Commit | Line | Data |
---|---|---|
bb2f9e9c PP |
1 | // Show ToC at a specific location for a GitHub rendering |
2 | ifdef::env-github[] | |
3 | :toc: macro | |
4 | endif::env-github[] | |
5 | ||
6 | ifndef::env-github[] | |
71aaa3f7 | 7 | :toc: left |
bb2f9e9c PP |
8 | endif::env-github[] |
9 | ||
10 | // This is to mimic what GitHub does so that anchors work in an offline | |
11 | // rendering too. | |
12 | :idprefix: | |
13 | :idseparator: - | |
71aaa3f7 | 14 | |
bb2f9e9c | 15 | // Other attributes |
71aaa3f7 PP |
16 | :py3: Python{nbsp}3 |
17 | ||
bb2f9e9c PP |
18 | = Normand |
19 | Philippe Proulx | |
20 | ||
df0f8552 PP |
21 | image::normand-logo.png[] |
22 | ||
71aaa3f7 PP |
23 | [.normal] |
24 | image:https://img.shields.io/pypi/v/normand.svg?label=Latest%20version[link="https://pypi.python.org/pypi/normand"] | |
25 | ||
26 | [.lead] | |
27 | _**Normand**_ is a text-to-binary processor with its own language. | |
28 | ||
29 | This package offers both a portable {py3} module and a command-line | |
30 | tool. | |
31 | ||
1b8aa84a | 32 | WARNING: This version of Normand is 0.5, meaning both the Normand |
71aaa3f7 PP |
33 | language and the module/CLI interface aren't stable. |
34 | ||
bb2f9e9c PP |
35 | ifdef::env-github[] |
36 | // ToC location for a GitHub rendering | |
37 | toc::[] | |
38 | endif::env-github[] | |
39 | ||
71aaa3f7 PP |
40 | == Introduction |
41 | ||
42 | The purpose of Normand is to consume human-readable text representing | |
43 | bytes and to produce the corresponding binary data. | |
44 | ||
45 | .Simple bytes input. | |
46 | ==== | |
47 | Consider the following Normand input: | |
48 | ||
49 | ---- | |
50 | 4f 55 32 bb $167 fe %10100111 a9 $-32 | |
51 | ---- | |
52 | ||
53 | The generated nine bytes are: | |
54 | ||
55 | ---- | |
56 | 4f 55 32 bb a7 fe a7 a9 e0 | |
57 | ---- | |
58 | ==== | |
59 | ||
60 | As you can see in the last example, the fundamental unit of the Normand | |
61 | language is the _byte_. The order in which you list bytes will be the | |
62 | order of the generated data. | |
63 | ||
64 | The Normand language is more than simple lists of bytes, though. Its | |
65 | main features are: | |
66 | ||
67 | Comments, including a bunch of insignificant symbols which may improve readability:: | |
68 | + | |
69 | Input: | |
70 | + | |
71 | ---- | |
72 | ff bb %1101:0010 # This is a comment | |
73 | 78 29 af $192 # This too # 99 $-80 | |
74 | fe80::6257:18ff:fea3:4229 | |
75 | 60:57:18:a3:42:29 | |
76 | 10839636-5d65-4a68-8e6a-21608ddf7258 | |
77 | ---- | |
78 | + | |
79 | Output: | |
80 | + | |
81 | ---- | |
82 | ff bb d2 78 29 af c0 99 b0 fe 80 62 57 18 ff fe | |
83 | a3 42 29 60 57 18 a3 42 29 10 83 96 36 5d 65 4a | |
84 | 68 8e 6a 21 60 8d df 72 58 | |
85 | ---- | |
86 | ||
87 | Hexadecimal, decimal, and binary byte constants:: | |
88 | + | |
89 | Input: | |
90 | + | |
91 | ---- | |
92 | aa bb $247 $-89 %0011_0010 %11.01= 10/10 | |
93 | ---- | |
94 | + | |
95 | Output: | |
96 | + | |
97 | ---- | |
98 | aa bb f7 a7 32 da | |
99 | ---- | |
100 | ||
101 | UTF-8, UTF-16, and UTF-32 literal strings:: | |
102 | + | |
103 | Input: | |
104 | + | |
105 | ---- | |
106 | "hello world!" 00 | |
107 | u16le"stress\nverdict 🤣" | |
108 | ---- | |
109 | + | |
110 | Output: | |
111 | + | |
112 | ---- | |
113 | 68 65 6c 6c 6f 20 77 6f 72 6c 64 21 00 73 00 74 ┆ hello world!•s•t | |
114 | 00 72 00 65 00 73 00 73 00 0a 00 76 00 65 00 72 ┆ •r•e•s•s•••v•e•r | |
115 | 00 64 00 69 00 63 00 74 00 20 00 3e d8 23 dd ┆ •d•i•c•t• •>•#• | |
116 | ---- | |
117 | ||
118 | Labels: special variables holding the offset where they're defined:: | |
119 | + | |
120 | ---- | |
121 | <beg> b2 52 e3 bc 91 05 | |
122 | $100 $50 <chair> 33 9f fe | |
123 | 25 e9 89 8a <end> | |
124 | ---- | |
125 | ||
126 | Variables:: | |
127 | + | |
128 | ---- | |
129 | 5e 65 {tower = 47} c6 7f f2 c4 | |
130 | 44 {hurl = tower - 14} b5 {tower = hurl} 26 2d | |
131 | ---- | |
132 | + | |
133 | The value of a variable assignment is the evaluation of a valid {py3} | |
134 | expression which may include label and variable names. | |
135 | ||
05f81895 | 136 | Fixed-length integer with a given length (8{nbsp}bits to 64{nbsp}bits) and byte order:: |
71aaa3f7 PP |
137 | + |
138 | Input: | |
139 | + | |
140 | ---- | |
141 | {strength = 4} | |
142 | {be} 67 <lbl> 44 $178 {(end - lbl) * 8 + strength : 16} $99 <end> | |
143 | {le} {-1993 : 32} | |
144 | ---- | |
145 | + | |
146 | Output: | |
147 | + | |
148 | ---- | |
149 | 67 44 b2 00 2c 63 37 f8 ff ff | |
150 | ---- | |
151 | + | |
05f81895 PP |
152 | The encoded integer is the evaluation of a valid {py3} expression which |
153 | may include label and variable names. | |
154 | ||
155 | https://en.wikipedia.org/wiki/LEB128[LEB128] integer:: | |
156 | + | |
157 | Input: | |
158 | + | |
159 | ---- | |
160 | aa bb cc {-1993 : sleb128} <meow> dd ee ff | |
161 | {meow * 199 : uleb128} | |
162 | ---- | |
163 | + | |
164 | Output: | |
165 | + | |
166 | ---- | |
167 | aa bb cc b7 70 dd ee ff e3 07 | |
168 | ---- | |
169 | + | |
170 | The encoded integer is the evaluation of a valid {py3} expression which | |
71aaa3f7 PP |
171 | may include label and variable names. |
172 | ||
173 | Repetition:: | |
174 | + | |
175 | Input: | |
176 | + | |
177 | ---- | |
2adf4336 | 178 | aa bb * 5 cc <zoom> "yeah\0" * {zoom * 3} |
71aaa3f7 PP |
179 | ---- |
180 | + | |
181 | Output: | |
182 | + | |
183 | ---- | |
2adf4336 PP |
184 | aa bb bb bb bb bb cc 79 65 61 68 00 79 65 61 68 ┆ •••••••yeah•yeah |
185 | 00 79 65 61 68 00 79 65 61 68 00 79 65 61 68 00 ┆ •yeah•yeah•yeah• | |
186 | 79 65 61 68 00 79 65 61 68 00 79 65 61 68 00 79 ┆ yeah•yeah•yeah•y | |
187 | 65 61 68 00 79 65 61 68 00 79 65 61 68 00 79 65 ┆ eah•yeah•yeah•ye | |
188 | 61 68 00 79 65 61 68 00 79 65 61 68 00 79 65 61 ┆ ah•yeah•yeah•yea | |
189 | 68 00 79 65 61 68 00 79 65 61 68 00 79 65 61 68 ┆ h•yeah•yeah•yeah | |
71aaa3f7 | 190 | 00 79 65 61 68 00 79 65 61 68 00 79 65 61 68 00 ┆ •yeah•yeah•yeah• |
71aaa3f7 PP |
191 | ---- |
192 | ||
193 | ||
194 | Multilevel grouping:: | |
195 | + | |
196 | Input: | |
197 | + | |
198 | ---- | |
199 | ff ((aa bb "zoom" cc) * 5) * 3 $-34 * 4 | |
200 | ---- | |
201 | + | |
202 | Output: | |
203 | + | |
204 | ---- | |
205 | ff aa bb 7a 6f 6f 6d cc aa bb 7a 6f 6f 6d cc aa ┆ •••zoom•••zoom•• | |
206 | bb 7a 6f 6f 6d cc aa bb 7a 6f 6f 6d cc aa bb 7a ┆ •zoom•••zoom•••z | |
207 | 6f 6f 6d cc aa bb 7a 6f 6f 6d cc aa bb 7a 6f 6f ┆ oom•••zoom•••zoo | |
208 | 6d cc aa bb 7a 6f 6f 6d cc aa bb 7a 6f 6f 6d cc ┆ m•••zoom•••zoom• | |
209 | aa bb 7a 6f 6f 6d cc aa bb 7a 6f 6f 6d cc aa bb ┆ ••zoom•••zoom••• | |
210 | 7a 6f 6f 6d cc aa bb 7a 6f 6f 6d cc aa bb 7a 6f ┆ zoom•••zoom•••zo | |
211 | 6f 6d cc aa bb 7a 6f 6f 6d cc de de de de ┆ om•••zoom••••• | |
212 | ---- | |
213 | ||
214 | Precise error reporting:: | |
215 | + | |
216 | ---- | |
217 | /tmp/meow.normand:10:24 - Expecting a bit (`0` or `1`). | |
218 | ---- | |
219 | + | |
220 | ---- | |
221 | /tmp/meow.normand:32:6 - Unexpected character `k`. | |
222 | ---- | |
223 | + | |
224 | ---- | |
2adf4336 | 225 | /tmp/meow.normand:24:19 - Illegal (unknown or unreachable) variable/label name `meow` in expression `(meow - 45) // 8`; the legal names are {`mix`, `zoom`}. |
71aaa3f7 PP |
226 | ---- |
227 | + | |
228 | ---- | |
229 | /tmp/meow.normand:18:9 - Value 315 is outside the 8-bit range when evaluating expression `end - ICITTE` at byte offset 45. | |
230 | ---- | |
231 | ||
232 | You can use Normand to track data source files in your favorite VCS | |
233 | instead of raw binary files. The binary files that Normand generates can | |
234 | be used to test file format decoding, including malformatted data, for | |
235 | example, as well as for education. | |
236 | ||
237 | See <<learn-normand>> to explore all the Normand features. | |
238 | ||
239 | == Install Normand | |
240 | ||
241 | Normand requires Python ≥ 3.4. | |
242 | ||
243 | To install Normand: | |
244 | ||
245 | ---- | |
246 | $ python3 -m pip install --user normand | |
247 | ---- | |
248 | ||
249 | See | |
250 | https://packaging.python.org/en/latest/tutorials/installing-packages/#installing-to-the-user-site[Installing to the User Site] | |
251 | to learn more about a user site installation. | |
252 | ||
253 | [NOTE] | |
254 | ==== | |
255 | Normand has a single module file, `normand.py`, which you can copy as is | |
af3cf417 | 256 | to your project to use it (both the <<python3-api,`normand.parse()`>> |
71aaa3f7 PP |
257 | function and the <<command-line-tool,command-line tool>>). |
258 | ||
259 | `normand.py` has _no external dependencies_, but if you're using | |
260 | Python{nbsp}3.4, you'll need a local copy of the standard `typing` | |
261 | module. | |
262 | ==== | |
263 | ||
264 | == Learn Normand | |
265 | ||
266 | A Normand text input is a sequence of items which represent a sequence | |
267 | of raw bytes. | |
268 | ||
269 | [[state]] During the processing of items to data, Normand relies on a | |
270 | current state: | |
271 | ||
272 | [%header%autowidth] | |
273 | |=== | |
af3cf417 | 274 | |State variable |Description |Initial value: <<python3-api,{py3} API>> |Initial value: <<command-line-tool,CLI>> |
71aaa3f7 PP |
275 | |
276 | |[[cur-offset]] Current offset | |
277 | | | |
05f81895 PP |
278 | The current offset has an effect on the value of <<label,labels>> and of |
279 | the special `ICITTE` name in <<fixed-length-integer,fixed-length | |
280 | integer>>, <<leb-128-integer,LEB128 integer>>, and | |
71aaa3f7 PP |
281 | <<variable-assignment,variable assignment>> expression evaluation. |
282 | ||
283 | Each generated byte increments the current offset. | |
284 | ||
285 | A <<current-offset-setting,current offset setting>> may change the | |
286 | current offset. | |
287 | |`init_offset` parameter of the `parse()` function. | |
288 | |`--offset` option. | |
289 | ||
290 | |[[cur-bo]] Current byte order | |
291 | | | |
05f81895 PP |
292 | The current byte order has an effect on the encoding of |
293 | <<fixed-length-integer,fixed-length integers>>. | |
71aaa3f7 PP |
294 | |
295 | A <<current-byte-order-setting,current byte order setting>> may change | |
296 | the current byte order. | |
297 | |`init_byte_order` parameter of the `parse()` function. | |
298 | |`--byte-order` option. | |
299 | ||
300 | |<<label,Labels>> | |
301 | |Mapping of label names to integral values. | |
302 | |`init_labels` parameter of the `parse()` function. | |
303 | |One or more `--label` options. | |
304 | ||
305 | |<<variable-assignment,Variables>> | |
306 | |Mapping of variable names to integral values. | |
307 | |`init_variables` parameter of the `parse()` function. | |
308 | |One or more `--var` options. | |
309 | |=== | |
310 | ||
311 | The available items are: | |
312 | ||
313 | * A <<byte-constant,constant integer>> representing a single byte. | |
314 | ||
315 | * A <<literal-string,literal string>> representing a sequence of bytes | |
316 | encoding UTF-8, UTF-16, or UTF-32 data. | |
317 | ||
318 | * A <<current-byte-order-setting,current byte order setting>> (big or | |
319 | little endian). | |
320 | ||
05f81895 PP |
321 | * A <<fixed-length-integer,fixed-length integer>> using the |
322 | <<cur-bo,current byte order>> and of which the value is the result of | |
323 | a {py3} expression. | |
324 | ||
325 | * An <<leb128-integer,LEB128 integer>> of which the value is the result | |
326 | of a {py3} expression. | |
71aaa3f7 PP |
327 | |
328 | * A <<current-offset-setting,current offset setting>>. | |
329 | ||
330 | * A <<label,label>>, that is, a named constant holding the current | |
331 | offset. | |
332 | + | |
333 | This is similar to an assembly label. | |
334 | ||
335 | * A <<variable-assignment,variable assignment>> associating a name to | |
336 | the integral result of an evaluated {py3} expression. | |
337 | ||
338 | * A <<group,group>>, that is, a scoped sequence of items. | |
339 | ||
340 | Moreover, you can <<repetition,repeat>> any item above, except an offset | |
2adf4336 PP |
341 | or a label, a given fixed or variable number of times. This is called a |
342 | repetition. | |
71aaa3f7 PP |
343 | |
344 | A Normand comment may exist: | |
345 | ||
346 | * Between items, possibly within a group. | |
347 | * Between the nibbles of a constant hexadecimal byte. | |
348 | * Between the bits of a constant binary byte. | |
349 | * Between the last item and the ``pass:[*]`` character of a repetition, | |
2adf4336 PP |
350 | and between that ``pass:[*]`` character and the following number |
351 | or expression. | |
71aaa3f7 PP |
352 | |
353 | A comment is anything between two ``pass:[#]`` characters on the same | |
354 | line, or from ``pass:[#]`` until the end of the line. Whitespaces and | |
355 | the following symbol characters are also considered comments where a | |
356 | comment may exist: | |
357 | ||
358 | ---- | |
359 | ! @ / \ ? & : ; . , + [ ] _ = | - | |
360 | ---- | |
361 | ||
362 | The latter serve to improve readability so that you may write, for | |
363 | example, a MAC address or a UUID as is. | |
364 | ||
365 | You can test the examples of this section with the `normand` | |
366 | <<command-line-tool,command-line tool>> as such: | |
367 | ||
368 | ---- | |
369 | $ normand file | hexdump -C | |
370 | ---- | |
371 | ||
372 | where `file` is the name of a file containing the Normand input. | |
373 | ||
374 | === Byte constant | |
375 | ||
376 | A _byte constant_ represents a single byte. | |
377 | ||
378 | A byte constant is: | |
379 | ||
380 | Hexadecimal form:: | |
381 | Two consecutive hexits. | |
382 | ||
383 | Decimal form:: | |
384 | A decimal number after the `$` prefix. | |
385 | ||
386 | Binary form:: | |
387 | Eight bits after the `%` prefix. | |
388 | ||
389 | ==== | |
390 | Input: | |
391 | ||
392 | ---- | |
393 | ab cd [3d 8F] CC | |
394 | ---- | |
395 | ||
396 | Output: | |
397 | ||
398 | ---- | |
399 | ab cd 3d 8f cc | |
400 | ---- | |
401 | ==== | |
402 | ||
403 | ==== | |
404 | Input: | |
405 | ||
406 | ---- | |
407 | $192 %1100/0011 $ -77 | |
408 | ---- | |
409 | ||
410 | Output: | |
411 | ||
412 | ---- | |
413 | c0 c3 b3 | |
414 | ---- | |
415 | ==== | |
416 | ||
417 | ==== | |
418 | Input: | |
419 | ||
420 | ---- | |
421 | 58f64689-6316-4d55-8a1a-04cada366172 | |
422 | fe80::6257:18ff:fea3:4229 | |
423 | ---- | |
424 | ||
425 | Output: | |
426 | ||
427 | ---- | |
428 | 58 f6 46 89 63 16 4d 55 8a 1a 04 ca da 36 61 72 ┆ X•F•c•MU•••••6ar | |
429 | fe 80 62 57 18 ff fe a3 42 29 ┆ ••bW••••B) | |
430 | ---- | |
431 | ==== | |
432 | ||
433 | ==== | |
434 | Input: | |
435 | ||
436 | ---- | |
437 | %01110011 %01100001 %01101100 %01110101 %01110100 | |
438 | ---- | |
439 | ||
440 | Output: | |
441 | ||
442 | ---- | |
443 | 73 61 6c 75 74 ┆ salut | |
444 | ---- | |
445 | ==== | |
446 | ||
447 | === Literal string | |
448 | ||
449 | A _literal string_ represents the UTF-8-, UTF-16-, or UTF-32-encoded | |
450 | bytes of a string. | |
451 | ||
452 | The string to encode isn't implicitly null-terminated: use `\0` at the | |
453 | end of the string to add a null character. | |
454 | ||
455 | A literal string is: | |
456 | ||
457 | . **Optional**: one of the following encodings instead of UTF-8: | |
458 | + | |
459 | -- | |
460 | [horizontal] | |
461 | `u16be`:: UTF-16BE. | |
462 | `u16le`:: UTF-16LE. | |
463 | `u32be`:: UTF-32BE. | |
464 | `u32le`:: UTF-32LE. | |
465 | -- | |
466 | ||
467 | . The ``pass:["]`` prefix. | |
468 | ||
469 | . A sequence of zero or more characters, possibly containing escape | |
470 | sequences. | |
471 | + | |
472 | An escape sequence is the ``\`` character followed by one of: | |
473 | + | |
474 | -- | |
475 | [horizontal] | |
476 | `0`:: Null (U+0000) | |
477 | `a`:: Alert (U+0007) | |
478 | `b`:: Backspace (U+0008) | |
479 | `e`:: Escape (U+001B) | |
480 | `f`:: Form feed (U+000C) | |
481 | `n`:: End of line (U+000A) | |
482 | `r`:: Carriage return (U+000D) | |
483 | `t`:: Character tabulation (U+0009) | |
484 | `v`:: Line tabulation (U+000B) | |
485 | ``\``:: Reverse solidus (U+005C) | |
486 | ``pass:["]``:: Quotation mark (U+0022) | |
487 | -- | |
488 | ||
489 | . The ``pass:["]`` suffix. | |
490 | ||
491 | ==== | |
492 | Input: | |
493 | ||
494 | ---- | |
495 | "coucou tout le monde!" | |
496 | ---- | |
497 | ||
498 | Output: | |
499 | ||
500 | ---- | |
501 | 63 6f 75 63 6f 75 20 74 6f 75 74 20 6c 65 20 6d ┆ coucou tout le m | |
502 | 6f 6e 64 65 21 ┆ onde! | |
503 | ---- | |
504 | ==== | |
505 | ||
506 | ==== | |
507 | Input: | |
508 | ||
509 | ---- | |
510 | u16le"I am not young enough to know everything." | |
511 | ---- | |
512 | ||
513 | Output: | |
514 | ||
515 | ---- | |
516 | 49 00 20 00 61 00 6d 00 20 00 6e 00 6f 00 74 00 ┆ I• •a•m• •n•o•t• | |
517 | 20 00 79 00 6f 00 75 00 6e 00 67 00 20 00 65 00 ┆ •y•o•u•n•g• •e• | |
518 | 6e 00 6f 00 75 00 67 00 68 00 20 00 74 00 6f 00 ┆ n•o•u•g•h• •t•o• | |
519 | 20 00 6b 00 6e 00 6f 00 77 00 20 00 65 00 76 00 ┆ •k•n•o•w• •e•v• | |
520 | 65 00 72 00 79 00 74 00 68 00 69 00 6e 00 67 00 ┆ e•r•y•t•h•i•n•g• | |
521 | 2e 00 ┆ .• | |
522 | ---- | |
523 | ==== | |
524 | ||
525 | ==== | |
526 | Input: | |
527 | ||
528 | ---- | |
529 | u32be "\"illusion is the first\nof all pleasures\" 🦉" | |
530 | ---- | |
531 | ||
532 | Output: | |
533 | ||
534 | ---- | |
535 | 00 00 00 22 00 00 00 69 00 00 00 6c 00 00 00 6c ┆ •••"•••i•••l•••l | |
536 | 00 00 00 75 00 00 00 73 00 00 00 69 00 00 00 6f ┆ •••u•••s•••i•••o | |
537 | 00 00 00 6e 00 00 00 20 00 00 00 69 00 00 00 73 ┆ •••n••• •••i•••s | |
538 | 00 00 00 20 00 00 00 74 00 00 00 68 00 00 00 65 ┆ ••• •••t•••h•••e | |
539 | 00 00 00 20 00 00 00 66 00 00 00 69 00 00 00 72 ┆ ••• •••f•••i•••r | |
540 | 00 00 00 73 00 00 00 74 00 00 00 0a 00 00 00 6f ┆ •••s•••t•••••••o | |
541 | 00 00 00 66 00 00 00 20 00 00 00 61 00 00 00 6c ┆ •••f••• •••a•••l | |
542 | 00 00 00 6c 00 00 00 20 00 00 00 70 00 00 00 6c ┆ •••l••• •••p•••l | |
543 | 00 00 00 65 00 00 00 61 00 00 00 73 00 00 00 75 ┆ •••e•••a•••s•••u | |
544 | 00 00 00 72 00 00 00 65 00 00 00 73 00 00 00 22 ┆ •••r•••e•••s•••" | |
545 | 00 00 00 20 00 01 f9 89 ┆ ••• •••• | |
546 | ---- | |
547 | ==== | |
548 | ||
549 | === Current byte order setting | |
550 | ||
551 | This special item sets the <<cur-bo,_current byte order_>>. | |
552 | ||
553 | The two accepted forms are: | |
554 | ||
555 | [horizontal] | |
556 | ``pass:[{be}]``:: Set the current byte order to big endian. | |
557 | ``pass:[{le}]``:: Set the current byte order to little endian. | |
558 | ||
05f81895 | 559 | === Fixed-length integer |
71aaa3f7 | 560 | |
05f81895 PP |
561 | A _fixed-length integer_ represents a fixed number of bytes encoding an |
562 | unsigned or signed integer which is the result of evaluating a {py3} | |
563 | expression using the <<cur-bo,current byte order>>. | |
71aaa3f7 | 564 | |
05f81895 | 565 | A fixed-length integer is: |
71aaa3f7 PP |
566 | |
567 | . The ``pass:[{]`` prefix. | |
568 | ||
569 | . A valid {py3} expression. | |
05f81895 PP |
570 | + |
571 | For a fixed-length integer at some source location{nbsp}__**L**__, this | |
572 | expression may contain the name of any accessible <<label,label>> (not | |
573 | within a nested group), including the name of a label defined | |
574 | after{nbsp}__**L**__, as well as the name of any | |
575 | <<variable-assignment,variable>> known at{nbsp}__**L**__. | |
576 | + | |
577 | The value of the special name `ICITTE` in this expression is the | |
578 | <<cur-offset,current offset>> (before encoding the integer). | |
71aaa3f7 PP |
579 | |
580 | . The `:` character. | |
581 | ||
582 | . An encoding length in bits amongst `8`, `16`, `24`, `32`, `40`, | |
583 | `48`, `56`, and `64`. | |
584 | ||
585 | . The `}` suffix. | |
586 | ||
587 | ==== | |
588 | Input: | |
589 | ||
590 | ---- | |
591 | {le} {345:16} | |
592 | {be} {-0xabcd:32} | |
593 | ---- | |
594 | ||
595 | Output: | |
596 | ||
597 | ---- | |
598 | 59 01 ff ff 54 33 | |
599 | ---- | |
600 | ==== | |
601 | ||
602 | ==== | |
603 | Input: | |
604 | ||
605 | ---- | |
606 | {be} | |
607 | ||
608 | # String length in bits | |
609 | {8 * (str_end - str_beg) : 16} | |
610 | ||
611 | # String | |
612 | <str_beg> | |
613 | "hello world!" | |
614 | <str_end> | |
615 | ---- | |
616 | ||
617 | Output: | |
618 | ||
619 | ---- | |
620 | 00 60 68 65 6c 6c 6f 20 77 6f 72 6c 64 21 ┆ •`hello world! | |
621 | ---- | |
622 | ==== | |
623 | ||
624 | ==== | |
625 | Input: | |
626 | ||
627 | ---- | |
628 | {20 - ICITTE : 8} * 10 | |
629 | ---- | |
630 | ||
631 | Output: | |
632 | ||
633 | ---- | |
634 | 14 13 12 11 10 0f 0e 0d 0c 0b | |
635 | ---- | |
636 | ==== | |
637 | ||
05f81895 PP |
638 | === LEB128 integer |
639 | ||
640 | An _LEB128 integer_ represents a variable number of bytes encoding an | |
641 | unsigned or signed integer which is the result of evaluating a {py3} | |
642 | expression following the https://en.wikipedia.org/wiki/LEB128[LEB128] | |
643 | format. | |
644 | ||
645 | An LEB128 integer is: | |
646 | ||
647 | . The ``pass:[{]`` prefix. | |
648 | ||
649 | . A valid {py3} expression. | |
650 | + | |
651 | For an LEB128 integer at some source location{nbsp}__**L**__, this | |
652 | expression may contain: | |
653 | + | |
654 | -- | |
655 | * The name of any <<label,label>> defined before{nbsp}__**L**__. | |
656 | * The name of any <<variable-assignment,variable>> known at{nbsp}__**L**__ | |
657 | which doesn't, directly or indirectly, refer to a label | |
658 | defined after{nbsp}__**L**__. | |
659 | -- | |
660 | + | |
661 | The value of the special name `ICITTE` in this expression is the | |
662 | <<cur-offset,current offset>> (before encoding the integer). | |
663 | ||
664 | . The `:` character. | |
665 | ||
666 | . One of: | |
667 | + | |
668 | -- | |
669 | [horizontal] | |
670 | `uleb128`:: Use the unsigned LEB128 format. | |
671 | `sleb128`:: Use the signed LEB128 format. | |
672 | -- | |
673 | ||
674 | . The `}` suffix. | |
675 | ||
676 | ==== | |
677 | Input: | |
678 | ||
679 | ---- | |
680 | {624485 : uleb128} | |
681 | ---- | |
682 | ||
683 | Output: | |
684 | ||
685 | ---- | |
686 | e5 8e 26 | |
687 | ---- | |
688 | ==== | |
689 | ||
690 | ==== | |
691 | Input: | |
692 | ||
693 | ---- | |
694 | aa bb cc dd | |
695 | <meow> | |
696 | ee ff | |
697 | {-981238311 + (meow * -23) : sleb128} | |
698 | "hello" | |
699 | ---- | |
700 | ||
c2b79cf6 PP |
701 | Output: |
702 | ||
05f81895 PP |
703 | ---- |
704 | aa bb cc dd ee ff fd fa 8d ac 7c 68 65 6c 6c 6f ┆ ••••••••••|hello | |
705 | ---- | |
706 | ==== | |
707 | ||
71aaa3f7 PP |
708 | === Current offset setting |
709 | ||
710 | This special item sets the <<cur-offset,_current offset_>>. | |
711 | ||
712 | A current offset setting is: | |
713 | ||
714 | . The `<` prefix. | |
715 | ||
716 | . A positive integer (hexadecimal starting with `0x` or `0X` accepted) | |
717 | which is the new current offset. | |
718 | ||
719 | . The `>` suffix. | |
720 | ||
721 | ==== | |
722 | Input: | |
723 | ||
724 | ---- | |
725 | {ICITTE : 8} * 8 | |
726 | <0x61> {ICITTE : 8} * 8 | |
727 | ---- | |
728 | ||
729 | Output: | |
730 | ||
731 | ---- | |
732 | 00 01 02 03 04 05 06 07 61 62 63 64 65 66 67 68 ┆ ••••••••abcdefgh | |
733 | ---- | |
734 | ==== | |
735 | ||
736 | ==== | |
737 | Input: | |
738 | ||
739 | ---- | |
740 | aa bb cc dd <meow> ee ff | |
741 | <12> 11 22 33 <mix> 44 55 | |
742 | {meow : 8} {mix : 8} | |
743 | ---- | |
744 | ||
745 | Output: | |
746 | ||
747 | ---- | |
748 | aa bb cc dd ee ff 11 22 33 44 55 04 0f ┆ •••••••"3DU•• | |
749 | ---- | |
750 | ==== | |
751 | ||
752 | === Label | |
753 | ||
754 | A _label_ associates a name to the <<cur-offset,current offset>>. | |
755 | ||
756 | All the labels of a whole Normand input must have unique names. | |
757 | ||
05f81895 | 758 | A label must not share the name of a <<variable-assignment,variable>> |
71aaa3f7 PP |
759 | name. |
760 | ||
71aaa3f7 PP |
761 | A label is: |
762 | ||
763 | . The `<` prefix. | |
764 | ||
05f81895 PP |
765 | . A valid {py3} name which is not `ICITTE` (see |
766 | <<fixed-length-integer>>, <<leb128-integer>>, and | |
767 | <<variable-assignment>> to learn more). | |
71aaa3f7 PP |
768 | |
769 | . The `>` suffix. | |
770 | ||
771 | === Variable assignment | |
772 | ||
773 | A _variable assignment_ associates a name to the integral result of an | |
774 | evaluated {py3} expression. | |
775 | ||
05f81895 | 776 | A variable assignment is: |
71aaa3f7 PP |
777 | |
778 | . The ``pass:[{]`` prefix. | |
779 | ||
05f81895 PP |
780 | . A valid {py3} name which is not `ICITTE` (see |
781 | <<fixed-length-integer>>, <<leb128-integer>>, and | |
782 | <<variable-assignment>> to learn more). | |
71aaa3f7 PP |
783 | |
784 | . The `=` character. | |
785 | ||
786 | . A valid {py3} expression. | |
05f81895 PP |
787 | + |
788 | For a variable assignment at some source location{nbsp}__**L**__, this | |
789 | expression may contain the name of any accessible <<label,label>> (not | |
790 | within a nested group), including the name of a label defined | |
791 | after{nbsp}__**L**__, as well as the name of any | |
792 | <<variable-assignment,variable>> known at{nbsp}__**L**__. | |
793 | + | |
794 | The value of the special name `ICITTE` in this expression is the | |
795 | <<cur-offset,current offset>>. | |
71aaa3f7 PP |
796 | |
797 | . The `}` suffix. | |
798 | ||
799 | ==== | |
800 | Input: | |
801 | ||
802 | ---- | |
803 | {mix = 101} {le} | |
804 | {meow = 42} 11 22 {meow:8} 33 {meow = ICITTE + 17} | |
805 | "yooo" {meow + mix : 16} | |
806 | ---- | |
807 | ||
808 | Output: | |
809 | ||
810 | ---- | |
811 | 11 22 2a 33 79 6f 6f 6f 7a 00 ┆ •"*3yoooz• | |
812 | ---- | |
813 | ==== | |
814 | ||
815 | === Group | |
816 | ||
817 | A _group_ is a scoped sequence of items. | |
818 | ||
819 | The <<label,labels>> within a group aren't visible outside of it. | |
820 | ||
821 | The main purpose of a group is to <<repetition,repeat>> more than a | |
822 | single item. | |
823 | ||
824 | A group is: | |
825 | ||
826 | . The `(` prefix. | |
827 | ||
828 | . Zero or more items. | |
829 | ||
830 | . The `)` suffix. | |
831 | ||
832 | ==== | |
833 | Input: | |
834 | ||
835 | ---- | |
836 | ((aa bb cc) dd () ee) "leclerc" | |
837 | ---- | |
838 | ||
839 | Output: | |
840 | ||
841 | ---- | |
842 | aa bb cc dd ee 6c 65 63 6c 65 72 63 ┆ •••••leclerc | |
843 | ---- | |
844 | ==== | |
845 | ||
846 | ==== | |
847 | Input: | |
848 | ||
849 | ---- | |
850 | ((aa bb cc) * 3 dd ee) * 5 | |
851 | ---- | |
852 | ||
853 | Output: | |
854 | ||
855 | ---- | |
856 | aa bb cc aa bb cc aa bb cc dd ee aa bb cc aa bb | |
857 | cc aa bb cc dd ee aa bb cc aa bb cc aa bb cc dd | |
858 | ee aa bb cc aa bb cc aa bb cc dd ee aa bb cc aa | |
859 | bb cc aa bb cc dd ee | |
860 | ---- | |
861 | ==== | |
862 | ||
863 | ==== | |
864 | Input: | |
865 | ||
866 | ---- | |
867 | {be} | |
868 | ( | |
869 | <str_beg> u16le"sébastien diaz" <str_end> | |
870 | {ICITTE - str_beg : 8} | |
871 | {(end - str_beg) * 5 : 24} | |
872 | ) * 3 | |
873 | <end> | |
874 | ---- | |
875 | ||
876 | Output: | |
877 | ||
878 | ---- | |
879 | 73 00 e9 00 62 00 61 00 73 00 74 00 69 00 65 00 ┆ s•••b•a•s•t•i•e• | |
880 | 6e 00 20 00 64 00 69 00 61 00 7a 00 1c 00 01 e0 ┆ n• •d•i•a•z••••• | |
881 | 73 00 e9 00 62 00 61 00 73 00 74 00 69 00 65 00 ┆ s•••b•a•s•t•i•e• | |
882 | 6e 00 20 00 64 00 69 00 61 00 7a 00 1c 00 01 40 ┆ n• •d•i•a•z••••@ | |
883 | 73 00 e9 00 62 00 61 00 73 00 74 00 69 00 65 00 ┆ s•••b•a•s•t•i•e• | |
884 | 6e 00 20 00 64 00 69 00 61 00 7a 00 1c 00 00 a0 ┆ n• •d•i•a•z••••• | |
885 | ---- | |
886 | ==== | |
887 | ||
888 | === Repetition | |
889 | ||
890 | A _repetition_ represents the bytes of an item repeated a given number | |
891 | of times. | |
892 | ||
893 | A repetition is: | |
894 | ||
895 | . Any item. | |
896 | ||
897 | . The ``pass:[*]`` character. | |
898 | ||
2adf4336 PP |
899 | . One of: |
900 | ||
901 | ** A positive integer (hexadecimal starting with `0x` or `0X` accepted) | |
902 | which is the number of times to repeat the previous item. | |
903 | ||
904 | ** The ``pass:[{]`` prefix, a valid {py3} expression, and the | |
905 | ``pass:[}]`` suffix. | |
05f81895 PP |
906 | + |
907 | For a repetition at some source location{nbsp}__**L**__, this expression | |
908 | may contain: | |
909 | + | |
910 | -- | |
911 | * The name of any <<label,label>> defined before{nbsp}__**L**__ and | |
912 | which isn't part of its repeated item. | |
913 | * The name of any <<variable-assignment,variable>> known | |
914 | at{nbsp}__**L**__, which isn't part of its repeated item, and which | |
915 | doesn't, directly or indirectly, refer to a label defined | |
916 | after{nbsp}__**L**__. | |
917 | -- | |
918 | + | |
919 | This expression must not contain the special name `ICITTE`. | |
71aaa3f7 PP |
920 | |
921 | ==== | |
922 | Input: | |
923 | ||
924 | ---- | |
925 | {end - ICITTE - 1 : 8} * 0x100 <end> | |
926 | ---- | |
927 | ||
928 | Output: | |
929 | ||
930 | ---- | |
931 | ff fe fd fc fb fa f9 f8 f7 f6 f5 f4 f3 f2 f1 f0 ┆ •••••••••••••••• | |
932 | ef ee ed ec eb ea e9 e8 e7 e6 e5 e4 e3 e2 e1 e0 ┆ •••••••••••••••• | |
933 | df de dd dc db da d9 d8 d7 d6 d5 d4 d3 d2 d1 d0 ┆ •••••••••••••••• | |
934 | cf ce cd cc cb ca c9 c8 c7 c6 c5 c4 c3 c2 c1 c0 ┆ •••••••••••••••• | |
935 | bf be bd bc bb ba b9 b8 b7 b6 b5 b4 b3 b2 b1 b0 ┆ •••••••••••••••• | |
936 | af ae ad ac ab aa a9 a8 a7 a6 a5 a4 a3 a2 a1 a0 ┆ •••••••••••••••• | |
937 | 9f 9e 9d 9c 9b 9a 99 98 97 96 95 94 93 92 91 90 ┆ •••••••••••••••• | |
938 | 8f 8e 8d 8c 8b 8a 89 88 87 86 85 84 83 82 81 80 ┆ •••••••••••••••• | |
939 | 7f 7e 7d 7c 7b 7a 79 78 77 76 75 74 73 72 71 70 ┆ •~}|{zyxwvutsrqp | |
940 | 6f 6e 6d 6c 6b 6a 69 68 67 66 65 64 63 62 61 60 ┆ onmlkjihgfedcba` | |
941 | 5f 5e 5d 5c 5b 5a 59 58 57 56 55 54 53 52 51 50 ┆ _^]\[ZYXWVUTSRQP | |
942 | 4f 4e 4d 4c 4b 4a 49 48 47 46 45 44 43 42 41 40 ┆ ONMLKJIHGFEDCBA@ | |
943 | 3f 3e 3d 3c 3b 3a 39 38 37 36 35 34 33 32 31 30 ┆ ?>=<;:9876543210 | |
944 | 2f 2e 2d 2c 2b 2a 29 28 27 26 25 24 23 22 21 20 ┆ /.-,+*)('&%$#"! | |
945 | 1f 1e 1d 1c 1b 1a 19 18 17 16 15 14 13 12 11 10 ┆ •••••••••••••••• | |
946 | 0f 0e 0d 0c 0b 0a 09 08 07 06 05 04 03 02 01 00 ┆ •••••••••••••••• | |
947 | ---- | |
948 | ==== | |
949 | ||
2adf4336 PP |
950 | ==== |
951 | Input: | |
952 | ||
953 | ---- | |
954 | {times = 1} | |
955 | aa bb cc dd | |
956 | ( | |
957 | <here> | |
958 | (ee ff) * {here + 1} | |
959 | 11 22 33 * {times} | |
960 | {times = times + 1} | |
961 | ) * 3 | |
962 | "coucou!" | |
963 | ---- | |
964 | ||
965 | Output: | |
966 | ||
967 | ---- | |
968 | aa bb cc dd ee ff ee ff ee ff ee ff ee ff 11 22 ┆ •••••••••••••••" | |
969 | 33 ee ff ee ff ee ff ee ff ee ff ee ff ee ff ee ┆ 3••••••••••••••• | |
970 | ff ee ff ee ff ee ff ee ff ee ff ee ff ee ff ee ┆ •••••••••••••••• | |
971 | ff ee ff ee ff 11 22 33 33 ee ff ee ff ee ff ee ┆ ••••••"33••••••• | |
972 | ff ee ff ee ff ee ff ee ff ee ff ee ff ee ff ee ┆ •••••••••••••••• | |
973 | ff ee ff ee ff ee ff ee ff ee ff ee ff ee ff ee ┆ •••••••••••••••• | |
974 | ff ee ff ee ff ee ff ee ff ee ff ee ff ee ff ee ┆ •••••••••••••••• | |
975 | ff ee ff ee ff ee ff ee ff ee ff ee ff ee ff ee ┆ •••••••••••••••• | |
976 | ff ee ff ee ff ee ff ee ff ee ff ee ff ee ff ee ┆ •••••••••••••••• | |
977 | ff ee ff ee ff ee ff ee ff ee ff ee ff ee ff ee ┆ •••••••••••••••• | |
978 | ff ee ff ee ff ee ff ee ff ee ff ee ff 11 22 33 ┆ ••••••••••••••"3 | |
979 | 33 33 63 6f 75 63 6f 75 21 ┆ 33coucou! | |
980 | ---- | |
981 | ==== | |
982 | ||
983 | ==== | |
984 | This example shows how to use a repetition as a conditional section | |
985 | depending on some predefined variable. | |
986 | ||
987 | Input: | |
988 | ||
989 | ---- | |
990 | aa bb cc dd | |
991 | (ee ff "meow mix" 00) * {cond} | |
992 | {be} {-1993:16} | |
993 | ---- | |
994 | ||
995 | Output (`cond` is 0): | |
996 | ||
997 | ---- | |
998 | aa bb cc dd f8 37 | |
999 | ---- | |
1000 | ||
1001 | Output (`cond` is 1): | |
1002 | ||
1003 | ---- | |
1004 | aa bb cc dd ee ff 6d 65 6f 77 20 6d 69 78 00 f8 ┆ ••••••meow mix•• | |
1005 | 37 ┆ 7 | |
1006 | ---- | |
1007 | ==== | |
1008 | ||
71aaa3f7 PP |
1009 | == Command-line tool |
1010 | ||
1011 | If you <<install-normand,installed>> the `normand` package, then you | |
1012 | can use the `normand` command-line tool: | |
1013 | ||
1014 | ---- | |
1015 | $ normand <<< '"ma gang de malades"' | hexdump -C | |
1016 | ---- | |
1017 | ||
1018 | ---- | |
1019 | 00000000 6d 61 20 67 61 6e 67 20 64 65 20 6d 61 6c 61 64 |ma gang de malad| | |
1020 | 00000010 65 73 |es| | |
1021 | ---- | |
1022 | ||
1023 | If you copy the `normand.py` module to your own project, then you can | |
1024 | run the module itself: | |
1025 | ||
1026 | ---- | |
1027 | $ python3 -m normand <<< '"ma gang de malades"' | hexdump -C | |
1028 | ---- | |
1029 | ||
1030 | ---- | |
1031 | 00000000 6d 61 20 67 61 6e 67 20 64 65 20 6d 61 6c 61 64 |ma gang de malad| | |
1032 | 00000010 65 73 |es| | |
1033 | ---- | |
1034 | ||
1035 | Without a path argument, the `normand` tool reads from the standard | |
1036 | input. | |
1037 | ||
1038 | The `normand` tool prints the generated binary data to the standard | |
1039 | output. | |
1040 | ||
1041 | Various options control the initial <<state,state>> of the processor: | |
1042 | use the `--help` option to learn more. | |
1043 | ||
1044 | == {py3} API | |
1045 | ||
1046 | The whole `normand` package/module API is: | |
1047 | ||
1048 | [source,python] | |
1049 | ---- | |
1050 | class ByteOrder(enum.Enum): | |
1051 | # Big endian. | |
1052 | BE = ... | |
1053 | ||
1054 | # Little endian. | |
1055 | LE = ... | |
1056 | ||
1057 | ||
71aaa3f7 PP |
1058 | class TextLoc: |
1059 | # Line number. | |
1060 | @property | |
1061 | def line_no(self) -> int: | |
1062 | ... | |
1063 | ||
1064 | # Column number. | |
1065 | @property | |
1066 | def col_no(self) -> int: | |
1067 | ... | |
1068 | ||
1069 | ||
1070 | class ParseError(RuntimeError): | |
1071 | # Source text location. | |
1072 | @property | |
1073 | def text_loc(self) -> TextLoc: | |
1074 | ... | |
1075 | ||
1076 | ||
1b8aa84a PP |
1077 | SymbolsT = typing.Dict[str, int] |
1078 | ||
1079 | ||
71aaa3f7 PP |
1080 | class ParseResult: |
1081 | # Generated data. | |
1082 | @property | |
1083 | def data(self) -> bytearray: | |
1084 | ... | |
1085 | ||
1086 | # Updated variable values. | |
1087 | @property | |
1b8aa84a | 1088 | def variables(self) -> SymbolsT: |
71aaa3f7 PP |
1089 | ... |
1090 | ||
1091 | # Updated main group label values. | |
1092 | @property | |
1b8aa84a | 1093 | def labels(self) -> SymbolsT: |
71aaa3f7 PP |
1094 | ... |
1095 | ||
1096 | # Final offset. | |
1097 | @property | |
1098 | def offset(self) -> int: | |
1099 | ... | |
1100 | ||
1101 | # Final byte order. | |
1102 | @property | |
1b8aa84a | 1103 | def byte_order(self) -> typing.Optional[ByteOrder]: |
71aaa3f7 PP |
1104 | ... |
1105 | ||
1b8aa84a | 1106 | |
71aaa3f7 | 1107 | def parse(normand: str, |
1b8aa84a PP |
1108 | init_variables: typing.Optional[SymbolsT] = None, |
1109 | init_labels: typing.Optional[SymbolsT] = None, | |
71aaa3f7 PP |
1110 | init_offset: int = 0, |
1111 | init_byte_order: typing.Optional[ByteOrder] = None) -> ParseResult: | |
1112 | ... | |
1113 | ---- | |
1114 | ||
1115 | The `normand` parameter is the actual <<learn-normand,Normand input>> | |
1116 | while the other parameters control the initial <<state,state>>. | |
1117 | ||
1118 | The `parse()` function raises a `ParseError` instance should it fail to | |
1119 | parse the `normand` string for any reason. | |
bf8f3b38 PP |
1120 | |
1121 | == Development | |
1122 | ||
1123 | Normand is a https://python-poetry.org/[Poetry] project. | |
1124 | ||
1125 | To develop it, install it through Poetry and enter the virtual | |
1126 | environment: | |
1127 | ||
1128 | ---- | |
1129 | $ poetry install | |
1130 | $ poetry shell | |
1131 | $ normand <<< '"lol" * 10 0a' | |
1132 | ---- | |
1133 | ||
1134 | `normand.py` is processed by: | |
1135 | ||
1136 | * https://microsoft.github.io/pyright/[Pyright] | |
1137 | * https://github.com/psf/black[Black] | |
1138 | * https://pycqa.github.io/isort/[isort] | |
1139 | ||
1140 | === Testing | |
1141 | ||
1142 | Use https://docs.pytest.org/[pytest] to test Normand once the package is | |
1143 | part of your virtual environment, for example: | |
1144 | ||
1145 | ---- | |
1146 | $ poetry install | |
1147 | $ poetry run pip3 install pytest | |
1148 | $ poetry run pytest | |
1149 | ---- | |
1150 | ||
1151 | The `pytest` project is currently not a development dependency in | |
1152 | `pyproject.toml` due to backward compatibiliy issues with | |
1153 | Python{nbsp}3.4. | |
1154 | ||
1155 | In the `tests` directory, each `*.nt` file is a test. The file name | |
1156 | prefix indicates what it's meant to test: | |
1157 | ||
1158 | `pass-`:: | |
1159 | Everything above the `---` line is the valid Normand input | |
1160 | to test. | |
1161 | + | |
1162 | Everything below the `---` line is the expected data | |
1163 | (whitespace-separated hexadecimal bytes). | |
1164 | ||
1165 | `fail-`:: | |
1166 | Everything above the `---` line is the invalid Normand input | |
1167 | to test. | |
1168 | + | |
1169 | Everything below the `---` line is the expected error message having | |
1170 | this form: | |
1171 | + | |
1172 | ---- | |
1173 | LINE:COL - MESSAGE | |
1174 | ---- | |
1175 | ||
1176 | === Contributing | |
1177 | ||
1178 | Normand uses https://review.lttng.org/admin/repos/normand,general[Gerrit] | |
1179 | for code review. | |
1180 | ||
1181 | To report a bug, https://github.com/efficios/normand/issues/new[create a | |
1182 | GitHub issue]. |