Commit | Line | Data |
---|---|---|
71aaa3f7 PP |
1 | = Normand |
2 | Philippe Proulx | |
3 | :toc: left | |
4 | ||
5 | :py3: Python{nbsp}3 | |
6 | ||
7 | [.normal] | |
8 | image:https://img.shields.io/pypi/v/normand.svg?label=Latest%20version[link="https://pypi.python.org/pypi/normand"] | |
9 | ||
10 | [.lead] | |
11 | _**Normand**_ is a text-to-binary processor with its own language. | |
12 | ||
13 | This package offers both a portable {py3} module and a command-line | |
14 | tool. | |
15 | ||
16 | WARNING: This version of Normand is 0.1, meaning both the Normand | |
17 | language and the module/CLI interface aren't stable. | |
18 | ||
19 | == Introduction | |
20 | ||
21 | The purpose of Normand is to consume human-readable text representing | |
22 | bytes and to produce the corresponding binary data. | |
23 | ||
24 | .Simple bytes input. | |
25 | ==== | |
26 | Consider the following Normand input: | |
27 | ||
28 | ---- | |
29 | 4f 55 32 bb $167 fe %10100111 a9 $-32 | |
30 | ---- | |
31 | ||
32 | The generated nine bytes are: | |
33 | ||
34 | ---- | |
35 | 4f 55 32 bb a7 fe a7 a9 e0 | |
36 | ---- | |
37 | ==== | |
38 | ||
39 | As you can see in the last example, the fundamental unit of the Normand | |
40 | language is the _byte_. The order in which you list bytes will be the | |
41 | order of the generated data. | |
42 | ||
43 | The Normand language is more than simple lists of bytes, though. Its | |
44 | main features are: | |
45 | ||
46 | Comments, including a bunch of insignificant symbols which may improve readability:: | |
47 | + | |
48 | Input: | |
49 | + | |
50 | ---- | |
51 | ff bb %1101:0010 # This is a comment | |
52 | 78 29 af $192 # This too # 99 $-80 | |
53 | fe80::6257:18ff:fea3:4229 | |
54 | 60:57:18:a3:42:29 | |
55 | 10839636-5d65-4a68-8e6a-21608ddf7258 | |
56 | ---- | |
57 | + | |
58 | Output: | |
59 | + | |
60 | ---- | |
61 | ff bb d2 78 29 af c0 99 b0 fe 80 62 57 18 ff fe | |
62 | a3 42 29 60 57 18 a3 42 29 10 83 96 36 5d 65 4a | |
63 | 68 8e 6a 21 60 8d df 72 58 | |
64 | ---- | |
65 | ||
66 | Hexadecimal, decimal, and binary byte constants:: | |
67 | + | |
68 | Input: | |
69 | + | |
70 | ---- | |
71 | aa bb $247 $-89 %0011_0010 %11.01= 10/10 | |
72 | ---- | |
73 | + | |
74 | Output: | |
75 | + | |
76 | ---- | |
77 | aa bb f7 a7 32 da | |
78 | ---- | |
79 | ||
80 | UTF-8, UTF-16, and UTF-32 literal strings:: | |
81 | + | |
82 | Input: | |
83 | + | |
84 | ---- | |
85 | "hello world!" 00 | |
86 | u16le"stress\nverdict 🤣" | |
87 | ---- | |
88 | + | |
89 | Output: | |
90 | + | |
91 | ---- | |
92 | 68 65 6c 6c 6f 20 77 6f 72 6c 64 21 00 73 00 74 ┆ hello world!•s•t | |
93 | 00 72 00 65 00 73 00 73 00 0a 00 76 00 65 00 72 ┆ •r•e•s•s•••v•e•r | |
94 | 00 64 00 69 00 63 00 74 00 20 00 3e d8 23 dd ┆ •d•i•c•t• •>•#• | |
95 | ---- | |
96 | ||
97 | Labels: special variables holding the offset where they're defined:: | |
98 | + | |
99 | ---- | |
100 | <beg> b2 52 e3 bc 91 05 | |
101 | $100 $50 <chair> 33 9f fe | |
102 | 25 e9 89 8a <end> | |
103 | ---- | |
104 | ||
105 | Variables:: | |
106 | + | |
107 | ---- | |
108 | 5e 65 {tower = 47} c6 7f f2 c4 | |
109 | 44 {hurl = tower - 14} b5 {tower = hurl} 26 2d | |
110 | ---- | |
111 | + | |
112 | The value of a variable assignment is the evaluation of a valid {py3} | |
113 | expression which may include label and variable names. | |
114 | ||
115 | Value encoding with a specific length (8{nbsp}bits to 64{nbsp}bits) and byte order:: | |
116 | + | |
117 | Input: | |
118 | + | |
119 | ---- | |
120 | {strength = 4} | |
121 | {be} 67 <lbl> 44 $178 {(end - lbl) * 8 + strength : 16} $99 <end> | |
122 | {le} {-1993 : 32} | |
123 | ---- | |
124 | + | |
125 | Output: | |
126 | + | |
127 | ---- | |
128 | 67 44 b2 00 2c 63 37 f8 ff ff | |
129 | ---- | |
130 | + | |
131 | The encoded value is the evaluation of a valid {py3} expression which | |
132 | may include label and variable names. | |
133 | ||
134 | Repetition:: | |
135 | + | |
136 | Input: | |
137 | + | |
138 | ---- | |
139 | aa bb * 5 cc "yeah\0" * 8 | |
140 | ---- | |
141 | + | |
142 | Output: | |
143 | + | |
144 | ---- | |
145 | aa bb bb bb bb bb cc 79 65 61 68 00 79 65 61 68 ┆ •••••••yeah.yeah | |
146 | 00 79 65 61 68 00 79 65 61 68 00 79 65 61 68 00 ┆ •yeah•yeah•yeah• | |
147 | 79 65 61 68 00 79 65 61 68 00 79 65 61 68 00 ┆ yeah•yeah•yeah• | |
148 | ---- | |
149 | ||
150 | ||
151 | Multilevel grouping:: | |
152 | + | |
153 | Input: | |
154 | + | |
155 | ---- | |
156 | ff ((aa bb "zoom" cc) * 5) * 3 $-34 * 4 | |
157 | ---- | |
158 | + | |
159 | Output: | |
160 | + | |
161 | ---- | |
162 | ff aa bb 7a 6f 6f 6d cc aa bb 7a 6f 6f 6d cc aa ┆ •••zoom•••zoom•• | |
163 | bb 7a 6f 6f 6d cc aa bb 7a 6f 6f 6d cc aa bb 7a ┆ •zoom•••zoom•••z | |
164 | 6f 6f 6d cc aa bb 7a 6f 6f 6d cc aa bb 7a 6f 6f ┆ oom•••zoom•••zoo | |
165 | 6d cc aa bb 7a 6f 6f 6d cc aa bb 7a 6f 6f 6d cc ┆ m•••zoom•••zoom• | |
166 | aa bb 7a 6f 6f 6d cc aa bb 7a 6f 6f 6d cc aa bb ┆ ••zoom•••zoom••• | |
167 | 7a 6f 6f 6d cc aa bb 7a 6f 6f 6d cc aa bb 7a 6f ┆ zoom•••zoom•••zo | |
168 | 6f 6d cc aa bb 7a 6f 6f 6d cc de de de de ┆ om•••zoom••••• | |
169 | ---- | |
170 | ||
171 | Precise error reporting:: | |
172 | + | |
173 | ---- | |
174 | /tmp/meow.normand:10:24 - Expecting a bit (`0` or `1`). | |
175 | ---- | |
176 | + | |
177 | ---- | |
178 | /tmp/meow.normand:32:6 - Unexpected character `k`. | |
179 | ---- | |
180 | + | |
181 | ---- | |
182 | /tmp/meow.normand:24:19 - Unknown variable/label name `meow` in expression `(meow - 45) // 8`. | |
183 | ---- | |
184 | + | |
185 | ---- | |
186 | /tmp/meow.normand:18:9 - Value 315 is outside the 8-bit range when evaluating expression `end - ICITTE` at byte offset 45. | |
187 | ---- | |
188 | ||
189 | You can use Normand to track data source files in your favorite VCS | |
190 | instead of raw binary files. The binary files that Normand generates can | |
191 | be used to test file format decoding, including malformatted data, for | |
192 | example, as well as for education. | |
193 | ||
194 | See <<learn-normand>> to explore all the Normand features. | |
195 | ||
196 | == Install Normand | |
197 | ||
198 | Normand requires Python ≥ 3.4. | |
199 | ||
200 | To install Normand: | |
201 | ||
202 | ---- | |
203 | $ python3 -m pip install --user normand | |
204 | ---- | |
205 | ||
206 | See | |
207 | https://packaging.python.org/en/latest/tutorials/installing-packages/#installing-to-the-user-site[Installing to the User Site] | |
208 | to learn more about a user site installation. | |
209 | ||
210 | [NOTE] | |
211 | ==== | |
212 | Normand has a single module file, `normand.py`, which you can copy as is | |
213 | to your project to use it (both the <<python-3-api,`normand.parse()`>> | |
214 | function and the <<command-line-tool,command-line tool>>). | |
215 | ||
216 | `normand.py` has _no external dependencies_, but if you're using | |
217 | Python{nbsp}3.4, you'll need a local copy of the standard `typing` | |
218 | module. | |
219 | ==== | |
220 | ||
221 | == Learn Normand | |
222 | ||
223 | A Normand text input is a sequence of items which represent a sequence | |
224 | of raw bytes. | |
225 | ||
226 | [[state]] During the processing of items to data, Normand relies on a | |
227 | current state: | |
228 | ||
229 | [%header%autowidth] | |
230 | |=== | |
231 | |State variable |Description |Initial value: <<python-3-api,{py3} API>> |Initial value: <<command-line-tool,CLI>> | |
232 | ||
233 | |[[cur-offset]] Current offset | |
234 | | | |
235 | The current offset has an effect on the value of | |
236 | <<label,labels>> and of the special `ICITTE` name in <<value,value>> and | |
237 | <<variable-assignment,variable assignment>> expression evaluation. | |
238 | ||
239 | Each generated byte increments the current offset. | |
240 | ||
241 | A <<current-offset-setting,current offset setting>> may change the | |
242 | current offset. | |
243 | |`init_offset` parameter of the `parse()` function. | |
244 | |`--offset` option. | |
245 | ||
246 | |[[cur-bo]] Current byte order | |
247 | | | |
248 | The current byte order has an effect on the encoding of <<value,values>>. | |
249 | ||
250 | A <<current-byte-order-setting,current byte order setting>> may change | |
251 | the current byte order. | |
252 | |`init_byte_order` parameter of the `parse()` function. | |
253 | |`--byte-order` option. | |
254 | ||
255 | |<<label,Labels>> | |
256 | |Mapping of label names to integral values. | |
257 | |`init_labels` parameter of the `parse()` function. | |
258 | |One or more `--label` options. | |
259 | ||
260 | |<<variable-assignment,Variables>> | |
261 | |Mapping of variable names to integral values. | |
262 | |`init_variables` parameter of the `parse()` function. | |
263 | |One or more `--var` options. | |
264 | |=== | |
265 | ||
266 | The available items are: | |
267 | ||
268 | * A <<byte-constant,constant integer>> representing a single byte. | |
269 | ||
270 | * A <<literal-string,literal string>> representing a sequence of bytes | |
271 | encoding UTF-8, UTF-16, or UTF-32 data. | |
272 | ||
273 | * A <<current-byte-order-setting,current byte order setting>> (big or | |
274 | little endian). | |
275 | ||
276 | * A <<value,{py3} expression to be evaluated>> as an unsigned or signed | |
277 | integer to be encoded on one or more bytes using the current byte | |
278 | order. | |
279 | ||
280 | * A <<current-offset-setting,current offset setting>>. | |
281 | ||
282 | * A <<label,label>>, that is, a named constant holding the current | |
283 | offset. | |
284 | + | |
285 | This is similar to an assembly label. | |
286 | ||
287 | * A <<variable-assignment,variable assignment>> associating a name to | |
288 | the integral result of an evaluated {py3} expression. | |
289 | ||
290 | * A <<group,group>>, that is, a scoped sequence of items. | |
291 | ||
292 | Moreover, you can <<repetition,repeat>> any item above, except an offset | |
293 | or a label, a given number of times. This is called a repetition. | |
294 | ||
295 | A Normand comment may exist: | |
296 | ||
297 | * Between items, possibly within a group. | |
298 | * Between the nibbles of a constant hexadecimal byte. | |
299 | * Between the bits of a constant binary byte. | |
300 | * Between the last item and the ``pass:[*]`` character of a repetition, | |
301 | and between that ``pass:[*]`` character and the following number. | |
302 | ||
303 | A comment is anything between two ``pass:[#]`` characters on the same | |
304 | line, or from ``pass:[#]`` until the end of the line. Whitespaces and | |
305 | the following symbol characters are also considered comments where a | |
306 | comment may exist: | |
307 | ||
308 | ---- | |
309 | ! @ / \ ? & : ; . , + [ ] _ = | - | |
310 | ---- | |
311 | ||
312 | The latter serve to improve readability so that you may write, for | |
313 | example, a MAC address or a UUID as is. | |
314 | ||
315 | You can test the examples of this section with the `normand` | |
316 | <<command-line-tool,command-line tool>> as such: | |
317 | ||
318 | ---- | |
319 | $ normand file | hexdump -C | |
320 | ---- | |
321 | ||
322 | where `file` is the name of a file containing the Normand input. | |
323 | ||
324 | === Byte constant | |
325 | ||
326 | A _byte constant_ represents a single byte. | |
327 | ||
328 | A byte constant is: | |
329 | ||
330 | Hexadecimal form:: | |
331 | Two consecutive hexits. | |
332 | ||
333 | Decimal form:: | |
334 | A decimal number after the `$` prefix. | |
335 | ||
336 | Binary form:: | |
337 | Eight bits after the `%` prefix. | |
338 | ||
339 | ==== | |
340 | Input: | |
341 | ||
342 | ---- | |
343 | ab cd [3d 8F] CC | |
344 | ---- | |
345 | ||
346 | Output: | |
347 | ||
348 | ---- | |
349 | ab cd 3d 8f cc | |
350 | ---- | |
351 | ==== | |
352 | ||
353 | ==== | |
354 | Input: | |
355 | ||
356 | ---- | |
357 | $192 %1100/0011 $ -77 | |
358 | ---- | |
359 | ||
360 | Output: | |
361 | ||
362 | ---- | |
363 | c0 c3 b3 | |
364 | ---- | |
365 | ==== | |
366 | ||
367 | ==== | |
368 | Input: | |
369 | ||
370 | ---- | |
371 | 58f64689-6316-4d55-8a1a-04cada366172 | |
372 | fe80::6257:18ff:fea3:4229 | |
373 | ---- | |
374 | ||
375 | Output: | |
376 | ||
377 | ---- | |
378 | 58 f6 46 89 63 16 4d 55 8a 1a 04 ca da 36 61 72 ┆ X•F•c•MU•••••6ar | |
379 | fe 80 62 57 18 ff fe a3 42 29 ┆ ••bW••••B) | |
380 | ---- | |
381 | ==== | |
382 | ||
383 | ==== | |
384 | Input: | |
385 | ||
386 | ---- | |
387 | %01110011 %01100001 %01101100 %01110101 %01110100 | |
388 | ---- | |
389 | ||
390 | Output: | |
391 | ||
392 | ---- | |
393 | 73 61 6c 75 74 ┆ salut | |
394 | ---- | |
395 | ==== | |
396 | ||
397 | === Literal string | |
398 | ||
399 | A _literal string_ represents the UTF-8-, UTF-16-, or UTF-32-encoded | |
400 | bytes of a string. | |
401 | ||
402 | The string to encode isn't implicitly null-terminated: use `\0` at the | |
403 | end of the string to add a null character. | |
404 | ||
405 | A literal string is: | |
406 | ||
407 | . **Optional**: one of the following encodings instead of UTF-8: | |
408 | + | |
409 | -- | |
410 | [horizontal] | |
411 | `u16be`:: UTF-16BE. | |
412 | `u16le`:: UTF-16LE. | |
413 | `u32be`:: UTF-32BE. | |
414 | `u32le`:: UTF-32LE. | |
415 | -- | |
416 | ||
417 | . The ``pass:["]`` prefix. | |
418 | ||
419 | . A sequence of zero or more characters, possibly containing escape | |
420 | sequences. | |
421 | + | |
422 | An escape sequence is the ``\`` character followed by one of: | |
423 | + | |
424 | -- | |
425 | [horizontal] | |
426 | `0`:: Null (U+0000) | |
427 | `a`:: Alert (U+0007) | |
428 | `b`:: Backspace (U+0008) | |
429 | `e`:: Escape (U+001B) | |
430 | `f`:: Form feed (U+000C) | |
431 | `n`:: End of line (U+000A) | |
432 | `r`:: Carriage return (U+000D) | |
433 | `t`:: Character tabulation (U+0009) | |
434 | `v`:: Line tabulation (U+000B) | |
435 | ``\``:: Reverse solidus (U+005C) | |
436 | ``pass:["]``:: Quotation mark (U+0022) | |
437 | -- | |
438 | ||
439 | . The ``pass:["]`` suffix. | |
440 | ||
441 | ==== | |
442 | Input: | |
443 | ||
444 | ---- | |
445 | "coucou tout le monde!" | |
446 | ---- | |
447 | ||
448 | Output: | |
449 | ||
450 | ---- | |
451 | 63 6f 75 63 6f 75 20 74 6f 75 74 20 6c 65 20 6d ┆ coucou tout le m | |
452 | 6f 6e 64 65 21 ┆ onde! | |
453 | ---- | |
454 | ==== | |
455 | ||
456 | ==== | |
457 | Input: | |
458 | ||
459 | ---- | |
460 | u16le"I am not young enough to know everything." | |
461 | ---- | |
462 | ||
463 | Output: | |
464 | ||
465 | ---- | |
466 | 49 00 20 00 61 00 6d 00 20 00 6e 00 6f 00 74 00 ┆ I• •a•m• •n•o•t• | |
467 | 20 00 79 00 6f 00 75 00 6e 00 67 00 20 00 65 00 ┆ •y•o•u•n•g• •e• | |
468 | 6e 00 6f 00 75 00 67 00 68 00 20 00 74 00 6f 00 ┆ n•o•u•g•h• •t•o• | |
469 | 20 00 6b 00 6e 00 6f 00 77 00 20 00 65 00 76 00 ┆ •k•n•o•w• •e•v• | |
470 | 65 00 72 00 79 00 74 00 68 00 69 00 6e 00 67 00 ┆ e•r•y•t•h•i•n•g• | |
471 | 2e 00 ┆ .• | |
472 | ---- | |
473 | ==== | |
474 | ||
475 | ==== | |
476 | Input: | |
477 | ||
478 | ---- | |
479 | u32be "\"illusion is the first\nof all pleasures\" 🦉" | |
480 | ---- | |
481 | ||
482 | Output: | |
483 | ||
484 | ---- | |
485 | 00 00 00 22 00 00 00 69 00 00 00 6c 00 00 00 6c ┆ •••"•••i•••l•••l | |
486 | 00 00 00 75 00 00 00 73 00 00 00 69 00 00 00 6f ┆ •••u•••s•••i•••o | |
487 | 00 00 00 6e 00 00 00 20 00 00 00 69 00 00 00 73 ┆ •••n••• •••i•••s | |
488 | 00 00 00 20 00 00 00 74 00 00 00 68 00 00 00 65 ┆ ••• •••t•••h•••e | |
489 | 00 00 00 20 00 00 00 66 00 00 00 69 00 00 00 72 ┆ ••• •••f•••i•••r | |
490 | 00 00 00 73 00 00 00 74 00 00 00 0a 00 00 00 6f ┆ •••s•••t•••••••o | |
491 | 00 00 00 66 00 00 00 20 00 00 00 61 00 00 00 6c ┆ •••f••• •••a•••l | |
492 | 00 00 00 6c 00 00 00 20 00 00 00 70 00 00 00 6c ┆ •••l••• •••p•••l | |
493 | 00 00 00 65 00 00 00 61 00 00 00 73 00 00 00 75 ┆ •••e•••a•••s•••u | |
494 | 00 00 00 72 00 00 00 65 00 00 00 73 00 00 00 22 ┆ •••r•••e•••s•••" | |
495 | 00 00 00 20 00 01 f9 89 ┆ ••• •••• | |
496 | ---- | |
497 | ==== | |
498 | ||
499 | === Current byte order setting | |
500 | ||
501 | This special item sets the <<cur-bo,_current byte order_>>. | |
502 | ||
503 | The two accepted forms are: | |
504 | ||
505 | [horizontal] | |
506 | ``pass:[{be}]``:: Set the current byte order to big endian. | |
507 | ``pass:[{le}]``:: Set the current byte order to little endian. | |
508 | ||
509 | === Value | |
510 | ||
511 | A _value_ represents a fixed number of bytes encoding an unsigned or | |
512 | signed integer which is the result of evaluating a {py3} expression | |
513 | using the <<cur-bo,current byte order>>. | |
514 | ||
515 | For a value at some source location{nbsp}__**L**__, its {py3} expression | |
516 | may contain the name of any accessible <<label,label>>, including the | |
517 | name of a label defined after{nbsp}__**L**__, as well as the name of any | |
518 | <<variable-assignment,variable>> known at{nbsp}__**L**__. | |
519 | ||
520 | An accessible label is either: | |
521 | ||
522 | * Outside of the current <<group,group>>. | |
523 | * Within the same immediate group (not within a nested group). | |
524 | ||
525 | In the {py3} expression of a value, the value of the special name | |
526 | `ICITTE` is the <<cur-offset,current offset>> (before encoding the | |
527 | value). | |
528 | ||
529 | A value is: | |
530 | ||
531 | . The ``pass:[{]`` prefix. | |
532 | ||
533 | . A valid {py3} expression. | |
534 | ||
535 | . The `:` character. | |
536 | ||
537 | . An encoding length in bits amongst `8`, `16`, `24`, `32`, `40`, | |
538 | `48`, `56`, and `64`. | |
539 | ||
540 | . The `}` suffix. | |
541 | ||
542 | ==== | |
543 | Input: | |
544 | ||
545 | ---- | |
546 | {le} {345:16} | |
547 | {be} {-0xabcd:32} | |
548 | ---- | |
549 | ||
550 | Output: | |
551 | ||
552 | ---- | |
553 | 59 01 ff ff 54 33 | |
554 | ---- | |
555 | ==== | |
556 | ||
557 | ==== | |
558 | Input: | |
559 | ||
560 | ---- | |
561 | {be} | |
562 | ||
563 | # String length in bits | |
564 | {8 * (str_end - str_beg) : 16} | |
565 | ||
566 | # String | |
567 | <str_beg> | |
568 | "hello world!" | |
569 | <str_end> | |
570 | ---- | |
571 | ||
572 | Output: | |
573 | ||
574 | ---- | |
575 | 00 60 68 65 6c 6c 6f 20 77 6f 72 6c 64 21 ┆ •`hello world! | |
576 | ---- | |
577 | ==== | |
578 | ||
579 | ==== | |
580 | Input: | |
581 | ||
582 | ---- | |
583 | {20 - ICITTE : 8} * 10 | |
584 | ---- | |
585 | ||
586 | Output: | |
587 | ||
588 | ---- | |
589 | 14 13 12 11 10 0f 0e 0d 0c 0b | |
590 | ---- | |
591 | ==== | |
592 | ||
593 | === Current offset setting | |
594 | ||
595 | This special item sets the <<cur-offset,_current offset_>>. | |
596 | ||
597 | A current offset setting is: | |
598 | ||
599 | . The `<` prefix. | |
600 | ||
601 | . A positive integer (hexadecimal starting with `0x` or `0X` accepted) | |
602 | which is the new current offset. | |
603 | ||
604 | . The `>` suffix. | |
605 | ||
606 | ==== | |
607 | Input: | |
608 | ||
609 | ---- | |
610 | {ICITTE : 8} * 8 | |
611 | <0x61> {ICITTE : 8} * 8 | |
612 | ---- | |
613 | ||
614 | Output: | |
615 | ||
616 | ---- | |
617 | 00 01 02 03 04 05 06 07 61 62 63 64 65 66 67 68 ┆ ••••••••abcdefgh | |
618 | ---- | |
619 | ==== | |
620 | ||
621 | ==== | |
622 | Input: | |
623 | ||
624 | ---- | |
625 | aa bb cc dd <meow> ee ff | |
626 | <12> 11 22 33 <mix> 44 55 | |
627 | {meow : 8} {mix : 8} | |
628 | ---- | |
629 | ||
630 | Output: | |
631 | ||
632 | ---- | |
633 | aa bb cc dd ee ff 11 22 33 44 55 04 0f ┆ •••••••"3DU•• | |
634 | ---- | |
635 | ==== | |
636 | ||
637 | === Label | |
638 | ||
639 | A _label_ associates a name to the <<cur-offset,current offset>>. | |
640 | ||
641 | All the labels of a whole Normand input must have unique names. | |
642 | ||
643 | A label may not share the name of a <<variable-assignment,variable>> | |
644 | name. | |
645 | ||
646 | A label name may not be `ICITTE` (see <<value>> and | |
647 | <<variable-assignment>> to learn more). | |
648 | ||
649 | A label is: | |
650 | ||
651 | . The `<` prefix. | |
652 | ||
653 | . A valid {py3} name which is not `ICITTE`. | |
654 | ||
655 | . The `>` suffix. | |
656 | ||
657 | === Variable assignment | |
658 | ||
659 | A _variable assignment_ associates a name to the integral result of an | |
660 | evaluated {py3} expression. | |
661 | ||
662 | For a variable assignment at some source location{nbsp}__**L**__, its | |
663 | {py3} expression may contain the name of any accessible <<label,label>>, | |
664 | including the name of a label defined after{nbsp}__**L**__, as well as | |
665 | the name of any variable known at{nbsp}__**L**__. | |
666 | ||
667 | An accessible label is either: | |
668 | ||
669 | * Outside of the current <<group,group>>. | |
670 | * Within the same immediate group (not within a nested group). | |
671 | ||
672 | A variable name may not be `ICITTE` (see <<value>> and | |
673 | <<variable-assignment>> to learn more). | |
674 | ||
675 | In the {py3} expression of a variable assignment, the special name | |
676 | `ICITTE` is the <<cur-offset,current offset>>. | |
677 | ||
678 | A variable is: | |
679 | ||
680 | . The ``pass:[{]`` prefix. | |
681 | ||
682 | . A valid {py3} name which is not `ICITTE`. | |
683 | ||
684 | . The `=` character. | |
685 | ||
686 | . A valid {py3} expression. | |
687 | ||
688 | . The `}` suffix. | |
689 | ||
690 | ==== | |
691 | Input: | |
692 | ||
693 | ---- | |
694 | {mix = 101} {le} | |
695 | {meow = 42} 11 22 {meow:8} 33 {meow = ICITTE + 17} | |
696 | "yooo" {meow + mix : 16} | |
697 | ---- | |
698 | ||
699 | Output: | |
700 | ||
701 | ---- | |
702 | 11 22 2a 33 79 6f 6f 6f 7a 00 ┆ •"*3yoooz• | |
703 | ---- | |
704 | ==== | |
705 | ||
706 | === Group | |
707 | ||
708 | A _group_ is a scoped sequence of items. | |
709 | ||
710 | The <<label,labels>> within a group aren't visible outside of it. | |
711 | ||
712 | The main purpose of a group is to <<repetition,repeat>> more than a | |
713 | single item. | |
714 | ||
715 | A group is: | |
716 | ||
717 | . The `(` prefix. | |
718 | ||
719 | . Zero or more items. | |
720 | ||
721 | . The `)` suffix. | |
722 | ||
723 | ==== | |
724 | Input: | |
725 | ||
726 | ---- | |
727 | ((aa bb cc) dd () ee) "leclerc" | |
728 | ---- | |
729 | ||
730 | Output: | |
731 | ||
732 | ---- | |
733 | aa bb cc dd ee 6c 65 63 6c 65 72 63 ┆ •••••leclerc | |
734 | ---- | |
735 | ==== | |
736 | ||
737 | ==== | |
738 | Input: | |
739 | ||
740 | ---- | |
741 | ((aa bb cc) * 3 dd ee) * 5 | |
742 | ---- | |
743 | ||
744 | Output: | |
745 | ||
746 | ---- | |
747 | aa bb cc aa bb cc aa bb cc dd ee aa bb cc aa bb | |
748 | cc aa bb cc dd ee aa bb cc aa bb cc aa bb cc dd | |
749 | ee aa bb cc aa bb cc aa bb cc dd ee aa bb cc aa | |
750 | bb cc aa bb cc dd ee | |
751 | ---- | |
752 | ==== | |
753 | ||
754 | ==== | |
755 | Input: | |
756 | ||
757 | ---- | |
758 | {be} | |
759 | ( | |
760 | <str_beg> u16le"sébastien diaz" <str_end> | |
761 | {ICITTE - str_beg : 8} | |
762 | {(end - str_beg) * 5 : 24} | |
763 | ) * 3 | |
764 | <end> | |
765 | ---- | |
766 | ||
767 | Output: | |
768 | ||
769 | ---- | |
770 | 73 00 e9 00 62 00 61 00 73 00 74 00 69 00 65 00 ┆ s•••b•a•s•t•i•e• | |
771 | 6e 00 20 00 64 00 69 00 61 00 7a 00 1c 00 01 e0 ┆ n• •d•i•a•z••••• | |
772 | 73 00 e9 00 62 00 61 00 73 00 74 00 69 00 65 00 ┆ s•••b•a•s•t•i•e• | |
773 | 6e 00 20 00 64 00 69 00 61 00 7a 00 1c 00 01 40 ┆ n• •d•i•a•z••••@ | |
774 | 73 00 e9 00 62 00 61 00 73 00 74 00 69 00 65 00 ┆ s•••b•a•s•t•i•e• | |
775 | 6e 00 20 00 64 00 69 00 61 00 7a 00 1c 00 00 a0 ┆ n• •d•i•a•z••••• | |
776 | ---- | |
777 | ==== | |
778 | ||
779 | === Repetition | |
780 | ||
781 | A _repetition_ represents the bytes of an item repeated a given number | |
782 | of times. | |
783 | ||
784 | A repetition is: | |
785 | ||
786 | . Any item. | |
787 | ||
788 | . The ``pass:[*]`` character. | |
789 | ||
790 | . A positive integer (hexadecimal starting with `0x` or `0X` accepted) | |
791 | which is the number of times to repeat the previous item. | |
792 | ||
793 | ==== | |
794 | Input: | |
795 | ||
796 | ---- | |
797 | {end - ICITTE - 1 : 8} * 0x100 <end> | |
798 | ---- | |
799 | ||
800 | Output: | |
801 | ||
802 | ---- | |
803 | ff fe fd fc fb fa f9 f8 f7 f6 f5 f4 f3 f2 f1 f0 ┆ •••••••••••••••• | |
804 | ef ee ed ec eb ea e9 e8 e7 e6 e5 e4 e3 e2 e1 e0 ┆ •••••••••••••••• | |
805 | df de dd dc db da d9 d8 d7 d6 d5 d4 d3 d2 d1 d0 ┆ •••••••••••••••• | |
806 | cf ce cd cc cb ca c9 c8 c7 c6 c5 c4 c3 c2 c1 c0 ┆ •••••••••••••••• | |
807 | bf be bd bc bb ba b9 b8 b7 b6 b5 b4 b3 b2 b1 b0 ┆ •••••••••••••••• | |
808 | af ae ad ac ab aa a9 a8 a7 a6 a5 a4 a3 a2 a1 a0 ┆ •••••••••••••••• | |
809 | 9f 9e 9d 9c 9b 9a 99 98 97 96 95 94 93 92 91 90 ┆ •••••••••••••••• | |
810 | 8f 8e 8d 8c 8b 8a 89 88 87 86 85 84 83 82 81 80 ┆ •••••••••••••••• | |
811 | 7f 7e 7d 7c 7b 7a 79 78 77 76 75 74 73 72 71 70 ┆ •~}|{zyxwvutsrqp | |
812 | 6f 6e 6d 6c 6b 6a 69 68 67 66 65 64 63 62 61 60 ┆ onmlkjihgfedcba` | |
813 | 5f 5e 5d 5c 5b 5a 59 58 57 56 55 54 53 52 51 50 ┆ _^]\[ZYXWVUTSRQP | |
814 | 4f 4e 4d 4c 4b 4a 49 48 47 46 45 44 43 42 41 40 ┆ ONMLKJIHGFEDCBA@ | |
815 | 3f 3e 3d 3c 3b 3a 39 38 37 36 35 34 33 32 31 30 ┆ ?>=<;:9876543210 | |
816 | 2f 2e 2d 2c 2b 2a 29 28 27 26 25 24 23 22 21 20 ┆ /.-,+*)('&%$#"! | |
817 | 1f 1e 1d 1c 1b 1a 19 18 17 16 15 14 13 12 11 10 ┆ •••••••••••••••• | |
818 | 0f 0e 0d 0c 0b 0a 09 08 07 06 05 04 03 02 01 00 ┆ •••••••••••••••• | |
819 | ---- | |
820 | ==== | |
821 | ||
822 | == Command-line tool | |
823 | ||
824 | If you <<install-normand,installed>> the `normand` package, then you | |
825 | can use the `normand` command-line tool: | |
826 | ||
827 | ---- | |
828 | $ normand <<< '"ma gang de malades"' | hexdump -C | |
829 | ---- | |
830 | ||
831 | ---- | |
832 | 00000000 6d 61 20 67 61 6e 67 20 64 65 20 6d 61 6c 61 64 |ma gang de malad| | |
833 | 00000010 65 73 |es| | |
834 | ---- | |
835 | ||
836 | If you copy the `normand.py` module to your own project, then you can | |
837 | run the module itself: | |
838 | ||
839 | ---- | |
840 | $ python3 -m normand <<< '"ma gang de malades"' | hexdump -C | |
841 | ---- | |
842 | ||
843 | ---- | |
844 | 00000000 6d 61 20 67 61 6e 67 20 64 65 20 6d 61 6c 61 64 |ma gang de malad| | |
845 | 00000010 65 73 |es| | |
846 | ---- | |
847 | ||
848 | Without a path argument, the `normand` tool reads from the standard | |
849 | input. | |
850 | ||
851 | The `normand` tool prints the generated binary data to the standard | |
852 | output. | |
853 | ||
854 | Various options control the initial <<state,state>> of the processor: | |
855 | use the `--help` option to learn more. | |
856 | ||
857 | == {py3} API | |
858 | ||
859 | The whole `normand` package/module API is: | |
860 | ||
861 | [source,python] | |
862 | ---- | |
863 | class ByteOrder(enum.Enum): | |
864 | # Big endian. | |
865 | BE = ... | |
866 | ||
867 | # Little endian. | |
868 | LE = ... | |
869 | ||
870 | ||
871 | VarsT = typing.Dict[str, int] | |
872 | ||
873 | ||
874 | class TextLoc: | |
875 | # Line number. | |
876 | @property | |
877 | def line_no(self) -> int: | |
878 | ... | |
879 | ||
880 | # Column number. | |
881 | @property | |
882 | def col_no(self) -> int: | |
883 | ... | |
884 | ||
885 | ||
886 | class ParseError(RuntimeError): | |
887 | # Source text location. | |
888 | @property | |
889 | def text_loc(self) -> TextLoc: | |
890 | ... | |
891 | ||
892 | ||
893 | class ParseResult: | |
894 | # Generated data. | |
895 | @property | |
896 | def data(self) -> bytearray: | |
897 | ... | |
898 | ||
899 | # Updated variable values. | |
900 | @property | |
901 | def variables(self) -> VarsT: | |
902 | ... | |
903 | ||
904 | # Updated main group label values. | |
905 | @property | |
906 | def labels(self) -> VarsT: | |
907 | ... | |
908 | ||
909 | # Final offset. | |
910 | @property | |
911 | def offset(self) -> int: | |
912 | ... | |
913 | ||
914 | # Final byte order. | |
915 | @property | |
916 | def byte_order(self) -> typing.Optional[int]: | |
917 | ... | |
918 | ||
919 | def parse(normand: str, | |
920 | init_variables: typing.Optional[VarsT] = None, | |
921 | init_labels: typing.Optional[VarsT] = None, | |
922 | init_offset: int = 0, | |
923 | init_byte_order: typing.Optional[ByteOrder] = None) -> ParseResult: | |
924 | ... | |
925 | ---- | |
926 | ||
927 | The `normand` parameter is the actual <<learn-normand,Normand input>> | |
928 | while the other parameters control the initial <<state,state>>. | |
929 | ||
930 | The `parse()` function raises a `ParseError` instance should it fail to | |
931 | parse the `normand` string for any reason. |