image2aa 0.1.4

Convert image to ASCII Art.
Documentation 
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<!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 `/home/sangenya/.cargo/registry/src/github.com-1ecc6299db9ec823/jpeg-decoder-0.1.22/src/idct.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>idct.rs - source</title><link rel="stylesheet" type="text/css" href="../../normalize.css"><link rel="stylesheet" type="text/css" href="../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" type="text/css" href="../../light.css"  id="themeStyle"><link rel="stylesheet" type="text/css" href="../../dark.css" disabled ><link rel="stylesheet" type="text/css" href="../../ayu.css" disabled ><script id="default-settings"></script><script src="../../storage.js"></script><script src="../../crates.js"></script><noscript><link rel="stylesheet" href="../../noscript.css"></noscript><link rel="icon" type="image/svg+xml" href="../../favicon.svg">
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</pre><pre class="rust">
<span class="comment">// Malicious JPEG files can cause operations in the idct to overflow.</span>
<span class="comment">// One example is tests/crashtest/images/imagetestsuite/b0b8914cc5f7a6eff409f16d8cc236c5.jpg</span>
<span class="comment">// That&#39;s why wrapping operators are needed.</span>
<span class="kw">use</span> <span class="kw">crate</span><span class="ident">::parser::Dimensions</span>;
<span class="kw">use</span> <span class="ident">std</span>::{<span class="ident">convert::TryFrom</span>, <span class="ident">num::Wrapping</span>};

<span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn</span> <span class="ident">choose_idct_size</span>(<span class="ident">full_size</span>: <span class="ident">Dimensions</span>, <span class="ident">requested_size</span>: <span class="ident">Dimensions</span>) <span class="op">-</span><span class="op">&gt;</span> <span class="ident">usize</span> {
    <span class="kw">fn</span> <span class="ident">scaled</span>(<span class="ident">len</span>: <span class="ident">u16</span>, <span class="ident">scale</span>: <span class="ident">usize</span>) <span class="op">-</span><span class="op">&gt;</span> <span class="ident">u16</span> { ((<span class="ident">len</span> <span class="kw">as</span> <span class="ident">u32</span> <span class="op">*</span> <span class="ident">scale</span> <span class="kw">as</span> <span class="ident">u32</span> <span class="op">-</span> <span class="number">1</span>) <span class="op">/</span> <span class="number">8</span> <span class="op">+</span> <span class="number">1</span>) <span class="kw">as</span> <span class="ident">u16</span> }

    <span class="kw">for</span> <span class="kw-2">&amp;</span><span class="ident">scale</span> <span class="kw">in</span> <span class="kw-2">&amp;</span>[<span class="number">1</span>, <span class="number">2</span>, <span class="number">4</span>] {
        <span class="kw">if</span> <span class="ident">scaled</span>(<span class="ident">full_size</span>.<span class="ident">width</span>, <span class="ident">scale</span>) <span class="op">&gt;</span><span class="op">=</span> <span class="ident">requested_size</span>.<span class="ident">width</span> <span class="op">|</span><span class="op">|</span> <span class="ident">scaled</span>(<span class="ident">full_size</span>.<span class="ident">height</span>, <span class="ident">scale</span>) <span class="op">&gt;</span><span class="op">=</span> <span class="ident">requested_size</span>.<span class="ident">height</span> {
            <span class="kw">return</span> <span class="ident">scale</span>;
        }
    }

    <span class="number">8</span>
}

<span class="attribute">#[<span class="ident">test</span>]</span>
<span class="kw">fn</span> <span class="ident">test_choose_idct_size</span>() {
    <span class="macro">assert_eq!</span>(<span class="ident">choose_idct_size</span>(<span class="ident">Dimensions</span>{<span class="ident">width</span>: <span class="number">5472</span>, <span class="ident">height</span>: <span class="number">3648</span>}, <span class="ident">Dimensions</span>{<span class="ident">width</span>: <span class="number">200</span>, <span class="ident">height</span>: <span class="number">200</span>}), <span class="number">1</span>);
    <span class="macro">assert_eq!</span>(<span class="ident">choose_idct_size</span>(<span class="ident">Dimensions</span>{<span class="ident">width</span>: <span class="number">5472</span>, <span class="ident">height</span>: <span class="number">3648</span>}, <span class="ident">Dimensions</span>{<span class="ident">width</span>: <span class="number">500</span>, <span class="ident">height</span>: <span class="number">500</span>}), <span class="number">1</span>);
    <span class="macro">assert_eq!</span>(<span class="ident">choose_idct_size</span>(<span class="ident">Dimensions</span>{<span class="ident">width</span>: <span class="number">5472</span>, <span class="ident">height</span>: <span class="number">3648</span>}, <span class="ident">Dimensions</span>{<span class="ident">width</span>: <span class="number">684</span>, <span class="ident">height</span>: <span class="number">456</span>}), <span class="number">1</span>);
    <span class="macro">assert_eq!</span>(<span class="ident">choose_idct_size</span>(<span class="ident">Dimensions</span>{<span class="ident">width</span>: <span class="number">5472</span>, <span class="ident">height</span>: <span class="number">3648</span>}, <span class="ident">Dimensions</span>{<span class="ident">width</span>: <span class="number">999</span>, <span class="ident">height</span>: <span class="number">456</span>}), <span class="number">1</span>);
    <span class="macro">assert_eq!</span>(<span class="ident">choose_idct_size</span>(<span class="ident">Dimensions</span>{<span class="ident">width</span>: <span class="number">5472</span>, <span class="ident">height</span>: <span class="number">3648</span>}, <span class="ident">Dimensions</span>{<span class="ident">width</span>: <span class="number">684</span>, <span class="ident">height</span>: <span class="number">999</span>}), <span class="number">1</span>);
    <span class="macro">assert_eq!</span>(<span class="ident">choose_idct_size</span>(<span class="ident">Dimensions</span>{<span class="ident">width</span>: <span class="number">500</span>, <span class="ident">height</span>: <span class="number">333</span>}, <span class="ident">Dimensions</span>{<span class="ident">width</span>: <span class="number">63</span>, <span class="ident">height</span>: <span class="number">42</span>}), <span class="number">1</span>);

    <span class="macro">assert_eq!</span>(<span class="ident">choose_idct_size</span>(<span class="ident">Dimensions</span>{<span class="ident">width</span>: <span class="number">5472</span>, <span class="ident">height</span>: <span class="number">3648</span>}, <span class="ident">Dimensions</span>{<span class="ident">width</span>: <span class="number">685</span>, <span class="ident">height</span>: <span class="number">999</span>}), <span class="number">2</span>);
    <span class="macro">assert_eq!</span>(<span class="ident">choose_idct_size</span>(<span class="ident">Dimensions</span>{<span class="ident">width</span>: <span class="number">5472</span>, <span class="ident">height</span>: <span class="number">3648</span>}, <span class="ident">Dimensions</span>{<span class="ident">width</span>: <span class="number">1000</span>, <span class="ident">height</span>: <span class="number">1000</span>}), <span class="number">2</span>);
    <span class="macro">assert_eq!</span>(<span class="ident">choose_idct_size</span>(<span class="ident">Dimensions</span>{<span class="ident">width</span>: <span class="number">5472</span>, <span class="ident">height</span>: <span class="number">3648</span>}, <span class="ident">Dimensions</span>{<span class="ident">width</span>: <span class="number">1400</span>, <span class="ident">height</span>: <span class="number">1400</span>}), <span class="number">4</span>);

    <span class="macro">assert_eq!</span>(<span class="ident">choose_idct_size</span>(<span class="ident">Dimensions</span>{<span class="ident">width</span>: <span class="number">5472</span>, <span class="ident">height</span>: <span class="number">3648</span>}, <span class="ident">Dimensions</span>{<span class="ident">width</span>: <span class="number">5472</span>, <span class="ident">height</span>: <span class="number">3648</span>}), <span class="number">8</span>);
    <span class="macro">assert_eq!</span>(<span class="ident">choose_idct_size</span>(<span class="ident">Dimensions</span>{<span class="ident">width</span>: <span class="number">5472</span>, <span class="ident">height</span>: <span class="number">3648</span>}, <span class="ident">Dimensions</span>{<span class="ident">width</span>: <span class="number">16384</span>, <span class="ident">height</span>: <span class="number">16384</span>}), <span class="number">8</span>);
    <span class="macro">assert_eq!</span>(<span class="ident">choose_idct_size</span>(<span class="ident">Dimensions</span>{<span class="ident">width</span>: <span class="number">1</span>, <span class="ident">height</span>: <span class="number">1</span>}, <span class="ident">Dimensions</span>{<span class="ident">width</span>: <span class="number">65535</span>, <span class="ident">height</span>: <span class="number">65535</span>}), <span class="number">8</span>);
    <span class="macro">assert_eq!</span>(<span class="ident">choose_idct_size</span>(<span class="ident">Dimensions</span>{<span class="ident">width</span>: <span class="number">5472</span>, <span class="ident">height</span>: <span class="number">3648</span>}, <span class="ident">Dimensions</span>{<span class="ident">width</span>: <span class="number">16384</span>, <span class="ident">height</span>: <span class="number">16384</span>}), <span class="number">8</span>);
}

<span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn</span> <span class="ident">dequantize_and_idct_block</span>(<span class="ident">scale</span>: <span class="ident">usize</span>, <span class="ident">coefficients</span>: <span class="kw-2">&amp;</span>[<span class="ident">i16</span>], <span class="ident">quantization_table</span>: <span class="kw-2">&amp;</span>[<span class="ident">u16</span>; <span class="number">64</span>], <span class="ident">output_linestride</span>: <span class="ident">usize</span>, <span class="ident">output</span>: <span class="kw-2">&amp;</span><span class="kw-2">mut</span> [<span class="ident">u8</span>]) {
    <span class="kw">match</span> <span class="ident">scale</span> {
        <span class="number">8</span> <span class="op">=</span><span class="op">&gt;</span> <span class="ident">dequantize_and_idct_block_8x8</span>(<span class="ident">coefficients</span>, <span class="ident">quantization_table</span>, <span class="ident">output_linestride</span>, <span class="ident">output</span>),
        <span class="number">4</span> <span class="op">=</span><span class="op">&gt;</span> <span class="ident">dequantize_and_idct_block_4x4</span>(<span class="ident">coefficients</span>, <span class="ident">quantization_table</span>, <span class="ident">output_linestride</span>, <span class="ident">output</span>),
        <span class="number">2</span> <span class="op">=</span><span class="op">&gt;</span> <span class="ident">dequantize_and_idct_block_2x2</span>(<span class="ident">coefficients</span>, <span class="ident">quantization_table</span>, <span class="ident">output_linestride</span>, <span class="ident">output</span>),
        <span class="number">1</span> <span class="op">=</span><span class="op">&gt;</span> <span class="ident">dequantize_and_idct_block_1x1</span>(<span class="ident">coefficients</span>, <span class="ident">quantization_table</span>, <span class="ident">output_linestride</span>, <span class="ident">output</span>),
        <span class="kw">_</span> <span class="op">=</span><span class="op">&gt;</span> <span class="macro">panic!</span>(<span class="string">&quot;Unsupported IDCT scale {}/8&quot;</span>, <span class="ident">scale</span>),
    }
}

<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">dequantize_and_idct_block_8x8</span>(
    <span class="ident">coefficients</span>: <span class="kw-2">&amp;</span>[<span class="ident">i16</span>],
    <span class="ident">quantization_table</span>: <span class="kw-2">&amp;</span>[<span class="ident">u16</span>; <span class="number">64</span>],
    <span class="ident">output_linestride</span>: <span class="ident">usize</span>,
    <span class="ident">output</span>: <span class="kw-2">&amp;</span><span class="kw-2">mut</span> [<span class="ident">u8</span>]
) {
    <span class="kw">let</span> <span class="ident">output</span> <span class="op">=</span> <span class="ident">output</span>
        .<span class="ident">chunks_mut</span>(<span class="ident">output_linestride</span>);
    <span class="ident">dequantize_and_idct_block_8x8_inner</span>(<span class="ident">coefficients</span>, <span class="ident">quantization_table</span>, <span class="ident">output</span>)
}

<span class="comment">// This is based on stb_image&#39;s &#39;stbi__idct_block&#39;.</span>
<span class="kw">fn</span> <span class="ident">dequantize_and_idct_block_8x8_inner</span><span class="op">&lt;</span><span class="lifetime">&#39;a</span>, <span class="ident">I</span><span class="op">&gt;</span>(
    <span class="ident">coefficients</span>: <span class="kw-2">&amp;</span>[<span class="ident">i16</span>],
    <span class="ident">quantization_table</span>: <span class="kw-2">&amp;</span>[<span class="ident">u16</span>; <span class="number">64</span>],
    <span class="ident">output</span>: <span class="ident">I</span>,
) <span class="kw">where</span>
    <span class="ident">I</span>: <span class="ident">IntoIterator</span><span class="op">&lt;</span><span class="ident">Item</span> <span class="op">=</span> <span class="kw-2">&amp;</span><span class="lifetime">&#39;a</span> <span class="kw-2">mut</span> [<span class="ident">u8</span>]<span class="op">&gt;</span>,
    <span class="ident">I::IntoIter</span>: <span class="ident">ExactSizeIterator</span><span class="op">&lt;</span><span class="ident">Item</span> <span class="op">=</span> <span class="kw-2">&amp;</span><span class="lifetime">&#39;a</span> <span class="kw-2">mut</span> [<span class="ident">u8</span>]<span class="op">&gt;</span>,
{
    <span class="kw">let</span> <span class="ident">output</span> <span class="op">=</span> <span class="ident">output</span>.<span class="ident">into_iter</span>();
    <span class="macro">debug_assert!</span>(
        <span class="ident">output</span>.<span class="ident">len</span>() <span class="op">&gt;</span><span class="op">=</span> <span class="number">8</span>,
        <span class="string">&quot;Output iterator has the wrong length: {}&quot;</span>,
        <span class="ident">output</span>.<span class="ident">len</span>()
    );

    <span class="comment">// optimizer hint to eliminate bounds checks within loops</span>
    <span class="macro">assert!</span>(<span class="ident">coefficients</span>.<span class="ident">len</span>() <span class="op">=</span><span class="op">=</span> <span class="number">64</span>);

    <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">temp</span> <span class="op">=</span> [<span class="ident">Wrapping</span>(<span class="number">0</span>); <span class="number">64</span>];

    <span class="comment">// columns</span>
    <span class="kw">for</span> <span class="ident">i</span> <span class="kw">in</span> <span class="number">0</span>..<span class="number">8</span> {
        <span class="kw">if</span> <span class="ident">coefficients</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">8</span>] <span class="op">=</span><span class="op">=</span> <span class="number">0</span>
            <span class="op">&amp;&amp;</span> <span class="ident">coefficients</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">16</span>] <span class="op">=</span><span class="op">=</span> <span class="number">0</span>
            <span class="op">&amp;&amp;</span> <span class="ident">coefficients</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">24</span>] <span class="op">=</span><span class="op">=</span> <span class="number">0</span>
            <span class="op">&amp;&amp;</span> <span class="ident">coefficients</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">32</span>] <span class="op">=</span><span class="op">=</span> <span class="number">0</span>
            <span class="op">&amp;&amp;</span> <span class="ident">coefficients</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">40</span>] <span class="op">=</span><span class="op">=</span> <span class="number">0</span>
            <span class="op">&amp;&amp;</span> <span class="ident">coefficients</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">48</span>] <span class="op">=</span><span class="op">=</span> <span class="number">0</span>
            <span class="op">&amp;&amp;</span> <span class="ident">coefficients</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">56</span>] <span class="op">=</span><span class="op">=</span> <span class="number">0</span>
        {
            <span class="kw">let</span> <span class="ident">dcterm</span> <span class="op">=</span> <span class="ident">dequantize</span>(<span class="ident">coefficients</span>[<span class="ident">i</span>], <span class="ident">quantization_table</span>[<span class="ident">i</span>]) <span class="op">&lt;</span><span class="op">&lt;</span> <span class="number">2</span>;
            <span class="ident">temp</span>[<span class="ident">i</span>] <span class="op">=</span> <span class="ident">dcterm</span>;
            <span class="ident">temp</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">8</span>] <span class="op">=</span> <span class="ident">dcterm</span>;
            <span class="ident">temp</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">16</span>] <span class="op">=</span> <span class="ident">dcterm</span>;
            <span class="ident">temp</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">24</span>] <span class="op">=</span> <span class="ident">dcterm</span>;
            <span class="ident">temp</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">32</span>] <span class="op">=</span> <span class="ident">dcterm</span>;
            <span class="ident">temp</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">40</span>] <span class="op">=</span> <span class="ident">dcterm</span>;
            <span class="ident">temp</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">48</span>] <span class="op">=</span> <span class="ident">dcterm</span>;
            <span class="ident">temp</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">56</span>] <span class="op">=</span> <span class="ident">dcterm</span>;
        } <span class="kw">else</span> {
            <span class="kw">let</span> <span class="ident">s0</span> <span class="op">=</span> <span class="ident">dequantize</span>(<span class="ident">coefficients</span>[<span class="ident">i</span>], <span class="ident">quantization_table</span>[<span class="ident">i</span>]);
            <span class="kw">let</span> <span class="ident">s1</span> <span class="op">=</span> <span class="ident">dequantize</span>(<span class="ident">coefficients</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">8</span>], <span class="ident">quantization_table</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">8</span>]);
            <span class="kw">let</span> <span class="ident">s2</span> <span class="op">=</span> <span class="ident">dequantize</span>(<span class="ident">coefficients</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">16</span>], <span class="ident">quantization_table</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">16</span>]);
            <span class="kw">let</span> <span class="ident">s3</span> <span class="op">=</span> <span class="ident">dequantize</span>(<span class="ident">coefficients</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">24</span>], <span class="ident">quantization_table</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">24</span>]);
            <span class="kw">let</span> <span class="ident">s4</span> <span class="op">=</span> <span class="ident">dequantize</span>(<span class="ident">coefficients</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">32</span>], <span class="ident">quantization_table</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">32</span>]);
            <span class="kw">let</span> <span class="ident">s5</span> <span class="op">=</span> <span class="ident">dequantize</span>(<span class="ident">coefficients</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">40</span>], <span class="ident">quantization_table</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">40</span>]);
            <span class="kw">let</span> <span class="ident">s6</span> <span class="op">=</span> <span class="ident">dequantize</span>(<span class="ident">coefficients</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">48</span>], <span class="ident">quantization_table</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">48</span>]);
            <span class="kw">let</span> <span class="ident">s7</span> <span class="op">=</span> <span class="ident">dequantize</span>(<span class="ident">coefficients</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">56</span>], <span class="ident">quantization_table</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">56</span>]);

            <span class="kw">let</span> <span class="ident">Kernel</span> {
                <span class="ident">xs</span>: [<span class="ident">x0</span>, <span class="ident">x1</span>, <span class="ident">x2</span>, <span class="ident">x3</span>],
                <span class="ident">ts</span>: [<span class="ident">t0</span>, <span class="ident">t1</span>, <span class="ident">t2</span>, <span class="ident">t3</span>],
            } <span class="op">=</span> <span class="ident">kernel</span>(
                [<span class="ident">s0</span>, <span class="ident">s1</span>, <span class="ident">s2</span>, <span class="ident">s3</span>, <span class="ident">s4</span>, <span class="ident">s5</span>, <span class="ident">s6</span>, <span class="ident">s7</span>],
                <span class="comment">// constants scaled things up by 1&lt;&lt;12; let&#39;s bring them back</span>
                <span class="comment">// down, but keep 2 extra bits of precision</span>
                <span class="number">512</span>,
            );

            <span class="ident">temp</span>[<span class="ident">i</span>] <span class="op">=</span> (<span class="ident">x0</span> <span class="op">+</span> <span class="ident">t3</span>) <span class="op">&gt;</span><span class="op">&gt;</span> <span class="number">10</span>;
            <span class="ident">temp</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">56</span>] <span class="op">=</span> (<span class="ident">x0</span> <span class="op">-</span> <span class="ident">t3</span>) <span class="op">&gt;</span><span class="op">&gt;</span> <span class="number">10</span>;
            <span class="ident">temp</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">8</span>] <span class="op">=</span> (<span class="ident">x1</span> <span class="op">+</span> <span class="ident">t2</span>) <span class="op">&gt;</span><span class="op">&gt;</span> <span class="number">10</span>;
            <span class="ident">temp</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">48</span>] <span class="op">=</span> (<span class="ident">x1</span> <span class="op">-</span> <span class="ident">t2</span>) <span class="op">&gt;</span><span class="op">&gt;</span> <span class="number">10</span>;
            <span class="ident">temp</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">16</span>] <span class="op">=</span> (<span class="ident">x2</span> <span class="op">+</span> <span class="ident">t1</span>) <span class="op">&gt;</span><span class="op">&gt;</span> <span class="number">10</span>;
            <span class="ident">temp</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">40</span>] <span class="op">=</span> (<span class="ident">x2</span> <span class="op">-</span> <span class="ident">t1</span>) <span class="op">&gt;</span><span class="op">&gt;</span> <span class="number">10</span>;
            <span class="ident">temp</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">24</span>] <span class="op">=</span> (<span class="ident">x3</span> <span class="op">+</span> <span class="ident">t0</span>) <span class="op">&gt;</span><span class="op">&gt;</span> <span class="number">10</span>;
            <span class="ident">temp</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">32</span>] <span class="op">=</span> (<span class="ident">x3</span> <span class="op">-</span> <span class="ident">t0</span>) <span class="op">&gt;</span><span class="op">&gt;</span> <span class="number">10</span>;
        }
    }

    <span class="kw">for</span> (<span class="ident">chunk</span>, <span class="ident">output_chunk</span>) <span class="kw">in</span> <span class="ident">temp</span>.<span class="ident">chunks_exact</span>(<span class="number">8</span>).<span class="ident">zip</span>(<span class="ident">output</span>) {
        <span class="kw">let</span> <span class="ident">chunk</span> <span class="op">=</span> <span class="op">&lt;</span><span class="kw-2">&amp;</span>[<span class="kw">_</span>; <span class="number">8</span>]<span class="op">&gt;</span><span class="ident">::try_from</span>(<span class="ident">chunk</span>).<span class="ident">unwrap</span>();

        <span class="comment">// constants scaled things up by 1&lt;&lt;12, plus we had 1&lt;&lt;2 from first</span>
        <span class="comment">// loop, plus horizontal and vertical each scale by sqrt(8) so together</span>
        <span class="comment">// we&#39;ve got an extra 1&lt;&lt;3, so 1&lt;&lt;17 total we need to remove.</span>
        <span class="comment">// so we want to round that, which means adding 0.5 * 1&lt;&lt;17,</span>
        <span class="comment">// aka 65536. Also, we&#39;ll end up with -128 to 127 that we want</span>
        <span class="comment">// to encode as 0..255 by adding 128, so we&#39;ll add that before the shift</span>
        <span class="kw">const</span> <span class="ident">X_SCALE</span>: <span class="ident">i32</span> <span class="op">=</span> <span class="number">65536</span> <span class="op">+</span> (<span class="number">128</span> <span class="op">&lt;</span><span class="op">&lt;</span> <span class="number">17</span>);

        <span class="comment">// TODO When the minimum rust version supports it</span>
        <span class="comment">// let [s0, rest @ ..] = chunk;</span>
        <span class="kw">let</span> (<span class="ident">s0</span>, <span class="ident">rest</span>) <span class="op">=</span> <span class="ident">chunk</span>.<span class="ident">split_first</span>().<span class="ident">unwrap</span>();
        <span class="kw">if</span> <span class="kw-2">*</span><span class="ident">rest</span> <span class="op">=</span><span class="op">=</span> [<span class="ident">Wrapping</span>(<span class="number">0</span>); <span class="number">7</span>] {
            <span class="kw">let</span> <span class="ident">dcterm</span> <span class="op">=</span> <span class="ident">stbi_clamp</span>((<span class="ident">stbi_fsh</span>(<span class="kw-2">*</span><span class="ident">s0</span>) <span class="op">+</span> <span class="ident">Wrapping</span>(<span class="ident">X_SCALE</span>)) <span class="op">&gt;</span><span class="op">&gt;</span> <span class="number">17</span>);
            <span class="ident">output_chunk</span>[<span class="number">0</span>] <span class="op">=</span> <span class="ident">dcterm</span>;
            <span class="ident">output_chunk</span>[<span class="number">1</span>] <span class="op">=</span> <span class="ident">dcterm</span>;
            <span class="ident">output_chunk</span>[<span class="number">2</span>] <span class="op">=</span> <span class="ident">dcterm</span>;
            <span class="ident">output_chunk</span>[<span class="number">3</span>] <span class="op">=</span> <span class="ident">dcterm</span>;
            <span class="ident">output_chunk</span>[<span class="number">4</span>] <span class="op">=</span> <span class="ident">dcterm</span>;
            <span class="ident">output_chunk</span>[<span class="number">5</span>] <span class="op">=</span> <span class="ident">dcterm</span>;
            <span class="ident">output_chunk</span>[<span class="number">6</span>] <span class="op">=</span> <span class="ident">dcterm</span>;
            <span class="ident">output_chunk</span>[<span class="number">7</span>] <span class="op">=</span> <span class="ident">dcterm</span>;
        } <span class="kw">else</span> {
            <span class="kw">let</span> <span class="ident">Kernel</span> {
                <span class="ident">xs</span>: [<span class="ident">x0</span>, <span class="ident">x1</span>, <span class="ident">x2</span>, <span class="ident">x3</span>],
                <span class="ident">ts</span>: [<span class="ident">t0</span>, <span class="ident">t1</span>, <span class="ident">t2</span>, <span class="ident">t3</span>],
            } <span class="op">=</span> <span class="ident">kernel</span>(<span class="kw-2">*</span><span class="ident">chunk</span>, <span class="ident">X_SCALE</span>);

            <span class="ident">output_chunk</span>[<span class="number">0</span>] <span class="op">=</span> <span class="ident">stbi_clamp</span>((<span class="ident">x0</span> <span class="op">+</span> <span class="ident">t3</span>) <span class="op">&gt;</span><span class="op">&gt;</span> <span class="number">17</span>);
            <span class="ident">output_chunk</span>[<span class="number">7</span>] <span class="op">=</span> <span class="ident">stbi_clamp</span>((<span class="ident">x0</span> <span class="op">-</span> <span class="ident">t3</span>) <span class="op">&gt;</span><span class="op">&gt;</span> <span class="number">17</span>);
            <span class="ident">output_chunk</span>[<span class="number">1</span>] <span class="op">=</span> <span class="ident">stbi_clamp</span>((<span class="ident">x1</span> <span class="op">+</span> <span class="ident">t2</span>) <span class="op">&gt;</span><span class="op">&gt;</span> <span class="number">17</span>);
            <span class="ident">output_chunk</span>[<span class="number">6</span>] <span class="op">=</span> <span class="ident">stbi_clamp</span>((<span class="ident">x1</span> <span class="op">-</span> <span class="ident">t2</span>) <span class="op">&gt;</span><span class="op">&gt;</span> <span class="number">17</span>);
            <span class="ident">output_chunk</span>[<span class="number">2</span>] <span class="op">=</span> <span class="ident">stbi_clamp</span>((<span class="ident">x2</span> <span class="op">+</span> <span class="ident">t1</span>) <span class="op">&gt;</span><span class="op">&gt;</span> <span class="number">17</span>);
            <span class="ident">output_chunk</span>[<span class="number">5</span>] <span class="op">=</span> <span class="ident">stbi_clamp</span>((<span class="ident">x2</span> <span class="op">-</span> <span class="ident">t1</span>) <span class="op">&gt;</span><span class="op">&gt;</span> <span class="number">17</span>);
            <span class="ident">output_chunk</span>[<span class="number">3</span>] <span class="op">=</span> <span class="ident">stbi_clamp</span>((<span class="ident">x3</span> <span class="op">+</span> <span class="ident">t0</span>) <span class="op">&gt;</span><span class="op">&gt;</span> <span class="number">17</span>);
            <span class="ident">output_chunk</span>[<span class="number">4</span>] <span class="op">=</span> <span class="ident">stbi_clamp</span>((<span class="ident">x3</span> <span class="op">-</span> <span class="ident">t0</span>) <span class="op">&gt;</span><span class="op">&gt;</span> <span class="number">17</span>);
        }
    }
}

<span class="kw">struct</span> <span class="ident">Kernel</span> {
    <span class="ident">xs</span>: [<span class="ident">Wrapping</span><span class="op">&lt;</span><span class="ident">i32</span><span class="op">&gt;</span>; <span class="number">4</span>],
    <span class="ident">ts</span>: [<span class="ident">Wrapping</span><span class="op">&lt;</span><span class="ident">i32</span><span class="op">&gt;</span>; <span class="number">4</span>],
}

<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">fn</span> <span class="ident">kernel_x</span>([<span class="ident">s0</span>, <span class="ident">s2</span>, <span class="ident">s4</span>, <span class="ident">s6</span>]: [<span class="ident">Wrapping</span><span class="op">&lt;</span><span class="ident">i32</span><span class="op">&gt;</span>; <span class="number">4</span>], <span class="ident">x_scale</span>: <span class="ident">i32</span>) <span class="op">-</span><span class="op">&gt;</span> [<span class="ident">Wrapping</span><span class="op">&lt;</span><span class="ident">i32</span><span class="op">&gt;</span>; <span class="number">4</span>] {
    <span class="comment">// Even `chunk` indicies</span>
    <span class="kw">let</span> (<span class="ident">t2</span>, <span class="ident">t3</span>);
    {
        <span class="kw">let</span> <span class="ident">p2</span> <span class="op">=</span> <span class="ident">s2</span>;
        <span class="kw">let</span> <span class="ident">p3</span> <span class="op">=</span> <span class="ident">s6</span>;

        <span class="kw">let</span> <span class="ident">p1</span> <span class="op">=</span> (<span class="ident">p2</span> <span class="op">+</span> <span class="ident">p3</span>) <span class="op">*</span> <span class="ident">stbi_f2f</span>(<span class="number">0.5411961</span>);
        <span class="ident">t2</span> <span class="op">=</span> <span class="ident">p1</span> <span class="op">+</span> <span class="ident">p3</span> <span class="op">*</span> <span class="ident">stbi_f2f</span>(<span class="op">-</span><span class="number">1.847759065</span>);
        <span class="ident">t3</span> <span class="op">=</span> <span class="ident">p1</span> <span class="op">+</span> <span class="ident">p2</span> <span class="op">*</span> <span class="ident">stbi_f2f</span>(<span class="number">0.765366865</span>);
    }

    <span class="kw">let</span> (<span class="ident">t0</span>, <span class="ident">t1</span>);
    {
        <span class="kw">let</span> <span class="ident">p2</span> <span class="op">=</span> <span class="ident">s0</span>;
        <span class="kw">let</span> <span class="ident">p3</span> <span class="op">=</span> <span class="ident">s4</span>;

        <span class="ident">t0</span> <span class="op">=</span> <span class="ident">stbi_fsh</span>(<span class="ident">p2</span> <span class="op">+</span> <span class="ident">p3</span>);
        <span class="ident">t1</span> <span class="op">=</span> <span class="ident">stbi_fsh</span>(<span class="ident">p2</span> <span class="op">-</span> <span class="ident">p3</span>);
    }

    <span class="kw">let</span> <span class="ident">x0</span> <span class="op">=</span> <span class="ident">t0</span> <span class="op">+</span> <span class="ident">t3</span>;
    <span class="kw">let</span> <span class="ident">x3</span> <span class="op">=</span> <span class="ident">t0</span> <span class="op">-</span> <span class="ident">t3</span>;
    <span class="kw">let</span> <span class="ident">x1</span> <span class="op">=</span> <span class="ident">t1</span> <span class="op">+</span> <span class="ident">t2</span>;
    <span class="kw">let</span> <span class="ident">x2</span> <span class="op">=</span> <span class="ident">t1</span> <span class="op">-</span> <span class="ident">t2</span>;

    <span class="kw">let</span> <span class="ident">x_scale</span> <span class="op">=</span> <span class="ident">Wrapping</span>(<span class="ident">x_scale</span>);

    [<span class="ident">x0</span> <span class="op">+</span> <span class="ident">x_scale</span>, <span class="ident">x1</span> <span class="op">+</span> <span class="ident">x_scale</span>, <span class="ident">x2</span> <span class="op">+</span> <span class="ident">x_scale</span>, <span class="ident">x3</span> <span class="op">+</span> <span class="ident">x_scale</span>]
}

<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">fn</span> <span class="ident">kernel_t</span>([<span class="ident">s1</span>, <span class="ident">s3</span>, <span class="ident">s5</span>, <span class="ident">s7</span>]: [<span class="ident">Wrapping</span><span class="op">&lt;</span><span class="ident">i32</span><span class="op">&gt;</span>; <span class="number">4</span>]) <span class="op">-</span><span class="op">&gt;</span> [<span class="ident">Wrapping</span><span class="op">&lt;</span><span class="ident">i32</span><span class="op">&gt;</span>; <span class="number">4</span>] {
    <span class="comment">// Odd `chunk` indicies</span>
    <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">t0</span> <span class="op">=</span> <span class="ident">s7</span>;
    <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">t1</span> <span class="op">=</span> <span class="ident">s5</span>;
    <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">t2</span> <span class="op">=</span> <span class="ident">s3</span>;
    <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">t3</span> <span class="op">=</span> <span class="ident">s1</span>;

    <span class="kw">let</span> <span class="ident">p3</span> <span class="op">=</span> <span class="ident">t0</span> <span class="op">+</span> <span class="ident">t2</span>;
    <span class="kw">let</span> <span class="ident">p4</span> <span class="op">=</span> <span class="ident">t1</span> <span class="op">+</span> <span class="ident">t3</span>;
    <span class="kw">let</span> <span class="ident">p1</span> <span class="op">=</span> <span class="ident">t0</span> <span class="op">+</span> <span class="ident">t3</span>;
    <span class="kw">let</span> <span class="ident">p2</span> <span class="op">=</span> <span class="ident">t1</span> <span class="op">+</span> <span class="ident">t2</span>;
    <span class="kw">let</span> <span class="ident">p5</span> <span class="op">=</span> (<span class="ident">p3</span> <span class="op">+</span> <span class="ident">p4</span>) <span class="op">*</span> <span class="ident">stbi_f2f</span>(<span class="number">1.175875602</span>);

    <span class="ident">t0</span> <span class="kw-2">*</span><span class="op">=</span> <span class="ident">stbi_f2f</span>(<span class="number">0.298631336</span>);
    <span class="ident">t1</span> <span class="kw-2">*</span><span class="op">=</span> <span class="ident">stbi_f2f</span>(<span class="number">2.053119869</span>);
    <span class="ident">t2</span> <span class="kw-2">*</span><span class="op">=</span> <span class="ident">stbi_f2f</span>(<span class="number">3.072711026</span>);
    <span class="ident">t3</span> <span class="kw-2">*</span><span class="op">=</span> <span class="ident">stbi_f2f</span>(<span class="number">1.501321110</span>);

    <span class="kw">let</span> <span class="ident">p1</span> <span class="op">=</span> <span class="ident">p5</span> <span class="op">+</span> <span class="ident">p1</span> <span class="op">*</span> <span class="ident">stbi_f2f</span>(<span class="op">-</span><span class="number">0.899976223</span>);
    <span class="kw">let</span> <span class="ident">p2</span> <span class="op">=</span> <span class="ident">p5</span> <span class="op">+</span> <span class="ident">p2</span> <span class="op">*</span> <span class="ident">stbi_f2f</span>(<span class="op">-</span><span class="number">2.562915447</span>);
    <span class="kw">let</span> <span class="ident">p3</span> <span class="op">=</span> <span class="ident">p3</span> <span class="op">*</span> <span class="ident">stbi_f2f</span>(<span class="op">-</span><span class="number">1.961570560</span>);
    <span class="kw">let</span> <span class="ident">p4</span> <span class="op">=</span> <span class="ident">p4</span> <span class="op">*</span> <span class="ident">stbi_f2f</span>(<span class="op">-</span><span class="number">0.390180644</span>);

    <span class="ident">t3</span> <span class="op">+</span><span class="op">=</span> <span class="ident">p1</span> <span class="op">+</span> <span class="ident">p4</span>;
    <span class="ident">t2</span> <span class="op">+</span><span class="op">=</span> <span class="ident">p2</span> <span class="op">+</span> <span class="ident">p3</span>;
    <span class="ident">t1</span> <span class="op">+</span><span class="op">=</span> <span class="ident">p2</span> <span class="op">+</span> <span class="ident">p4</span>;
    <span class="ident">t0</span> <span class="op">+</span><span class="op">=</span> <span class="ident">p1</span> <span class="op">+</span> <span class="ident">p3</span>;

    [<span class="ident">t0</span>, <span class="ident">t1</span>, <span class="ident">t2</span>, <span class="ident">t3</span>]
}

<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">fn</span> <span class="ident">kernel</span>([<span class="ident">s0</span>, <span class="ident">s1</span>, <span class="ident">s2</span>, <span class="ident">s3</span>, <span class="ident">s4</span>, <span class="ident">s5</span>, <span class="ident">s6</span>, <span class="ident">s7</span>]: [<span class="ident">Wrapping</span><span class="op">&lt;</span><span class="ident">i32</span><span class="op">&gt;</span>; <span class="number">8</span>], <span class="ident">x_scale</span>: <span class="ident">i32</span>) <span class="op">-</span><span class="op">&gt;</span> <span class="ident">Kernel</span> {
    <span class="ident">Kernel</span> {
        <span class="ident">xs</span>: <span class="ident">kernel_x</span>([<span class="ident">s0</span>, <span class="ident">s2</span>, <span class="ident">s4</span>, <span class="ident">s6</span>], <span class="ident">x_scale</span>),
        <span class="ident">ts</span>: <span class="ident">kernel_t</span>([<span class="ident">s1</span>, <span class="ident">s3</span>, <span class="ident">s5</span>, <span class="ident">s7</span>]),
    }
}

<span class="attribute">#[<span class="ident">inline</span>(<span class="ident">always</span>)]</span>
<span class="kw">fn</span> <span class="ident">dequantize</span>(<span class="ident">c</span>: <span class="ident">i16</span>, <span class="ident">q</span>: <span class="ident">u16</span>) <span class="op">-</span><span class="op">&gt;</span> <span class="ident">Wrapping</span><span class="op">&lt;</span><span class="ident">i32</span><span class="op">&gt;</span> {
    <span class="ident">Wrapping</span>(<span class="ident">i32::from</span>(<span class="ident">c</span>) <span class="op">*</span> <span class="ident">i32::from</span>(<span class="ident">q</span>))
}

<span class="comment">// 4x4 and 2x2 IDCT based on Rakesh Dugad and Narendra Ahuja: &quot;A Fast Scheme for Image Size Change in the Compressed Domain&quot; (2001).</span>
<span class="comment">// http://sylvana.net/jpegcrop/jidctred/</span>
<span class="kw">fn</span> <span class="ident">dequantize_and_idct_block_4x4</span>(<span class="ident">coefficients</span>: <span class="kw-2">&amp;</span>[<span class="ident">i16</span>], <span class="ident">quantization_table</span>: <span class="kw-2">&amp;</span>[<span class="ident">u16</span>; <span class="number">64</span>], <span class="ident">output_linestride</span>: <span class="ident">usize</span>, <span class="ident">output</span>: <span class="kw-2">&amp;</span><span class="kw-2">mut</span> [<span class="ident">u8</span>]) {
    <span class="macro">debug_assert_eq!</span>(<span class="ident">coefficients</span>.<span class="ident">len</span>(), <span class="number">64</span>);
    <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">temp</span> <span class="op">=</span> [<span class="ident">Wrapping</span>(<span class="number">0i32</span>); <span class="number">4</span> <span class="op">*</span> <span class="number">4</span>];

    <span class="kw">const</span> <span class="ident">CONST_BITS</span>: <span class="ident">usize</span> <span class="op">=</span> <span class="number">12</span>;
    <span class="kw">const</span> <span class="ident">PASS1_BITS</span>: <span class="ident">usize</span> <span class="op">=</span> <span class="number">2</span>;
    <span class="kw">const</span> <span class="ident">FINAL_BITS</span>: <span class="ident">usize</span> <span class="op">=</span> <span class="ident">CONST_BITS</span> <span class="op">+</span> <span class="ident">PASS1_BITS</span> <span class="op">+</span> <span class="number">3</span>;

    <span class="comment">// columns</span>
    <span class="kw">for</span> <span class="ident">i</span> <span class="kw">in</span> <span class="number">0</span>..<span class="number">4</span> {
        <span class="kw">let</span> <span class="ident">s0</span> <span class="op">=</span> <span class="ident">Wrapping</span>(<span class="ident">coefficients</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">8</span> <span class="op">*</span> <span class="number">0</span>] <span class="kw">as</span> <span class="ident">i32</span> <span class="op">*</span> <span class="ident">quantization_table</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">8</span> <span class="op">*</span> <span class="number">0</span>] <span class="kw">as</span> <span class="ident">i32</span>);
        <span class="kw">let</span> <span class="ident">s1</span> <span class="op">=</span> <span class="ident">Wrapping</span>(<span class="ident">coefficients</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">8</span> <span class="op">*</span> <span class="number">1</span>] <span class="kw">as</span> <span class="ident">i32</span> <span class="op">*</span> <span class="ident">quantization_table</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">8</span> <span class="op">*</span> <span class="number">1</span>] <span class="kw">as</span> <span class="ident">i32</span>);
        <span class="kw">let</span> <span class="ident">s2</span> <span class="op">=</span> <span class="ident">Wrapping</span>(<span class="ident">coefficients</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">8</span> <span class="op">*</span> <span class="number">2</span>] <span class="kw">as</span> <span class="ident">i32</span> <span class="op">*</span> <span class="ident">quantization_table</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">8</span> <span class="op">*</span> <span class="number">2</span>] <span class="kw">as</span> <span class="ident">i32</span>);
        <span class="kw">let</span> <span class="ident">s3</span> <span class="op">=</span> <span class="ident">Wrapping</span>(<span class="ident">coefficients</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">8</span> <span class="op">*</span> <span class="number">3</span>] <span class="kw">as</span> <span class="ident">i32</span> <span class="op">*</span> <span class="ident">quantization_table</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">8</span> <span class="op">*</span> <span class="number">3</span>] <span class="kw">as</span> <span class="ident">i32</span>);

        <span class="kw">let</span> <span class="ident">x0</span> <span class="op">=</span> (<span class="ident">s0</span> <span class="op">+</span> <span class="ident">s2</span>) <span class="op">&lt;</span><span class="op">&lt;</span> <span class="ident">PASS1_BITS</span>;
        <span class="kw">let</span> <span class="ident">x2</span> <span class="op">=</span> (<span class="ident">s0</span> <span class="op">-</span> <span class="ident">s2</span>) <span class="op">&lt;</span><span class="op">&lt;</span> <span class="ident">PASS1_BITS</span>;

        <span class="kw">let</span> <span class="ident">p1</span> <span class="op">=</span> (<span class="ident">s1</span> <span class="op">+</span> <span class="ident">s3</span>) <span class="op">*</span> <span class="ident">stbi_f2f</span>(<span class="number">0.541196100</span>);
        <span class="kw">let</span> <span class="ident">t0</span> <span class="op">=</span> (<span class="ident">p1</span> <span class="op">+</span> <span class="ident">s3</span> <span class="op">*</span> <span class="ident">stbi_f2f</span>(<span class="op">-</span><span class="number">1.847759065</span>) <span class="op">+</span> <span class="ident">Wrapping</span>(<span class="number">512</span>)) <span class="op">&gt;</span><span class="op">&gt;</span> (<span class="ident">CONST_BITS</span> <span class="op">-</span> <span class="ident">PASS1_BITS</span>);
        <span class="kw">let</span> <span class="ident">t2</span> <span class="op">=</span> (<span class="ident">p1</span> <span class="op">+</span> <span class="ident">s1</span> <span class="op">*</span> <span class="ident">stbi_f2f</span>(<span class="number">0.765366865</span>) <span class="op">+</span> <span class="ident">Wrapping</span>(<span class="number">512</span>)) <span class="op">&gt;</span><span class="op">&gt;</span> (<span class="ident">CONST_BITS</span> <span class="op">-</span> <span class="ident">PASS1_BITS</span>);

        <span class="ident">temp</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">4</span> <span class="op">*</span> <span class="number">0</span>] <span class="op">=</span> <span class="ident">x0</span> <span class="op">+</span> <span class="ident">t2</span>;
        <span class="ident">temp</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">4</span> <span class="op">*</span> <span class="number">3</span>] <span class="op">=</span> <span class="ident">x0</span> <span class="op">-</span> <span class="ident">t2</span>;
        <span class="ident">temp</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">4</span> <span class="op">*</span> <span class="number">1</span>] <span class="op">=</span> <span class="ident">x2</span> <span class="op">+</span> <span class="ident">t0</span>;
        <span class="ident">temp</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">4</span> <span class="op">*</span> <span class="number">2</span>] <span class="op">=</span> <span class="ident">x2</span> <span class="op">-</span> <span class="ident">t0</span>;
    }

    <span class="kw">for</span> <span class="ident">i</span> <span class="kw">in</span> <span class="number">0</span> .. <span class="number">4</span> {
        <span class="kw">let</span> <span class="ident">s0</span> <span class="op">=</span> <span class="ident">temp</span>[<span class="ident">i</span> <span class="op">*</span> <span class="number">4</span> <span class="op">+</span> <span class="number">0</span>];
        <span class="kw">let</span> <span class="ident">s1</span> <span class="op">=</span> <span class="ident">temp</span>[<span class="ident">i</span> <span class="op">*</span> <span class="number">4</span> <span class="op">+</span> <span class="number">1</span>];
        <span class="kw">let</span> <span class="ident">s2</span> <span class="op">=</span> <span class="ident">temp</span>[<span class="ident">i</span> <span class="op">*</span> <span class="number">4</span> <span class="op">+</span> <span class="number">2</span>];
        <span class="kw">let</span> <span class="ident">s3</span> <span class="op">=</span> <span class="ident">temp</span>[<span class="ident">i</span> <span class="op">*</span> <span class="number">4</span> <span class="op">+</span> <span class="number">3</span>];

        <span class="kw">let</span> <span class="ident">x0</span> <span class="op">=</span> (<span class="ident">s0</span> <span class="op">+</span> <span class="ident">s2</span>) <span class="op">&lt;</span><span class="op">&lt;</span> <span class="ident">CONST_BITS</span>;
        <span class="kw">let</span> <span class="ident">x2</span> <span class="op">=</span> (<span class="ident">s0</span> <span class="op">-</span> <span class="ident">s2</span>) <span class="op">&lt;</span><span class="op">&lt;</span> <span class="ident">CONST_BITS</span>;

        <span class="kw">let</span> <span class="ident">p1</span> <span class="op">=</span> (<span class="ident">s1</span> <span class="op">+</span> <span class="ident">s3</span>) <span class="op">*</span> <span class="ident">stbi_f2f</span>(<span class="number">0.541196100</span>);
        <span class="kw">let</span> <span class="ident">t0</span> <span class="op">=</span> <span class="ident">p1</span> <span class="op">+</span> <span class="ident">s3</span> <span class="op">*</span> <span class="ident">stbi_f2f</span>(<span class="op">-</span><span class="number">1.847759065</span>);
        <span class="kw">let</span> <span class="ident">t2</span> <span class="op">=</span> <span class="ident">p1</span> <span class="op">+</span> <span class="ident">s1</span> <span class="op">*</span> <span class="ident">stbi_f2f</span>(<span class="number">0.765366865</span>);

        <span class="comment">// constants scaled things up by 1&lt;&lt;12, plus we had 1&lt;&lt;2 from first</span>
        <span class="comment">// loop, plus horizontal and vertical each scale by sqrt(8) so together</span>
        <span class="comment">// we&#39;ve got an extra 1&lt;&lt;3, so 1&lt;&lt;17 total we need to remove.</span>
        <span class="comment">// so we want to round that, which means adding 0.5 * 1&lt;&lt;17,</span>
        <span class="comment">// aka 65536. Also, we&#39;ll end up with -128 to 127 that we want</span>
        <span class="comment">// to encode as 0..255 by adding 128, so we&#39;ll add that before the shift</span>
        <span class="kw">let</span> <span class="ident">x0</span> <span class="op">=</span> <span class="ident">x0</span> <span class="op">+</span> <span class="ident">Wrapping</span>(<span class="number">1</span> <span class="op">&lt;</span><span class="op">&lt;</span> (<span class="ident">FINAL_BITS</span> <span class="op">-</span> <span class="number">1</span>)) <span class="op">+</span> <span class="ident">Wrapping</span>(<span class="number">128</span> <span class="op">&lt;</span><span class="op">&lt;</span> <span class="ident">FINAL_BITS</span>);
        <span class="kw">let</span> <span class="ident">x2</span> <span class="op">=</span> <span class="ident">x2</span> <span class="op">+</span> <span class="ident">Wrapping</span>(<span class="number">1</span> <span class="op">&lt;</span><span class="op">&lt;</span> (<span class="ident">FINAL_BITS</span> <span class="op">-</span> <span class="number">1</span>)) <span class="op">+</span> <span class="ident">Wrapping</span>(<span class="number">128</span> <span class="op">&lt;</span><span class="op">&lt;</span> <span class="ident">FINAL_BITS</span>);

        <span class="ident">output</span>[<span class="ident">i</span> <span class="op">*</span> <span class="ident">output_linestride</span> <span class="op">+</span> <span class="number">0</span>] <span class="op">=</span> <span class="ident">stbi_clamp</span>((<span class="ident">x0</span> <span class="op">+</span> <span class="ident">t2</span>) <span class="op">&gt;</span><span class="op">&gt;</span> <span class="ident">FINAL_BITS</span>);
        <span class="ident">output</span>[<span class="ident">i</span> <span class="op">*</span> <span class="ident">output_linestride</span> <span class="op">+</span> <span class="number">3</span>] <span class="op">=</span> <span class="ident">stbi_clamp</span>((<span class="ident">x0</span> <span class="op">-</span> <span class="ident">t2</span>) <span class="op">&gt;</span><span class="op">&gt;</span> <span class="ident">FINAL_BITS</span>);
        <span class="ident">output</span>[<span class="ident">i</span> <span class="op">*</span> <span class="ident">output_linestride</span> <span class="op">+</span> <span class="number">1</span>] <span class="op">=</span> <span class="ident">stbi_clamp</span>((<span class="ident">x2</span> <span class="op">+</span> <span class="ident">t0</span>) <span class="op">&gt;</span><span class="op">&gt;</span> <span class="ident">FINAL_BITS</span>);
        <span class="ident">output</span>[<span class="ident">i</span> <span class="op">*</span> <span class="ident">output_linestride</span> <span class="op">+</span> <span class="number">2</span>] <span class="op">=</span> <span class="ident">stbi_clamp</span>((<span class="ident">x2</span> <span class="op">-</span> <span class="ident">t0</span>) <span class="op">&gt;</span><span class="op">&gt;</span> <span class="ident">FINAL_BITS</span>);
    }
}

<span class="kw">fn</span> <span class="ident">dequantize_and_idct_block_2x2</span>(<span class="ident">coefficients</span>: <span class="kw-2">&amp;</span>[<span class="ident">i16</span>], <span class="ident">quantization_table</span>: <span class="kw-2">&amp;</span>[<span class="ident">u16</span>; <span class="number">64</span>], <span class="ident">output_linestride</span>: <span class="ident">usize</span>, <span class="ident">output</span>: <span class="kw-2">&amp;</span><span class="kw-2">mut</span> [<span class="ident">u8</span>]) {
    <span class="macro">debug_assert_eq!</span>(<span class="ident">coefficients</span>.<span class="ident">len</span>(), <span class="number">64</span>);

    <span class="kw">const</span> <span class="ident">SCALE_BITS</span>: <span class="ident">usize</span> <span class="op">=</span> <span class="number">3</span>;

    <span class="comment">// Column 0</span>
    <span class="kw">let</span> <span class="ident">s00</span> <span class="op">=</span> <span class="ident">Wrapping</span>(<span class="ident">coefficients</span>[<span class="number">8</span> <span class="op">*</span> <span class="number">0</span>] <span class="kw">as</span> <span class="ident">i32</span> <span class="op">*</span> <span class="ident">quantization_table</span>[<span class="number">8</span> <span class="op">*</span> <span class="number">0</span>] <span class="kw">as</span> <span class="ident">i32</span>);
    <span class="kw">let</span> <span class="ident">s10</span> <span class="op">=</span> <span class="ident">Wrapping</span>(<span class="ident">coefficients</span>[<span class="number">8</span> <span class="op">*</span> <span class="number">1</span>] <span class="kw">as</span> <span class="ident">i32</span> <span class="op">*</span> <span class="ident">quantization_table</span>[<span class="number">8</span> <span class="op">*</span> <span class="number">1</span>] <span class="kw">as</span> <span class="ident">i32</span>);

    <span class="kw">let</span> <span class="ident">x0</span> <span class="op">=</span> <span class="ident">s00</span> <span class="op">+</span> <span class="ident">s10</span>;
    <span class="kw">let</span> <span class="ident">x2</span> <span class="op">=</span> <span class="ident">s00</span> <span class="op">-</span> <span class="ident">s10</span>;

    <span class="comment">// Column 1</span>
    <span class="kw">let</span> <span class="ident">s01</span> <span class="op">=</span> <span class="ident">Wrapping</span>(<span class="ident">coefficients</span>[<span class="number">8</span> <span class="op">*</span> <span class="number">0</span> <span class="op">+</span> <span class="number">1</span>] <span class="kw">as</span> <span class="ident">i32</span> <span class="op">*</span> <span class="ident">quantization_table</span>[<span class="number">8</span> <span class="op">*</span> <span class="number">0</span> <span class="op">+</span> <span class="number">1</span>] <span class="kw">as</span> <span class="ident">i32</span>);
    <span class="kw">let</span> <span class="ident">s11</span> <span class="op">=</span> <span class="ident">Wrapping</span>(<span class="ident">coefficients</span>[<span class="number">8</span> <span class="op">*</span> <span class="number">1</span> <span class="op">+</span> <span class="number">1</span>] <span class="kw">as</span> <span class="ident">i32</span> <span class="op">*</span> <span class="ident">quantization_table</span>[<span class="number">8</span> <span class="op">*</span> <span class="number">1</span> <span class="op">+</span> <span class="number">1</span>] <span class="kw">as</span> <span class="ident">i32</span>);

    <span class="kw">let</span> <span class="ident">x1</span> <span class="op">=</span> <span class="ident">s01</span> <span class="op">+</span> <span class="ident">s11</span>;
    <span class="kw">let</span> <span class="ident">x3</span> <span class="op">=</span> <span class="ident">s01</span> <span class="op">-</span> <span class="ident">s11</span>;

    <span class="kw">let</span> <span class="ident">x0</span> <span class="op">=</span> <span class="ident">x0</span> <span class="op">+</span> <span class="ident">Wrapping</span>(<span class="number">1</span> <span class="op">&lt;</span><span class="op">&lt;</span> (<span class="ident">SCALE_BITS</span> <span class="op">-</span> <span class="number">1</span>)) <span class="op">+</span> <span class="ident">Wrapping</span>(<span class="number">128</span> <span class="op">&lt;</span><span class="op">&lt;</span> <span class="ident">SCALE_BITS</span>);
    <span class="kw">let</span> <span class="ident">x2</span> <span class="op">=</span> <span class="ident">x2</span> <span class="op">+</span> <span class="ident">Wrapping</span>(<span class="number">1</span> <span class="op">&lt;</span><span class="op">&lt;</span> (<span class="ident">SCALE_BITS</span> <span class="op">-</span> <span class="number">1</span>)) <span class="op">+</span> <span class="ident">Wrapping</span>(<span class="number">128</span> <span class="op">&lt;</span><span class="op">&lt;</span> <span class="ident">SCALE_BITS</span>);

    <span class="comment">// Row 0</span>
    <span class="ident">output</span>[<span class="number">0</span>] <span class="op">=</span> <span class="ident">stbi_clamp</span>((<span class="ident">x0</span> <span class="op">+</span> <span class="ident">x1</span>) <span class="op">&gt;</span><span class="op">&gt;</span> <span class="ident">SCALE_BITS</span>);
    <span class="ident">output</span>[<span class="number">1</span>] <span class="op">=</span> <span class="ident">stbi_clamp</span>((<span class="ident">x0</span> <span class="op">-</span> <span class="ident">x1</span>) <span class="op">&gt;</span><span class="op">&gt;</span> <span class="ident">SCALE_BITS</span>);

    <span class="comment">// Row 1</span>
    <span class="ident">output</span>[<span class="ident">output_linestride</span> <span class="op">+</span> <span class="number">0</span>] <span class="op">=</span> <span class="ident">stbi_clamp</span>((<span class="ident">x2</span> <span class="op">+</span> <span class="ident">x3</span>) <span class="op">&gt;</span><span class="op">&gt;</span> <span class="ident">SCALE_BITS</span>);
    <span class="ident">output</span>[<span class="ident">output_linestride</span> <span class="op">+</span> <span class="number">1</span>] <span class="op">=</span> <span class="ident">stbi_clamp</span>((<span class="ident">x2</span> <span class="op">-</span> <span class="ident">x3</span>) <span class="op">&gt;</span><span class="op">&gt;</span> <span class="ident">SCALE_BITS</span>);
}

<span class="kw">fn</span> <span class="ident">dequantize_and_idct_block_1x1</span>(<span class="ident">coefficients</span>: <span class="kw-2">&amp;</span>[<span class="ident">i16</span>], <span class="ident">quantization_table</span>: <span class="kw-2">&amp;</span>[<span class="ident">u16</span>; <span class="number">64</span>], <span class="ident">_output_linestride</span>: <span class="ident">usize</span>, <span class="ident">output</span>: <span class="kw-2">&amp;</span><span class="kw-2">mut</span> [<span class="ident">u8</span>]) {
    <span class="macro">debug_assert_eq!</span>(<span class="ident">coefficients</span>.<span class="ident">len</span>(), <span class="number">64</span>);

    <span class="kw">let</span> <span class="ident">s0</span> <span class="op">=</span> (<span class="ident">Wrapping</span>(<span class="ident">coefficients</span>[<span class="number">0</span>] <span class="kw">as</span> <span class="ident">i32</span> <span class="op">*</span> <span class="ident">quantization_table</span>[<span class="number">0</span>] <span class="kw">as</span> <span class="ident">i32</span>) <span class="op">+</span> <span class="ident">Wrapping</span>(<span class="number">128</span> <span class="op">*</span> <span class="number">8</span>)) <span class="op">/</span> <span class="ident">Wrapping</span>(<span class="number">8</span>);
    <span class="ident">output</span>[<span class="number">0</span>] <span class="op">=</span> <span class="ident">stbi_clamp</span>(<span class="ident">s0</span>);
}

<span class="comment">// take a -128..127 value and stbi__clamp it and convert to 0..255</span>
<span class="kw">fn</span> <span class="ident">stbi_clamp</span>(<span class="ident">x</span>: <span class="ident">Wrapping</span><span class="op">&lt;</span><span class="ident">i32</span><span class="op">&gt;</span>) <span class="op">-</span><span class="op">&gt;</span> <span class="ident">u8</span>
{
    <span class="ident">x</span>.<span class="number">0</span>.<span class="ident">max</span>(<span class="number">0</span>).<span class="ident">min</span>(<span class="number">255</span>) <span class="kw">as</span> <span class="ident">u8</span>
}

<span class="kw">fn</span> <span class="ident">stbi_f2f</span>(<span class="ident">x</span>: <span class="ident">f32</span>) <span class="op">-</span><span class="op">&gt;</span> <span class="ident">Wrapping</span><span class="op">&lt;</span><span class="ident">i32</span><span class="op">&gt;</span> {
    <span class="ident">Wrapping</span>((<span class="ident">x</span> <span class="op">*</span> <span class="number">4096.0</span> <span class="op">+</span> <span class="number">0.5</span>) <span class="kw">as</span> <span class="ident">i32</span>)
}

<span class="kw">fn</span> <span class="ident">stbi_fsh</span>(<span class="ident">x</span>: <span class="ident">Wrapping</span><span class="op">&lt;</span><span class="ident">i32</span><span class="op">&gt;</span>) <span class="op">-</span><span class="op">&gt;</span> <span class="ident">Wrapping</span><span class="op">&lt;</span><span class="ident">i32</span><span class="op">&gt;</span> {
    <span class="ident">x</span> <span class="op">&lt;</span><span class="op">&lt;</span> <span class="number">12</span>
}

<span class="attribute">#[<span class="ident">test</span>]</span>
<span class="kw">fn</span> <span class="ident">test_dequantize_and_idct_block_8x8</span>() {
    <span class="kw">let</span> <span class="ident">coefficients</span>: [<span class="ident">i16</span>; <span class="number">8</span> <span class="op">*</span> <span class="number">8</span>] <span class="op">=</span> [
        <span class="op">-</span><span class="number">14</span>, <span class="op">-</span><span class="number">39</span>, <span class="number">58</span>, <span class="op">-</span><span class="number">2</span>, <span class="number">3</span>, <span class="number">3</span>, <span class="number">0</span>, <span class="number">1</span>,
        <span class="number">11</span>, <span class="number">27</span>, <span class="number">4</span>, <span class="op">-</span><span class="number">3</span>, <span class="number">3</span>, <span class="number">0</span>, <span class="number">1</span>, <span class="number">0</span>,
        <span class="op">-</span><span class="number">6</span>, <span class="op">-</span><span class="number">13</span>, <span class="op">-</span><span class="number">9</span>, <span class="op">-</span><span class="number">1</span>, <span class="op">-</span><span class="number">2</span>, <span class="op">-</span><span class="number">1</span>, <span class="number">0</span>, <span class="number">0</span>,
        <span class="op">-</span><span class="number">4</span>, <span class="number">0</span>, <span class="op">-</span><span class="number">1</span>, <span class="op">-</span><span class="number">2</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>,
        <span class="number">3</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>,
        <span class="op">-</span><span class="number">3</span>, <span class="op">-</span><span class="number">2</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>,
        <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>,
        <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>];

    <span class="kw">let</span> <span class="ident">quantization_table</span>: [<span class="ident">u16</span>; <span class="number">8</span> <span class="op">*</span> <span class="number">8</span>] <span class="op">=</span> [
        <span class="number">8</span>, <span class="number">6</span>, <span class="number">5</span>, <span class="number">8</span>, <span class="number">12</span>, <span class="number">20</span>, <span class="number">26</span>, <span class="number">31</span>,
        <span class="number">6</span>, <span class="number">6</span>, <span class="number">7</span>, <span class="number">10</span>, <span class="number">13</span>, <span class="number">29</span>, <span class="number">30</span>, <span class="number">28</span>,
        <span class="number">7</span>, <span class="number">7</span>, <span class="number">8</span>, <span class="number">12</span>, <span class="number">20</span>, <span class="number">29</span>, <span class="number">35</span>, <span class="number">28</span>,
        <span class="number">7</span>, <span class="number">9</span>, <span class="number">11</span>, <span class="number">15</span>, <span class="number">26</span>, <span class="number">44</span>, <span class="number">40</span>, <span class="number">31</span>,
        <span class="number">9</span>, <span class="number">11</span>, <span class="number">19</span>, <span class="number">28</span>, <span class="number">34</span>, <span class="number">55</span>, <span class="number">52</span>, <span class="number">39</span>,
        <span class="number">12</span>, <span class="number">18</span>, <span class="number">28</span>, <span class="number">32</span>, <span class="number">41</span>, <span class="number">52</span>, <span class="number">57</span>, <span class="number">46</span>,
        <span class="number">25</span>, <span class="number">32</span>, <span class="number">39</span>, <span class="number">44</span>, <span class="number">52</span>, <span class="number">61</span>, <span class="number">60</span>, <span class="number">51</span>,
        <span class="number">36</span>, <span class="number">46</span>, <span class="number">48</span>, <span class="number">49</span>, <span class="number">56</span>, <span class="number">50</span>, <span class="number">52</span>, <span class="number">50</span>];
    <span class="kw">let</span> <span class="ident">output_linestride</span>: <span class="ident">usize</span> <span class="op">=</span> <span class="number">8</span>;
    <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">output</span> <span class="op">=</span> [<span class="number">0u8</span>; <span class="number">8</span> <span class="op">*</span> <span class="number">8</span>];
    <span class="ident">dequantize_and_idct_block_8x8</span>(
        <span class="kw-2">&amp;</span><span class="ident">coefficients</span>,
        <span class="kw-2">&amp;</span><span class="ident">quantization_table</span>,
        <span class="ident">output_linestride</span>,
        <span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="ident">output</span>);
    <span class="kw">let</span> <span class="ident">expected_output</span> <span class="op">=</span> [
        <span class="number">118</span>, <span class="number">92</span>, <span class="number">110</span>, <span class="number">83</span>, <span class="number">77</span>, <span class="number">93</span>, <span class="number">144</span>, <span class="number">198</span>,
        <span class="number">172</span>, <span class="number">116</span>, <span class="number">114</span>, <span class="number">87</span>, <span class="number">78</span>, <span class="number">93</span>, <span class="number">146</span>, <span class="number">191</span>,
        <span class="number">194</span>, <span class="number">107</span>, <span class="number">91</span>, <span class="number">76</span>, <span class="number">71</span>, <span class="number">93</span>, <span class="number">160</span>, <span class="number">198</span>,
        <span class="number">196</span>, <span class="number">100</span>, <span class="number">80</span>, <span class="number">74</span>, <span class="number">67</span>, <span class="number">92</span>, <span class="number">174</span>, <span class="number">209</span>,
        <span class="number">182</span>, <span class="number">104</span>, <span class="number">88</span>, <span class="number">81</span>, <span class="number">68</span>, <span class="number">89</span>, <span class="number">178</span>, <span class="number">206</span>,
        <span class="number">105</span>, <span class="number">64</span>, <span class="number">59</span>, <span class="number">59</span>, <span class="number">63</span>, <span class="number">94</span>, <span class="number">183</span>, <span class="number">201</span>,
        <span class="number">35</span>, <span class="number">27</span>, <span class="number">28</span>, <span class="number">37</span>, <span class="number">72</span>, <span class="number">121</span>, <span class="number">203</span>, <span class="number">204</span>,
        <span class="number">37</span>, <span class="number">45</span>, <span class="number">41</span>, <span class="number">47</span>, <span class="number">98</span>, <span class="number">154</span>, <span class="number">223</span>, <span class="number">208</span>];
    <span class="macro">assert_eq!</span>(<span class="kw-2">&amp;</span><span class="ident">output</span>[..], <span class="kw-2">&amp;</span><span class="ident">expected_output</span>[..]);
}

<span class="attribute">#[<span class="ident">test</span>]</span>
<span class="kw">fn</span> <span class="ident">test_dequantize_and_idct_block_8x8_all_zero</span>() {
    <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">output</span> <span class="op">=</span> [<span class="number">0u8</span>; <span class="number">8</span> <span class="op">*</span> <span class="number">8</span>];
    <span class="ident">dequantize_and_idct_block_8x8</span>(
        <span class="kw-2">&amp;</span>[<span class="number">0</span>; <span class="number">8</span><span class="kw-2">*</span><span class="number">8</span>],
        <span class="kw-2">&amp;</span>[<span class="number">666</span>; <span class="number">8</span><span class="kw-2">*</span><span class="number">8</span>],
        <span class="number">8</span>,
        <span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="ident">output</span>);
    <span class="macro">assert_eq!</span>(<span class="kw-2">&amp;</span><span class="ident">output</span>[..], <span class="kw-2">&amp;</span>[<span class="number">128</span>; <span class="number">8</span><span class="kw-2">*</span><span class="number">8</span>][..]);
}

<span class="attribute">#[<span class="ident">test</span>]</span>
<span class="kw">fn</span> <span class="ident">test_dequantize_and_idct_block_8x8_saturated</span>() {
    <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">output</span> <span class="op">=</span> [<span class="number">0u8</span>; <span class="number">8</span> <span class="op">*</span> <span class="number">8</span>];
    <span class="ident">dequantize_and_idct_block_8x8</span>(
        <span class="kw-2">&amp;</span>[<span class="ident">std::i16::MAX</span>; <span class="number">8</span><span class="kw-2">*</span><span class="number">8</span>],
        <span class="kw-2">&amp;</span>[<span class="ident">std::u16::MAX</span>; <span class="number">8</span><span class="kw-2">*</span><span class="number">8</span>],
        <span class="number">8</span>,
        <span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="ident">output</span>);
    <span class="kw">let</span> <span class="ident">expected</span> <span class="op">=</span> [
        <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">255</span>, <span class="number">255</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">255</span>,
        <span class="number">0</span>, <span class="number">0</span>, <span class="number">215</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">255</span>, <span class="number">255</span>, <span class="number">0</span>,
        <span class="number">255</span>, <span class="number">255</span>, <span class="number">255</span>, <span class="number">255</span>, <span class="number">255</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">255</span>,
        <span class="number">0</span>, <span class="number">0</span>, <span class="number">255</span>, <span class="number">0</span>, <span class="number">255</span>, <span class="number">0</span>, <span class="number">255</span>, <span class="number">255</span>,
        <span class="number">0</span>, <span class="number">0</span>, <span class="number">255</span>, <span class="number">255</span>, <span class="number">0</span>, <span class="number">255</span>, <span class="number">0</span>, <span class="number">0</span>,
        <span class="number">255</span>, <span class="number">255</span>, <span class="number">0</span>, <span class="number">255</span>, <span class="number">255</span>, <span class="number">255</span>, <span class="number">170</span>, <span class="number">0</span>,
        <span class="number">0</span>, <span class="number">255</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">255</span>,
        <span class="number">255</span>, <span class="number">255</span>, <span class="number">0</span>, <span class="number">255</span>, <span class="number">0</span>, <span class="number">255</span>, <span class="number">0</span>, <span class="number">0</span>];
    <span class="macro">assert_eq!</span>(<span class="kw-2">&amp;</span><span class="ident">output</span>[..], <span class="kw-2">&amp;</span><span class="ident">expected</span>[..]);
}
</pre></div>
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