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</pre><pre class="rust">
<span class="doccomment">//! Utility functions</span>
<span class="kw">use</span> <span class="ident">std::iter::repeat</span>;
<span class="kw">use</span> <span class="ident">num_iter::range_step</span>;
<span class="attribute">#[<span class="ident">inline</span>(<span class="ident">always</span>)]</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">unpack_bits</span><span class="op"><</span><span class="ident">F</span><span class="op">></span>(<span class="ident">buf</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> [<span class="ident">u8</span>], <span class="ident">channels</span>: <span class="ident">usize</span>, <span class="ident">bit_depth</span>: <span class="ident">u8</span>, <span class="ident">func</span>: <span class="ident">F</span>)
<span class="kw">where</span> <span class="ident">F</span>: <span class="ident">Fn</span>(<span class="ident">u8</span>, <span class="kw-2">&</span><span class="kw-2">mut</span>[<span class="ident">u8</span>]) {
<span class="kw">let</span> <span class="ident">bits</span> <span class="op">=</span> <span class="ident">buf</span>.<span class="ident">len</span>()<span class="op">/</span><span class="ident">channels</span><span class="kw-2">*</span><span class="ident">bit_depth</span> <span class="kw">as</span> <span class="ident">usize</span>;
<span class="kw">let</span> <span class="ident">extra_bits</span> <span class="op">=</span> <span class="ident">bits</span> <span class="op">%</span> <span class="number">8</span>;
<span class="kw">let</span> <span class="ident">entries</span> <span class="op">=</span> <span class="ident">bits</span> <span class="op">/</span> <span class="number">8</span> <span class="op">+</span> <span class="kw">match</span> <span class="ident">extra_bits</span> {
<span class="number">0</span> <span class="op">=</span><span class="op">></span> <span class="number">0</span>,
<span class="kw">_</span> <span class="op">=</span><span class="op">></span> <span class="number">1</span>
};
<span class="kw">let</span> <span class="ident">skip</span> <span class="op">=</span> <span class="kw">match</span> <span class="ident">extra_bits</span> {
<span class="number">0</span> <span class="op">=</span><span class="op">></span> <span class="number">0</span>,
<span class="ident">n</span> <span class="op">=</span><span class="op">></span> (<span class="number">8</span><span class="op">-</span><span class="ident">n</span>) <span class="op">/</span> <span class="ident">bit_depth</span> <span class="kw">as</span> <span class="ident">usize</span>
};
<span class="kw">let</span> <span class="ident">mask</span> <span class="op">=</span> ((<span class="number">1u16</span> <span class="op"><</span><span class="op"><</span> <span class="ident">bit_depth</span>) <span class="op">-</span> <span class="number">1</span>) <span class="kw">as</span> <span class="ident">u8</span>;
<span class="kw">let</span> <span class="ident">i</span> <span class="op">=</span>
(<span class="number">0</span>..<span class="ident">entries</span>)
.<span class="ident">rev</span>() <span class="comment">// reverse iterator</span>
.<span class="ident">flat_map</span>(<span class="op">|</span><span class="ident">idx</span><span class="op">|</span>
<span class="comment">// this has to be reversed too</span>
<span class="ident">range_step</span>(<span class="number">0</span>, <span class="number">8</span>, <span class="ident">bit_depth</span>)
.<span class="ident">zip</span>(<span class="ident">repeat</span>(<span class="ident">idx</span>))
)
.<span class="ident">skip</span>(<span class="ident">skip</span>);
<span class="kw">let</span> <span class="ident">channels</span> <span class="op">=</span> <span class="ident">channels</span> <span class="kw">as</span> <span class="ident">isize</span>;
<span class="kw">let</span> <span class="ident">j</span> <span class="op">=</span> <span class="ident">range_step</span>(<span class="ident">buf</span>.<span class="ident">len</span>() <span class="kw">as</span> <span class="ident">isize</span> <span class="op">-</span> <span class="ident">channels</span>, <span class="op">-</span><span class="ident">channels</span>, <span class="op">-</span><span class="ident">channels</span>);
<span class="comment">//let j = range_step(0, buf.len(), channels).rev(); // ideal solution;</span>
<span class="kw">for</span> ((<span class="ident">shift</span>, <span class="ident">i</span>), <span class="ident">j</span>) <span class="kw">in</span> <span class="ident">i</span>.<span class="ident">zip</span>(<span class="ident">j</span>) {
<span class="kw">let</span> <span class="ident">pixel</span> <span class="op">=</span> (<span class="ident">buf</span>[<span class="ident">i</span>] <span class="op">&</span> (<span class="ident">mask</span> <span class="op"><</span><span class="op"><</span> <span class="ident">shift</span>)) <span class="op">></span><span class="op">></span> <span class="ident">shift</span>;
<span class="ident">func</span>(<span class="ident">pixel</span>, <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">buf</span>[<span class="ident">j</span> <span class="kw">as</span> <span class="ident">usize</span>..(<span class="ident">j</span> <span class="op">+</span> <span class="ident">channels</span>) <span class="kw">as</span> <span class="ident">usize</span>])
}
}
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">expand_trns_line</span>(<span class="ident">buf</span>: <span class="kw-2">&</span><span class="kw-2">mut</span>[<span class="ident">u8</span>], <span class="ident">trns</span>: <span class="kw-2">&</span>[<span class="ident">u8</span>], <span class="ident">channels</span>: <span class="ident">usize</span>) {
<span class="kw">let</span> <span class="ident">channels</span> <span class="op">=</span> <span class="ident">channels</span> <span class="kw">as</span> <span class="ident">isize</span>;
<span class="kw">let</span> <span class="ident">i</span> <span class="op">=</span> <span class="ident">range_step</span>(<span class="ident">buf</span>.<span class="ident">len</span>() <span class="kw">as</span> <span class="ident">isize</span> <span class="op">/</span> (<span class="ident">channels</span><span class="op">+</span><span class="number">1</span>) <span class="op">*</span> <span class="ident">channels</span> <span class="op">-</span> <span class="ident">channels</span>, <span class="op">-</span><span class="ident">channels</span>, <span class="op">-</span><span class="ident">channels</span>);
<span class="kw">let</span> <span class="ident">j</span> <span class="op">=</span> <span class="ident">range_step</span>(<span class="ident">buf</span>.<span class="ident">len</span>() <span class="kw">as</span> <span class="ident">isize</span> <span class="op">-</span> (<span class="ident">channels</span><span class="op">+</span><span class="number">1</span>), <span class="op">-</span>(<span class="ident">channels</span><span class="op">+</span><span class="number">1</span>), <span class="op">-</span>(<span class="ident">channels</span><span class="op">+</span><span class="number">1</span>));
<span class="kw">let</span> <span class="ident">channels</span> <span class="op">=</span> <span class="ident">channels</span> <span class="kw">as</span> <span class="ident">usize</span>;
<span class="kw">for</span> (<span class="ident">i</span>, <span class="ident">j</span>) <span class="kw">in</span> <span class="ident">i</span>.<span class="ident">zip</span>(<span class="ident">j</span>) {
<span class="kw">let</span> <span class="ident">i_pixel</span> <span class="op">=</span> <span class="ident">i</span> <span class="kw">as</span> <span class="ident">usize</span>;
<span class="kw">let</span> <span class="ident">j_chunk</span> <span class="op">=</span> <span class="ident">j</span> <span class="kw">as</span> <span class="ident">usize</span>;
<span class="kw">if</span> <span class="kw-2">&</span><span class="ident">buf</span>[<span class="ident">i_pixel</span>..<span class="ident">i_pixel</span><span class="op">+</span><span class="ident">channels</span>] <span class="op">=</span><span class="op">=</span> <span class="ident">trns</span> {
<span class="ident">buf</span>[<span class="ident">j_chunk</span><span class="op">+</span><span class="ident">channels</span>] <span class="op">=</span> <span class="number">0</span>
} <span class="kw">else</span> {
<span class="ident">buf</span>[<span class="ident">j_chunk</span><span class="op">+</span><span class="ident">channels</span>] <span class="op">=</span> <span class="number">0xFF</span>
}
<span class="kw">for</span> <span class="ident">k</span> <span class="kw">in</span> (<span class="number">0</span>..<span class="ident">channels</span>).<span class="ident">rev</span>() {
<span class="ident">buf</span>[<span class="ident">j_chunk</span><span class="op">+</span><span class="ident">k</span>] <span class="op">=</span> <span class="ident">buf</span>[<span class="ident">i_pixel</span><span class="op">+</span><span class="ident">k</span>];
}
}
}
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">expand_trns_line16</span>(<span class="ident">buf</span>: <span class="kw-2">&</span><span class="kw-2">mut</span>[<span class="ident">u8</span>], <span class="ident">trns</span>: <span class="kw-2">&</span>[<span class="ident">u8</span>], <span class="ident">channels</span>: <span class="ident">usize</span>) {
<span class="kw">let</span> <span class="ident">channels</span> <span class="op">=</span> <span class="ident">channels</span> <span class="kw">as</span> <span class="ident">isize</span>;
<span class="kw">let</span> <span class="ident">c2</span> <span class="op">=</span> <span class="number">2</span> <span class="op">*</span> <span class="ident">channels</span>;
<span class="kw">let</span> <span class="ident">i</span> <span class="op">=</span> <span class="ident">range_step</span>(<span class="ident">buf</span>.<span class="ident">len</span>() <span class="kw">as</span> <span class="ident">isize</span> <span class="op">/</span> (<span class="ident">c2</span><span class="op">+</span><span class="number">2</span>) <span class="op">*</span> <span class="ident">c2</span> <span class="op">-</span> <span class="ident">c2</span>, <span class="op">-</span><span class="ident">c2</span>, <span class="op">-</span><span class="ident">c2</span>);
<span class="kw">let</span> <span class="ident">j</span> <span class="op">=</span> <span class="ident">range_step</span>(<span class="ident">buf</span>.<span class="ident">len</span>() <span class="kw">as</span> <span class="ident">isize</span> <span class="op">-</span> (<span class="ident">c2</span><span class="op">+</span><span class="number">2</span>), <span class="op">-</span>(<span class="ident">c2</span><span class="op">+</span><span class="number">2</span>), <span class="op">-</span>(<span class="ident">c2</span><span class="op">+</span><span class="number">2</span>));
<span class="kw">let</span> <span class="ident">c2</span> <span class="op">=</span> <span class="ident">c2</span> <span class="kw">as</span> <span class="ident">usize</span>;
<span class="kw">for</span> (<span class="ident">i</span>, <span class="ident">j</span>) <span class="kw">in</span> <span class="ident">i</span>.<span class="ident">zip</span>(<span class="ident">j</span>) {
<span class="kw">let</span> <span class="ident">i_pixel</span> <span class="op">=</span> <span class="ident">i</span> <span class="kw">as</span> <span class="ident">usize</span>;
<span class="kw">let</span> <span class="ident">j_chunk</span> <span class="op">=</span> <span class="ident">j</span> <span class="kw">as</span> <span class="ident">usize</span>;
<span class="kw">if</span> <span class="kw-2">&</span><span class="ident">buf</span>[<span class="ident">i_pixel</span>..<span class="ident">i_pixel</span><span class="op">+</span><span class="ident">c2</span>] <span class="op">=</span><span class="op">=</span> <span class="ident">trns</span> {
<span class="ident">buf</span>[<span class="ident">j_chunk</span><span class="op">+</span><span class="ident">c2</span>] <span class="op">=</span> <span class="number">0</span>;
<span class="ident">buf</span>[<span class="ident">j_chunk</span><span class="op">+</span><span class="ident">c2</span> <span class="op">+</span> <span class="number">1</span>] <span class="op">=</span> <span class="number">0</span>
} <span class="kw">else</span> {
<span class="ident">buf</span>[<span class="ident">j_chunk</span><span class="op">+</span><span class="ident">c2</span>] <span class="op">=</span> <span class="number">0xFF</span>;
<span class="ident">buf</span>[<span class="ident">j_chunk</span><span class="op">+</span><span class="ident">c2</span> <span class="op">+</span> <span class="number">1</span>] <span class="op">=</span> <span class="number">0xFF</span>
}
<span class="kw">for</span> <span class="ident">k</span> <span class="kw">in</span> (<span class="number">0</span>..<span class="ident">c2</span>).<span class="ident">rev</span>() {
<span class="ident">buf</span>[<span class="ident">j_chunk</span><span class="op">+</span><span class="ident">k</span>] <span class="op">=</span> <span class="ident">buf</span>[<span class="ident">i_pixel</span><span class="op">+</span><span class="ident">k</span>];
}
}
}
<span class="doccomment">/// This iterator iterates over the different passes of an image Adam7 encoded</span>
<span class="doccomment">/// PNG image</span>
<span class="doccomment">/// The pattern is:</span>
<span class="doccomment">/// 16462646</span>
<span class="doccomment">/// 77777777</span>
<span class="doccomment">/// 56565656</span>
<span class="doccomment">/// 77777777</span>
<span class="doccomment">/// 36463646</span>
<span class="doccomment">/// 77777777</span>
<span class="doccomment">/// 56565656</span>
<span class="doccomment">/// 77777777</span>
<span class="doccomment">///</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>)]</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">Adam7Iterator</span> {
<span class="ident">line</span>: <span class="ident">u32</span>,
<span class="ident">lines</span>: <span class="ident">u32</span>,
<span class="ident">line_width</span>: <span class="ident">u32</span>,
<span class="ident">current_pass</span>: <span class="ident">u8</span>,
<span class="ident">width</span>: <span class="ident">u32</span>,
<span class="ident">height</span>: <span class="ident">u32</span>,
}
<span class="kw">impl</span> <span class="ident">Adam7Iterator</span> {
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">new</span>(<span class="ident">width</span>: <span class="ident">u32</span>, <span class="ident">height</span>: <span class="ident">u32</span>) <span class="op">-</span><span class="op">></span> <span class="ident">Adam7Iterator</span> {
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">this</span> <span class="op">=</span> <span class="ident">Adam7Iterator</span> {
<span class="ident">line</span>: <span class="number">0</span>,
<span class="ident">lines</span>: <span class="number">0</span>,
<span class="ident">line_width</span>: <span class="number">0</span>,
<span class="ident">current_pass</span>: <span class="number">1</span>,
<span class="ident">width</span>: <span class="ident">width</span>,
<span class="ident">height</span>: <span class="ident">height</span>
};
<span class="ident">this</span>.<span class="ident">init_pass</span>();
<span class="ident">this</span>
}
<span class="doccomment">/// Calculates the bounds of the current pass</span>
<span class="kw">fn</span> <span class="ident">init_pass</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) {
<span class="kw">let</span> <span class="ident">w</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">width</span> <span class="kw">as</span> <span class="ident">f64</span>;
<span class="kw">let</span> <span class="ident">h</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">height</span> <span class="kw">as</span> <span class="ident">f64</span>;
<span class="kw">let</span> (<span class="ident">line_width</span>, <span class="ident">lines</span>) <span class="op">=</span> <span class="kw">match</span> <span class="self">self</span>.<span class="ident">current_pass</span> {
<span class="number">1</span> <span class="op">=</span><span class="op">></span> (<span class="ident">w</span><span class="op">/</span><span class="number">8.0</span>, <span class="ident">h</span><span class="op">/</span><span class="number">8.0</span>),
<span class="number">2</span> <span class="op">=</span><span class="op">></span> ((<span class="ident">w</span><span class="op">-</span><span class="number">4.0</span>)<span class="op">/</span><span class="number">8.0</span>, <span class="ident">h</span><span class="op">/</span><span class="number">8.0</span>),
<span class="number">3</span> <span class="op">=</span><span class="op">></span> (<span class="ident">w</span><span class="op">/</span><span class="number">4.0</span>, (<span class="ident">h</span><span class="op">-</span><span class="number">4.0</span>)<span class="op">/</span><span class="number">8.0</span>),
<span class="number">4</span> <span class="op">=</span><span class="op">></span> ((<span class="ident">w</span><span class="op">-</span><span class="number">2.0</span>)<span class="op">/</span><span class="number">4.0</span>, <span class="ident">h</span><span class="op">/</span><span class="number">4.0</span>),
<span class="number">5</span> <span class="op">=</span><span class="op">></span> (<span class="ident">w</span><span class="op">/</span><span class="number">2.0</span>, (<span class="ident">h</span><span class="op">-</span><span class="number">2.0</span>)<span class="op">/</span><span class="number">4.0</span>),
<span class="number">6</span> <span class="op">=</span><span class="op">></span> ((<span class="ident">w</span><span class="op">-</span><span class="number">1.0</span>)<span class="op">/</span><span class="number">2.0</span>, <span class="ident">h</span><span class="op">/</span><span class="number">2.0</span>),
<span class="number">7</span> <span class="op">=</span><span class="op">></span> (<span class="ident">w</span>, (<span class="ident">h</span><span class="op">-</span><span class="number">1.0</span>)<span class="op">/</span><span class="number">2.0</span>),
<span class="kw">_</span> <span class="op">=</span><span class="op">></span> <span class="macro">unreachable!</span>()
};
<span class="self">self</span>.<span class="ident">line_width</span> <span class="op">=</span> <span class="ident">line_width</span>.<span class="ident">ceil</span>() <span class="kw">as</span> <span class="ident">u32</span>;
<span class="self">self</span>.<span class="ident">lines</span> <span class="op">=</span> <span class="ident">lines</span>.<span class="ident">ceil</span>() <span class="kw">as</span> <span class="ident">u32</span>;
<span class="self">self</span>.<span class="ident">line</span> <span class="op">=</span> <span class="number">0</span>;
}
<span class="doccomment">/// The current pass#.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">current_pass</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="ident">u8</span> {
<span class="self">self</span>.<span class="ident">current_pass</span>
}
}
<span class="doccomment">/// Iterates over the (passes, lines, widths)</span>
<span class="kw">impl</span> <span class="ident">Iterator</span> <span class="kw">for</span> <span class="ident">Adam7Iterator</span> {
<span class="kw">type</span> <span class="ident">Item</span> <span class="op">=</span> (<span class="ident">u8</span>, <span class="ident">u32</span>, <span class="ident">u32</span>);
<span class="kw">fn</span> <span class="ident">next</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="prelude-ty">Option</span><span class="op"><</span>(<span class="ident">u8</span>, <span class="ident">u32</span>, <span class="ident">u32</span>)<span class="op">></span> {
<span class="kw">if</span> <span class="self">self</span>.<span class="ident">line</span> <span class="op"><</span> <span class="self">self</span>.<span class="ident">lines</span> <span class="op">&&</span> <span class="self">self</span>.<span class="ident">line_width</span> <span class="op">></span> <span class="number">0</span> {
<span class="kw">let</span> <span class="ident">this_line</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">line</span>;
<span class="self">self</span>.<span class="ident">line</span> <span class="op">+</span><span class="op">=</span> <span class="number">1</span>;
<span class="prelude-val">Some</span>((<span class="self">self</span>.<span class="ident">current_pass</span>, <span class="ident">this_line</span>, <span class="self">self</span>.<span class="ident">line_width</span>))
} <span class="kw">else</span> <span class="kw">if</span> <span class="self">self</span>.<span class="ident">current_pass</span> <span class="op"><</span> <span class="number">7</span> {
<span class="self">self</span>.<span class="ident">current_pass</span> <span class="op">+</span><span class="op">=</span> <span class="number">1</span>;
<span class="self">self</span>.<span class="ident">init_pass</span>();
<span class="self">self</span>.<span class="ident">next</span>()
} <span class="kw">else</span> {
<span class="prelude-val">None</span>
}
}
}
<span class="macro">macro_rules!</span> <span class="ident">expand_pass</span>(
(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">img</span>:<span class="ident">expr</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">scanline</span>:<span class="ident">expr</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">j</span>:<span class="ident">ident</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">pos</span>:<span class="ident">expr</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">bytes_pp</span>:<span class="ident">expr</span>) <span class="op">=</span><span class="op">></span> {
<span class="kw">for</span> (<span class="macro-nonterminal">$</span><span class="macro-nonterminal">j</span>, <span class="ident">pixel</span>) <span class="kw">in</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">scanline</span>.<span class="ident">chunks</span>(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">bytes_pp</span>).<span class="ident">enumerate</span>() {
<span class="kw">for</span> (<span class="ident">offset</span>, <span class="ident">val</span>) <span class="kw">in</span> <span class="ident">pixel</span>.<span class="ident">iter</span>().<span class="ident">enumerate</span>() {
<span class="macro-nonterminal">$</span><span class="macro-nonterminal">img</span>[<span class="macro-nonterminal">$</span><span class="macro-nonterminal">pos</span> <span class="op">+</span> <span class="ident">offset</span>] <span class="op">=</span> <span class="kw-2">*</span><span class="ident">val</span>
}
}
}
);
<span class="doccomment">/// Expands an Adam 7 pass</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">expand_pass</span>(
<span class="ident">img</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> [<span class="ident">u8</span>], <span class="ident">width</span>: <span class="ident">u32</span>, <span class="ident">scanline</span>: <span class="kw-2">&</span>[<span class="ident">u8</span>],
<span class="ident">pass</span>: <span class="ident">u8</span>, <span class="ident">line_no</span>: <span class="ident">u32</span>, <span class="ident">bytes_pp</span>: <span class="ident">u8</span>) {
<span class="kw">let</span> <span class="ident">line_no</span> <span class="op">=</span> <span class="ident">line_no</span> <span class="kw">as</span> <span class="ident">usize</span>;
<span class="kw">let</span> <span class="ident">width</span> <span class="op">=</span> <span class="ident">width</span> <span class="kw">as</span> <span class="ident">usize</span>;
<span class="kw">let</span> <span class="ident">bytes_pp</span> <span class="op">=</span> <span class="ident">bytes_pp</span> <span class="kw">as</span> <span class="ident">usize</span>;
<span class="kw">match</span> <span class="ident">pass</span> {
<span class="number">1</span> <span class="op">=</span><span class="op">></span> <span class="macro">expand_pass!</span>(<span class="ident">img</span>, <span class="ident">scanline</span>, <span class="ident">j</span>, <span class="number">8</span><span class="kw-2">*</span><span class="ident">line_no</span> <span class="op">*</span> <span class="ident">width</span> <span class="op">+</span> <span class="ident">bytes_pp</span> <span class="op">*</span> <span class="ident">j</span><span class="kw-2">*</span><span class="number">8</span> , <span class="ident">bytes_pp</span>),
<span class="number">2</span> <span class="op">=</span><span class="op">></span> <span class="macro">expand_pass!</span>(<span class="ident">img</span>, <span class="ident">scanline</span>, <span class="ident">j</span>, <span class="number">8</span><span class="kw-2">*</span><span class="ident">line_no</span> <span class="op">*</span> <span class="ident">width</span> <span class="op">+</span> <span class="ident">bytes_pp</span> <span class="kw-2">*</span>(<span class="ident">j</span><span class="kw-2">*</span><span class="number">8</span> <span class="op">+</span> <span class="number">4</span>), <span class="ident">bytes_pp</span>),
<span class="number">3</span> <span class="op">=</span><span class="op">></span> <span class="macro">expand_pass!</span>(<span class="ident">img</span>, <span class="ident">scanline</span>, <span class="ident">j</span>, (<span class="number">8</span><span class="kw-2">*</span><span class="ident">line_no</span><span class="op">+</span><span class="number">4</span>) <span class="op">*</span> <span class="ident">width</span> <span class="op">+</span> <span class="ident">bytes_pp</span> <span class="op">*</span> <span class="ident">j</span><span class="kw-2">*</span><span class="number">4</span> , <span class="ident">bytes_pp</span>),
<span class="number">4</span> <span class="op">=</span><span class="op">></span> <span class="macro">expand_pass!</span>(<span class="ident">img</span>, <span class="ident">scanline</span>, <span class="ident">j</span>, <span class="number">4</span><span class="kw-2">*</span><span class="ident">line_no</span> <span class="op">*</span> <span class="ident">width</span> <span class="op">+</span> <span class="ident">bytes_pp</span> <span class="kw-2">*</span>(<span class="ident">j</span><span class="kw-2">*</span><span class="number">4</span> <span class="op">+</span> <span class="number">2</span>), <span class="ident">bytes_pp</span>),
<span class="number">5</span> <span class="op">=</span><span class="op">></span> <span class="macro">expand_pass!</span>(<span class="ident">img</span>, <span class="ident">scanline</span>, <span class="ident">j</span>, (<span class="number">4</span><span class="kw-2">*</span><span class="ident">line_no</span><span class="op">+</span><span class="number">2</span>) <span class="op">*</span> <span class="ident">width</span> <span class="op">+</span> <span class="ident">bytes_pp</span> <span class="op">*</span> <span class="ident">j</span><span class="kw-2">*</span><span class="number">2</span> , <span class="ident">bytes_pp</span>),
<span class="number">6</span> <span class="op">=</span><span class="op">></span> <span class="macro">expand_pass!</span>(<span class="ident">img</span>, <span class="ident">scanline</span>, <span class="ident">j</span>, <span class="number">2</span><span class="kw-2">*</span><span class="ident">line_no</span> <span class="op">*</span> <span class="ident">width</span> <span class="op">+</span> <span class="ident">bytes_pp</span> <span class="kw-2">*</span>(<span class="ident">j</span><span class="kw-2">*</span><span class="number">2</span><span class="op">+</span><span class="number">1</span>) , <span class="ident">bytes_pp</span>),
<span class="number">7</span> <span class="op">=</span><span class="op">></span> <span class="macro">expand_pass!</span>(<span class="ident">img</span>, <span class="ident">scanline</span>, <span class="ident">j</span>, (<span class="number">2</span><span class="kw-2">*</span><span class="ident">line_no</span><span class="op">+</span><span class="number">1</span>) <span class="op">*</span> <span class="ident">width</span> <span class="op">+</span> <span class="ident">bytes_pp</span> <span class="op">*</span> <span class="ident">j</span> , <span class="ident">bytes_pp</span>),
<span class="kw">_</span> <span class="op">=</span><span class="op">></span> {}
}
}
<span class="comment">// Copies data from `src` to `dst`</span>
<span class="comment">//</span>
<span class="comment">// Panics if the length of `dst` is less than the length of `src`.</span>
<span class="comment">// NOTE: this is copied from the stdlib (`std::slice::bytes::copy_memory`).</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">copy_memory</span>(<span class="ident">src</span>: <span class="kw-2">&</span>[<span class="ident">u8</span>], <span class="ident">dst</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> [<span class="ident">u8</span>]) {
<span class="kw">let</span> <span class="ident">len_src</span> <span class="op">=</span> <span class="ident">src</span>.<span class="ident">len</span>();
<span class="macro">assert!</span>(<span class="ident">dst</span>.<span class="ident">len</span>() <span class="op">></span><span class="op">=</span> <span class="ident">len_src</span>);
<span class="comment">// `dst` is unaliasable, so we know statically it doesn't overlap</span>
<span class="comment">// with `src`.</span>
<span class="kw">unsafe</span> {
<span class="ident">::std::ptr::copy_nonoverlapping</span>(<span class="ident">src</span>.<span class="ident">as_ptr</span>(),
<span class="ident">dst</span>.<span class="ident">as_mut_ptr</span>(),
<span class="ident">len_src</span>);
}
}
<span class="attribute">#[<span class="ident">test</span>]</span>
<span class="kw">fn</span> <span class="ident">test_adam7</span>() {
<span class="comment">/*
1646
7777
5656
7777
*/</span>
<span class="kw">let</span> <span class="ident">it</span> <span class="op">=</span> <span class="ident">Adam7Iterator::new</span>(<span class="number">4</span>, <span class="number">4</span>);
<span class="kw">let</span> <span class="ident">passes</span>: <span class="ident">Vec</span><span class="op"><</span><span class="kw">_</span><span class="op">></span> <span class="op">=</span> <span class="ident">it</span>.<span class="ident">collect</span>();
<span class="macro">assert_eq!</span>(<span class="kw-2">&</span><span class="kw-2">*</span><span class="ident">passes</span>, <span class="kw-2">&</span>[(<span class="number">1</span>, <span class="number">0</span>, <span class="number">1</span>), (<span class="number">4</span>, <span class="number">0</span>, <span class="number">1</span>), (<span class="number">5</span>, <span class="number">0</span>, <span class="number">2</span>), (<span class="number">6</span>, <span class="number">0</span>, <span class="number">2</span>), (<span class="number">6</span>, <span class="number">1</span>, <span class="number">2</span>), (<span class="number">7</span>, <span class="number">0</span>, <span class="number">4</span>), (<span class="number">7</span>, <span class="number">1</span>, <span class="number">4</span>)]);
}
</pre></div>
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