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num_args()

--[[--
num_args takes in 5.1 byte code and extracts the number of arguments
from its function header.
Source: http://ace.ajax.org/build/kitchen-sink.html
--]]--


function num_args(func)
    function int(t)
        return t:byte(1)+t:byte(2)*0x100+t:byte(3)*0x10000+t:byte(4)*0x1000000
    end

	local dump = string.dump(func)
	local offset, cursor = int(dump:sub(13)), offset + 26
	--Get the params and var flag (whether there's a ... in the param)
	return dump:sub(cursor):byte(), dump:sub(cursor+1):byte()
end

-- Usage:
-- num_args(function(a,b,c,d, ...) end) -- return 4, 7
https://snipt.net/embed/79e94b17cb84f052ea4184882cfe3db4/
/raw/79e94b17cb84f052ea4184882cfe3db4/
79e94b17cb84f052ea4184882cfe3db4
lua
Lua
20
2019-06-26T15:50:43
True
False
False
/api/public/snipt/39633/
num_args
<table class="highlighttable"><tr><td class="linenos"><div class="linenodiv"><pre><a href="#L-1"> 1</a> <a href="#L-2"> 2</a> <a href="#L-3"> 3</a> <a href="#L-4"> 4</a> <a href="#L-5"> 5</a> <a href="#L-6"> 6</a> <a href="#L-7"> 7</a> <a href="#L-8"> 8</a> <a href="#L-9"> 9</a> <a href="#L-10">10</a> <a href="#L-11">11</a> <a href="#L-12">12</a> <a href="#L-13">13</a> <a href="#L-14">14</a> <a href="#L-15">15</a> <a href="#L-16">16</a> <a href="#L-17">17</a> <a href="#L-18">18</a> <a href="#L-19">19</a> <a href="#L-20">20</a></pre></div></td><td class="code"><div class="highlight"><pre><span></span><span id="L-1"><a name="L-1"></a><span class="cm">--[[--</span> </span><span id="L-2"><a name="L-2"></a><span class="cm">num_args takes in 5.1 byte code and extracts the number of arguments</span> </span><span id="L-3"><a name="L-3"></a><span class="cm">from its function header.</span> </span><span id="L-4"><a name="L-4"></a><span class="cm">Source: http://ace.ajax.org/build/kitchen-sink.html</span> </span><span id="L-5"><a name="L-5"></a><span class="cm">--]]</span><span class="c1">--</span> </span><span id="L-6"><a name="L-6"></a> </span><span id="L-7"><a name="L-7"></a> </span><span id="L-8"><a name="L-8"></a><span class="k">function</span> <span class="nf">num_args</span><span class="p">(</span><span class="n">func</span><span class="p">)</span> </span><span id="L-9"><a name="L-9"></a> <span class="k">function</span> <span class="nf">int</span><span class="p">(</span><span class="n">t</span><span class="p">)</span> </span><span id="L-10"><a name="L-10"></a> <span class="k">return</span> <span class="n">t</span><span class="p">:</span><span class="n">byte</span><span class="p">(</span><span class="mi">1</span><span class="p">)</span><span class="o">+</span><span class="n">t</span><span class="p">:</span><span class="n">byte</span><span class="p">(</span><span class="mi">2</span><span class="p">)</span><span class="o">*</span><span class="mh">0x100</span><span class="o">+</span><span class="n">t</span><span class="p">:</span><span class="n">byte</span><span class="p">(</span><span class="mi">3</span><span class="p">)</span><span class="o">*</span><span class="mh">0x10000</span><span class="o">+</span><span class="n">t</span><span class="p">:</span><span class="n">byte</span><span class="p">(</span><span class="mi">4</span><span class="p">)</span><span class="o">*</span><span class="mh">0x1000000</span> </span><span id="L-11"><a name="L-11"></a> <span class="k">end</span> </span><span id="L-12"><a name="L-12"></a> </span><span id="L-13"><a name="L-13"></a> <span class="kd">local</span> <span class="n">dump</span> <span class="o">=</span> <span class="nb">string.dump</span><span class="p">(</span><span class="n">func</span><span class="p">)</span> </span><span id="L-14"><a name="L-14"></a> <span class="kd">local</span> <span class="n">offset</span><span class="p">,</span> <span class="n">cursor</span> <span class="o">=</span> <span class="n">int</span><span class="p">(</span><span class="n">dump</span><span class="p">:</span><span class="n">sub</span><span class="p">(</span><span class="mi">13</span><span class="p">)),</span> <span class="n">offset</span> <span class="o">+</span> <span class="mi">26</span> </span><span id="L-15"><a name="L-15"></a> <span class="c1">--Get the params and var flag (whether there&#39;s a ... in the param)</span> </span><span id="L-16"><a name="L-16"></a> <span class="k">return</span> <span class="n">dump</span><span class="p">:</span><span class="n">sub</span><span class="p">(</span><span class="n">cursor</span><span class="p">):</span><span class="n">byte</span><span class="p">(),</span> <span class="n">dump</span><span class="p">:</span><span class="n">sub</span><span class="p">(</span><span class="n">cursor</span><span class="o">+</span><span class="mi">1</span><span class="p">):</span><span class="n">byte</span><span class="p">()</span> </span><span id="L-17"><a name="L-17"></a><span class="k">end</span> </span><span id="L-18"><a name="L-18"></a> </span><span id="L-19"><a name="L-19"></a><span class="c1">-- Usage:</span> </span><span id="L-20"><a name="L-20"></a><span class="c1">-- num_args(function(a,b,c,d, ...) end) -- return 4, 7</span> </span></pre></div> </td></tr></table>
function, lua, util