| value = -bit; |
| } |
| }, |
| <span class="kw">_ </span>=> <span class="kw">return </span><span class="prelude-val">Err</span>(Error::Format(<span class="string">"unexpected huffman code"</span>.to_owned())), |
| } |
| |
| <span class="kw">let </span>range = Range { |
| start: index, |
| end: spectral_selection.end, |
| }; |
| index = refine_non_zeroes(reader, coefficients, huffman, range, zero_run_length, bit)<span class="question-mark">?</span>; |
| |
| <span class="kw">if </span>value != <span class="number">0 </span>{ |
| coefficients[UNZIGZAG[index <span class="kw">as </span>usize] <span class="kw">as </span>usize] = value; |
| } |
| |
| index += <span class="number">1</span>; |
| } |
| } |
| |
| <span class="prelude-val">Ok</span>(()) |
| } |
| |
| <span class="kw">fn </span>refine_non_zeroes<R: Read>(reader: <span class="kw-2">&mut </span>R, |
| coefficients: <span class="kw-2">&mut </span>[i16], |
| huffman: <span class="kw-2">&mut </span>HuffmanDecoder, |
| range: Range<u8>, |
| zrl: u8, |
| bit: i16) -> <span class="prelude-ty">Result</span><u8> { |
| <span class="macro">debug_assert_eq!</span>(coefficients.len(), <span class="number">64</span>); |
| |
| <span class="kw">let </span>last = range.end - <span class="number">1</span>; |
| <span class="kw">let </span><span class="kw-2">mut </span>zero_run_length = zrl; |
| |
| <span class="kw">for </span>i <span class="kw">in </span>range { |
| <span class="kw">let </span>index = UNZIGZAG[i <span class="kw">as </span>usize] <span class="kw">as </span>usize; |
| |
| <span class="kw">if </span>coefficients[index] == <span class="number">0 </span>{ |
| <span class="kw">if </span>zero_run_length == <span class="number">0 </span>{ |
| <span class="kw">return </span><span class="prelude-val">Ok</span>(i); |
| } |
| |
| zero_run_length -= <span class="number">1</span>; |
| } |
| <span class="kw">else if </span>huffman.get_bits(reader, <span class="number">1</span>)<span class="question-mark">? </span>== <span class="number">1 </span>&& coefficients[index] & bit == <span class="number">0 </span>{ |
| <span class="kw">if </span>coefficients[index] > <span class="number">0 </span>{ |
| coefficients[index] += bit; |
| } |
| <span class="kw">else </span>{ |
| coefficients[index] -= bit; |
| } |
| } |
| } |
| |
| <span class="prelude-val">Ok</span>(last) |
| } |
| |
| <span class="kw">fn </span>compute_image(components: <span class="kw-2">&</span>[Component], |
| <span class="kw-2">mut </span>data: Vec<Vec<u8>>, |
| output_size: Dimensions, |
| is_jfif: bool, |
| color_transform: <span class="prelude-ty">Option</span><AdobeColorTransform>) -> <span class="prelude-ty">Result</span><Vec<u8>> { |
| <span class="kw">if </span>data.is_empty() || data.iter().any(Vec::is_empty) { |
| <span class="kw">return </span><span class="prelude-val">Err</span>(Error::Format(<span class="string">"not all components have data"</span>.to_owned())); |
| } |
| |
| <span class="kw">if </span>components.len() == <span class="number">1 </span>{ |
| <span class="kw">let </span>component = <span class="kw-2">&</span>components[<span class="number">0</span>]; |
| <span class="kw">let </span><span class="kw-2">mut </span>decoded: Vec<u8> = data.remove(<span class="number">0</span>); |
| |
| <span class="kw">let </span>width = component.size.width <span class="kw">as </span>usize; |
| <span class="kw">let </span>height = component.size.height <span class="kw">as </span>usize; |
| <span class="kw">let </span>size = width * height; |
| <span class="kw">let </span>line_stride = component.block_size.width <span class="kw">as </span>usize * component.dct_scale; |
| |
| <span class="comment">// if the image width is a multiple of the block size, |
| // then we don't have to move bytes in the decoded data |
| </span><span class="kw">if </span>usize::from(output_size.width) != line_stride { |
| <span class="kw">let </span><span class="kw-2">mut </span>buffer = <span class="macro">vec!</span>[<span class="number">0u8</span>; width]; |
| <span class="comment">// The first line already starts at index 0, so we need to move only lines 1..height |
| </span><span class="kw">for </span>y <span class="kw">in </span><span class="number">1</span>..height { |
| <span class="kw">let </span>destination_idx = y * width; |
| <span class="kw">let </span>source_idx = y * line_stride; |
| <span class="comment">// We could use copy_within, but we need to support old rust versions |
| </span>buffer.copy_from_slice(<span class="kw-2">&</span>decoded[source_idx..][..width]); |
| <span class="kw">let </span>destination = <span class="kw-2">&mut </span>decoded[destination_idx..][..width]; |
| destination.copy_from_slice(<span class="kw-2">&</span>buffer); |
| } |
| } |
| decoded.resize(size, <span class="number">0</span>); |
| <span class="prelude-val">Ok</span>(decoded) |
| } |
| <span class="kw">else </span>{ |
| compute_image_parallel(components, data, output_size, is_jfif, color_transform) |
| } |
| } |
| |
| <span class="attribute">#[cfg(feature=<span class="string">"rayon"</span>)] |
| </span><span class="kw">fn </span>compute_image_parallel(components: <span class="kw-2">&</span>[Component], |
| data: Vec<Vec<u8>>, |
| output_size: Dimensions, |
| is_jfif: bool, |
| color_transform: <span class="prelude-ty">Option</span><AdobeColorTransform>) -> <span class="prelude-ty">Result</span><Vec<u8>> { |
| <span class="kw">use </span>rayon::prelude::<span class="kw-2">*</span>; |
| |
| <span class="kw">let </span>color_convert_func = choose_color_convert_func(components.len(), is_jfif, color_transform)<span class="question-mark">?</span>; |
| <span class="kw">let </span>upsampler = Upsampler::new(components, output_size.width, output_size.height)<span class="question-mark">?</span>; |
| <span class="kw">let </span>line_size = output_size.width <span class="kw">as </span>usize * components.len(); |
| <span class="kw">let </span><span class="kw-2">mut </span>image = <span class="macro">vec!</span>[<span class="number">0u8</span>; line_size * output_size.height <span class="kw">as </span>usize]; |
| |
| image.par_chunks_mut(line_size) |
| .with_max_len(<span class="number">1</span>) |
| .enumerate() |
| .for_each(|(row, line)| { |
| upsampler.upsample_and_interleave_row(<span class="kw-2">&</span>data, row, output_size.width <span class="kw">as </span>usize, line); |
| color_convert_func(line); |
| }); |
| |
| <span class="prelude-val">Ok</span>(image) |
| } |
| |
| <span class="attribute">#[cfg(not(feature=<span class="string">"rayon"</span>))] |
| </span><span class="kw">fn </span>compute_image_parallel(components: <span class="kw-2">&</span>[Component], |
| data: Vec<Vec<u8>>, |
| output_size: Dimensions, |
| is_jfif: bool, |
| color_transform: <span class="prelude-ty">Option</span><AdobeColorTransform>) -> <span class="prelude-ty">Result</span><Vec<u8>> { |
| <span class="kw">let </span>color_convert_func = choose_color_convert_func(components.len(), is_jfif, color_transform)<span class="question-mark">?</span>; |
| <span class="kw">let </span>upsampler = Upsampler::new(components, output_size.width, output_size.height)<span class="question-mark">?</span>; |
| <span class="kw">let </span>line_size = output_size.width <span class="kw">as </span>usize * components.len(); |
| <span class="kw">let </span><span class="kw-2">mut </span>image = <span class="macro">vec!</span>[<span class="number">0u8</span>; line_size * output_size.height <span class="kw">as </span>usize]; |
| |
| <span class="kw">for </span>(row, line) <span class="kw">in </span>image.chunks_mut(line_size) |
| .enumerate() { |
| upsampler.upsample_and_interleave_row(<span class="kw-2">&</span>data, row, output_size.width <span class="kw">as </span>usize, line); |
| color_convert_func(line); |
| } |
| |
| <span class="prelude-val">Ok</span>(image) |
| } |
| |
| <span class="kw">fn </span>choose_color_convert_func(component_count: usize, |
| _is_jfif: bool, |
| color_transform: <span class="prelude-ty">Option</span><AdobeColorTransform>) |
| -> <span class="prelude-ty">Result</span><<span class="kw">fn</span>(<span class="kw-2">&mut </span>[u8])> { |
| <span class="kw">match </span>component_count { |
| <span class="number">3 </span>=> { |
| <span class="comment">// http://www.sno.phy.queensu.ca/~phil/exiftool/TagNames/JPEG.html#Adobe |
| // Unknown means the data is RGB, so we don't need to perform any color conversion on it. |
| </span><span class="kw">if </span>color_transform == <span class="prelude-val">Some</span>(AdobeColorTransform::Unknown) { |
| <span class="prelude-val">Ok</span>(color_convert_line_null) |
| } |
| <span class="kw">else </span>{ |
| <span class="prelude-val">Ok</span>(color_convert_line_ycbcr) |
| } |
| }, |
| <span class="number">4 </span>=> { |
| <span class="comment">// http://www.sno.phy.queensu.ca/~phil/exiftool/TagNames/JPEG.html#Adobe |
| </span><span class="kw">match </span>color_transform { |
| <span class="prelude-val">Some</span>(AdobeColorTransform::Unknown) => <span class="prelude-val">Ok</span>(color_convert_line_cmyk), |
| <span class="prelude-val">Some</span>(<span class="kw">_</span>) => <span class="prelude-val">Ok</span>(color_convert_line_ycck), |
| <span class="prelude-val">None </span>=> <span class="prelude-val">Err</span>(Error::Format(<span class="string">"4 components without Adobe APP14 metadata to indicate color space"</span>.to_owned())), |
| } |
| }, |
| <span class="kw">_ </span>=> <span class="macro">panic!</span>(), |
| } |
| } |
| |
| <span class="kw">fn </span>color_convert_line_null(_data: <span class="kw-2">&mut </span>[u8]) { |
| } |
| |
| <span class="kw">fn </span>color_convert_line_ycbcr(data: <span class="kw-2">&mut </span>[u8]) { |
| <span class="kw">for </span>chunk <span class="kw">in </span>data.chunks_exact_mut(<span class="number">3</span>) { |
| <span class="kw">let </span>(r, g, b) = ycbcr_to_rgb(chunk[<span class="number">0</span>], chunk[<span class="number">1</span>], chunk[<span class="number">2</span>]); |
| chunk[<span class="number">0</span>] = r; |
| chunk[<span class="number">1</span>] = g; |
| chunk[<span class="number">2</span>] = b; |
| } |
| } |
| |
| <span class="kw">fn </span>color_convert_line_ycck(data: <span class="kw-2">&mut </span>[u8]) { |
| <span class="kw">for </span>chunk <span class="kw">in </span>data.chunks_exact_mut(<span class="number">4</span>) { |
| <span class="kw">let </span>(r, g, b) = ycbcr_to_rgb(chunk[<span class="number">0</span>], chunk[<span class="number">1</span>], chunk[<span class="number">2</span>]); |
| <span class="kw">let </span>k = chunk[<span class="number">3</span>]; |
| chunk[<span class="number">0</span>] = r; |
| chunk[<span class="number">1</span>] = g; |
| chunk[<span class="number">2</span>] = b; |
| chunk[<span class="number">3</span>] = <span class="number">255 </span>- k; |
| |
| } |
| } |
| |
| <span class="kw">fn </span>color_convert_line_cmyk(data: <span class="kw-2">&mut </span>[u8]) { |
| <span class="kw">for </span>chunk <span class="kw">in </span>data.chunks_exact_mut(<span class="number">4</span>) { |
| chunk[<span class="number">0</span>] = <span class="number">255 </span>- chunk[<span class="number">0</span>]; |
| chunk[<span class="number">1</span>] = <span class="number">255 </span>- chunk[<span class="number">1</span>]; |
| chunk[<span class="number">2</span>] = <span class="number">255 </span>- chunk[<span class="number">2</span>]; |
| chunk[<span class="number">3</span>] = <span class="number">255 </span>- chunk[<span class="number">3</span>]; |
| } |
| } |
| |
| <span class="comment">// ITU-R BT.601 |
| </span><span class="kw">fn </span>ycbcr_to_rgb(y: u8, cb: u8, cr: u8) -> (u8, u8, u8) { |
| <span class="kw">let </span>y = y <span class="kw">as </span>f32; |
| <span class="kw">let </span>cb = cb <span class="kw">as </span>f32 - <span class="number">128.0</span>; |
| <span class="kw">let </span>cr = cr <span class="kw">as </span>f32 - <span class="number">128.0</span>; |
| |
| <span class="kw">let </span>r = y + <span class="number">1.40200 </span>* cr; |
| <span class="kw">let </span>g = y - <span class="number">0.34414 </span>* cb - <span class="number">0.71414 </span>* cr; |
| <span class="kw">let </span>b = y + <span class="number">1.77200 </span>* cb; |
| |
| <span class="comment">// TODO: Rust has defined float-to-int conversion as saturating, |
| // which is exactly what we need here. However, as of this writing |
| // it still hasn't reached the stable channel. |
| // This can be simplified to `(r + 0.5) as u8` without any clamping |
| // as soon as our MSRV reaches the version that has saturating casts. |
| // The version without explicit clamping is also noticeably faster. |
| </span>(clamp_to_u8((r + <span class="number">0.5</span>) <span class="kw">as </span>i32) <span class="kw">as </span>u8, |
| clamp_to_u8((g + <span class="number">0.5</span>) <span class="kw">as </span>i32) <span class="kw">as </span>u8, |
| clamp_to_u8((b + <span class="number">0.5</span>) <span class="kw">as </span>i32) <span class="kw">as </span>u8) |
| } |
| |
| <span class="kw">fn </span>clamp_to_u8(value: i32) -> i32 { |
| <span class="kw">let </span>value = std::cmp::max(value, <span class="number">0</span>); |
| std::cmp::min(value, <span class="number">255</span>) |
| } |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../" data-current-crate="jpeg_decoder" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |
