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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 | ||
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 | ||
32 | WARNING: This version of Normand is 0.1, meaning both the Normand | |
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 | ||
136 | Value encoding with a specific length (8{nbsp}bits to 64{nbsp}bits) and byte order:: | |
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 | + | |
152 | The encoded value is the evaluation of a valid {py3} expression which | |
153 | may include label and variable names. | |
154 | ||
155 | Repetition:: | |
156 | + | |
157 | Input: | |
158 | + | |
159 | ---- | |
2adf4336 | 160 | aa bb * 5 cc <zoom> "yeah\0" * {zoom * 3} |
71aaa3f7 PP |
161 | ---- |
162 | + | |
163 | Output: | |
164 | + | |
165 | ---- | |
2adf4336 PP |
166 | aa bb bb bb bb bb cc 79 65 61 68 00 79 65 61 68 ┆ •••••••yeah•yeah |
167 | 00 79 65 61 68 00 79 65 61 68 00 79 65 61 68 00 ┆ •yeah•yeah•yeah• | |
168 | 79 65 61 68 00 79 65 61 68 00 79 65 61 68 00 79 ┆ yeah•yeah•yeah•y | |
169 | 65 61 68 00 79 65 61 68 00 79 65 61 68 00 79 65 ┆ eah•yeah•yeah•ye | |
170 | 61 68 00 79 65 61 68 00 79 65 61 68 00 79 65 61 ┆ ah•yeah•yeah•yea | |
171 | 68 00 79 65 61 68 00 79 65 61 68 00 79 65 61 68 ┆ h•yeah•yeah•yeah | |
71aaa3f7 | 172 | 00 79 65 61 68 00 79 65 61 68 00 79 65 61 68 00 ┆ •yeah•yeah•yeah• |
71aaa3f7 PP |
173 | ---- |
174 | ||
175 | ||
176 | Multilevel grouping:: | |
177 | + | |
178 | Input: | |
179 | + | |
180 | ---- | |
181 | ff ((aa bb "zoom" cc) * 5) * 3 $-34 * 4 | |
182 | ---- | |
183 | + | |
184 | Output: | |
185 | + | |
186 | ---- | |
187 | ff aa bb 7a 6f 6f 6d cc aa bb 7a 6f 6f 6d cc aa ┆ •••zoom•••zoom•• | |
188 | bb 7a 6f 6f 6d cc aa bb 7a 6f 6f 6d cc aa bb 7a ┆ •zoom•••zoom•••z | |
189 | 6f 6f 6d cc aa bb 7a 6f 6f 6d cc aa bb 7a 6f 6f ┆ oom•••zoom•••zoo | |
190 | 6d cc aa bb 7a 6f 6f 6d cc aa bb 7a 6f 6f 6d cc ┆ m•••zoom•••zoom• | |
191 | aa bb 7a 6f 6f 6d cc aa bb 7a 6f 6f 6d cc aa bb ┆ ••zoom•••zoom••• | |
192 | 7a 6f 6f 6d cc aa bb 7a 6f 6f 6d cc aa bb 7a 6f ┆ zoom•••zoom•••zo | |
193 | 6f 6d cc aa bb 7a 6f 6f 6d cc de de de de ┆ om•••zoom••••• | |
194 | ---- | |
195 | ||
196 | Precise error reporting:: | |
197 | + | |
198 | ---- | |
199 | /tmp/meow.normand:10:24 - Expecting a bit (`0` or `1`). | |
200 | ---- | |
201 | + | |
202 | ---- | |
203 | /tmp/meow.normand:32:6 - Unexpected character `k`. | |
204 | ---- | |
205 | + | |
206 | ---- | |
2adf4336 | 207 | /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 |
208 | ---- |
209 | + | |
210 | ---- | |
211 | /tmp/meow.normand:18:9 - Value 315 is outside the 8-bit range when evaluating expression `end - ICITTE` at byte offset 45. | |
212 | ---- | |
213 | ||
214 | You can use Normand to track data source files in your favorite VCS | |
215 | instead of raw binary files. The binary files that Normand generates can | |
216 | be used to test file format decoding, including malformatted data, for | |
217 | example, as well as for education. | |
218 | ||
219 | See <<learn-normand>> to explore all the Normand features. | |
220 | ||
221 | == Install Normand | |
222 | ||
223 | Normand requires Python ≥ 3.4. | |
224 | ||
225 | To install Normand: | |
226 | ||
227 | ---- | |
228 | $ python3 -m pip install --user normand | |
229 | ---- | |
230 | ||
231 | See | |
232 | https://packaging.python.org/en/latest/tutorials/installing-packages/#installing-to-the-user-site[Installing to the User Site] | |
233 | to learn more about a user site installation. | |
234 | ||
235 | [NOTE] | |
236 | ==== | |
237 | Normand has a single module file, `normand.py`, which you can copy as is | |
238 | to your project to use it (both the <<python-3-api,`normand.parse()`>> | |
239 | function and the <<command-line-tool,command-line tool>>). | |
240 | ||
241 | `normand.py` has _no external dependencies_, but if you're using | |
242 | Python{nbsp}3.4, you'll need a local copy of the standard `typing` | |
243 | module. | |
244 | ==== | |
245 | ||
246 | == Learn Normand | |
247 | ||
248 | A Normand text input is a sequence of items which represent a sequence | |
249 | of raw bytes. | |
250 | ||
251 | [[state]] During the processing of items to data, Normand relies on a | |
252 | current state: | |
253 | ||
254 | [%header%autowidth] | |
255 | |=== | |
256 | |State variable |Description |Initial value: <<python-3-api,{py3} API>> |Initial value: <<command-line-tool,CLI>> | |
257 | ||
258 | |[[cur-offset]] Current offset | |
259 | | | |
260 | The current offset has an effect on the value of | |
261 | <<label,labels>> and of the special `ICITTE` name in <<value,value>> and | |
262 | <<variable-assignment,variable assignment>> expression evaluation. | |
263 | ||
264 | Each generated byte increments the current offset. | |
265 | ||
266 | A <<current-offset-setting,current offset setting>> may change the | |
267 | current offset. | |
268 | |`init_offset` parameter of the `parse()` function. | |
269 | |`--offset` option. | |
270 | ||
271 | |[[cur-bo]] Current byte order | |
272 | | | |
273 | The current byte order has an effect on the encoding of <<value,values>>. | |
274 | ||
275 | A <<current-byte-order-setting,current byte order setting>> may change | |
276 | the current byte order. | |
277 | |`init_byte_order` parameter of the `parse()` function. | |
278 | |`--byte-order` option. | |
279 | ||
280 | |<<label,Labels>> | |
281 | |Mapping of label names to integral values. | |
282 | |`init_labels` parameter of the `parse()` function. | |
283 | |One or more `--label` options. | |
284 | ||
285 | |<<variable-assignment,Variables>> | |
286 | |Mapping of variable names to integral values. | |
287 | |`init_variables` parameter of the `parse()` function. | |
288 | |One or more `--var` options. | |
289 | |=== | |
290 | ||
291 | The available items are: | |
292 | ||
293 | * A <<byte-constant,constant integer>> representing a single byte. | |
294 | ||
295 | * A <<literal-string,literal string>> representing a sequence of bytes | |
296 | encoding UTF-8, UTF-16, or UTF-32 data. | |
297 | ||
298 | * A <<current-byte-order-setting,current byte order setting>> (big or | |
299 | little endian). | |
300 | ||
301 | * A <<value,{py3} expression to be evaluated>> as an unsigned or signed | |
302 | integer to be encoded on one or more bytes using the current byte | |
303 | order. | |
304 | ||
305 | * A <<current-offset-setting,current offset setting>>. | |
306 | ||
307 | * A <<label,label>>, that is, a named constant holding the current | |
308 | offset. | |
309 | + | |
310 | This is similar to an assembly label. | |
311 | ||
312 | * A <<variable-assignment,variable assignment>> associating a name to | |
313 | the integral result of an evaluated {py3} expression. | |
314 | ||
315 | * A <<group,group>>, that is, a scoped sequence of items. | |
316 | ||
317 | Moreover, you can <<repetition,repeat>> any item above, except an offset | |
2adf4336 PP |
318 | or a label, a given fixed or variable number of times. This is called a |
319 | repetition. | |
71aaa3f7 PP |
320 | |
321 | A Normand comment may exist: | |
322 | ||
323 | * Between items, possibly within a group. | |
324 | * Between the nibbles of a constant hexadecimal byte. | |
325 | * Between the bits of a constant binary byte. | |
326 | * Between the last item and the ``pass:[*]`` character of a repetition, | |
2adf4336 PP |
327 | and between that ``pass:[*]`` character and the following number |
328 | or expression. | |
71aaa3f7 PP |
329 | |
330 | A comment is anything between two ``pass:[#]`` characters on the same | |
331 | line, or from ``pass:[#]`` until the end of the line. Whitespaces and | |
332 | the following symbol characters are also considered comments where a | |
333 | comment may exist: | |
334 | ||
335 | ---- | |
336 | ! @ / \ ? & : ; . , + [ ] _ = | - | |
337 | ---- | |
338 | ||
339 | The latter serve to improve readability so that you may write, for | |
340 | example, a MAC address or a UUID as is. | |
341 | ||
342 | You can test the examples of this section with the `normand` | |
343 | <<command-line-tool,command-line tool>> as such: | |
344 | ||
345 | ---- | |
346 | $ normand file | hexdump -C | |
347 | ---- | |
348 | ||
349 | where `file` is the name of a file containing the Normand input. | |
350 | ||
351 | === Byte constant | |
352 | ||
353 | A _byte constant_ represents a single byte. | |
354 | ||
355 | A byte constant is: | |
356 | ||
357 | Hexadecimal form:: | |
358 | Two consecutive hexits. | |
359 | ||
360 | Decimal form:: | |
361 | A decimal number after the `$` prefix. | |
362 | ||
363 | Binary form:: | |
364 | Eight bits after the `%` prefix. | |
365 | ||
366 | ==== | |
367 | Input: | |
368 | ||
369 | ---- | |
370 | ab cd [3d 8F] CC | |
371 | ---- | |
372 | ||
373 | Output: | |
374 | ||
375 | ---- | |
376 | ab cd 3d 8f cc | |
377 | ---- | |
378 | ==== | |
379 | ||
380 | ==== | |
381 | Input: | |
382 | ||
383 | ---- | |
384 | $192 %1100/0011 $ -77 | |
385 | ---- | |
386 | ||
387 | Output: | |
388 | ||
389 | ---- | |
390 | c0 c3 b3 | |
391 | ---- | |
392 | ==== | |
393 | ||
394 | ==== | |
395 | Input: | |
396 | ||
397 | ---- | |
398 | 58f64689-6316-4d55-8a1a-04cada366172 | |
399 | fe80::6257:18ff:fea3:4229 | |
400 | ---- | |
401 | ||
402 | Output: | |
403 | ||
404 | ---- | |
405 | 58 f6 46 89 63 16 4d 55 8a 1a 04 ca da 36 61 72 ┆ X•F•c•MU•••••6ar | |
406 | fe 80 62 57 18 ff fe a3 42 29 ┆ ••bW••••B) | |
407 | ---- | |
408 | ==== | |
409 | ||
410 | ==== | |
411 | Input: | |
412 | ||
413 | ---- | |
414 | %01110011 %01100001 %01101100 %01110101 %01110100 | |
415 | ---- | |
416 | ||
417 | Output: | |
418 | ||
419 | ---- | |
420 | 73 61 6c 75 74 ┆ salut | |
421 | ---- | |
422 | ==== | |
423 | ||
424 | === Literal string | |
425 | ||
426 | A _literal string_ represents the UTF-8-, UTF-16-, or UTF-32-encoded | |
427 | bytes of a string. | |
428 | ||
429 | The string to encode isn't implicitly null-terminated: use `\0` at the | |
430 | end of the string to add a null character. | |
431 | ||
432 | A literal string is: | |
433 | ||
434 | . **Optional**: one of the following encodings instead of UTF-8: | |
435 | + | |
436 | -- | |
437 | [horizontal] | |
438 | `u16be`:: UTF-16BE. | |
439 | `u16le`:: UTF-16LE. | |
440 | `u32be`:: UTF-32BE. | |
441 | `u32le`:: UTF-32LE. | |
442 | -- | |
443 | ||
444 | . The ``pass:["]`` prefix. | |
445 | ||
446 | . A sequence of zero or more characters, possibly containing escape | |
447 | sequences. | |
448 | + | |
449 | An escape sequence is the ``\`` character followed by one of: | |
450 | + | |
451 | -- | |
452 | [horizontal] | |
453 | `0`:: Null (U+0000) | |
454 | `a`:: Alert (U+0007) | |
455 | `b`:: Backspace (U+0008) | |
456 | `e`:: Escape (U+001B) | |
457 | `f`:: Form feed (U+000C) | |
458 | `n`:: End of line (U+000A) | |
459 | `r`:: Carriage return (U+000D) | |
460 | `t`:: Character tabulation (U+0009) | |
461 | `v`:: Line tabulation (U+000B) | |
462 | ``\``:: Reverse solidus (U+005C) | |
463 | ``pass:["]``:: Quotation mark (U+0022) | |
464 | -- | |
465 | ||
466 | . The ``pass:["]`` suffix. | |
467 | ||
468 | ==== | |
469 | Input: | |
470 | ||
471 | ---- | |
472 | "coucou tout le monde!" | |
473 | ---- | |
474 | ||
475 | Output: | |
476 | ||
477 | ---- | |
478 | 63 6f 75 63 6f 75 20 74 6f 75 74 20 6c 65 20 6d ┆ coucou tout le m | |
479 | 6f 6e 64 65 21 ┆ onde! | |
480 | ---- | |
481 | ==== | |
482 | ||
483 | ==== | |
484 | Input: | |
485 | ||
486 | ---- | |
487 | u16le"I am not young enough to know everything." | |
488 | ---- | |
489 | ||
490 | Output: | |
491 | ||
492 | ---- | |
493 | 49 00 20 00 61 00 6d 00 20 00 6e 00 6f 00 74 00 ┆ I• •a•m• •n•o•t• | |
494 | 20 00 79 00 6f 00 75 00 6e 00 67 00 20 00 65 00 ┆ •y•o•u•n•g• •e• | |
495 | 6e 00 6f 00 75 00 67 00 68 00 20 00 74 00 6f 00 ┆ n•o•u•g•h• •t•o• | |
496 | 20 00 6b 00 6e 00 6f 00 77 00 20 00 65 00 76 00 ┆ •k•n•o•w• •e•v• | |
497 | 65 00 72 00 79 00 74 00 68 00 69 00 6e 00 67 00 ┆ e•r•y•t•h•i•n•g• | |
498 | 2e 00 ┆ .• | |
499 | ---- | |
500 | ==== | |
501 | ||
502 | ==== | |
503 | Input: | |
504 | ||
505 | ---- | |
506 | u32be "\"illusion is the first\nof all pleasures\" 🦉" | |
507 | ---- | |
508 | ||
509 | Output: | |
510 | ||
511 | ---- | |
512 | 00 00 00 22 00 00 00 69 00 00 00 6c 00 00 00 6c ┆ •••"•••i•••l•••l | |
513 | 00 00 00 75 00 00 00 73 00 00 00 69 00 00 00 6f ┆ •••u•••s•••i•••o | |
514 | 00 00 00 6e 00 00 00 20 00 00 00 69 00 00 00 73 ┆ •••n••• •••i•••s | |
515 | 00 00 00 20 00 00 00 74 00 00 00 68 00 00 00 65 ┆ ••• •••t•••h•••e | |
516 | 00 00 00 20 00 00 00 66 00 00 00 69 00 00 00 72 ┆ ••• •••f•••i•••r | |
517 | 00 00 00 73 00 00 00 74 00 00 00 0a 00 00 00 6f ┆ •••s•••t•••••••o | |
518 | 00 00 00 66 00 00 00 20 00 00 00 61 00 00 00 6c ┆ •••f••• •••a•••l | |
519 | 00 00 00 6c 00 00 00 20 00 00 00 70 00 00 00 6c ┆ •••l••• •••p•••l | |
520 | 00 00 00 65 00 00 00 61 00 00 00 73 00 00 00 75 ┆ •••e•••a•••s•••u | |
521 | 00 00 00 72 00 00 00 65 00 00 00 73 00 00 00 22 ┆ •••r•••e•••s•••" | |
522 | 00 00 00 20 00 01 f9 89 ┆ ••• •••• | |
523 | ---- | |
524 | ==== | |
525 | ||
526 | === Current byte order setting | |
527 | ||
528 | This special item sets the <<cur-bo,_current byte order_>>. | |
529 | ||
530 | The two accepted forms are: | |
531 | ||
532 | [horizontal] | |
533 | ``pass:[{be}]``:: Set the current byte order to big endian. | |
534 | ``pass:[{le}]``:: Set the current byte order to little endian. | |
535 | ||
536 | === Value | |
537 | ||
538 | A _value_ represents a fixed number of bytes encoding an unsigned or | |
539 | signed integer which is the result of evaluating a {py3} expression | |
540 | using the <<cur-bo,current byte order>>. | |
541 | ||
542 | For a value at some source location{nbsp}__**L**__, its {py3} expression | |
543 | may contain the name of any accessible <<label,label>>, including the | |
544 | name of a label defined after{nbsp}__**L**__, as well as the name of any | |
545 | <<variable-assignment,variable>> known at{nbsp}__**L**__. | |
546 | ||
547 | An accessible label is either: | |
548 | ||
549 | * Outside of the current <<group,group>>. | |
550 | * Within the same immediate group (not within a nested group). | |
551 | ||
552 | In the {py3} expression of a value, the value of the special name | |
553 | `ICITTE` is the <<cur-offset,current offset>> (before encoding the | |
554 | value). | |
555 | ||
556 | A value is: | |
557 | ||
558 | . The ``pass:[{]`` prefix. | |
559 | ||
560 | . A valid {py3} expression. | |
561 | ||
562 | . The `:` character. | |
563 | ||
564 | . An encoding length in bits amongst `8`, `16`, `24`, `32`, `40`, | |
565 | `48`, `56`, and `64`. | |
566 | ||
567 | . The `}` suffix. | |
568 | ||
569 | ==== | |
570 | Input: | |
571 | ||
572 | ---- | |
573 | {le} {345:16} | |
574 | {be} {-0xabcd:32} | |
575 | ---- | |
576 | ||
577 | Output: | |
578 | ||
579 | ---- | |
580 | 59 01 ff ff 54 33 | |
581 | ---- | |
582 | ==== | |
583 | ||
584 | ==== | |
585 | Input: | |
586 | ||
587 | ---- | |
588 | {be} | |
589 | ||
590 | # String length in bits | |
591 | {8 * (str_end - str_beg) : 16} | |
592 | ||
593 | # String | |
594 | <str_beg> | |
595 | "hello world!" | |
596 | <str_end> | |
597 | ---- | |
598 | ||
599 | Output: | |
600 | ||
601 | ---- | |
602 | 00 60 68 65 6c 6c 6f 20 77 6f 72 6c 64 21 ┆ •`hello world! | |
603 | ---- | |
604 | ==== | |
605 | ||
606 | ==== | |
607 | Input: | |
608 | ||
609 | ---- | |
610 | {20 - ICITTE : 8} * 10 | |
611 | ---- | |
612 | ||
613 | Output: | |
614 | ||
615 | ---- | |
616 | 14 13 12 11 10 0f 0e 0d 0c 0b | |
617 | ---- | |
618 | ==== | |
619 | ||
620 | === Current offset setting | |
621 | ||
622 | This special item sets the <<cur-offset,_current offset_>>. | |
623 | ||
624 | A current offset setting is: | |
625 | ||
626 | . The `<` prefix. | |
627 | ||
628 | . A positive integer (hexadecimal starting with `0x` or `0X` accepted) | |
629 | which is the new current offset. | |
630 | ||
631 | . The `>` suffix. | |
632 | ||
633 | ==== | |
634 | Input: | |
635 | ||
636 | ---- | |
637 | {ICITTE : 8} * 8 | |
638 | <0x61> {ICITTE : 8} * 8 | |
639 | ---- | |
640 | ||
641 | Output: | |
642 | ||
643 | ---- | |
644 | 00 01 02 03 04 05 06 07 61 62 63 64 65 66 67 68 ┆ ••••••••abcdefgh | |
645 | ---- | |
646 | ==== | |
647 | ||
648 | ==== | |
649 | Input: | |
650 | ||
651 | ---- | |
652 | aa bb cc dd <meow> ee ff | |
653 | <12> 11 22 33 <mix> 44 55 | |
654 | {meow : 8} {mix : 8} | |
655 | ---- | |
656 | ||
657 | Output: | |
658 | ||
659 | ---- | |
660 | aa bb cc dd ee ff 11 22 33 44 55 04 0f ┆ •••••••"3DU•• | |
661 | ---- | |
662 | ==== | |
663 | ||
664 | === Label | |
665 | ||
666 | A _label_ associates a name to the <<cur-offset,current offset>>. | |
667 | ||
668 | All the labels of a whole Normand input must have unique names. | |
669 | ||
670 | A label may not share the name of a <<variable-assignment,variable>> | |
671 | name. | |
672 | ||
673 | A label name may not be `ICITTE` (see <<value>> and | |
674 | <<variable-assignment>> to learn more). | |
675 | ||
676 | A label is: | |
677 | ||
678 | . The `<` prefix. | |
679 | ||
680 | . A valid {py3} name which is not `ICITTE`. | |
681 | ||
682 | . The `>` suffix. | |
683 | ||
684 | === Variable assignment | |
685 | ||
686 | A _variable assignment_ associates a name to the integral result of an | |
687 | evaluated {py3} expression. | |
688 | ||
689 | For a variable assignment at some source location{nbsp}__**L**__, its | |
690 | {py3} expression may contain the name of any accessible <<label,label>>, | |
691 | including the name of a label defined after{nbsp}__**L**__, as well as | |
692 | the name of any variable known at{nbsp}__**L**__. | |
693 | ||
694 | An accessible label is either: | |
695 | ||
696 | * Outside of the current <<group,group>>. | |
697 | * Within the same immediate group (not within a nested group). | |
698 | ||
1f182c43 | 699 | A variable name may not be `ICITTE`. |
71aaa3f7 PP |
700 | |
701 | In the {py3} expression of a variable assignment, the special name | |
702 | `ICITTE` is the <<cur-offset,current offset>>. | |
703 | ||
704 | A variable is: | |
705 | ||
706 | . The ``pass:[{]`` prefix. | |
707 | ||
708 | . A valid {py3} name which is not `ICITTE`. | |
709 | ||
710 | . The `=` character. | |
711 | ||
712 | . A valid {py3} expression. | |
713 | ||
714 | . The `}` suffix. | |
715 | ||
716 | ==== | |
717 | Input: | |
718 | ||
719 | ---- | |
720 | {mix = 101} {le} | |
721 | {meow = 42} 11 22 {meow:8} 33 {meow = ICITTE + 17} | |
722 | "yooo" {meow + mix : 16} | |
723 | ---- | |
724 | ||
725 | Output: | |
726 | ||
727 | ---- | |
728 | 11 22 2a 33 79 6f 6f 6f 7a 00 ┆ •"*3yoooz• | |
729 | ---- | |
730 | ==== | |
731 | ||
732 | === Group | |
733 | ||
734 | A _group_ is a scoped sequence of items. | |
735 | ||
736 | The <<label,labels>> within a group aren't visible outside of it. | |
737 | ||
738 | The main purpose of a group is to <<repetition,repeat>> more than a | |
739 | single item. | |
740 | ||
741 | A group is: | |
742 | ||
743 | . The `(` prefix. | |
744 | ||
745 | . Zero or more items. | |
746 | ||
747 | . The `)` suffix. | |
748 | ||
749 | ==== | |
750 | Input: | |
751 | ||
752 | ---- | |
753 | ((aa bb cc) dd () ee) "leclerc" | |
754 | ---- | |
755 | ||
756 | Output: | |
757 | ||
758 | ---- | |
759 | aa bb cc dd ee 6c 65 63 6c 65 72 63 ┆ •••••leclerc | |
760 | ---- | |
761 | ==== | |
762 | ||
763 | ==== | |
764 | Input: | |
765 | ||
766 | ---- | |
767 | ((aa bb cc) * 3 dd ee) * 5 | |
768 | ---- | |
769 | ||
770 | Output: | |
771 | ||
772 | ---- | |
773 | aa bb cc aa bb cc aa bb cc dd ee aa bb cc aa bb | |
774 | cc aa bb cc dd ee aa bb cc aa bb cc aa bb cc dd | |
775 | ee aa bb cc aa bb cc aa bb cc dd ee aa bb cc aa | |
776 | bb cc aa bb cc dd ee | |
777 | ---- | |
778 | ==== | |
779 | ||
780 | ==== | |
781 | Input: | |
782 | ||
783 | ---- | |
784 | {be} | |
785 | ( | |
786 | <str_beg> u16le"sébastien diaz" <str_end> | |
787 | {ICITTE - str_beg : 8} | |
788 | {(end - str_beg) * 5 : 24} | |
789 | ) * 3 | |
790 | <end> | |
791 | ---- | |
792 | ||
793 | Output: | |
794 | ||
795 | ---- | |
796 | 73 00 e9 00 62 00 61 00 73 00 74 00 69 00 65 00 ┆ s•••b•a•s•t•i•e• | |
797 | 6e 00 20 00 64 00 69 00 61 00 7a 00 1c 00 01 e0 ┆ n• •d•i•a•z••••• | |
798 | 73 00 e9 00 62 00 61 00 73 00 74 00 69 00 65 00 ┆ s•••b•a•s•t•i•e• | |
799 | 6e 00 20 00 64 00 69 00 61 00 7a 00 1c 00 01 40 ┆ n• •d•i•a•z••••@ | |
800 | 73 00 e9 00 62 00 61 00 73 00 74 00 69 00 65 00 ┆ s•••b•a•s•t•i•e• | |
801 | 6e 00 20 00 64 00 69 00 61 00 7a 00 1c 00 00 a0 ┆ n• •d•i•a•z••••• | |
802 | ---- | |
803 | ==== | |
804 | ||
805 | === Repetition | |
806 | ||
807 | A _repetition_ represents the bytes of an item repeated a given number | |
808 | of times. | |
809 | ||
810 | A repetition is: | |
811 | ||
812 | . Any item. | |
813 | ||
814 | . The ``pass:[*]`` character. | |
815 | ||
2adf4336 PP |
816 | . One of: |
817 | ||
818 | ** A positive integer (hexadecimal starting with `0x` or `0X` accepted) | |
819 | which is the number of times to repeat the previous item. | |
820 | ||
821 | ** The ``pass:[{]`` prefix, a valid {py3} expression, and the | |
822 | ``pass:[}]`` suffix. | |
823 | ||
824 | When using an expression, it can't refer, directly or indirectly, to a | |
825 | subsequent label name and to the reserved `ICITTE` name. | |
71aaa3f7 PP |
826 | |
827 | ==== | |
828 | Input: | |
829 | ||
830 | ---- | |
831 | {end - ICITTE - 1 : 8} * 0x100 <end> | |
832 | ---- | |
833 | ||
834 | Output: | |
835 | ||
836 | ---- | |
837 | ff fe fd fc fb fa f9 f8 f7 f6 f5 f4 f3 f2 f1 f0 ┆ •••••••••••••••• | |
838 | ef ee ed ec eb ea e9 e8 e7 e6 e5 e4 e3 e2 e1 e0 ┆ •••••••••••••••• | |
839 | df de dd dc db da d9 d8 d7 d6 d5 d4 d3 d2 d1 d0 ┆ •••••••••••••••• | |
840 | cf ce cd cc cb ca c9 c8 c7 c6 c5 c4 c3 c2 c1 c0 ┆ •••••••••••••••• | |
841 | bf be bd bc bb ba b9 b8 b7 b6 b5 b4 b3 b2 b1 b0 ┆ •••••••••••••••• | |
842 | af ae ad ac ab aa a9 a8 a7 a6 a5 a4 a3 a2 a1 a0 ┆ •••••••••••••••• | |
843 | 9f 9e 9d 9c 9b 9a 99 98 97 96 95 94 93 92 91 90 ┆ •••••••••••••••• | |
844 | 8f 8e 8d 8c 8b 8a 89 88 87 86 85 84 83 82 81 80 ┆ •••••••••••••••• | |
845 | 7f 7e 7d 7c 7b 7a 79 78 77 76 75 74 73 72 71 70 ┆ •~}|{zyxwvutsrqp | |
846 | 6f 6e 6d 6c 6b 6a 69 68 67 66 65 64 63 62 61 60 ┆ onmlkjihgfedcba` | |
847 | 5f 5e 5d 5c 5b 5a 59 58 57 56 55 54 53 52 51 50 ┆ _^]\[ZYXWVUTSRQP | |
848 | 4f 4e 4d 4c 4b 4a 49 48 47 46 45 44 43 42 41 40 ┆ ONMLKJIHGFEDCBA@ | |
849 | 3f 3e 3d 3c 3b 3a 39 38 37 36 35 34 33 32 31 30 ┆ ?>=<;:9876543210 | |
850 | 2f 2e 2d 2c 2b 2a 29 28 27 26 25 24 23 22 21 20 ┆ /.-,+*)('&%$#"! | |
851 | 1f 1e 1d 1c 1b 1a 19 18 17 16 15 14 13 12 11 10 ┆ •••••••••••••••• | |
852 | 0f 0e 0d 0c 0b 0a 09 08 07 06 05 04 03 02 01 00 ┆ •••••••••••••••• | |
853 | ---- | |
854 | ==== | |
855 | ||
2adf4336 PP |
856 | ==== |
857 | Input: | |
858 | ||
859 | ---- | |
860 | {times = 1} | |
861 | aa bb cc dd | |
862 | ( | |
863 | <here> | |
864 | (ee ff) * {here + 1} | |
865 | 11 22 33 * {times} | |
866 | {times = times + 1} | |
867 | ) * 3 | |
868 | "coucou!" | |
869 | ---- | |
870 | ||
871 | Output: | |
872 | ||
873 | ---- | |
874 | aa bb cc dd ee ff ee ff ee ff ee ff ee ff 11 22 ┆ •••••••••••••••" | |
875 | 33 ee ff ee ff ee ff ee ff ee ff ee ff ee ff ee ┆ 3••••••••••••••• | |
876 | ff ee ff ee ff ee ff ee ff ee ff ee ff ee ff ee ┆ •••••••••••••••• | |
877 | ff ee ff ee ff 11 22 33 33 ee ff ee ff ee ff ee ┆ ••••••"33••••••• | |
878 | ff ee ff ee ff ee ff ee ff ee ff ee ff ee ff ee ┆ •••••••••••••••• | |
879 | ff ee ff ee ff ee ff ee ff ee ff ee ff ee ff ee ┆ •••••••••••••••• | |
880 | ff ee ff ee ff ee ff ee ff ee ff ee ff ee ff ee ┆ •••••••••••••••• | |
881 | ff ee ff ee ff ee ff ee ff ee ff ee ff ee ff ee ┆ •••••••••••••••• | |
882 | ff ee ff ee ff ee ff ee ff ee ff ee ff ee ff ee ┆ •••••••••••••••• | |
883 | ff ee ff ee ff ee ff ee ff ee ff ee ff ee ff ee ┆ •••••••••••••••• | |
884 | ff ee ff ee ff ee ff ee ff ee ff ee ff 11 22 33 ┆ ••••••••••••••"3 | |
885 | 33 33 63 6f 75 63 6f 75 21 ┆ 33coucou! | |
886 | ---- | |
887 | ==== | |
888 | ||
889 | ==== | |
890 | This example shows how to use a repetition as a conditional section | |
891 | depending on some predefined variable. | |
892 | ||
893 | Input: | |
894 | ||
895 | ---- | |
896 | aa bb cc dd | |
897 | (ee ff "meow mix" 00) * {cond} | |
898 | {be} {-1993:16} | |
899 | ---- | |
900 | ||
901 | Output (`cond` is 0): | |
902 | ||
903 | ---- | |
904 | aa bb cc dd f8 37 | |
905 | ---- | |
906 | ||
907 | Output (`cond` is 1): | |
908 | ||
909 | ---- | |
910 | aa bb cc dd ee ff 6d 65 6f 77 20 6d 69 78 00 f8 ┆ ••••••meow mix•• | |
911 | 37 ┆ 7 | |
912 | ---- | |
913 | ==== | |
914 | ||
71aaa3f7 PP |
915 | == Command-line tool |
916 | ||
917 | If you <<install-normand,installed>> the `normand` package, then you | |
918 | can use the `normand` command-line tool: | |
919 | ||
920 | ---- | |
921 | $ normand <<< '"ma gang de malades"' | hexdump -C | |
922 | ---- | |
923 | ||
924 | ---- | |
925 | 00000000 6d 61 20 67 61 6e 67 20 64 65 20 6d 61 6c 61 64 |ma gang de malad| | |
926 | 00000010 65 73 |es| | |
927 | ---- | |
928 | ||
929 | If you copy the `normand.py` module to your own project, then you can | |
930 | run the module itself: | |
931 | ||
932 | ---- | |
933 | $ python3 -m normand <<< '"ma gang de malades"' | hexdump -C | |
934 | ---- | |
935 | ||
936 | ---- | |
937 | 00000000 6d 61 20 67 61 6e 67 20 64 65 20 6d 61 6c 61 64 |ma gang de malad| | |
938 | 00000010 65 73 |es| | |
939 | ---- | |
940 | ||
941 | Without a path argument, the `normand` tool reads from the standard | |
942 | input. | |
943 | ||
944 | The `normand` tool prints the generated binary data to the standard | |
945 | output. | |
946 | ||
947 | Various options control the initial <<state,state>> of the processor: | |
948 | use the `--help` option to learn more. | |
949 | ||
950 | == {py3} API | |
951 | ||
952 | The whole `normand` package/module API is: | |
953 | ||
954 | [source,python] | |
955 | ---- | |
956 | class ByteOrder(enum.Enum): | |
957 | # Big endian. | |
958 | BE = ... | |
959 | ||
960 | # Little endian. | |
961 | LE = ... | |
962 | ||
963 | ||
964 | VarsT = typing.Dict[str, int] | |
965 | ||
966 | ||
967 | class TextLoc: | |
968 | # Line number. | |
969 | @property | |
970 | def line_no(self) -> int: | |
971 | ... | |
972 | ||
973 | # Column number. | |
974 | @property | |
975 | def col_no(self) -> int: | |
976 | ... | |
977 | ||
978 | ||
979 | class ParseError(RuntimeError): | |
980 | # Source text location. | |
981 | @property | |
982 | def text_loc(self) -> TextLoc: | |
983 | ... | |
984 | ||
985 | ||
986 | class ParseResult: | |
987 | # Generated data. | |
988 | @property | |
989 | def data(self) -> bytearray: | |
990 | ... | |
991 | ||
992 | # Updated variable values. | |
993 | @property | |
994 | def variables(self) -> VarsT: | |
995 | ... | |
996 | ||
997 | # Updated main group label values. | |
998 | @property | |
999 | def labels(self) -> VarsT: | |
1000 | ... | |
1001 | ||
1002 | # Final offset. | |
1003 | @property | |
1004 | def offset(self) -> int: | |
1005 | ... | |
1006 | ||
1007 | # Final byte order. | |
1008 | @property | |
1009 | def byte_order(self) -> typing.Optional[int]: | |
1010 | ... | |
1011 | ||
1012 | def parse(normand: str, | |
1013 | init_variables: typing.Optional[VarsT] = None, | |
1014 | init_labels: typing.Optional[VarsT] = None, | |
1015 | init_offset: int = 0, | |
1016 | init_byte_order: typing.Optional[ByteOrder] = None) -> ParseResult: | |
1017 | ... | |
1018 | ---- | |
1019 | ||
1020 | The `normand` parameter is the actual <<learn-normand,Normand input>> | |
1021 | while the other parameters control the initial <<state,state>>. | |
1022 | ||
1023 | The `parse()` function raises a `ParseError` instance should it fail to | |
1024 | parse the `normand` string for any reason. |