1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
|
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<title>Mu - 001help.cc</title>
<meta name="Generator" content="Vim/8.1">
<meta name="plugin-version" content="vim8.1_v1">
<meta name="syntax" content="cpp">
<meta name="settings" content="number_lines,use_css,pre_wrap,no_foldcolumn,expand_tabs,line_ids,prevent_copy=">
<meta name="colorscheme" content="minimal-light">
<style type="text/css">
<!--
pre { white-space: pre-wrap; font-family: monospace; color: #000000; background-color: #c6c6c6; }
body { font-size:12pt; font-family: monospace; color: #000000; background-color: #c6c6c6; }
a { color:inherit; }
* { font-size:12pt; font-size: 1em; }
.CommentedCode { color: #8a8a8a; }
.LineNr { }
.Constant { color: #008787; }
.Comment { color: #005faf; }
.Delimiter { color: #c000c0; }
.Special { color: #d70000; }
.Identifier { color: #af5f00; }
.Normal { color: #000000; background-color: #c6c6c6; padding-bottom: 1px; }
.PreProc { color: #c000c0; }
.cSpecial { color: #008000; }
-->
</style>
<script type='text/javascript'>
<!--
/* function to open any folds containing a jumped-to line before jumping to it */
function JumpToLine()
{
var lineNum;
lineNum = window.location.hash;
lineNum = lineNum.substr(1); /* strip off '#' */
if (lineNum.indexOf('L') == -1) {
lineNum = 'L'+lineNum;
}
var lineElem = document.getElementById(lineNum);
/* Always jump to new location even if the line was hidden inside a fold, or
* we corrected the raw number to a line ID.
*/
if (lineElem) {
lineElem.scrollIntoView(true);
}
return true;
}
if ('onhashchange' in window) {
window.onhashchange = JumpToLine;
}
-->
</script>
</head>
<body onload='JumpToLine();'>
<a href='https://github.com/akkartik/mu/blob/master/001help.cc'>https://github.com/akkartik/mu/blob/master/001help.cc</a>
<pre id='vimCodeElement'>
<span id="L1" class="LineNr"> 1 </span><span class="Comment">//: Everything this project/binary supports.</span>
<span id="L2" class="LineNr"> 2 </span><span class="Comment">//: This should give you a sense for what to look forward to in later layers.</span>
<span id="L3" class="LineNr"> 3 </span>
<span id="L4" class="LineNr"> 4 </span><span class="Delimiter">:(before "End Commandline Parsing")</span>
<span id="L5" class="LineNr"> 5 </span><span class="Normal">if</span> <span class="Delimiter">(</span>argc <= <span class="Constant">1</span> || <a href='001help.cc.html#L96'>is_equal</a><span class="Delimiter">(</span>argv[<span class="Constant">1</span>]<span class="Delimiter">,</span> <span class="Constant">"--help"</span><span class="Delimiter">))</span> <span class="Delimiter">{</span>
<span id="L6" class="LineNr"> 6 </span> <span class="Comment">//: this is the functionality later layers will provide</span>
<span id="L7" class="LineNr"> 7 </span> <span class="Comment">// currently no automated tests for commandline arg parsing</span>
<span id="L8" class="LineNr"> 8 </span> cerr << get<span class="Delimiter">(</span><span class="Special"><a href='001help.cc.html#L53'>Help</a></span><span class="Delimiter">,</span> <span class="Constant">"usage"</span><span class="Delimiter">);</span>
<span id="L9" class="LineNr"> 9 </span> <span class="Identifier">return</span> <span class="Constant">0</span><span class="Delimiter">;</span>
<span id="L10" class="LineNr"> 10 </span><span class="Delimiter">}</span>
<span id="L11" class="LineNr"> 11 </span>
<span id="L12" class="LineNr"> 12 </span><span class="Comment">//: Support for option parsing.</span>
<span id="L13" class="LineNr"> 13 </span><span class="Comment">//: Options always begin with '--' and are always the first arguments. An</span>
<span id="L14" class="LineNr"> 14 </span><span class="Comment">//: option will never follow a non-option.</span>
<span id="L15" class="LineNr"> 15 </span><span class="Normal">char</span>** <a href='001help.cc.html#L15'>arg</a> = &argv[<span class="Constant">1</span>]<span class="Delimiter">;</span>
<span id="L16" class="LineNr"> 16 </span><span class="Normal">while</span> <span class="Delimiter">(</span>argc > <span class="Constant">1</span> && <a href='001help.cc.html#L100'>starts_with</a><span class="Delimiter">(</span>*arg<span class="Delimiter">,</span> <span class="Constant">"--"</span><span class="Delimiter">))</span> <span class="Delimiter">{</span>
<span id="L17" class="LineNr"> 17 </span> <span class="Normal">if</span> <span class="Delimiter">(</span><span class="Constant">false</span><span class="Delimiter">)</span>
<span id="L18" class="LineNr"> 18 </span> <span class="Delimiter">;</span> <span class="Comment">// no-op branch just so any further additions can consistently always start with 'else'</span>
<span id="L19" class="LineNr"> 19 </span> <span class="Comment">// End Commandline Options(*arg)</span>
<span id="L20" class="LineNr"> 20 </span> <span class="Normal">else</span>
<span id="L21" class="LineNr"> 21 </span> cerr << <span class="Constant">"skipping unknown option "</span> << *arg << <span class="cSpecial">'\n'</span><span class="Delimiter">;</span>
<span id="L22" class="LineNr"> 22 </span> --argc<span class="Delimiter">;</span> ++argv<span class="Delimiter">;</span> ++arg<span class="Delimiter">;</span>
<span id="L23" class="LineNr"> 23 </span><span class="Delimiter">}</span>
<span id="L24" class="LineNr"> 24 </span>
<span id="L25" class="LineNr"> 25 </span><span class="Normal">if</span> <span class="Delimiter">(</span><a href='001help.cc.html#L96'>is_equal</a><span class="Delimiter">(</span>argv[<span class="Constant">1</span>]<span class="Delimiter">,</span> <span class="Constant">"help"</span><span class="Delimiter">))</span> <span class="Delimiter">{</span>
<span id="L26" class="LineNr"> 26 </span> <span class="Normal">if</span> <span class="Delimiter">(</span>argc == <span class="Constant">2</span><span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L27" class="LineNr"> 27 </span> cerr << <span class="Constant">"help on what?\n"</span><span class="Delimiter">;</span>
<span id="L28" class="LineNr"> 28 </span> <a href='001help.cc.html#L46'>help_contents</a><span class="Delimiter">();</span>
<span id="L29" class="LineNr"> 29 </span> <span class="Identifier">return</span> <span class="Constant">0</span><span class="Delimiter">;</span>
<span id="L30" class="LineNr"> 30 </span> <span class="Delimiter">}</span>
<span id="L31" class="LineNr"> 31 </span> string key<span class="Delimiter">(</span>argv[<span class="Constant">2</span>]<span class="Delimiter">);</span>
<span id="L32" class="LineNr"> 32 </span> <span class="Comment">// End Help Special-cases(key)</span>
<span id="L33" class="LineNr"> 33 </span> <span class="Normal">if</span> <span class="Delimiter">(</span><a href='001help.cc.html#L254'>contains_key</a><span class="Delimiter">(</span><span class="Special"><a href='001help.cc.html#L53'>Help</a></span><span class="Delimiter">,</span> key<span class="Delimiter">))</span> <span class="Delimiter">{</span>
<span id="L34" class="LineNr"> 34 </span> cerr << get<span class="Delimiter">(</span><span class="Special"><a href='001help.cc.html#L53'>Help</a></span><span class="Delimiter">,</span> key<span class="Delimiter">);</span>
<span id="L35" class="LineNr"> 35 </span> <span class="Identifier">return</span> <span class="Constant">0</span><span class="Delimiter">;</span>
<span id="L36" class="LineNr"> 36 </span> <span class="Delimiter">}</span>
<span id="L37" class="LineNr"> 37 </span> <span class="Normal">else</span> <span class="Delimiter">{</span>
<span id="L38" class="LineNr"> 38 </span> cerr << <span class="Constant">"No help found for '"</span> << key << <span class="Constant">"'\n"</span><span class="Delimiter">;</span>
<span id="L39" class="LineNr"> 39 </span> <a href='001help.cc.html#L46'>help_contents</a><span class="Delimiter">();</span>
<span id="L40" class="LineNr"> 40 </span> cerr << <span class="Constant">"Please check your command for typos.\n"</span><span class="Delimiter">;</span>
<span id="L41" class="LineNr"> 41 </span> <span class="Identifier">return</span> <span class="Constant">1</span><span class="Delimiter">;</span>
<span id="L42" class="LineNr"> 42 </span> <span class="Delimiter">}</span>
<span id="L43" class="LineNr"> 43 </span><span class="Delimiter">}</span>
<span id="L44" class="LineNr"> 44 </span>
<span id="L45" class="LineNr"> 45 </span><span class="Delimiter">:(code)</span>
<span id="L46" class="LineNr"> 46 </span><span class="Normal">void</span> <a href='001help.cc.html#L46'>help_contents</a><span class="Delimiter">()</span> <span class="Delimiter">{</span>
<span id="L47" class="LineNr"> 47 </span> cerr << <span class="Constant">"Available top-level topics:\n"</span><span class="Delimiter">;</span>
<span id="L48" class="LineNr"> 48 </span> cerr << <span class="Constant">" usage\n"</span><span class="Delimiter">;</span>
<span id="L49" class="LineNr"> 49 </span> <span class="Comment">// End Help Contents</span>
<span id="L50" class="LineNr"> 50 </span><span class="Delimiter">}</span>
<span id="L51" class="LineNr"> 51 </span>
<span id="L52" class="LineNr"> 52 </span><span class="Delimiter">:(before "End Globals")</span>
<span id="L53" class="LineNr"> 53 </span>map<string<span class="Delimiter">,</span> string> <span class="Special"><a href='001help.cc.html#L53'>Help</a></span><span class="Delimiter">;</span>
<span id="L54" class="LineNr"> 54 </span><span class="Delimiter">:(before "End Includes")</span>
<span id="L55" class="LineNr"> 55 </span><span class="PreProc">#include </span><span class="Constant"><map></span>
<span id="L56" class="LineNr"> 56 </span><span class="Normal">using</span> std::map<span class="Delimiter">;</span>
<span id="L57" class="LineNr"> 57 </span><span class="Delimiter">:(before "End One-time Setup")</span>
<span id="L58" class="LineNr"> 58 </span><a href='001help.cc.html#L60'>init_help</a><span class="Delimiter">();</span>
<span id="L59" class="LineNr"> 59 </span><span class="Delimiter">:(code)</span>
<span id="L60" class="LineNr"> 60 </span><span class="Normal">void</span> <a href='001help.cc.html#L60'>init_help</a><span class="Delimiter">()</span> <span class="Delimiter">{</span>
<span id="L61" class="LineNr"> 61 </span> <a href='001help.cc.html#L250'>put</a><span class="Delimiter">(</span><span class="Special"><a href='001help.cc.html#L53'>Help</a></span><span class="Delimiter">,</span> <span class="Constant">"usage"</span><span class="Delimiter">,</span>
<span id="L62" class="LineNr"> 62 </span> <span class="Constant">"Welcome to SubX, a better way to program in machine code.\n"</span>
<span id="L63" class="LineNr"> 63 </span> <span class="Constant">"SubX uses a subset of the x86 instruction set. SubX programs will run\n"</span>
<span id="L64" class="LineNr"> 64 </span> <span class="Constant">"without modification on Linux computers.\n"</span>
<span id="L65" class="LineNr"> 65 </span> <span class="Constant">"It provides a better experience and better error messages than\n"</span>
<span id="L66" class="LineNr"> 66 </span> <span class="Constant">"programming directly in machine code, but you have to stick to the\n"</span>
<span id="L67" class="LineNr"> 67 </span> <span class="Constant">"instructions it supports.\n"</span>
<span id="L68" class="LineNr"> 68 </span> <span class="Constant">"\n"</span>
<span id="L69" class="LineNr"> 69 </span> <span class="Constant">"== Ways to invoke subx\n"</span>
<span id="L70" class="LineNr"> 70 </span> <span class="Constant">"- Run tests:\n"</span>
<span id="L71" class="LineNr"> 71 </span> <span class="Constant">" subx test\n"</span>
<span id="L72" class="LineNr"> 72 </span> <span class="Constant">"- See this message:\n"</span>
<span id="L73" class="LineNr"> 73 </span> <span class="Constant">" subx --help\n"</span>
<span id="L74" class="LineNr"> 74 </span> <span class="Constant">"- Convert a textual SubX program into a standard ELF binary that you can\n"</span>
<span id="L75" class="LineNr"> 75 </span> <span class="Constant">" <a href='011run.cc.html#L83'>run</a> on your computer:\n"</span>
<span id="L76" class="LineNr"> 76 </span> <span class="Constant">" subx translate input1.subx input2.subx ... -o <output ELF binary>\n"</span>
<span id="L77" class="LineNr"> 77 </span> <span class="Constant">"- Run a SubX binary using SubX itself (for better error messages):\n"</span>
<span id="L78" class="LineNr"> 78 </span> <span class="Constant">" subx <a href='011run.cc.html#L83'>run</a> <ELF binary>\n"</span>
<span id="L79" class="LineNr"> 79 </span> <span class="Constant">"\n"</span>
<span id="L80" class="LineNr"> 80 </span> <span class="Constant">"== Debugging aids\n"</span>
<span id="L81" class="LineNr"> 81 </span> <span class="Constant">"- Add '--trace' to any of these commands to save a trace.\n"</span>
<span id="L82" class="LineNr"> 82 </span> <span class="Constant">"- Add '--debug' to add information to traces. 'subx --debug translate' will\n"</span>
<span id="L83" class="LineNr"> 83 </span> <span class="Constant">" save metadata to disk that 'subx --debug --trace run' uses to make traces\n"</span>
<span id="L84" class="LineNr"> 84 </span> <span class="Constant">" more informative.\n"</span>
<span id="L85" class="LineNr"> 85 </span> <span class="Constant">"\n"</span>
<span id="L86" class="LineNr"> 86 </span> <span class="Constant">"Options starting with '--' must always come before any other arguments.\n"</span>
<span id="L87" class="LineNr"> 87 </span> <span class="Constant">"\n"</span>
<span id="L88" class="LineNr"> 88 </span> <span class="Constant">"To start learning how to write SubX programs, see Readme.md (particularly\n"</span>
<span id="L89" class="LineNr"> 89 </span> <span class="Constant">"the section on the x86 instruction set) and then <a href='011run.cc.html#L83'>run</a>:\n"</span>
<span id="L90" class="LineNr"> 90 </span> <span class="Constant">" subx help\n"</span>
<span id="L91" class="LineNr"> 91 </span> <span class="Delimiter">);</span>
<span id="L92" class="LineNr"> 92 </span> <span class="Comment">// End Help Texts</span>
<span id="L93" class="LineNr"> 93 </span><span class="Delimiter">}</span>
<span id="L94" class="LineNr"> 94 </span>
<span id="L95" class="LineNr"> 95 </span><span class="Delimiter">:(code)</span>
<span id="L96" class="LineNr"> 96 </span><span class="Normal">bool</span> <a href='001help.cc.html#L96'>is_equal</a><span class="Delimiter">(</span><span class="Normal">char</span>* s<span class="Delimiter">,</span> <span class="Normal">const</span> <span class="Normal">char</span>* lit<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L97" class="LineNr"> 97 </span> <span class="Identifier">return</span> strncmp<span class="Delimiter">(</span>s<span class="Delimiter">,</span> lit<span class="Delimiter">,</span> strlen<span class="Delimiter">(</span>lit<span class="Delimiter">))</span> == <span class="Constant">0</span><span class="Delimiter">;</span>
<span id="L98" class="LineNr"> 98 </span><span class="Delimiter">}</span>
<span id="L99" class="LineNr"> 99 </span>
<span id="L100" class="LineNr">100 </span><span class="Normal">bool</span> <a href='001help.cc.html#L100'>starts_with</a><span class="Delimiter">(</span><span class="Normal">const</span> string& s<span class="Delimiter">,</span> <span class="Normal">const</span> string& pat<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L101" class="LineNr">101 </span> string::const_iterator a=s<span class="Delimiter">.</span>begin<span class="Delimiter">(),</span> b=pat<span class="Delimiter">.</span>begin<span class="Delimiter">();</span>
<span id="L102" class="LineNr">102 </span> <span class="Normal">for</span> <span class="Delimiter">(</span><span class="Comment">/*</span><span class="Comment">nada</span><span class="Comment">*/</span><span class="Delimiter">;</span> a!=s<span class="Delimiter">.</span>end<span class="Delimiter">()</span> && b!=pat<span class="Delimiter">.</span>end<span class="Delimiter">();</span> ++a<span class="Delimiter">,</span> ++b<span class="Delimiter">)</span>
<span id="L103" class="LineNr">103 </span> <span class="Normal">if</span> <span class="Delimiter">(</span>*a != *b<span class="Delimiter">)</span> <span class="Identifier">return</span> <span class="Constant">false</span><span class="Delimiter">;</span>
<span id="L104" class="LineNr">104 </span> <span class="Identifier">return</span> b == pat<span class="Delimiter">.</span>end<span class="Delimiter">();</span>
<span id="L105" class="LineNr">105 </span><span class="Delimiter">}</span>
<span id="L106" class="LineNr">106 </span>
<span id="L107" class="LineNr">107 </span><span class="Comment">//: I'll throw some style conventions here for want of a better place for them.</span>
<span id="L108" class="LineNr">108 </span><span class="Comment">//: As a rule I hate style guides. Do what you want, that's my motto. But since</span>
<span id="L109" class="LineNr">109 </span><span class="Comment">//: we're dealing with C/C++, the one big thing we want to avoid is undefined</span>
<span id="L110" class="LineNr">110 </span><span class="Comment">//: behavior. If a compiler ever encounters undefined behavior it can make</span>
<span id="L111" class="LineNr">111 </span><span class="Comment">//: your program do anything it wants.</span>
<span id="L112" class="LineNr">112 </span><span class="Comment">//:</span>
<span id="L113" class="LineNr">113 </span><span class="Comment">//: For reference, my checklist of undefined behaviors to watch out for:</span>
<span id="L114" class="LineNr">114 </span><span class="Comment">//: out-of-bounds access</span>
<span id="L115" class="LineNr">115 </span><span class="Comment">//: uninitialized variables</span>
<span id="L116" class="LineNr">116 </span><span class="Comment">//: use after free</span>
<span id="L117" class="LineNr">117 </span><span class="Comment">//: dereferencing invalid pointers: null, a new of size 0, others</span>
<span id="L118" class="LineNr">118 </span><span class="Comment">//:</span>
<span id="L119" class="LineNr">119 </span><span class="Comment">//: casting a large number to a type too small to hold it</span>
<span id="L120" class="LineNr">120 </span><span class="Comment">//:</span>
<span id="L121" class="LineNr">121 </span><span class="Comment">//: integer overflow</span>
<span id="L122" class="LineNr">122 </span><span class="Comment">//: division by zero and other undefined expressions</span>
<span id="L123" class="LineNr">123 </span><span class="Comment">//: left-shift by negative count</span>
<span id="L124" class="LineNr">124 </span><span class="Comment">//: shifting values by more than or equal to the number of bits they contain</span>
<span id="L125" class="LineNr">125 </span><span class="Comment">//: bitwise operations on signed numbers</span>
<span id="L126" class="LineNr">126 </span><span class="Comment">//:</span>
<span id="L127" class="LineNr">127 </span><span class="Comment">//: Converting pointers to types of different alignment requirements</span>
<span id="L128" class="LineNr">128 </span><span class="Comment">//: T* -> void* -> T*: defined</span>
<span id="L129" class="LineNr">129 </span><span class="Comment">//: T* -> U* -> T*: defined if non-function pointers and alignment requirements are same</span>
<span id="L130" class="LineNr">130 </span><span class="Comment">//: function pointers may be cast to other function pointers</span>
<span id="L131" class="LineNr">131 </span><span class="Comment">//:</span>
<span id="L132" class="LineNr">132 </span><span class="Comment">//: Casting a numeric value into a value that can't be represented by the target type (either directly or via static_cast)</span>
<span id="L133" class="LineNr">133 </span><span class="Comment">//:</span>
<span id="L134" class="LineNr">134 </span><span class="Comment">//: To guard against these, some conventions:</span>
<span id="L135" class="LineNr">135 </span><span class="Comment">//:</span>
<span id="L136" class="LineNr">136 </span><span class="Comment">//: 0. Initialize all primitive variables in functions and constructors.</span>
<span id="L137" class="LineNr">137 </span><span class="Comment">//:</span>
<span id="L138" class="LineNr">138 </span><span class="Comment">//: 1. Minimize use of pointers and pointer arithmetic. Avoid 'new' and</span>
<span id="L139" class="LineNr">139 </span><span class="Comment">//: 'delete' as far as possible. Rely on STL to perform memory management to</span>
<span id="L140" class="LineNr">140 </span><span class="Comment">//: avoid use-after-free issues (and memory leaks).</span>
<span id="L141" class="LineNr">141 </span><span class="Comment">//:</span>
<span id="L142" class="LineNr">142 </span><span class="Comment">//: 2. Avoid naked arrays to avoid out-of-bounds access. Never use operator[]</span>
<span id="L143" class="LineNr">143 </span><span class="Comment">//: except with map. Use at() with STL vectors and so on.</span>
<span id="L144" class="LineNr">144 </span><span class="Comment">//:</span>
<span id="L145" class="LineNr">145 </span><span class="Comment">//: 3. Valgrind all the things.</span>
<span id="L146" class="LineNr">146 </span><span class="Comment">//:</span>
<span id="L147" class="LineNr">147 </span><span class="Comment">//: 4. Avoid unsigned numbers. Not strictly an undefined-behavior issue, but</span>
<span id="L148" class="LineNr">148 </span><span class="Comment">//: the extra range doesn't matter, and it's one less confusing category of</span>
<span id="L149" class="LineNr">149 </span><span class="Comment">//: interaction gotchas to worry about.</span>
<span id="L150" class="LineNr">150 </span><span class="Comment">//:</span>
<span id="L151" class="LineNr">151 </span><span class="Comment">//: Corollary: don't use the size() method on containers, since it returns an</span>
<span id="L152" class="LineNr">152 </span><span class="Comment">//: unsigned and that'll cause warnings about mixing signed and unsigned,</span>
<span id="L153" class="LineNr">153 </span><span class="Comment">//: yadda-yadda. Instead use this macro below to perform an unsafe cast to</span>
<span id="L154" class="LineNr">154 </span><span class="Comment">//: signed. We'll just give up immediately if a container's ever too large.</span>
<span id="L155" class="LineNr">155 </span><span class="Comment">//: Basically, Mu is not concerned about this being a little slower than it</span>
<span id="L156" class="LineNr">156 </span><span class="Comment">//: could be. (<a href="https://gist.github.com/rygorous/e0f055bfb74e3d5f0af20690759de5a7">https://gist.github.com/rygorous/e0f055bfb74e3d5f0af20690759de5a7</a>)</span>
<span id="L157" class="LineNr">157 </span><span class="Comment">//:</span>
<span id="L158" class="LineNr">158 </span><span class="Comment">//: Addendum to corollary: We're going to uniformly use int everywhere, to</span>
<span id="L159" class="LineNr">159 </span><span class="Comment">//: indicate that we're oblivious to number size, and since Clang on 32-bit</span>
<span id="L160" class="LineNr">160 </span><span class="Comment">//: platforms doesn't yet support multiplication over 64-bit integers, and</span>
<span id="L161" class="LineNr">161 </span><span class="Comment">//: since multiplying two integers seems like a more common situation to end</span>
<span id="L162" class="LineNr">162 </span><span class="Comment">//: up in than integer overflow.</span>
<span id="L163" class="LineNr">163 </span><span class="Delimiter">:(before "End Includes")</span>
<span id="L164" class="LineNr">164 </span><span class="PreProc">#define SIZE(</span><span class="Special">X</span><span class="PreProc">) (assert((</span><span class="Special">X</span><span class="PreProc">)</span><span class="Delimiter">.</span><span class="PreProc">size() < (</span><span class="Constant">1LL</span><span class="PreProc"><<(</span><span class="Normal">sizeof</span><span class="PreProc">(</span><span class="Normal">int</span><span class="PreProc">)*</span><span class="Constant">8</span><span class="PreProc">-</span><span class="Constant">2</span><span class="PreProc">)))</span><span class="Delimiter">,</span><span class="PreProc"> </span><span class="Normal">static_cast</span><span class="PreProc"><</span><span class="Normal">int</span><span class="PreProc">>((</span><span class="Special">X</span><span class="PreProc">)</span><span class="Delimiter">.</span><span class="PreProc">size()))</span>
<span id="L165" class="LineNr">165 </span>
<span id="L166" class="LineNr">166 </span><span class="Comment">//: 5. Integer overflow is guarded against at runtime using the -ftrapv flag</span>
<span id="L167" class="LineNr">167 </span><span class="Comment">//: to the compiler, supported by Clang (GCC version only works sometimes:</span>
<span id="L168" class="LineNr">168 </span><span class="Comment">//: <a href="http://stackoverflow.com/questions/20851061/how-to-make-gcc-ftrapv-work">http://stackoverflow.com/questions/20851061/how-to-make-gcc-ftrapv-work</a>).</span>
<span id="L169" class="LineNr">169 </span><span class="Delimiter">:(before "atexit(reset)")</span>
<span id="L170" class="LineNr">170 </span><a href='001help.cc.html#L175'>initialize_signal_handlers</a><span class="Delimiter">();</span> <span class="Comment">// not always necessary, but doesn't hurt</span>
<span id="L171" class="LineNr">171 </span><span class="CommentedCode">//? cerr << INT_MAX+1 << '\n'; // test overflow</span>
<span id="L172" class="LineNr">172 </span><span class="CommentedCode">//? assert(false); // test SIGABRT</span>
<span id="L173" class="LineNr">173 </span><span class="Delimiter">:(code)</span>
<span id="L174" class="LineNr">174 </span><span class="Comment">// based on <a href="https://spin.atomicobject.com/2013/01/13/exceptions-stack-traces-c">https://spin.atomicobject.com/2013/01/13/exceptions-stack-traces-c</a></span>
<span id="L175" class="LineNr">175 </span><span class="Normal">void</span> <a href='001help.cc.html#L175'>initialize_signal_handlers</a><span class="Delimiter">()</span> <span class="Delimiter">{</span>
<span id="L176" class="LineNr">176 </span> <span class="Normal">struct</span> sigaction action<span class="Delimiter">;</span>
<span id="L177" class="LineNr">177 </span> bzero<span class="Delimiter">(</span>&action<span class="Delimiter">,</span> <span class="Normal">sizeof</span><span class="Delimiter">(</span>action<span class="Delimiter">));</span>
<span id="L178" class="LineNr">178 </span> action<span class="Delimiter">.</span>sa_sigaction = <a href='001help.cc.html#L183'>dump_and_exit</a><span class="Delimiter">;</span>
<span id="L179" class="LineNr">179 </span> sigemptyset<span class="Delimiter">(</span>&action<span class="Delimiter">.</span>sa_mask<span class="Delimiter">);</span>
<span id="L180" class="LineNr">180 </span> sigaction<span class="Delimiter">(</span><span class="Constant">SIGABRT</span><span class="Delimiter">,</span> &action<span class="Delimiter">,</span> <span class="Constant">NULL</span><span class="Delimiter">);</span> <span class="Comment">// assert() failure or integer overflow on linux (with -ftrapv)</span>
<span id="L181" class="LineNr">181 </span> sigaction<span class="Delimiter">(</span><span class="Constant">SIGILL</span><span class="Delimiter">,</span> &action<span class="Delimiter">,</span> <span class="Constant">NULL</span><span class="Delimiter">);</span> <span class="Comment">// integer overflow on OS X (with -ftrapv)</span>
<span id="L182" class="LineNr">182 </span><span class="Delimiter">}</span>
<span id="L183" class="LineNr">183 </span><span class="Normal">void</span> <a href='001help.cc.html#L183'>dump_and_exit</a><span class="Delimiter">(</span><span class="Normal">int</span> sig<span class="Delimiter">,</span> siginfo_t* <span class="Comment">/*</span><span class="Comment">unused</span><span class="Comment">*/</span><span class="Delimiter">,</span> <span class="Normal">void</span>* <span class="Comment">/*</span><span class="Comment">unused</span><span class="Comment">*/</span><span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L184" class="LineNr">184 </span> <span class="Normal">switch</span> <span class="Delimiter">(</span>sig<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L185" class="LineNr">185 </span> <span class="Normal">case</span> <span class="Constant">SIGABRT</span>:
<span id="L186" class="LineNr">186 </span> <span class="PreProc">#ifndef __APPLE__</span>
<span id="L187" class="LineNr">187 </span> cerr << <span class="Constant">"SIGABRT: might be an integer overflow if it wasn't an assert() failure\n"</span><span class="Delimiter">;</span>
<span id="L188" class="LineNr">188 </span> _Exit<span class="Delimiter">(</span><span class="Constant">1</span><span class="Delimiter">);</span>
<span id="L189" class="LineNr">189 </span> <span class="PreProc">#endif</span>
<span id="L190" class="LineNr">190 </span> <span class="Identifier">break</span><span class="Delimiter">;</span>
<span id="L191" class="LineNr">191 </span> <span class="Normal">case</span> <span class="Constant">SIGILL</span>:
<span id="L192" class="LineNr">192 </span> <span class="PreProc">#ifdef __APPLE__</span>
<span id="L193" class="LineNr">193 </span> cerr << <span class="Constant">"SIGILL: most likely caused by integer overflow\n"</span><span class="Delimiter">;</span>
<span id="L194" class="LineNr">194 </span> _Exit<span class="Delimiter">(</span><span class="Constant">1</span><span class="Delimiter">);</span>
<span id="L195" class="LineNr">195 </span> <span class="PreProc">#endif</span>
<span id="L196" class="LineNr">196 </span> <span class="Identifier">break</span><span class="Delimiter">;</span>
<span id="L197" class="LineNr">197 </span> <span class="Normal">default</span>:
<span id="L198" class="LineNr">198 </span> <span class="Identifier">break</span><span class="Delimiter">;</span>
<span id="L199" class="LineNr">199 </span> <span class="Delimiter">}</span>
<span id="L200" class="LineNr">200 </span><span class="Delimiter">}</span>
<span id="L201" class="LineNr">201 </span><span class="Delimiter">:(before "End Includes")</span>
<span id="L202" class="LineNr">202 </span><span class="PreProc">#include </span><span class="Constant"><signal.h></span>
<span id="L203" class="LineNr">203 </span>
<span id="L204" class="LineNr">204 </span><span class="Comment">//: For good measure we'll also enable SIGFPE.</span>
<span id="L205" class="LineNr">205 </span><span class="Delimiter">:(before "atexit(reset)")</span>
<span id="L206" class="LineNr">206 </span><a href='001help.cc.html#L219'>feenableexcept</a><span class="Delimiter">(</span>FE_OVERFLOW | FE_UNDERFLOW<span class="Delimiter">);</span>
<span id="L207" class="LineNr">207 </span><span class="CommentedCode">//? assert(sizeof(int) == 4 && sizeof(float) == 4);</span>
<span id="L208" class="LineNr">208 </span><span class="CommentedCode">//? // | exp | mantissa</span>
<span id="L209" class="LineNr">209 </span><span class="CommentedCode">//? int smallest_subnormal = 0b00000000000000000000000000000001;</span>
<span id="L210" class="LineNr">210 </span><span class="CommentedCode">//? float smallest_subnormal_f = *reinterpret_cast<float*>(&smallest_subnormal);</span>
<span id="L211" class="LineNr">211 </span><span class="CommentedCode">//? cerr << "ε: " << smallest_subnormal_f << '\n';</span>
<span id="L212" class="LineNr">212 </span><span class="CommentedCode">//? cerr << "ε/2: " << smallest_subnormal_f/2 << " (underflow)\n"; // test SIGFPE</span>
<span id="L213" class="LineNr">213 </span><span class="Delimiter">:(before "End Includes")</span>
<span id="L214" class="LineNr">214 </span><span class="PreProc">#include </span><span class="Constant"><fenv.h></span>
<span id="L215" class="LineNr">215 </span><span class="Delimiter">:(code)</span>
<span id="L216" class="LineNr">216 </span><span class="PreProc">#ifdef __APPLE__</span>
<span id="L217" class="LineNr">217 </span><span class="Comment">// Public domain polyfill for feenableexcept on OS X</span>
<span id="L218" class="LineNr">218 </span><span class="Comment">// <a href="http://www-personal.umich.edu/~williams/archive/computation/fe-handling-example.c">http://www-personal.umich.edu/~williams/archive/computation/fe-handling-example.c</a></span>
<span id="L219" class="LineNr">219 </span><span class="Normal">int</span> <a href='001help.cc.html#L219'>feenableexcept</a><span class="Delimiter">(</span><span class="Normal">unsigned</span> <span class="Normal">int</span> excepts<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L220" class="LineNr">220 </span> <span class="Normal">static</span> fenv_t fenv<span class="Delimiter">;</span>
<span id="L221" class="LineNr">221 </span> <span class="Normal">unsigned</span> <span class="Normal">int</span> new_excepts = excepts & FE_ALL_EXCEPT<span class="Delimiter">;</span>
<span id="L222" class="LineNr">222 </span> <span class="Normal">unsigned</span> <span class="Normal">int</span> old_excepts<span class="Delimiter">;</span>
<span id="L223" class="LineNr">223 </span> <span class="Normal">if</span> <span class="Delimiter">(</span>fegetenv<span class="Delimiter">(</span>&fenv<span class="Delimiter">))</span> <span class="Identifier">return</span> -<span class="Constant">1</span><span class="Delimiter">;</span>
<span id="L224" class="LineNr">224 </span> old_excepts = fenv<span class="Delimiter">.</span>__control & FE_ALL_EXCEPT<span class="Delimiter">;</span>
<span id="L225" class="LineNr">225 </span> fenv<span class="Delimiter">.</span>__control &= ~new_excepts<span class="Delimiter">;</span>
<span id="L226" class="LineNr">226 </span> fenv<span class="Delimiter">.</span>__mxcsr &= ~<span class="Delimiter">(</span>new_excepts << <span class="Constant">7</span><span class="Delimiter">);</span>
<span id="L227" class="LineNr">227 </span> <span class="Identifier">return</span> fesetenv<span class="Delimiter">(</span>&fenv<span class="Delimiter">)</span> ? -<span class="Constant">1</span> : old_excepts<span class="Delimiter">;</span>
<span id="L228" class="LineNr">228 </span><span class="Delimiter">}</span>
<span id="L229" class="LineNr">229 </span><span class="PreProc">#endif</span>
<span id="L230" class="LineNr">230 </span>
<span id="L231" class="LineNr">231 </span><span class="Comment">//: 6. Map's operator[] being non-const is fucking evil.</span>
<span id="L232" class="LineNr">232 </span><span class="Delimiter">:(before "Globals")</span> <span class="Comment">// can't generate prototypes for these</span>
<span id="L233" class="LineNr">233 </span><span class="Comment">// from <a href="http://stackoverflow.com/questions/152643/idiomatic-c-for-reading-from-a-const-map">http://stackoverflow.com/questions/152643/idiomatic-c-for-reading-from-a-const-map</a></span>
<span id="L234" class="LineNr">234 </span><span class="Normal">template</span><<span class="Normal">typename</span> <span class="Special">T</span>> <span class="Normal">typename</span> <span class="Special">T</span>::mapped_type& get<span class="Delimiter">(</span><span class="Special">T</span>& map<span class="Delimiter">,</span> <span class="Normal">typename</span> <span class="Special">T</span>::key_type <span class="Normal">const</span>& key<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L235" class="LineNr">235 </span> <span class="Normal">typename</span> <span class="Special">T</span>::iterator iter<span class="Delimiter">(</span>map<span class="Delimiter">.</span>find<span class="Delimiter">(</span>key<span class="Delimiter">));</span>
<span id="L236" class="LineNr">236 </span> <span class="Normal">if</span> <span class="Delimiter">(</span>iter == map<span class="Delimiter">.</span>end<span class="Delimiter">())</span> <span class="Delimiter">{</span>
<span id="L237" class="LineNr">237 </span> cerr << <span class="Constant">"get couldn't find key '"</span> << key << <span class="Constant">"'\n"</span><span class="Delimiter">;</span>
<span id="L238" class="LineNr">238 </span> assert<span class="Delimiter">(</span>iter != map<span class="Delimiter">.</span>end<span class="Delimiter">());</span>
<span id="L239" class="LineNr">239 </span> <span class="Delimiter">}</span>
<span id="L240" class="LineNr">240 </span> <span class="Identifier">return</span> iter<span class="Delimiter">-></span>second<span class="Delimiter">;</span>
<span id="L241" class="LineNr">241 </span><span class="Delimiter">}</span>
<span id="L242" class="LineNr">242 </span><span class="Normal">template</span><<span class="Normal">typename</span> <span class="Special">T</span>> <span class="Normal">typename</span> <span class="Special">T</span>::mapped_type <span class="Normal">const</span>& get<span class="Delimiter">(</span><span class="Normal">const</span> <span class="Special">T</span>& map<span class="Delimiter">,</span> <span class="Normal">typename</span> <span class="Special">T</span>::key_type <span class="Normal">const</span>& key<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L243" class="LineNr">243 </span> <span class="Normal">typename</span> <span class="Special">T</span>::const_iterator iter<span class="Delimiter">(</span>map<span class="Delimiter">.</span>find<span class="Delimiter">(</span>key<span class="Delimiter">));</span>
<span id="L244" class="LineNr">244 </span> <span class="Normal">if</span> <span class="Delimiter">(</span>iter == map<span class="Delimiter">.</span>end<span class="Delimiter">())</span> <span class="Delimiter">{</span>
<span id="L245" class="LineNr">245 </span> cerr << <span class="Constant">"get couldn't find key '"</span> << key << <span class="Constant">"'\n"</span><span class="Delimiter">;</span>
<span id="L246" class="LineNr">246 </span> assert<span class="Delimiter">(</span>iter != map<span class="Delimiter">.</span>end<span class="Delimiter">());</span>
<span id="L247" class="LineNr">247 </span> <span class="Delimiter">}</span>
<span id="L248" class="LineNr">248 </span> <span class="Identifier">return</span> iter<span class="Delimiter">-></span>second<span class="Delimiter">;</span>
<span id="L249" class="LineNr">249 </span><span class="Delimiter">}</span>
<span id="L250" class="LineNr">250 </span><span class="Normal">template</span><<span class="Normal">typename</span> <span class="Special">T</span>> <span class="Normal">typename</span> <span class="Special">T</span>::mapped_type <span class="Normal">const</span>& <a href='001help.cc.html#L250'>put</a><span class="Delimiter">(</span><span class="Special">T</span>& map<span class="Delimiter">,</span> <span class="Normal">typename</span> <span class="Special">T</span>::key_type <span class="Normal">const</span>& key<span class="Delimiter">,</span> <span class="Normal">typename</span> <span class="Special">T</span>::mapped_type <span class="Normal">const</span>& value<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L251" class="LineNr">251 </span> map[key] = value<span class="Delimiter">;</span>
<span id="L252" class="LineNr">252 </span> <span class="Identifier">return</span> map[key]<span class="Delimiter">;</span>
<span id="L253" class="LineNr">253 </span><span class="Delimiter">}</span>
<span id="L254" class="LineNr">254 </span><span class="Normal">template</span><<span class="Normal">typename</span> <span class="Special">T</span>> <span class="Normal">bool</span> <a href='001help.cc.html#L254'>contains_key</a><span class="Delimiter">(</span><span class="Special">T</span>& map<span class="Delimiter">,</span> <span class="Normal">typename</span> <span class="Special">T</span>::key_type <span class="Normal">const</span>& key<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L255" class="LineNr">255 </span> <span class="Identifier">return</span> map<span class="Delimiter">.</span>find<span class="Delimiter">(</span>key<span class="Delimiter">)</span> != map<span class="Delimiter">.</span>end<span class="Delimiter">();</span>
<span id="L256" class="LineNr">256 </span><span class="Delimiter">}</span>
<span id="L257" class="LineNr">257 </span><span class="Normal">template</span><<span class="Normal">typename</span> <span class="Special">T</span>> <span class="Normal">typename</span> <span class="Special">T</span>::mapped_type& <a href='001help.cc.html#L257'>get_or_insert</a><span class="Delimiter">(</span><span class="Special">T</span>& map<span class="Delimiter">,</span> <span class="Normal">typename</span> <span class="Special">T</span>::key_type <span class="Normal">const</span>& key<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L258" class="LineNr">258 </span> <span class="Identifier">return</span> map[key]<span class="Delimiter">;</span>
<span id="L259" class="LineNr">259 </span><span class="Delimiter">}</span>
<span id="L260" class="LineNr">260 </span><span class="Normal">template</span><<span class="Normal">typename</span> <span class="Special">T</span>> <span class="Normal">typename</span> <span class="Special">T</span>::mapped_type <span class="Normal">const</span>& <a href='001help.cc.html#L260'>put_new</a><span class="Delimiter">(</span><span class="Special">T</span>& map<span class="Delimiter">,</span> <span class="Normal">typename</span> <span class="Special">T</span>::key_type <span class="Normal">const</span>& key<span class="Delimiter">,</span> <span class="Normal">typename</span> <span class="Special">T</span>::mapped_type <span class="Normal">const</span>& value<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L261" class="LineNr">261 </span> assert<span class="Delimiter">(</span>map<span class="Delimiter">.</span>find<span class="Delimiter">(</span>key<span class="Delimiter">)</span> == map<span class="Delimiter">.</span>end<span class="Delimiter">());</span>
<span id="L262" class="LineNr">262 </span> map[key] = value<span class="Delimiter">;</span>
<span id="L263" class="LineNr">263 </span> <span class="Identifier">return</span> map[key]<span class="Delimiter">;</span>
<span id="L264" class="LineNr">264 </span><span class="Delimiter">}</span>
<span id="L265" class="LineNr">265 </span><span class="Comment">//: The contract: any container that relies on get_or_insert should never call</span>
<span id="L266" class="LineNr">266 </span><span class="Comment">//: contains_key.</span>
<span id="L267" class="LineNr">267 </span>
<span id="L268" class="LineNr">268 </span><span class="Comment">//: 7. istreams are a royal pain in the arse. You have to be careful about</span>
<span id="L269" class="LineNr">269 </span><span class="Comment">//: what subclass you try to putback into. You have to watch out for the pesky</span>
<span id="L270" class="LineNr">270 </span><span class="Comment">//: failbit and badbit. Just avoid eof() and use this helper instead.</span>
<span id="L271" class="LineNr">271 </span><span class="Delimiter">:(code)</span>
<span id="L272" class="LineNr">272 </span><span class="Normal">bool</span> <a href='001help.cc.html#L272'>has_data</a><span class="Delimiter">(</span>istream& in<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L273" class="LineNr">273 </span> <span class="Identifier">return</span> in && !in<span class="Delimiter">.</span>eof<span class="Delimiter">();</span>
<span id="L274" class="LineNr">274 </span><span class="Delimiter">}</span>
<span id="L275" class="LineNr">275 </span>
<span id="L276" class="LineNr">276 </span><span class="Delimiter">:(before "End Includes")</span>
<span id="L277" class="LineNr">277 </span><span class="PreProc">#include </span><span class="Constant"><assert.h></span>
<span id="L278" class="LineNr">278 </span>
<span id="L279" class="LineNr">279 </span><span class="PreProc">#include </span><span class="Constant"><iostream></span>
<span id="L280" class="LineNr">280 </span><span class="Normal">using</span> std::istream<span class="Delimiter">;</span>
<span id="L281" class="LineNr">281 </span><span class="Normal">using</span> std::ostream<span class="Delimiter">;</span>
<span id="L282" class="LineNr">282 </span><span class="Normal">using</span> std::iostream<span class="Delimiter">;</span>
<span id="L283" class="LineNr">283 </span><span class="Normal">using</span> std::cin<span class="Delimiter">;</span>
<span id="L284" class="LineNr">284 </span><span class="Normal">using</span> std::cout<span class="Delimiter">;</span>
<span id="L285" class="LineNr">285 </span><span class="Normal">using</span> std::cerr<span class="Delimiter">;</span>
<span id="L286" class="LineNr">286 </span><span class="PreProc">#include </span><span class="Constant"><iomanip></span>
<span id="L287" class="LineNr">287 </span>
<span id="L288" class="LineNr">288 </span><span class="PreProc">#include </span><span class="Constant"><string.h></span>
<span id="L289" class="LineNr">289 </span><span class="PreProc">#include </span><span class="Constant"><string></span>
<span id="L290" class="LineNr">290 </span><span class="Normal">using</span> std::string<span class="Delimiter">;</span>
<span id="L291" class="LineNr">291 </span>
<span id="L292" class="LineNr">292 </span><span class="PreProc">#include </span><span class="Constant"><algorithm></span>
<span id="L293" class="LineNr">293 </span><span class="Normal">using</span> std::min<span class="Delimiter">;</span>
<span id="L294" class="LineNr">294 </span><span class="Normal">using</span> std::max<span class="Delimiter">;</span>
</pre>
</body>
</html>
<!-- vim: set foldmethod=manual : -->
|