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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 | ||
71aaa3f7 PP |
21 | [.normal] |
22 | image:https://img.shields.io/pypi/v/normand.svg?label=Latest%20version[link="https://pypi.python.org/pypi/normand"] | |
23 | ||
24 | [.lead] | |
25 | _**Normand**_ is a text-to-binary processor with its own language. | |
26 | ||
27 | This package offers both a portable {py3} module and a command-line | |
28 | tool. | |
29 | ||
30 | WARNING: This version of Normand is 0.1, meaning both the Normand | |
31 | language and the module/CLI interface aren't stable. | |
32 | ||
bb2f9e9c PP |
33 | ifdef::env-github[] |
34 | // ToC location for a GitHub rendering | |
35 | toc::[] | |
36 | endif::env-github[] | |
37 | ||
71aaa3f7 PP |
38 | == Introduction |
39 | ||
40 | The purpose of Normand is to consume human-readable text representing | |
41 | bytes and to produce the corresponding binary data. | |
42 | ||
43 | .Simple bytes input. | |
44 | ==== | |
45 | Consider the following Normand input: | |
46 | ||
47 | ---- | |
48 | 4f 55 32 bb $167 fe %10100111 a9 $-32 | |
49 | ---- | |
50 | ||
51 | The generated nine bytes are: | |
52 | ||
53 | ---- | |
54 | 4f 55 32 bb a7 fe a7 a9 e0 | |
55 | ---- | |
56 | ==== | |
57 | ||
58 | As you can see in the last example, the fundamental unit of the Normand | |
59 | language is the _byte_. The order in which you list bytes will be the | |
60 | order of the generated data. | |
61 | ||
62 | The Normand language is more than simple lists of bytes, though. Its | |
63 | main features are: | |
64 | ||
65 | Comments, including a bunch of insignificant symbols which may improve readability:: | |
66 | + | |
67 | Input: | |
68 | + | |
69 | ---- | |
70 | ff bb %1101:0010 # This is a comment | |
71 | 78 29 af $192 # This too # 99 $-80 | |
72 | fe80::6257:18ff:fea3:4229 | |
73 | 60:57:18:a3:42:29 | |
74 | 10839636-5d65-4a68-8e6a-21608ddf7258 | |
75 | ---- | |
76 | + | |
77 | Output: | |
78 | + | |
79 | ---- | |
80 | ff bb d2 78 29 af c0 99 b0 fe 80 62 57 18 ff fe | |
81 | a3 42 29 60 57 18 a3 42 29 10 83 96 36 5d 65 4a | |
82 | 68 8e 6a 21 60 8d df 72 58 | |
83 | ---- | |
84 | ||
85 | Hexadecimal, decimal, and binary byte constants:: | |
86 | + | |
87 | Input: | |
88 | + | |
89 | ---- | |
90 | aa bb $247 $-89 %0011_0010 %11.01= 10/10 | |
91 | ---- | |
92 | + | |
93 | Output: | |
94 | + | |
95 | ---- | |
96 | aa bb f7 a7 32 da | |
97 | ---- | |
98 | ||
99 | UTF-8, UTF-16, and UTF-32 literal strings:: | |
100 | + | |
101 | Input: | |
102 | + | |
103 | ---- | |
104 | "hello world!" 00 | |
105 | u16le"stress\nverdict 🤣" | |
106 | ---- | |
107 | + | |
108 | Output: | |
109 | + | |
110 | ---- | |
111 | 68 65 6c 6c 6f 20 77 6f 72 6c 64 21 00 73 00 74 ┆ hello world!•s•t | |
112 | 00 72 00 65 00 73 00 73 00 0a 00 76 00 65 00 72 ┆ •r•e•s•s•••v•e•r | |
113 | 00 64 00 69 00 63 00 74 00 20 00 3e d8 23 dd ┆ •d•i•c•t• •>•#• | |
114 | ---- | |
115 | ||
116 | Labels: special variables holding the offset where they're defined:: | |
117 | + | |
118 | ---- | |
119 | <beg> b2 52 e3 bc 91 05 | |
120 | $100 $50 <chair> 33 9f fe | |
121 | 25 e9 89 8a <end> | |
122 | ---- | |
123 | ||
124 | Variables:: | |
125 | + | |
126 | ---- | |
127 | 5e 65 {tower = 47} c6 7f f2 c4 | |
128 | 44 {hurl = tower - 14} b5 {tower = hurl} 26 2d | |
129 | ---- | |
130 | + | |
131 | The value of a variable assignment is the evaluation of a valid {py3} | |
132 | expression which may include label and variable names. | |
133 | ||
134 | Value encoding with a specific length (8{nbsp}bits to 64{nbsp}bits) and byte order:: | |
135 | + | |
136 | Input: | |
137 | + | |
138 | ---- | |
139 | {strength = 4} | |
140 | {be} 67 <lbl> 44 $178 {(end - lbl) * 8 + strength : 16} $99 <end> | |
141 | {le} {-1993 : 32} | |
142 | ---- | |
143 | + | |
144 | Output: | |
145 | + | |
146 | ---- | |
147 | 67 44 b2 00 2c 63 37 f8 ff ff | |
148 | ---- | |
149 | + | |
150 | The encoded value is the evaluation of a valid {py3} expression which | |
151 | may include label and variable names. | |
152 | ||
153 | Repetition:: | |
154 | + | |
155 | Input: | |
156 | + | |
157 | ---- | |
158 | aa bb * 5 cc "yeah\0" * 8 | |
159 | ---- | |
160 | + | |
161 | Output: | |
162 | + | |
163 | ---- | |
164 | aa bb bb bb bb bb cc 79 65 61 68 00 79 65 61 68 ┆ •••••••yeah.yeah | |
165 | 00 79 65 61 68 00 79 65 61 68 00 79 65 61 68 00 ┆ •yeah•yeah•yeah• | |
166 | 79 65 61 68 00 79 65 61 68 00 79 65 61 68 00 ┆ yeah•yeah•yeah• | |
167 | ---- | |
168 | ||
169 | ||
170 | Multilevel grouping:: | |
171 | + | |
172 | Input: | |
173 | + | |
174 | ---- | |
175 | ff ((aa bb "zoom" cc) * 5) * 3 $-34 * 4 | |
176 | ---- | |
177 | + | |
178 | Output: | |
179 | + | |
180 | ---- | |
181 | ff aa bb 7a 6f 6f 6d cc aa bb 7a 6f 6f 6d cc aa ┆ •••zoom•••zoom•• | |
182 | bb 7a 6f 6f 6d cc aa bb 7a 6f 6f 6d cc aa bb 7a ┆ •zoom•••zoom•••z | |
183 | 6f 6f 6d cc aa bb 7a 6f 6f 6d cc aa bb 7a 6f 6f ┆ oom•••zoom•••zoo | |
184 | 6d cc aa bb 7a 6f 6f 6d cc aa bb 7a 6f 6f 6d cc ┆ m•••zoom•••zoom• | |
185 | aa bb 7a 6f 6f 6d cc aa bb 7a 6f 6f 6d cc aa bb ┆ ••zoom•••zoom••• | |
186 | 7a 6f 6f 6d cc aa bb 7a 6f 6f 6d cc aa bb 7a 6f ┆ zoom•••zoom•••zo | |
187 | 6f 6d cc aa bb 7a 6f 6f 6d cc de de de de ┆ om•••zoom••••• | |
188 | ---- | |
189 | ||
190 | Precise error reporting:: | |
191 | + | |
192 | ---- | |
193 | /tmp/meow.normand:10:24 - Expecting a bit (`0` or `1`). | |
194 | ---- | |
195 | + | |
196 | ---- | |
197 | /tmp/meow.normand:32:6 - Unexpected character `k`. | |
198 | ---- | |
199 | + | |
200 | ---- | |
201 | /tmp/meow.normand:24:19 - Unknown variable/label name `meow` in expression `(meow - 45) // 8`. | |
202 | ---- | |
203 | + | |
204 | ---- | |
205 | /tmp/meow.normand:18:9 - Value 315 is outside the 8-bit range when evaluating expression `end - ICITTE` at byte offset 45. | |
206 | ---- | |
207 | ||
208 | You can use Normand to track data source files in your favorite VCS | |
209 | instead of raw binary files. The binary files that Normand generates can | |
210 | be used to test file format decoding, including malformatted data, for | |
211 | example, as well as for education. | |
212 | ||
213 | See <<learn-normand>> to explore all the Normand features. | |
214 | ||
215 | == Install Normand | |
216 | ||
217 | Normand requires Python ≥ 3.4. | |
218 | ||
219 | To install Normand: | |
220 | ||
221 | ---- | |
222 | $ python3 -m pip install --user normand | |
223 | ---- | |
224 | ||
225 | See | |
226 | https://packaging.python.org/en/latest/tutorials/installing-packages/#installing-to-the-user-site[Installing to the User Site] | |
227 | to learn more about a user site installation. | |
228 | ||
229 | [NOTE] | |
230 | ==== | |
231 | Normand has a single module file, `normand.py`, which you can copy as is | |
232 | to your project to use it (both the <<python-3-api,`normand.parse()`>> | |
233 | function and the <<command-line-tool,command-line tool>>). | |
234 | ||
235 | `normand.py` has _no external dependencies_, but if you're using | |
236 | Python{nbsp}3.4, you'll need a local copy of the standard `typing` | |
237 | module. | |
238 | ==== | |
239 | ||
240 | == Learn Normand | |
241 | ||
242 | A Normand text input is a sequence of items which represent a sequence | |
243 | of raw bytes. | |
244 | ||
245 | [[state]] During the processing of items to data, Normand relies on a | |
246 | current state: | |
247 | ||
248 | [%header%autowidth] | |
249 | |=== | |
250 | |State variable |Description |Initial value: <<python-3-api,{py3} API>> |Initial value: <<command-line-tool,CLI>> | |
251 | ||
252 | |[[cur-offset]] Current offset | |
253 | | | |
254 | The current offset has an effect on the value of | |
255 | <<label,labels>> and of the special `ICITTE` name in <<value,value>> and | |
256 | <<variable-assignment,variable assignment>> expression evaluation. | |
257 | ||
258 | Each generated byte increments the current offset. | |
259 | ||
260 | A <<current-offset-setting,current offset setting>> may change the | |
261 | current offset. | |
262 | |`init_offset` parameter of the `parse()` function. | |
263 | |`--offset` option. | |
264 | ||
265 | |[[cur-bo]] Current byte order | |
266 | | | |
267 | The current byte order has an effect on the encoding of <<value,values>>. | |
268 | ||
269 | A <<current-byte-order-setting,current byte order setting>> may change | |
270 | the current byte order. | |
271 | |`init_byte_order` parameter of the `parse()` function. | |
272 | |`--byte-order` option. | |
273 | ||
274 | |<<label,Labels>> | |
275 | |Mapping of label names to integral values. | |
276 | |`init_labels` parameter of the `parse()` function. | |
277 | |One or more `--label` options. | |
278 | ||
279 | |<<variable-assignment,Variables>> | |
280 | |Mapping of variable names to integral values. | |
281 | |`init_variables` parameter of the `parse()` function. | |
282 | |One or more `--var` options. | |
283 | |=== | |
284 | ||
285 | The available items are: | |
286 | ||
287 | * A <<byte-constant,constant integer>> representing a single byte. | |
288 | ||
289 | * A <<literal-string,literal string>> representing a sequence of bytes | |
290 | encoding UTF-8, UTF-16, or UTF-32 data. | |
291 | ||
292 | * A <<current-byte-order-setting,current byte order setting>> (big or | |
293 | little endian). | |
294 | ||
295 | * A <<value,{py3} expression to be evaluated>> as an unsigned or signed | |
296 | integer to be encoded on one or more bytes using the current byte | |
297 | order. | |
298 | ||
299 | * A <<current-offset-setting,current offset setting>>. | |
300 | ||
301 | * A <<label,label>>, that is, a named constant holding the current | |
302 | offset. | |
303 | + | |
304 | This is similar to an assembly label. | |
305 | ||
306 | * A <<variable-assignment,variable assignment>> associating a name to | |
307 | the integral result of an evaluated {py3} expression. | |
308 | ||
309 | * A <<group,group>>, that is, a scoped sequence of items. | |
310 | ||
311 | Moreover, you can <<repetition,repeat>> any item above, except an offset | |
312 | or a label, a given number of times. This is called a repetition. | |
313 | ||
314 | A Normand comment may exist: | |
315 | ||
316 | * Between items, possibly within a group. | |
317 | * Between the nibbles of a constant hexadecimal byte. | |
318 | * Between the bits of a constant binary byte. | |
319 | * Between the last item and the ``pass:[*]`` character of a repetition, | |
320 | and between that ``pass:[*]`` character and the following number. | |
321 | ||
322 | A comment is anything between two ``pass:[#]`` characters on the same | |
323 | line, or from ``pass:[#]`` until the end of the line. Whitespaces and | |
324 | the following symbol characters are also considered comments where a | |
325 | comment may exist: | |
326 | ||
327 | ---- | |
328 | ! @ / \ ? & : ; . , + [ ] _ = | - | |
329 | ---- | |
330 | ||
331 | The latter serve to improve readability so that you may write, for | |
332 | example, a MAC address or a UUID as is. | |
333 | ||
334 | You can test the examples of this section with the `normand` | |
335 | <<command-line-tool,command-line tool>> as such: | |
336 | ||
337 | ---- | |
338 | $ normand file | hexdump -C | |
339 | ---- | |
340 | ||
341 | where `file` is the name of a file containing the Normand input. | |
342 | ||
343 | === Byte constant | |
344 | ||
345 | A _byte constant_ represents a single byte. | |
346 | ||
347 | A byte constant is: | |
348 | ||
349 | Hexadecimal form:: | |
350 | Two consecutive hexits. | |
351 | ||
352 | Decimal form:: | |
353 | A decimal number after the `$` prefix. | |
354 | ||
355 | Binary form:: | |
356 | Eight bits after the `%` prefix. | |
357 | ||
358 | ==== | |
359 | Input: | |
360 | ||
361 | ---- | |
362 | ab cd [3d 8F] CC | |
363 | ---- | |
364 | ||
365 | Output: | |
366 | ||
367 | ---- | |
368 | ab cd 3d 8f cc | |
369 | ---- | |
370 | ==== | |
371 | ||
372 | ==== | |
373 | Input: | |
374 | ||
375 | ---- | |
376 | $192 %1100/0011 $ -77 | |
377 | ---- | |
378 | ||
379 | Output: | |
380 | ||
381 | ---- | |
382 | c0 c3 b3 | |
383 | ---- | |
384 | ==== | |
385 | ||
386 | ==== | |
387 | Input: | |
388 | ||
389 | ---- | |
390 | 58f64689-6316-4d55-8a1a-04cada366172 | |
391 | fe80::6257:18ff:fea3:4229 | |
392 | ---- | |
393 | ||
394 | Output: | |
395 | ||
396 | ---- | |
397 | 58 f6 46 89 63 16 4d 55 8a 1a 04 ca da 36 61 72 ┆ X•F•c•MU•••••6ar | |
398 | fe 80 62 57 18 ff fe a3 42 29 ┆ ••bW••••B) | |
399 | ---- | |
400 | ==== | |
401 | ||
402 | ==== | |
403 | Input: | |
404 | ||
405 | ---- | |
406 | %01110011 %01100001 %01101100 %01110101 %01110100 | |
407 | ---- | |
408 | ||
409 | Output: | |
410 | ||
411 | ---- | |
412 | 73 61 6c 75 74 ┆ salut | |
413 | ---- | |
414 | ==== | |
415 | ||
416 | === Literal string | |
417 | ||
418 | A _literal string_ represents the UTF-8-, UTF-16-, or UTF-32-encoded | |
419 | bytes of a string. | |
420 | ||
421 | The string to encode isn't implicitly null-terminated: use `\0` at the | |
422 | end of the string to add a null character. | |
423 | ||
424 | A literal string is: | |
425 | ||
426 | . **Optional**: one of the following encodings instead of UTF-8: | |
427 | + | |
428 | -- | |
429 | [horizontal] | |
430 | `u16be`:: UTF-16BE. | |
431 | `u16le`:: UTF-16LE. | |
432 | `u32be`:: UTF-32BE. | |
433 | `u32le`:: UTF-32LE. | |
434 | -- | |
435 | ||
436 | . The ``pass:["]`` prefix. | |
437 | ||
438 | . A sequence of zero or more characters, possibly containing escape | |
439 | sequences. | |
440 | + | |
441 | An escape sequence is the ``\`` character followed by one of: | |
442 | + | |
443 | -- | |
444 | [horizontal] | |
445 | `0`:: Null (U+0000) | |
446 | `a`:: Alert (U+0007) | |
447 | `b`:: Backspace (U+0008) | |
448 | `e`:: Escape (U+001B) | |
449 | `f`:: Form feed (U+000C) | |
450 | `n`:: End of line (U+000A) | |
451 | `r`:: Carriage return (U+000D) | |
452 | `t`:: Character tabulation (U+0009) | |
453 | `v`:: Line tabulation (U+000B) | |
454 | ``\``:: Reverse solidus (U+005C) | |
455 | ``pass:["]``:: Quotation mark (U+0022) | |
456 | -- | |
457 | ||
458 | . The ``pass:["]`` suffix. | |
459 | ||
460 | ==== | |
461 | Input: | |
462 | ||
463 | ---- | |
464 | "coucou tout le monde!" | |
465 | ---- | |
466 | ||
467 | Output: | |
468 | ||
469 | ---- | |
470 | 63 6f 75 63 6f 75 20 74 6f 75 74 20 6c 65 20 6d ┆ coucou tout le m | |
471 | 6f 6e 64 65 21 ┆ onde! | |
472 | ---- | |
473 | ==== | |
474 | ||
475 | ==== | |
476 | Input: | |
477 | ||
478 | ---- | |
479 | u16le"I am not young enough to know everything." | |
480 | ---- | |
481 | ||
482 | Output: | |
483 | ||
484 | ---- | |
485 | 49 00 20 00 61 00 6d 00 20 00 6e 00 6f 00 74 00 ┆ I• •a•m• •n•o•t• | |
486 | 20 00 79 00 6f 00 75 00 6e 00 67 00 20 00 65 00 ┆ •y•o•u•n•g• •e• | |
487 | 6e 00 6f 00 75 00 67 00 68 00 20 00 74 00 6f 00 ┆ n•o•u•g•h• •t•o• | |
488 | 20 00 6b 00 6e 00 6f 00 77 00 20 00 65 00 76 00 ┆ •k•n•o•w• •e•v• | |
489 | 65 00 72 00 79 00 74 00 68 00 69 00 6e 00 67 00 ┆ e•r•y•t•h•i•n•g• | |
490 | 2e 00 ┆ .• | |
491 | ---- | |
492 | ==== | |
493 | ||
494 | ==== | |
495 | Input: | |
496 | ||
497 | ---- | |
498 | u32be "\"illusion is the first\nof all pleasures\" 🦉" | |
499 | ---- | |
500 | ||
501 | Output: | |
502 | ||
503 | ---- | |
504 | 00 00 00 22 00 00 00 69 00 00 00 6c 00 00 00 6c ┆ •••"•••i•••l•••l | |
505 | 00 00 00 75 00 00 00 73 00 00 00 69 00 00 00 6f ┆ •••u•••s•••i•••o | |
506 | 00 00 00 6e 00 00 00 20 00 00 00 69 00 00 00 73 ┆ •••n••• •••i•••s | |
507 | 00 00 00 20 00 00 00 74 00 00 00 68 00 00 00 65 ┆ ••• •••t•••h•••e | |
508 | 00 00 00 20 00 00 00 66 00 00 00 69 00 00 00 72 ┆ ••• •••f•••i•••r | |
509 | 00 00 00 73 00 00 00 74 00 00 00 0a 00 00 00 6f ┆ •••s•••t•••••••o | |
510 | 00 00 00 66 00 00 00 20 00 00 00 61 00 00 00 6c ┆ •••f••• •••a•••l | |
511 | 00 00 00 6c 00 00 00 20 00 00 00 70 00 00 00 6c ┆ •••l••• •••p•••l | |
512 | 00 00 00 65 00 00 00 61 00 00 00 73 00 00 00 75 ┆ •••e•••a•••s•••u | |
513 | 00 00 00 72 00 00 00 65 00 00 00 73 00 00 00 22 ┆ •••r•••e•••s•••" | |
514 | 00 00 00 20 00 01 f9 89 ┆ ••• •••• | |
515 | ---- | |
516 | ==== | |
517 | ||
518 | === Current byte order setting | |
519 | ||
520 | This special item sets the <<cur-bo,_current byte order_>>. | |
521 | ||
522 | The two accepted forms are: | |
523 | ||
524 | [horizontal] | |
525 | ``pass:[{be}]``:: Set the current byte order to big endian. | |
526 | ``pass:[{le}]``:: Set the current byte order to little endian. | |
527 | ||
528 | === Value | |
529 | ||
530 | A _value_ represents a fixed number of bytes encoding an unsigned or | |
531 | signed integer which is the result of evaluating a {py3} expression | |
532 | using the <<cur-bo,current byte order>>. | |
533 | ||
534 | For a value at some source location{nbsp}__**L**__, its {py3} expression | |
535 | may contain the name of any accessible <<label,label>>, including the | |
536 | name of a label defined after{nbsp}__**L**__, as well as the name of any | |
537 | <<variable-assignment,variable>> known at{nbsp}__**L**__. | |
538 | ||
539 | An accessible label is either: | |
540 | ||
541 | * Outside of the current <<group,group>>. | |
542 | * Within the same immediate group (not within a nested group). | |
543 | ||
544 | In the {py3} expression of a value, the value of the special name | |
545 | `ICITTE` is the <<cur-offset,current offset>> (before encoding the | |
546 | value). | |
547 | ||
548 | A value is: | |
549 | ||
550 | . The ``pass:[{]`` prefix. | |
551 | ||
552 | . A valid {py3} expression. | |
553 | ||
554 | . The `:` character. | |
555 | ||
556 | . An encoding length in bits amongst `8`, `16`, `24`, `32`, `40`, | |
557 | `48`, `56`, and `64`. | |
558 | ||
559 | . The `}` suffix. | |
560 | ||
561 | ==== | |
562 | Input: | |
563 | ||
564 | ---- | |
565 | {le} {345:16} | |
566 | {be} {-0xabcd:32} | |
567 | ---- | |
568 | ||
569 | Output: | |
570 | ||
571 | ---- | |
572 | 59 01 ff ff 54 33 | |
573 | ---- | |
574 | ==== | |
575 | ||
576 | ==== | |
577 | Input: | |
578 | ||
579 | ---- | |
580 | {be} | |
581 | ||
582 | # String length in bits | |
583 | {8 * (str_end - str_beg) : 16} | |
584 | ||
585 | # String | |
586 | <str_beg> | |
587 | "hello world!" | |
588 | <str_end> | |
589 | ---- | |
590 | ||
591 | Output: | |
592 | ||
593 | ---- | |
594 | 00 60 68 65 6c 6c 6f 20 77 6f 72 6c 64 21 ┆ •`hello world! | |
595 | ---- | |
596 | ==== | |
597 | ||
598 | ==== | |
599 | Input: | |
600 | ||
601 | ---- | |
602 | {20 - ICITTE : 8} * 10 | |
603 | ---- | |
604 | ||
605 | Output: | |
606 | ||
607 | ---- | |
608 | 14 13 12 11 10 0f 0e 0d 0c 0b | |
609 | ---- | |
610 | ==== | |
611 | ||
612 | === Current offset setting | |
613 | ||
614 | This special item sets the <<cur-offset,_current offset_>>. | |
615 | ||
616 | A current offset setting is: | |
617 | ||
618 | . The `<` prefix. | |
619 | ||
620 | . A positive integer (hexadecimal starting with `0x` or `0X` accepted) | |
621 | which is the new current offset. | |
622 | ||
623 | . The `>` suffix. | |
624 | ||
625 | ==== | |
626 | Input: | |
627 | ||
628 | ---- | |
629 | {ICITTE : 8} * 8 | |
630 | <0x61> {ICITTE : 8} * 8 | |
631 | ---- | |
632 | ||
633 | Output: | |
634 | ||
635 | ---- | |
636 | 00 01 02 03 04 05 06 07 61 62 63 64 65 66 67 68 ┆ ••••••••abcdefgh | |
637 | ---- | |
638 | ==== | |
639 | ||
640 | ==== | |
641 | Input: | |
642 | ||
643 | ---- | |
644 | aa bb cc dd <meow> ee ff | |
645 | <12> 11 22 33 <mix> 44 55 | |
646 | {meow : 8} {mix : 8} | |
647 | ---- | |
648 | ||
649 | Output: | |
650 | ||
651 | ---- | |
652 | aa bb cc dd ee ff 11 22 33 44 55 04 0f ┆ •••••••"3DU•• | |
653 | ---- | |
654 | ==== | |
655 | ||
656 | === Label | |
657 | ||
658 | A _label_ associates a name to the <<cur-offset,current offset>>. | |
659 | ||
660 | All the labels of a whole Normand input must have unique names. | |
661 | ||
662 | A label may not share the name of a <<variable-assignment,variable>> | |
663 | name. | |
664 | ||
665 | A label name may not be `ICITTE` (see <<value>> and | |
666 | <<variable-assignment>> to learn more). | |
667 | ||
668 | A label is: | |
669 | ||
670 | . The `<` prefix. | |
671 | ||
672 | . A valid {py3} name which is not `ICITTE`. | |
673 | ||
674 | . The `>` suffix. | |
675 | ||
676 | === Variable assignment | |
677 | ||
678 | A _variable assignment_ associates a name to the integral result of an | |
679 | evaluated {py3} expression. | |
680 | ||
681 | For a variable assignment at some source location{nbsp}__**L**__, its | |
682 | {py3} expression may contain the name of any accessible <<label,label>>, | |
683 | including the name of a label defined after{nbsp}__**L**__, as well as | |
684 | the name of any variable known at{nbsp}__**L**__. | |
685 | ||
686 | An accessible label is either: | |
687 | ||
688 | * Outside of the current <<group,group>>. | |
689 | * Within the same immediate group (not within a nested group). | |
690 | ||
1f182c43 | 691 | A variable name may not be `ICITTE`. |
71aaa3f7 PP |
692 | |
693 | In the {py3} expression of a variable assignment, the special name | |
694 | `ICITTE` is the <<cur-offset,current offset>>. | |
695 | ||
696 | A variable is: | |
697 | ||
698 | . The ``pass:[{]`` prefix. | |
699 | ||
700 | . A valid {py3} name which is not `ICITTE`. | |
701 | ||
702 | . The `=` character. | |
703 | ||
704 | . A valid {py3} expression. | |
705 | ||
706 | . The `}` suffix. | |
707 | ||
708 | ==== | |
709 | Input: | |
710 | ||
711 | ---- | |
712 | {mix = 101} {le} | |
713 | {meow = 42} 11 22 {meow:8} 33 {meow = ICITTE + 17} | |
714 | "yooo" {meow + mix : 16} | |
715 | ---- | |
716 | ||
717 | Output: | |
718 | ||
719 | ---- | |
720 | 11 22 2a 33 79 6f 6f 6f 7a 00 ┆ •"*3yoooz• | |
721 | ---- | |
722 | ==== | |
723 | ||
724 | === Group | |
725 | ||
726 | A _group_ is a scoped sequence of items. | |
727 | ||
728 | The <<label,labels>> within a group aren't visible outside of it. | |
729 | ||
730 | The main purpose of a group is to <<repetition,repeat>> more than a | |
731 | single item. | |
732 | ||
733 | A group is: | |
734 | ||
735 | . The `(` prefix. | |
736 | ||
737 | . Zero or more items. | |
738 | ||
739 | . The `)` suffix. | |
740 | ||
741 | ==== | |
742 | Input: | |
743 | ||
744 | ---- | |
745 | ((aa bb cc) dd () ee) "leclerc" | |
746 | ---- | |
747 | ||
748 | Output: | |
749 | ||
750 | ---- | |
751 | aa bb cc dd ee 6c 65 63 6c 65 72 63 ┆ •••••leclerc | |
752 | ---- | |
753 | ==== | |
754 | ||
755 | ==== | |
756 | Input: | |
757 | ||
758 | ---- | |
759 | ((aa bb cc) * 3 dd ee) * 5 | |
760 | ---- | |
761 | ||
762 | Output: | |
763 | ||
764 | ---- | |
765 | aa bb cc aa bb cc aa bb cc dd ee aa bb cc aa bb | |
766 | cc aa bb cc dd ee aa bb cc aa bb cc aa bb cc dd | |
767 | ee aa bb cc aa bb cc aa bb cc dd ee aa bb cc aa | |
768 | bb cc aa bb cc dd ee | |
769 | ---- | |
770 | ==== | |
771 | ||
772 | ==== | |
773 | Input: | |
774 | ||
775 | ---- | |
776 | {be} | |
777 | ( | |
778 | <str_beg> u16le"sébastien diaz" <str_end> | |
779 | {ICITTE - str_beg : 8} | |
780 | {(end - str_beg) * 5 : 24} | |
781 | ) * 3 | |
782 | <end> | |
783 | ---- | |
784 | ||
785 | Output: | |
786 | ||
787 | ---- | |
788 | 73 00 e9 00 62 00 61 00 73 00 74 00 69 00 65 00 ┆ s•••b•a•s•t•i•e• | |
789 | 6e 00 20 00 64 00 69 00 61 00 7a 00 1c 00 01 e0 ┆ n• •d•i•a•z••••• | |
790 | 73 00 e9 00 62 00 61 00 73 00 74 00 69 00 65 00 ┆ s•••b•a•s•t•i•e• | |
791 | 6e 00 20 00 64 00 69 00 61 00 7a 00 1c 00 01 40 ┆ n• •d•i•a•z••••@ | |
792 | 73 00 e9 00 62 00 61 00 73 00 74 00 69 00 65 00 ┆ s•••b•a•s•t•i•e• | |
793 | 6e 00 20 00 64 00 69 00 61 00 7a 00 1c 00 00 a0 ┆ n• •d•i•a•z••••• | |
794 | ---- | |
795 | ==== | |
796 | ||
797 | === Repetition | |
798 | ||
799 | A _repetition_ represents the bytes of an item repeated a given number | |
800 | of times. | |
801 | ||
802 | A repetition is: | |
803 | ||
804 | . Any item. | |
805 | ||
806 | . The ``pass:[*]`` character. | |
807 | ||
808 | . A positive integer (hexadecimal starting with `0x` or `0X` accepted) | |
809 | which is the number of times to repeat the previous item. | |
810 | ||
811 | ==== | |
812 | Input: | |
813 | ||
814 | ---- | |
815 | {end - ICITTE - 1 : 8} * 0x100 <end> | |
816 | ---- | |
817 | ||
818 | Output: | |
819 | ||
820 | ---- | |
821 | ff fe fd fc fb fa f9 f8 f7 f6 f5 f4 f3 f2 f1 f0 ┆ •••••••••••••••• | |
822 | ef ee ed ec eb ea e9 e8 e7 e6 e5 e4 e3 e2 e1 e0 ┆ •••••••••••••••• | |
823 | df de dd dc db da d9 d8 d7 d6 d5 d4 d3 d2 d1 d0 ┆ •••••••••••••••• | |
824 | cf ce cd cc cb ca c9 c8 c7 c6 c5 c4 c3 c2 c1 c0 ┆ •••••••••••••••• | |
825 | bf be bd bc bb ba b9 b8 b7 b6 b5 b4 b3 b2 b1 b0 ┆ •••••••••••••••• | |
826 | af ae ad ac ab aa a9 a8 a7 a6 a5 a4 a3 a2 a1 a0 ┆ •••••••••••••••• | |
827 | 9f 9e 9d 9c 9b 9a 99 98 97 96 95 94 93 92 91 90 ┆ •••••••••••••••• | |
828 | 8f 8e 8d 8c 8b 8a 89 88 87 86 85 84 83 82 81 80 ┆ •••••••••••••••• | |
829 | 7f 7e 7d 7c 7b 7a 79 78 77 76 75 74 73 72 71 70 ┆ •~}|{zyxwvutsrqp | |
830 | 6f 6e 6d 6c 6b 6a 69 68 67 66 65 64 63 62 61 60 ┆ onmlkjihgfedcba` | |
831 | 5f 5e 5d 5c 5b 5a 59 58 57 56 55 54 53 52 51 50 ┆ _^]\[ZYXWVUTSRQP | |
832 | 4f 4e 4d 4c 4b 4a 49 48 47 46 45 44 43 42 41 40 ┆ ONMLKJIHGFEDCBA@ | |
833 | 3f 3e 3d 3c 3b 3a 39 38 37 36 35 34 33 32 31 30 ┆ ?>=<;:9876543210 | |
834 | 2f 2e 2d 2c 2b 2a 29 28 27 26 25 24 23 22 21 20 ┆ /.-,+*)('&%$#"! | |
835 | 1f 1e 1d 1c 1b 1a 19 18 17 16 15 14 13 12 11 10 ┆ •••••••••••••••• | |
836 | 0f 0e 0d 0c 0b 0a 09 08 07 06 05 04 03 02 01 00 ┆ •••••••••••••••• | |
837 | ---- | |
838 | ==== | |
839 | ||
840 | == Command-line tool | |
841 | ||
842 | If you <<install-normand,installed>> the `normand` package, then you | |
843 | can use the `normand` command-line tool: | |
844 | ||
845 | ---- | |
846 | $ normand <<< '"ma gang de malades"' | hexdump -C | |
847 | ---- | |
848 | ||
849 | ---- | |
850 | 00000000 6d 61 20 67 61 6e 67 20 64 65 20 6d 61 6c 61 64 |ma gang de malad| | |
851 | 00000010 65 73 |es| | |
852 | ---- | |
853 | ||
854 | If you copy the `normand.py` module to your own project, then you can | |
855 | run the module itself: | |
856 | ||
857 | ---- | |
858 | $ python3 -m normand <<< '"ma gang de malades"' | hexdump -C | |
859 | ---- | |
860 | ||
861 | ---- | |
862 | 00000000 6d 61 20 67 61 6e 67 20 64 65 20 6d 61 6c 61 64 |ma gang de malad| | |
863 | 00000010 65 73 |es| | |
864 | ---- | |
865 | ||
866 | Without a path argument, the `normand` tool reads from the standard | |
867 | input. | |
868 | ||
869 | The `normand` tool prints the generated binary data to the standard | |
870 | output. | |
871 | ||
872 | Various options control the initial <<state,state>> of the processor: | |
873 | use the `--help` option to learn more. | |
874 | ||
875 | == {py3} API | |
876 | ||
877 | The whole `normand` package/module API is: | |
878 | ||
879 | [source,python] | |
880 | ---- | |
881 | class ByteOrder(enum.Enum): | |
882 | # Big endian. | |
883 | BE = ... | |
884 | ||
885 | # Little endian. | |
886 | LE = ... | |
887 | ||
888 | ||
889 | VarsT = typing.Dict[str, int] | |
890 | ||
891 | ||
892 | class TextLoc: | |
893 | # Line number. | |
894 | @property | |
895 | def line_no(self) -> int: | |
896 | ... | |
897 | ||
898 | # Column number. | |
899 | @property | |
900 | def col_no(self) -> int: | |
901 | ... | |
902 | ||
903 | ||
904 | class ParseError(RuntimeError): | |
905 | # Source text location. | |
906 | @property | |
907 | def text_loc(self) -> TextLoc: | |
908 | ... | |
909 | ||
910 | ||
911 | class ParseResult: | |
912 | # Generated data. | |
913 | @property | |
914 | def data(self) -> bytearray: | |
915 | ... | |
916 | ||
917 | # Updated variable values. | |
918 | @property | |
919 | def variables(self) -> VarsT: | |
920 | ... | |
921 | ||
922 | # Updated main group label values. | |
923 | @property | |
924 | def labels(self) -> VarsT: | |
925 | ... | |
926 | ||
927 | # Final offset. | |
928 | @property | |
929 | def offset(self) -> int: | |
930 | ... | |
931 | ||
932 | # Final byte order. | |
933 | @property | |
934 | def byte_order(self) -> typing.Optional[int]: | |
935 | ... | |
936 | ||
937 | def parse(normand: str, | |
938 | init_variables: typing.Optional[VarsT] = None, | |
939 | init_labels: typing.Optional[VarsT] = None, | |
940 | init_offset: int = 0, | |
941 | init_byte_order: typing.Optional[ByteOrder] = None) -> ParseResult: | |
942 | ... | |
943 | ---- | |
944 | ||
945 | The `normand` parameter is the actual <<learn-normand,Normand input>> | |
946 | while the other parameters control the initial <<state,state>>. | |
947 | ||
948 | The `parse()` function raises a `ParseError` instance should it fail to | |
949 | parse the `normand` string for any reason. |