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</pre></div><pre class="rust"><code><span class="kw">use </span>std::convert::TryFrom;

<span class="kw">pub mod </span>codegen;
<span class="kw">pub mod </span>lexer;
<span class="kw">pub mod </span>llvm;
<span class="kw">pub mod </span>parser;

<span class="doccomment">/// Fixed size of [`SmallCStr`] including the trailing `\0` byte.
</span><span class="kw">pub const </span>SMALL_STR_SIZE: usize = <span class="number">16</span>;

<span class="doccomment">/// Small C string on the stack with fixed size [`SMALL_STR_SIZE`].
///
/// This is specially crafted to interact with the LLVM C API and get rid of some heap allocations.
</span><span class="attr">#[derive(Debug, PartialEq)]
</span><span class="kw">pub struct </span>SmallCStr([u8; SMALL_STR_SIZE]);

<span class="kw">impl </span>SmallCStr {
    <span class="doccomment">/// Create a new C string from `src`.
    /// Returns [`None`] if `src` exceeds the fixed size or contains any `\0` bytes.
    </span><span class="kw">pub fn </span>new&lt;T: AsRef&lt;[u8]&gt;&gt;(src: <span class="kw-2">&amp;</span>T) -&gt; <span class="prelude-ty">Option</span>&lt;SmallCStr&gt; {
        <span class="kw">let </span>src = src.as_ref();
        <span class="kw">let </span>len = src.len();

        <span class="comment">// Check for \0 bytes.
        </span><span class="kw">let </span>contains_null = <span class="kw">unsafe </span>{ !libc::memchr(src.as_ptr().cast(), <span class="number">0</span>, len).is_null() };

        <span class="kw">if </span>contains_null || len &gt; SMALL_STR_SIZE - <span class="number">1 </span>{
            <span class="prelude-val">None
        </span>} <span class="kw">else </span>{
            <span class="kw">let </span><span class="kw-2">mut </span>dest = [<span class="number">0</span>; SMALL_STR_SIZE];
            dest[..len].copy_from_slice(src);
            <span class="prelude-val">Some</span>(SmallCStr(dest))
        }
    }

    <span class="doccomment">/// Return pointer to C string.
    </span><span class="kw">pub const fn </span>as_ptr(<span class="kw-2">&amp;</span><span class="self">self</span>) -&gt; <span class="kw-2">*const </span>libc::c_char {
        <span class="self">self</span>.<span class="number">0</span>.as_ptr().cast()
    }
}

<span class="kw">impl </span>TryFrom&lt;<span class="kw-2">&amp;</span>str&gt; <span class="kw">for </span>SmallCStr {
    <span class="kw">type </span>Error = ();

    <span class="kw">fn </span>try_from(value: <span class="kw-2">&amp;</span>str) -&gt; <span class="prelude-ty">Result</span>&lt;<span class="self">Self</span>, <span class="self">Self</span>::Error&gt; {
        SmallCStr::new(<span class="kw-2">&amp;</span>value).ok_or(())
    }
}

<span class="doccomment">/// Either type, for APIs accepting two types.
</span><span class="kw">pub enum </span>Either&lt;A, B&gt; {
    A(A),
    B(B),
}

<span class="attr">#[cfg(test)]
</span><span class="kw">mod </span>test {
    <span class="kw">use super</span>::{SmallCStr, SMALL_STR_SIZE};
    <span class="kw">use </span>std::convert::TryInto;

    <span class="attr">#[test]
    </span><span class="kw">fn </span>test_create() {
        <span class="kw">let </span>src = <span class="string">&quot;\x30\x31\x32\x33&quot;</span>;
        <span class="kw">let </span>scs = SmallCStr::new(<span class="kw-2">&amp;</span>src).unwrap();
        <span class="macro">assert_eq!</span>(<span class="kw-2">&amp;</span>scs.<span class="number">0</span>[..<span class="number">5</span>], <span class="kw-2">&amp;</span>[<span class="number">0x30</span>, <span class="number">0x31</span>, <span class="number">0x32</span>, <span class="number">0x33</span>, <span class="number">0x00</span>]);

        <span class="kw">let </span>src = <span class="string">b&quot;abcd1234&quot;</span>;
        <span class="kw">let </span>scs = SmallCStr::new(<span class="kw-2">&amp;</span>src).unwrap();
        <span class="macro">assert_eq!</span>(
            <span class="kw-2">&amp;</span>scs.<span class="number">0</span>[..<span class="number">9</span>],
            <span class="kw-2">&amp;</span>[<span class="number">0x61</span>, <span class="number">0x62</span>, <span class="number">0x63</span>, <span class="number">0x64</span>, <span class="number">0x31</span>, <span class="number">0x32</span>, <span class="number">0x33</span>, <span class="number">0x34</span>, <span class="number">0x00</span>]
        );
    }

    <span class="attr">#[test]
    </span><span class="kw">fn </span>test_contain_null() {
        <span class="kw">let </span>src = <span class="string">&quot;\x30\x00\x32\x33&quot;</span>;
        <span class="kw">let </span>scs = SmallCStr::new(<span class="kw-2">&amp;</span>src);
        <span class="macro">assert_eq!</span>(scs, <span class="prelude-val">None</span>);

        <span class="kw">let </span>src = <span class="string">&quot;\x30\x31\x32\x33\x00&quot;</span>;
        <span class="kw">let </span>scs = SmallCStr::new(<span class="kw-2">&amp;</span>src);
        <span class="macro">assert_eq!</span>(scs, <span class="prelude-val">None</span>);
    }

    <span class="attr">#[test]
    </span><span class="kw">fn </span>test_too_large() {
        <span class="kw">let </span>src = (<span class="number">0</span>..SMALL_STR_SIZE).map(|<span class="kw">_</span>| <span class="string">&#39;a&#39;</span>).collect::&lt;String&gt;();
        <span class="kw">let </span>scs = SmallCStr::new(<span class="kw-2">&amp;</span>src);
        <span class="macro">assert_eq!</span>(scs, <span class="prelude-val">None</span>);

        <span class="kw">let </span>src = (<span class="number">0</span>..SMALL_STR_SIZE + <span class="number">10</span>).map(|<span class="kw">_</span>| <span class="string">&#39;a&#39;</span>).collect::&lt;String&gt;();
        <span class="kw">let </span>scs = SmallCStr::new(<span class="kw-2">&amp;</span>src);
        <span class="macro">assert_eq!</span>(scs, <span class="prelude-val">None</span>);
    }

    <span class="attr">#[test]
    </span><span class="kw">fn </span>test_try_into() {
        <span class="kw">let </span>src = <span class="string">&quot;\x30\x31\x32\x33&quot;</span>;
        <span class="kw">let </span>scs: <span class="prelude-ty">Result</span>&lt;SmallCStr, ()&gt; = src.try_into();
        <span class="macro">assert!</span>(scs.is_ok());

        <span class="kw">let </span>src = (<span class="number">0</span>..SMALL_STR_SIZE).map(|<span class="kw">_</span>| <span class="string">&#39;a&#39;</span>).collect::&lt;String&gt;();
        <span class="kw">let </span>scs: <span class="prelude-ty">Result</span>&lt;SmallCStr, ()&gt; = src.as_str().try_into();
        <span class="macro">assert!</span>(scs.is_err());

        <span class="kw">let </span>src = (<span class="number">0</span>..SMALL_STR_SIZE + <span class="number">10</span>).map(|<span class="kw">_</span>| <span class="string">&#39;a&#39;</span>).collect::&lt;String&gt;();
        <span class="kw">let </span>scs: <span class="prelude-ty">Result</span>&lt;SmallCStr, ()&gt; = src.as_str().try_into();
        <span class="macro">assert!</span>(scs.is_err());
    }
}
</code></pre></div></section></main></body></html>
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</pre></div><pre class="rust"><code><span class="kw">use </span>std::convert::TryFrom;

<span class="kw">pub mod </span>codegen;
<span class="kw">pub mod </span>lexer;
<span class="kw">pub mod </span>llvm;
<span class="kw">pub mod </span>parser;

<span class="doccomment">/// Fixed size of [`SmallCStr`] including the trailing `\0` byte.
</span><span class="kw">pub const </span>SMALL_STR_SIZE: usize = <span class="number">16</span>;

<span class="doccomment">/// Small C string on the stack with fixed size [`SMALL_STR_SIZE`].
///
/// This is specially crafted to interact with the LLVM C API and get rid of some heap allocations.
</span><span class="attr">#[derive(Debug, PartialEq)]
</span><span class="kw">pub struct </span>SmallCStr([u8; SMALL_STR_SIZE]);

<span class="kw">impl </span>SmallCStr {
    <span class="doccomment">/// Create a new C string from `src`.
    /// Returns [`None`] if `src` exceeds the fixed size or contains any `\0` bytes.
    </span><span class="kw">pub fn </span>new&lt;T: AsRef&lt;[u8]&gt;&gt;(src: <span class="kw-2">&amp;</span>T) -&gt; <span class="prelude-ty">Option</span>&lt;SmallCStr&gt; {
        <span class="kw">let </span>src = src.as_ref();
        <span class="kw">let </span>len = src.len();

        <span class="comment">// Check for \0 bytes.
        </span><span class="kw">let </span>contains_null = <span class="kw">unsafe </span>{ !libc::memchr(src.as_ptr().cast(), <span class="number">0</span>, len).is_null() };

        <span class="kw">if </span>contains_null || len &gt; SMALL_STR_SIZE - <span class="number">1 </span>{
            <span class="prelude-val">None
        </span>} <span class="kw">else </span>{
            <span class="kw">let </span><span class="kw-2">mut </span>dest = [<span class="number">0</span>; SMALL_STR_SIZE];
            dest[..len].copy_from_slice(src);
            <span class="prelude-val">Some</span>(SmallCStr(dest))
        }
    }

    <span class="doccomment">/// Return pointer to C string.
    </span><span class="kw">pub const fn </span>as_ptr(<span class="kw-2">&amp;</span><span class="self">self</span>) -&gt; <span class="kw-2">*const </span>libc::c_char {
        <span class="self">self</span>.<span class="number">0</span>.as_ptr().cast()
    }
}

<span class="kw">impl </span>TryFrom&lt;<span class="kw-2">&amp;</span>str&gt; <span class="kw">for </span>SmallCStr {
    <span class="kw">type </span>Error = ();

    <span class="kw">fn </span>try_from(value: <span class="kw-2">&amp;</span>str) -&gt; <span class="prelude-ty">Result</span>&lt;<span class="self">Self</span>, <span class="self">Self</span>::Error&gt; {
        SmallCStr::new(<span class="kw-2">&amp;</span>value).ok_or(())
    }
}

<span class="doccomment">/// Either type, for APIs accepting two types.
</span><span class="kw">pub enum </span>Either&lt;A, B&gt; {
    A(A),
    B(B),
}

<span class="attr">#[cfg(test)]
</span><span class="kw">mod </span>test {
    <span class="kw">use super</span>::{SmallCStr, SMALL_STR_SIZE};
    <span class="kw">use </span>std::convert::TryInto;

    <span class="attr">#[test]
    </span><span class="kw">fn </span>test_create() {
        <span class="kw">let </span>src = <span class="string">&quot;\x30\x31\x32\x33&quot;</span>;
        <span class="kw">let </span>scs = SmallCStr::new(<span class="kw-2">&amp;</span>src).unwrap();
        <span class="macro">assert_eq!</span>(<span class="kw-2">&amp;</span>scs.<span class="number">0</span>[..<span class="number">5</span>], <span class="kw-2">&amp;</span>[<span class="number">0x30</span>, <span class="number">0x31</span>, <span class="number">0x32</span>, <span class="number">0x33</span>, <span class="number">0x00</span>]);

        <span class="kw">let </span>src = <span class="string">b&quot;abcd1234&quot;</span>;
        <span class="kw">let </span>scs = SmallCStr::new(<span class="kw-2">&amp;</span>src).unwrap();
        <span class="macro">assert_eq!</span>(
            <span class="kw-2">&amp;</span>scs.<span class="number">0</span>[..<span class="number">9</span>],
            <span class="kw-2">&amp;</span>[<span class="number">0x61</span>, <span class="number">0x62</span>, <span class="number">0x63</span>, <span class="number">0x64</span>, <span class="number">0x31</span>, <span class="number">0x32</span>, <span class="number">0x33</span>, <span class="number">0x34</span>, <span class="number">0x00</span>]
        );
    }

    <span class="attr">#[test]
    </span><span class="kw">fn </span>test_contain_null() {
        <span class="kw">let </span>src = <span class="string">&quot;\x30\x00\x32\x33&quot;</span>;
        <span class="kw">let </span>scs = SmallCStr::new(<span class="kw-2">&amp;</span>src);
        <span class="macro">assert_eq!</span>(scs, <span class="prelude-val">None</span>);

        <span class="kw">let </span>src = <span class="string">&quot;\x30\x31\x32\x33\x00&quot;</span>;
        <span class="kw">let </span>scs = SmallCStr::new(<span class="kw-2">&amp;</span>src);
        <span class="macro">assert_eq!</span>(scs, <span class="prelude-val">None</span>);
    }

    <span class="attr">#[test]
    </span><span class="kw">fn </span>test_too_large() {
        <span class="kw">let </span>src = (<span class="number">0</span>..SMALL_STR_SIZE).map(|<span class="kw">_</span>| <span class="string">&#39;a&#39;</span>).collect::&lt;String&gt;();
        <span class="kw">let </span>scs = SmallCStr::new(<span class="kw-2">&amp;</span>src);
        <span class="macro">assert_eq!</span>(scs, <span class="prelude-val">None</span>);

        <span class="kw">let </span>src = (<span class="number">0</span>..SMALL_STR_SIZE + <span class="number">10</span>).map(|<span class="kw">_</span>| <span class="string">&#39;a&#39;</span>).collect::&lt;String&gt;();
        <span class="kw">let </span>scs = SmallCStr::new(<span class="kw-2">&amp;</span>src);
        <span class="macro">assert_eq!</span>(scs, <span class="prelude-val">None</span>);
    }

    <span class="attr">#[test]
    </span><span class="kw">fn </span>test_try_into() {
        <span class="kw">let </span>src = <span class="string">&quot;\x30\x31\x32\x33&quot;</span>;
        <span class="kw">let </span>scs: <span class="prelude-ty">Result</span>&lt;SmallCStr, ()&gt; = src.try_into();
        <span class="macro">assert!</span>(scs.is_ok());

        <span class="kw">let </span>src = (<span class="number">0</span>..SMALL_STR_SIZE).map(|<span class="kw">_</span>| <span class="string">&#39;a&#39;</span>).collect::&lt;String&gt;();
        <span class="kw">let </span>scs: <span class="prelude-ty">Result</span>&lt;SmallCStr, ()&gt; = src.as_str().try_into();
        <span class="macro">assert!</span>(scs.is_err());

        <span class="kw">let </span>src = (<span class="number">0</span>..SMALL_STR_SIZE + <span class="number">10</span>).map(|<span class="kw">_</span>| <span class="string">&#39;a&#39;</span>).collect::&lt;String&gt;();
        <span class="kw">let </span>scs: <span class="prelude-ty">Result</span>&lt;SmallCStr, ()&gt; = src.as_str().try_into();
        <span class="macro">assert!</span>(scs.is_err());
    }
}
</code></pre></div></section></main></body></html>