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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 | ||
e57a18e1 | 32 | WARNING: This version of Normand is 0.8, 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 | ||
269f6eb3 | 136 | Fixed-length number 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} | |
269f6eb3 | 144 | {-3.141593 : 64} |
71aaa3f7 PP |
145 | ---- |
146 | + | |
147 | Output: | |
148 | + | |
149 | ---- | |
269f6eb3 PP |
150 | 67 44 b2 00 2c 63 37 f8 ff ff 7f bd c2 82 fb 21 |
151 | 09 c0 | |
71aaa3f7 PP |
152 | ---- |
153 | + | |
269f6eb3 | 154 | The encoded number is the evaluation of a valid {py3} expression which |
05f81895 PP |
155 | may include label and variable names. |
156 | ||
157 | https://en.wikipedia.org/wiki/LEB128[LEB128] integer:: | |
158 | + | |
159 | Input: | |
160 | + | |
161 | ---- | |
162 | aa bb cc {-1993 : sleb128} <meow> dd ee ff | |
163 | {meow * 199 : uleb128} | |
164 | ---- | |
165 | + | |
166 | Output: | |
167 | + | |
168 | ---- | |
169 | aa bb cc b7 70 dd ee ff e3 07 | |
170 | ---- | |
171 | + | |
172 | The encoded integer is the evaluation of a valid {py3} expression which | |
71aaa3f7 PP |
173 | may include label and variable names. |
174 | ||
175 | Repetition:: | |
176 | + | |
177 | Input: | |
178 | + | |
179 | ---- | |
2adf4336 | 180 | aa bb * 5 cc <zoom> "yeah\0" * {zoom * 3} |
e57a18e1 PP |
181 | |
182 | !repeat 3 | |
183 | ff ee "juice" | |
184 | !end | |
71aaa3f7 PP |
185 | ---- |
186 | + | |
187 | Output: | |
188 | + | |
189 | ---- | |
2adf4336 PP |
190 | aa bb bb bb bb bb cc 79 65 61 68 00 79 65 61 68 ┆ •••••••yeah•yeah |
191 | 00 79 65 61 68 00 79 65 61 68 00 79 65 61 68 00 ┆ •yeah•yeah•yeah• | |
192 | 79 65 61 68 00 79 65 61 68 00 79 65 61 68 00 79 ┆ yeah•yeah•yeah•y | |
193 | 65 61 68 00 79 65 61 68 00 79 65 61 68 00 79 65 ┆ eah•yeah•yeah•ye | |
194 | 61 68 00 79 65 61 68 00 79 65 61 68 00 79 65 61 ┆ ah•yeah•yeah•yea | |
195 | 68 00 79 65 61 68 00 79 65 61 68 00 79 65 61 68 ┆ h•yeah•yeah•yeah | |
71aaa3f7 | 196 | 00 79 65 61 68 00 79 65 61 68 00 79 65 61 68 00 ┆ •yeah•yeah•yeah• |
e57a18e1 PP |
197 | ff ee 6a 75 69 63 65 ff ee 6a 75 69 63 65 ff ee ┆ ••juice••juice•• |
198 | 6a 75 69 63 65 ┆ juice | |
71aaa3f7 PP |
199 | ---- |
200 | ||
676f6189 PP |
201 | Alignment:: |
202 | + | |
203 | Input: | |
204 | + | |
205 | ---- | |
206 | {be} | |
207 | ||
208 | {199:32} | |
209 | @64 {43:64} | |
210 | @16 {-123:16} | |
211 | @32~255 {5584:32} | |
212 | ---- | |
213 | + | |
214 | Output: | |
215 | + | |
216 | ---- | |
217 | 00 00 00 c7 00 00 00 00 00 00 00 00 00 00 00 2b | |
218 | ff 85 ff ff 00 00 15 d0 | |
219 | ---- | |
71aaa3f7 PP |
220 | |
221 | Multilevel grouping:: | |
222 | + | |
223 | Input: | |
224 | + | |
225 | ---- | |
226 | ff ((aa bb "zoom" cc) * 5) * 3 $-34 * 4 | |
227 | ---- | |
228 | + | |
229 | Output: | |
230 | + | |
231 | ---- | |
232 | ff aa bb 7a 6f 6f 6d cc aa bb 7a 6f 6f 6d cc aa ┆ •••zoom•••zoom•• | |
233 | bb 7a 6f 6f 6d cc aa bb 7a 6f 6f 6d cc aa bb 7a ┆ •zoom•••zoom•••z | |
234 | 6f 6f 6d cc aa bb 7a 6f 6f 6d cc aa bb 7a 6f 6f ┆ oom•••zoom•••zoo | |
235 | 6d cc aa bb 7a 6f 6f 6d cc aa bb 7a 6f 6f 6d cc ┆ m•••zoom•••zoom• | |
236 | aa bb 7a 6f 6f 6d cc aa bb 7a 6f 6f 6d cc aa bb ┆ ••zoom•••zoom••• | |
237 | 7a 6f 6f 6d cc aa bb 7a 6f 6f 6d cc aa bb 7a 6f ┆ zoom•••zoom•••zo | |
238 | 6f 6d cc aa bb 7a 6f 6f 6d cc de de de de ┆ om•••zoom••••• | |
239 | ---- | |
240 | ||
241 | Precise error reporting:: | |
242 | + | |
243 | ---- | |
244 | /tmp/meow.normand:10:24 - Expecting a bit (`0` or `1`). | |
245 | ---- | |
246 | + | |
247 | ---- | |
248 | /tmp/meow.normand:32:6 - Unexpected character `k`. | |
249 | ---- | |
250 | + | |
251 | ---- | |
2adf4336 | 252 | /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 |
253 | ---- |
254 | + | |
255 | ---- | |
256 | /tmp/meow.normand:18:9 - Value 315 is outside the 8-bit range when evaluating expression `end - ICITTE` at byte offset 45. | |
257 | ---- | |
258 | ||
259 | You can use Normand to track data source files in your favorite VCS | |
260 | instead of raw binary files. The binary files that Normand generates can | |
261 | be used to test file format decoding, including malformatted data, for | |
262 | example, as well as for education. | |
263 | ||
264 | See <<learn-normand>> to explore all the Normand features. | |
265 | ||
266 | == Install Normand | |
267 | ||
268 | Normand requires Python ≥ 3.4. | |
269 | ||
270 | To install Normand: | |
271 | ||
272 | ---- | |
273 | $ python3 -m pip install --user normand | |
274 | ---- | |
275 | ||
276 | See | |
277 | https://packaging.python.org/en/latest/tutorials/installing-packages/#installing-to-the-user-site[Installing to the User Site] | |
278 | to learn more about a user site installation. | |
279 | ||
280 | [NOTE] | |
281 | ==== | |
282 | Normand has a single module file, `normand.py`, which you can copy as is | |
af3cf417 | 283 | to your project to use it (both the <<python3-api,`normand.parse()`>> |
71aaa3f7 PP |
284 | function and the <<command-line-tool,command-line tool>>). |
285 | ||
286 | `normand.py` has _no external dependencies_, but if you're using | |
287 | Python{nbsp}3.4, you'll need a local copy of the standard `typing` | |
288 | module. | |
289 | ==== | |
290 | ||
291 | == Learn Normand | |
292 | ||
293 | A Normand text input is a sequence of items which represent a sequence | |
294 | of raw bytes. | |
295 | ||
296 | [[state]] During the processing of items to data, Normand relies on a | |
297 | current state: | |
298 | ||
299 | [%header%autowidth] | |
300 | |=== | |
af3cf417 | 301 | |State variable |Description |Initial value: <<python3-api,{py3} API>> |Initial value: <<command-line-tool,CLI>> |
71aaa3f7 PP |
302 | |
303 | |[[cur-offset]] Current offset | |
304 | | | |
05f81895 | 305 | The current offset has an effect on the value of <<label,labels>> and of |
269f6eb3 PP |
306 | the special `ICITTE` name in <<fixed-length-number,fixed-length |
307 | number>>, <<leb-128-integer,LEB128 integer>>, and | |
71aaa3f7 PP |
308 | <<variable-assignment,variable assignment>> expression evaluation. |
309 | ||
310 | Each generated byte increments the current offset. | |
311 | ||
312 | A <<current-offset-setting,current offset setting>> may change the | |
676f6189 PP |
313 | current offset without generating data. |
314 | ||
315 | An <<current-offset-alignment,current offset alignment>> generates | |
316 | padding bytes to make the current offset satisfy a given alignment. | |
71aaa3f7 PP |
317 | |`init_offset` parameter of the `parse()` function. |
318 | |`--offset` option. | |
319 | ||
320 | |[[cur-bo]] Current byte order | |
321 | | | |
05f81895 | 322 | The current byte order has an effect on the encoding of |
269f6eb3 | 323 | <<fixed-length-number,fixed-length numbers>>. |
71aaa3f7 PP |
324 | |
325 | A <<current-byte-order-setting,current byte order setting>> may change | |
326 | the current byte order. | |
327 | |`init_byte_order` parameter of the `parse()` function. | |
328 | |`--byte-order` option. | |
329 | ||
330 | |<<label,Labels>> | |
331 | |Mapping of label names to integral values. | |
332 | |`init_labels` parameter of the `parse()` function. | |
333 | |One or more `--label` options. | |
334 | ||
335 | |<<variable-assignment,Variables>> | |
336 | |Mapping of variable names to integral values. | |
337 | |`init_variables` parameter of the `parse()` function. | |
338 | |One or more `--var` options. | |
339 | |=== | |
340 | ||
341 | The available items are: | |
342 | ||
343 | * A <<byte-constant,constant integer>> representing a single byte. | |
344 | ||
345 | * A <<literal-string,literal string>> representing a sequence of bytes | |
346 | encoding UTF-8, UTF-16, or UTF-32 data. | |
347 | ||
348 | * A <<current-byte-order-setting,current byte order setting>> (big or | |
349 | little endian). | |
350 | ||
269f6eb3 PP |
351 | * A <<fixed-length-number,fixed-length number>> (integer or |
352 | floating point) using the <<cur-bo,current byte order>> and of which | |
353 | the value is the result of a {py3} expression. | |
05f81895 PP |
354 | |
355 | * An <<leb128-integer,LEB128 integer>> of which the value is the result | |
356 | of a {py3} expression. | |
71aaa3f7 PP |
357 | |
358 | * A <<current-offset-setting,current offset setting>>. | |
359 | ||
676f6189 PP |
360 | * A <<current-offset-alignment,current offset alignment>>. |
361 | ||
71aaa3f7 PP |
362 | * A <<label,label>>, that is, a named constant holding the current |
363 | offset. | |
364 | + | |
365 | This is similar to an assembly label. | |
366 | ||
367 | * A <<variable-assignment,variable assignment>> associating a name to | |
368 | the integral result of an evaluated {py3} expression. | |
369 | ||
370 | * A <<group,group>>, that is, a scoped sequence of items. | |
371 | ||
e57a18e1 PP |
372 | * A <<repetition-block,repetition block>>. |
373 | ||
374 | Moreover, you can repeat many items above a constant or variable number | |
375 | of times with the ``pass:[*]`` operator _after_ the item to repeat. This | |
376 | is called a <<post-item-repetition,post-item repetition>>. | |
71aaa3f7 PP |
377 | |
378 | A Normand comment may exist: | |
379 | ||
380 | * Between items, possibly within a group. | |
381 | * Between the nibbles of a constant hexadecimal byte. | |
382 | * Between the bits of a constant binary byte. | |
e57a18e1 PP |
383 | * Between the last item and the ``pass:[*]`` character of a post-item |
384 | repetition, and between that ``pass:[*]`` character and the following | |
385 | number or expression. | |
386 | * Between the ``!repeat``/``!r`` prefix and the following constant | |
387 | integer, name, or expression of a repetition block. | |
71aaa3f7 PP |
388 | |
389 | A comment is anything between two ``pass:[#]`` characters on the same | |
390 | line, or from ``pass:[#]`` until the end of the line. Whitespaces and | |
391 | the following symbol characters are also considered comments where a | |
392 | comment may exist: | |
393 | ||
394 | ---- | |
e57a18e1 | 395 | / \ ? & : ; . , + [ ] _ = | - |
71aaa3f7 PP |
396 | ---- |
397 | ||
398 | The latter serve to improve readability so that you may write, for | |
399 | example, a MAC address or a UUID as is. | |
400 | ||
401 | You can test the examples of this section with the `normand` | |
402 | <<command-line-tool,command-line tool>> as such: | |
403 | ||
404 | ---- | |
405 | $ normand file | hexdump -C | |
406 | ---- | |
407 | ||
408 | where `file` is the name of a file containing the Normand input. | |
409 | ||
410 | === Byte constant | |
411 | ||
412 | A _byte constant_ represents a single byte. | |
413 | ||
414 | A byte constant is: | |
415 | ||
416 | Hexadecimal form:: | |
417 | Two consecutive hexits. | |
418 | ||
419 | Decimal form:: | |
420 | A decimal number after the `$` prefix. | |
421 | ||
422 | Binary form:: | |
423 | Eight bits after the `%` prefix. | |
424 | ||
425 | ==== | |
426 | Input: | |
427 | ||
428 | ---- | |
429 | ab cd [3d 8F] CC | |
430 | ---- | |
431 | ||
432 | Output: | |
433 | ||
434 | ---- | |
435 | ab cd 3d 8f cc | |
436 | ---- | |
437 | ==== | |
438 | ||
439 | ==== | |
440 | Input: | |
441 | ||
442 | ---- | |
443 | $192 %1100/0011 $ -77 | |
444 | ---- | |
445 | ||
446 | Output: | |
447 | ||
448 | ---- | |
449 | c0 c3 b3 | |
450 | ---- | |
451 | ==== | |
452 | ||
453 | ==== | |
454 | Input: | |
455 | ||
456 | ---- | |
457 | 58f64689-6316-4d55-8a1a-04cada366172 | |
458 | fe80::6257:18ff:fea3:4229 | |
459 | ---- | |
460 | ||
461 | Output: | |
462 | ||
463 | ---- | |
464 | 58 f6 46 89 63 16 4d 55 8a 1a 04 ca da 36 61 72 ┆ X•F•c•MU•••••6ar | |
465 | fe 80 62 57 18 ff fe a3 42 29 ┆ ••bW••••B) | |
466 | ---- | |
467 | ==== | |
468 | ||
469 | ==== | |
470 | Input: | |
471 | ||
472 | ---- | |
473 | %01110011 %01100001 %01101100 %01110101 %01110100 | |
474 | ---- | |
475 | ||
476 | Output: | |
477 | ||
478 | ---- | |
479 | 73 61 6c 75 74 ┆ salut | |
480 | ---- | |
481 | ==== | |
482 | ||
483 | === Literal string | |
484 | ||
485 | A _literal string_ represents the UTF-8-, UTF-16-, or UTF-32-encoded | |
486 | bytes of a string. | |
487 | ||
488 | The string to encode isn't implicitly null-terminated: use `\0` at the | |
489 | end of the string to add a null character. | |
490 | ||
491 | A literal string is: | |
492 | ||
493 | . **Optional**: one of the following encodings instead of UTF-8: | |
494 | + | |
495 | -- | |
496 | [horizontal] | |
497 | `u16be`:: UTF-16BE. | |
498 | `u16le`:: UTF-16LE. | |
499 | `u32be`:: UTF-32BE. | |
500 | `u32le`:: UTF-32LE. | |
501 | -- | |
502 | ||
503 | . The ``pass:["]`` prefix. | |
504 | ||
505 | . A sequence of zero or more characters, possibly containing escape | |
506 | sequences. | |
507 | + | |
508 | An escape sequence is the ``\`` character followed by one of: | |
509 | + | |
510 | -- | |
511 | [horizontal] | |
512 | `0`:: Null (U+0000) | |
513 | `a`:: Alert (U+0007) | |
514 | `b`:: Backspace (U+0008) | |
515 | `e`:: Escape (U+001B) | |
516 | `f`:: Form feed (U+000C) | |
517 | `n`:: End of line (U+000A) | |
518 | `r`:: Carriage return (U+000D) | |
519 | `t`:: Character tabulation (U+0009) | |
520 | `v`:: Line tabulation (U+000B) | |
521 | ``\``:: Reverse solidus (U+005C) | |
522 | ``pass:["]``:: Quotation mark (U+0022) | |
523 | -- | |
524 | ||
525 | . The ``pass:["]`` suffix. | |
526 | ||
527 | ==== | |
528 | Input: | |
529 | ||
530 | ---- | |
531 | "coucou tout le monde!" | |
532 | ---- | |
533 | ||
534 | Output: | |
535 | ||
536 | ---- | |
537 | 63 6f 75 63 6f 75 20 74 6f 75 74 20 6c 65 20 6d ┆ coucou tout le m | |
538 | 6f 6e 64 65 21 ┆ onde! | |
539 | ---- | |
540 | ==== | |
541 | ||
542 | ==== | |
543 | Input: | |
544 | ||
545 | ---- | |
546 | u16le"I am not young enough to know everything." | |
547 | ---- | |
548 | ||
549 | Output: | |
550 | ||
551 | ---- | |
552 | 49 00 20 00 61 00 6d 00 20 00 6e 00 6f 00 74 00 ┆ I• •a•m• •n•o•t• | |
553 | 20 00 79 00 6f 00 75 00 6e 00 67 00 20 00 65 00 ┆ •y•o•u•n•g• •e• | |
554 | 6e 00 6f 00 75 00 67 00 68 00 20 00 74 00 6f 00 ┆ n•o•u•g•h• •t•o• | |
555 | 20 00 6b 00 6e 00 6f 00 77 00 20 00 65 00 76 00 ┆ •k•n•o•w• •e•v• | |
556 | 65 00 72 00 79 00 74 00 68 00 69 00 6e 00 67 00 ┆ e•r•y•t•h•i•n•g• | |
557 | 2e 00 ┆ .• | |
558 | ---- | |
559 | ==== | |
560 | ||
561 | ==== | |
562 | Input: | |
563 | ||
564 | ---- | |
565 | u32be "\"illusion is the first\nof all pleasures\" 🦉" | |
566 | ---- | |
567 | ||
568 | Output: | |
569 | ||
570 | ---- | |
571 | 00 00 00 22 00 00 00 69 00 00 00 6c 00 00 00 6c ┆ •••"•••i•••l•••l | |
572 | 00 00 00 75 00 00 00 73 00 00 00 69 00 00 00 6f ┆ •••u•••s•••i•••o | |
573 | 00 00 00 6e 00 00 00 20 00 00 00 69 00 00 00 73 ┆ •••n••• •••i•••s | |
574 | 00 00 00 20 00 00 00 74 00 00 00 68 00 00 00 65 ┆ ••• •••t•••h•••e | |
575 | 00 00 00 20 00 00 00 66 00 00 00 69 00 00 00 72 ┆ ••• •••f•••i•••r | |
576 | 00 00 00 73 00 00 00 74 00 00 00 0a 00 00 00 6f ┆ •••s•••t•••••••o | |
577 | 00 00 00 66 00 00 00 20 00 00 00 61 00 00 00 6c ┆ •••f••• •••a•••l | |
578 | 00 00 00 6c 00 00 00 20 00 00 00 70 00 00 00 6c ┆ •••l••• •••p•••l | |
579 | 00 00 00 65 00 00 00 61 00 00 00 73 00 00 00 75 ┆ •••e•••a•••s•••u | |
580 | 00 00 00 72 00 00 00 65 00 00 00 73 00 00 00 22 ┆ •••r•••e•••s•••" | |
581 | 00 00 00 20 00 01 f9 89 ┆ ••• •••• | |
582 | ---- | |
583 | ==== | |
584 | ||
585 | === Current byte order setting | |
586 | ||
587 | This special item sets the <<cur-bo,_current byte order_>>. | |
588 | ||
589 | The two accepted forms are: | |
590 | ||
591 | [horizontal] | |
592 | ``pass:[{be}]``:: Set the current byte order to big endian. | |
593 | ``pass:[{le}]``:: Set the current byte order to little endian. | |
594 | ||
269f6eb3 | 595 | === Fixed-length number |
71aaa3f7 | 596 | |
269f6eb3 PP |
597 | A _fixed-length number_ represents a fixed number of bytes encoding |
598 | either: | |
599 | ||
600 | * An unsigned or signed integer (two's complement). | |
601 | + | |
602 | The available lengths are 8, 16, 24, 32, 40, 48, 56, and 64. | |
603 | ||
604 | * A floating point number | |
605 | ([IEEE{nbsp}754-2008[https://standards.ieee.org/standard/754-2008.html]). | |
606 | + | |
607 | The available length are 32 (_binary32_) and 64 (_binary64_). | |
71aaa3f7 | 608 | |
269f6eb3 PP |
609 | The value is the result of evaluating a {py3} expression using the |
610 | <<cur-bo,current byte order>>. | |
611 | ||
612 | A fixed-length number is: | |
71aaa3f7 PP |
613 | |
614 | . The ``pass:[{]`` prefix. | |
615 | ||
616 | . A valid {py3} expression. | |
05f81895 | 617 | + |
269f6eb3 | 618 | For a fixed-length number at some source location{nbsp}__**L**__, this |
05f81895 PP |
619 | expression may contain the name of any accessible <<label,label>> (not |
620 | within a nested group), including the name of a label defined | |
621 | after{nbsp}__**L**__, as well as the name of any | |
622 | <<variable-assignment,variable>> known at{nbsp}__**L**__. | |
623 | + | |
269f6eb3 PP |
624 | The value of the special name `ICITTE` (`int` type) in this expression |
625 | is the <<cur-offset,current offset>> (before encoding the number). | |
71aaa3f7 PP |
626 | |
627 | . The `:` character. | |
628 | ||
269f6eb3 PP |
629 | . An encoding length in bits amongst: |
630 | + | |
631 | -- | |
632 | The expression evaluates to an `int` value:: | |
633 | `8`, `16`, `24`, `32`, `40`, `48`, `56`, and `64`. | |
634 | ||
635 | The expression evaluates to a `float` value:: | |
636 | `32` and `64`. | |
637 | -- | |
71aaa3f7 PP |
638 | |
639 | . The `}` suffix. | |
640 | ||
641 | ==== | |
642 | Input: | |
643 | ||
644 | ---- | |
645 | {le} {345:16} | |
646 | {be} {-0xabcd:32} | |
647 | ---- | |
648 | ||
649 | Output: | |
650 | ||
651 | ---- | |
652 | 59 01 ff ff 54 33 | |
653 | ---- | |
654 | ==== | |
655 | ||
656 | ==== | |
657 | Input: | |
658 | ||
659 | ---- | |
660 | {be} | |
661 | ||
662 | # String length in bits | |
663 | {8 * (str_end - str_beg) : 16} | |
664 | ||
665 | # String | |
666 | <str_beg> | |
667 | "hello world!" | |
668 | <str_end> | |
669 | ---- | |
670 | ||
671 | Output: | |
672 | ||
673 | ---- | |
674 | 00 60 68 65 6c 6c 6f 20 77 6f 72 6c 64 21 ┆ •`hello world! | |
675 | ---- | |
676 | ==== | |
677 | ||
678 | ==== | |
679 | Input: | |
680 | ||
681 | ---- | |
682 | {20 - ICITTE : 8} * 10 | |
683 | ---- | |
684 | ||
685 | Output: | |
686 | ||
687 | ---- | |
688 | 14 13 12 11 10 0f 0e 0d 0c 0b | |
689 | ---- | |
690 | ==== | |
691 | ||
269f6eb3 PP |
692 | ==== |
693 | Input: | |
694 | ||
695 | ---- | |
696 | {le} | |
697 | {2 * 0.0529 : 32} | |
698 | ---- | |
699 | ||
700 | Output: | |
701 | ||
702 | ---- | |
703 | ac ad d8 3d | |
704 | ---- | |
705 | ==== | |
706 | ||
05f81895 PP |
707 | === LEB128 integer |
708 | ||
709 | An _LEB128 integer_ represents a variable number of bytes encoding an | |
710 | unsigned or signed integer which is the result of evaluating a {py3} | |
711 | expression following the https://en.wikipedia.org/wiki/LEB128[LEB128] | |
712 | format. | |
713 | ||
714 | An LEB128 integer is: | |
715 | ||
716 | . The ``pass:[{]`` prefix. | |
717 | ||
718 | . A valid {py3} expression. | |
719 | + | |
720 | For an LEB128 integer at some source location{nbsp}__**L**__, this | |
721 | expression may contain: | |
722 | + | |
723 | -- | |
724 | * The name of any <<label,label>> defined before{nbsp}__**L**__. | |
725 | * The name of any <<variable-assignment,variable>> known at{nbsp}__**L**__ | |
726 | which doesn't, directly or indirectly, refer to a label | |
727 | defined after{nbsp}__**L**__. | |
728 | -- | |
729 | + | |
269f6eb3 PP |
730 | The value of the special name `ICITTE` (`int` type) in this expression |
731 | is the <<cur-offset,current offset>> (before encoding the integer). | |
05f81895 PP |
732 | |
733 | . The `:` character. | |
734 | ||
735 | . One of: | |
736 | + | |
737 | -- | |
738 | [horizontal] | |
739 | `uleb128`:: Use the unsigned LEB128 format. | |
740 | `sleb128`:: Use the signed LEB128 format. | |
741 | -- | |
742 | ||
743 | . The `}` suffix. | |
744 | ||
745 | ==== | |
746 | Input: | |
747 | ||
748 | ---- | |
749 | {624485 : uleb128} | |
750 | ---- | |
751 | ||
752 | Output: | |
753 | ||
754 | ---- | |
755 | e5 8e 26 | |
756 | ---- | |
757 | ==== | |
758 | ||
759 | ==== | |
760 | Input: | |
761 | ||
762 | ---- | |
763 | aa bb cc dd | |
764 | <meow> | |
765 | ee ff | |
766 | {-981238311 + (meow * -23) : sleb128} | |
767 | "hello" | |
768 | ---- | |
769 | ||
c2b79cf6 PP |
770 | Output: |
771 | ||
05f81895 PP |
772 | ---- |
773 | aa bb cc dd ee ff fd fa 8d ac 7c 68 65 6c 6c 6f ┆ ••••••••••|hello | |
774 | ---- | |
775 | ==== | |
776 | ||
71aaa3f7 PP |
777 | === Current offset setting |
778 | ||
779 | This special item sets the <<cur-offset,_current offset_>>. | |
780 | ||
781 | A current offset setting is: | |
782 | ||
783 | . The `<` prefix. | |
784 | ||
785 | . A positive integer (hexadecimal starting with `0x` or `0X` accepted) | |
786 | which is the new current offset. | |
787 | ||
788 | . The `>` suffix. | |
789 | ||
790 | ==== | |
791 | Input: | |
792 | ||
793 | ---- | |
794 | {ICITTE : 8} * 8 | |
795 | <0x61> {ICITTE : 8} * 8 | |
796 | ---- | |
797 | ||
798 | Output: | |
799 | ||
800 | ---- | |
801 | 00 01 02 03 04 05 06 07 61 62 63 64 65 66 67 68 ┆ ••••••••abcdefgh | |
802 | ---- | |
803 | ==== | |
804 | ||
805 | ==== | |
806 | Input: | |
807 | ||
808 | ---- | |
809 | aa bb cc dd <meow> ee ff | |
810 | <12> 11 22 33 <mix> 44 55 | |
811 | {meow : 8} {mix : 8} | |
812 | ---- | |
813 | ||
814 | Output: | |
815 | ||
816 | ---- | |
817 | aa bb cc dd ee ff 11 22 33 44 55 04 0f ┆ •••••••"3DU•• | |
818 | ---- | |
819 | ==== | |
820 | ||
676f6189 PP |
821 | === Current offset alignment |
822 | ||
00deb9fa | 823 | A _current offset alignment_ represents zero or more padding bytes to |
676f6189 PP |
824 | make the <<cur-offset,current offset>> meet a given |
825 | https://en.wikipedia.org/wiki/Data_structure_alignment[alignment] value. | |
826 | ||
827 | More specifically, for an alignment value of{nbsp}__**N**__{nbsp}bits, | |
828 | a current offset alignment represents the required padding bytes until | |
829 | the current offset is a multiple of __**N**__{nbsp}/{nbsp}8. | |
830 | ||
831 | A current offset alignment is: | |
832 | ||
833 | . The `@` prefix. | |
834 | ||
835 | . A positive integer (hexadecimal starting with `0x` or `0X` accepted) | |
836 | which is the alignment value in _bits_. | |
837 | + | |
838 | This value must be greater than zero and a multiple of{nbsp}8. | |
839 | ||
840 | . **Optional**: | |
841 | + | |
842 | -- | |
843 | . The ``pass:[~]`` prefix. | |
844 | . A positive integer (hexadecimal starting with `0x` or `0X` accepted) | |
845 | which is the value of the byte to use as padding to align the | |
846 | <<cur-offset,current offset>>. | |
847 | -- | |
848 | + | |
849 | Without this section, the padding byte value is zero. | |
850 | ||
851 | ==== | |
852 | Input: | |
853 | ||
854 | ---- | |
855 | 11 22 (@32 aa bb cc) * 3 | |
856 | ---- | |
857 | ||
858 | Output: | |
859 | ||
860 | ---- | |
861 | 11 22 00 00 aa bb cc 00 aa bb cc 00 aa bb cc | |
862 | ---- | |
863 | ==== | |
864 | ||
865 | ==== | |
866 | Input: | |
867 | ||
868 | ---- | |
869 | {le} | |
870 | 77 88 | |
871 | @32~0xcc {-893.5:32} | |
872 | @128~0x55 "meow" | |
873 | ---- | |
874 | ||
875 | Output: | |
876 | ||
877 | ---- | |
878 | 77 88 cc cc 00 60 5f c4 55 55 55 55 55 55 55 55 ┆ w••••`_•UUUUUUUU | |
879 | 6d 65 6f 77 ┆ meow | |
880 | ---- | |
881 | ==== | |
882 | ||
883 | ==== | |
884 | Input: | |
885 | ||
886 | ---- | |
887 | aa bb cc <29> @64~255 "zoom" | |
888 | ---- | |
889 | ||
890 | Output: | |
891 | ||
892 | ---- | |
893 | aa bb cc ff ff ff 7a 6f 6f 6d ┆ ••••••zoom | |
894 | ---- | |
895 | ==== | |
896 | ||
71aaa3f7 PP |
897 | === Label |
898 | ||
899 | A _label_ associates a name to the <<cur-offset,current offset>>. | |
900 | ||
901 | All the labels of a whole Normand input must have unique names. | |
902 | ||
05f81895 | 903 | A label must not share the name of a <<variable-assignment,variable>> |
71aaa3f7 PP |
904 | name. |
905 | ||
71aaa3f7 PP |
906 | A label is: |
907 | ||
908 | . The `<` prefix. | |
909 | ||
05f81895 | 910 | . A valid {py3} name which is not `ICITTE` (see |
269f6eb3 | 911 | <<fixed-length-number>>, <<leb128-integer>>, and |
05f81895 | 912 | <<variable-assignment>> to learn more). |
71aaa3f7 PP |
913 | |
914 | . The `>` suffix. | |
915 | ||
916 | === Variable assignment | |
917 | ||
918 | A _variable assignment_ associates a name to the integral result of an | |
919 | evaluated {py3} expression. | |
920 | ||
05f81895 | 921 | A variable assignment is: |
71aaa3f7 PP |
922 | |
923 | . The ``pass:[{]`` prefix. | |
924 | ||
05f81895 | 925 | . A valid {py3} name which is not `ICITTE` (see |
269f6eb3 | 926 | <<fixed-length-number>>, <<leb128-integer>>, and |
05f81895 | 927 | <<variable-assignment>> to learn more). |
71aaa3f7 PP |
928 | |
929 | . The `=` character. | |
930 | ||
931 | . A valid {py3} expression. | |
05f81895 PP |
932 | + |
933 | For a variable assignment at some source location{nbsp}__**L**__, this | |
934 | expression may contain the name of any accessible <<label,label>> (not | |
935 | within a nested group), including the name of a label defined | |
936 | after{nbsp}__**L**__, as well as the name of any | |
937 | <<variable-assignment,variable>> known at{nbsp}__**L**__. | |
938 | + | |
269f6eb3 PP |
939 | The value of the special name `ICITTE` (`int` type) in this expression |
940 | is the <<cur-offset,current offset>>. | |
71aaa3f7 PP |
941 | |
942 | . The `}` suffix. | |
943 | ||
944 | ==== | |
945 | Input: | |
946 | ||
947 | ---- | |
948 | {mix = 101} {le} | |
949 | {meow = 42} 11 22 {meow:8} 33 {meow = ICITTE + 17} | |
950 | "yooo" {meow + mix : 16} | |
951 | ---- | |
952 | ||
953 | Output: | |
954 | ||
955 | ---- | |
956 | 11 22 2a 33 79 6f 6f 6f 7a 00 ┆ •"*3yoooz• | |
957 | ---- | |
958 | ==== | |
959 | ||
960 | === Group | |
961 | ||
962 | A _group_ is a scoped sequence of items. | |
963 | ||
964 | The <<label,labels>> within a group aren't visible outside of it. | |
965 | ||
e57a18e1 PP |
966 | The main purpose of a group is to <<post-item-repetition,repeat>> more |
967 | than a single item and to isolate labels. | |
71aaa3f7 PP |
968 | |
969 | A group is: | |
970 | ||
971 | . The `(` prefix. | |
972 | ||
973 | . Zero or more items. | |
974 | ||
975 | . The `)` suffix. | |
976 | ||
977 | ==== | |
978 | Input: | |
979 | ||
980 | ---- | |
981 | ((aa bb cc) dd () ee) "leclerc" | |
982 | ---- | |
983 | ||
984 | Output: | |
985 | ||
986 | ---- | |
987 | aa bb cc dd ee 6c 65 63 6c 65 72 63 ┆ •••••leclerc | |
988 | ---- | |
989 | ==== | |
990 | ||
991 | ==== | |
992 | Input: | |
993 | ||
994 | ---- | |
995 | ((aa bb cc) * 3 dd ee) * 5 | |
996 | ---- | |
997 | ||
998 | Output: | |
999 | ||
1000 | ---- | |
1001 | aa bb cc aa bb cc aa bb cc dd ee aa bb cc aa bb | |
1002 | cc aa bb cc dd ee aa bb cc aa bb cc aa bb cc dd | |
1003 | ee aa bb cc aa bb cc aa bb cc dd ee aa bb cc aa | |
1004 | bb cc aa bb cc dd ee | |
1005 | ---- | |
1006 | ==== | |
1007 | ||
1008 | ==== | |
1009 | Input: | |
1010 | ||
1011 | ---- | |
1012 | {be} | |
1013 | ( | |
1014 | <str_beg> u16le"sébastien diaz" <str_end> | |
1015 | {ICITTE - str_beg : 8} | |
1016 | {(end - str_beg) * 5 : 24} | |
1017 | ) * 3 | |
1018 | <end> | |
1019 | ---- | |
1020 | ||
1021 | Output: | |
1022 | ||
1023 | ---- | |
1024 | 73 00 e9 00 62 00 61 00 73 00 74 00 69 00 65 00 ┆ s•••b•a•s•t•i•e• | |
1025 | 6e 00 20 00 64 00 69 00 61 00 7a 00 1c 00 01 e0 ┆ n• •d•i•a•z••••• | |
1026 | 73 00 e9 00 62 00 61 00 73 00 74 00 69 00 65 00 ┆ s•••b•a•s•t•i•e• | |
1027 | 6e 00 20 00 64 00 69 00 61 00 7a 00 1c 00 01 40 ┆ n• •d•i•a•z••••@ | |
1028 | 73 00 e9 00 62 00 61 00 73 00 74 00 69 00 65 00 ┆ s•••b•a•s•t•i•e• | |
1029 | 6e 00 20 00 64 00 69 00 61 00 7a 00 1c 00 00 a0 ┆ n• •d•i•a•z••••• | |
1030 | ---- | |
1031 | ==== | |
1032 | ||
e57a18e1 | 1033 | === Repetition block |
71aaa3f7 | 1034 | |
e57a18e1 PP |
1035 | A _repetition block_ represents the bytes of one or more items repeated |
1036 | a given number of times. | |
676f6189 | 1037 | |
e57a18e1 | 1038 | A repetition block is: |
71aaa3f7 | 1039 | |
e57a18e1 | 1040 | . The `!repeat` or `!r` prefix. |
71aaa3f7 | 1041 | |
2adf4336 PP |
1042 | . One of: |
1043 | ||
1044 | ** A positive integer (hexadecimal starting with `0x` or `0X` accepted) | |
1045 | which is the number of times to repeat the previous item. | |
1046 | ||
1047 | ** The ``pass:[{]`` prefix, a valid {py3} expression, and the | |
1048 | ``pass:[}]`` suffix. | |
05f81895 PP |
1049 | + |
1050 | For a repetition at some source location{nbsp}__**L**__, this expression | |
1051 | may contain: | |
1052 | + | |
1053 | -- | |
e57a18e1 | 1054 | * The name of any <<label,label>> defined before{nbsp}__**L**__. |
05f81895 | 1055 | * The name of any <<variable-assignment,variable>> known |
e57a18e1 PP |
1056 | at{nbsp}__**L**__ which doesn't, directly or indirectly, refer to a |
1057 | label defined after{nbsp}__**L**__. | |
05f81895 PP |
1058 | -- |
1059 | + | |
e57a18e1 PP |
1060 | The value of the special name `ICITTE` (`int` type) in this expression |
1061 | is the <<cur-offset,current offset>> (before handling the items to | |
1062 | repeat). | |
1063 | ||
1064 | ** A valid {py3} name. | |
1065 | + | |
1066 | For the name `__NAME__`, this is equivalent to the | |
1067 | `pass:[{]__NAME__pass:[}]` form above. | |
1068 | ||
1069 | . Zero or more items. | |
1070 | ||
1071 | . The `!end` suffix. | |
1072 | ||
1073 | You may also use a <<post-item-repetition,post-item repetition>> after | |
1074 | some items. The form ``!repeat{nbsp}__X__{nbsp}__ITEMS__{nbsp}!end`` | |
1075 | is equivalent to ``(__ITEMS__){nbsp}pass:[*]{nbsp}__X__``. | |
71aaa3f7 PP |
1076 | |
1077 | ==== | |
1078 | Input: | |
1079 | ||
1080 | ---- | |
e57a18e1 PP |
1081 | !repeat 0x100 |
1082 | {end - ICITTE - 1 : 8} | |
1083 | !end | |
1084 | ||
1085 | <end> | |
71aaa3f7 PP |
1086 | ---- |
1087 | ||
1088 | Output: | |
1089 | ||
1090 | ---- | |
1091 | ff fe fd fc fb fa f9 f8 f7 f6 f5 f4 f3 f2 f1 f0 ┆ •••••••••••••••• | |
1092 | ef ee ed ec eb ea e9 e8 e7 e6 e5 e4 e3 e2 e1 e0 ┆ •••••••••••••••• | |
1093 | df de dd dc db da d9 d8 d7 d6 d5 d4 d3 d2 d1 d0 ┆ •••••••••••••••• | |
1094 | cf ce cd cc cb ca c9 c8 c7 c6 c5 c4 c3 c2 c1 c0 ┆ •••••••••••••••• | |
1095 | bf be bd bc bb ba b9 b8 b7 b6 b5 b4 b3 b2 b1 b0 ┆ •••••••••••••••• | |
1096 | af ae ad ac ab aa a9 a8 a7 a6 a5 a4 a3 a2 a1 a0 ┆ •••••••••••••••• | |
1097 | 9f 9e 9d 9c 9b 9a 99 98 97 96 95 94 93 92 91 90 ┆ •••••••••••••••• | |
1098 | 8f 8e 8d 8c 8b 8a 89 88 87 86 85 84 83 82 81 80 ┆ •••••••••••••••• | |
1099 | 7f 7e 7d 7c 7b 7a 79 78 77 76 75 74 73 72 71 70 ┆ •~}|{zyxwvutsrqp | |
1100 | 6f 6e 6d 6c 6b 6a 69 68 67 66 65 64 63 62 61 60 ┆ onmlkjihgfedcba` | |
1101 | 5f 5e 5d 5c 5b 5a 59 58 57 56 55 54 53 52 51 50 ┆ _^]\[ZYXWVUTSRQP | |
1102 | 4f 4e 4d 4c 4b 4a 49 48 47 46 45 44 43 42 41 40 ┆ ONMLKJIHGFEDCBA@ | |
1103 | 3f 3e 3d 3c 3b 3a 39 38 37 36 35 34 33 32 31 30 ┆ ?>=<;:9876543210 | |
1104 | 2f 2e 2d 2c 2b 2a 29 28 27 26 25 24 23 22 21 20 ┆ /.-,+*)('&%$#"! | |
1105 | 1f 1e 1d 1c 1b 1a 19 18 17 16 15 14 13 12 11 10 ┆ •••••••••••••••• | |
1106 | 0f 0e 0d 0c 0b 0a 09 08 07 06 05 04 03 02 01 00 ┆ •••••••••••••••• | |
1107 | ---- | |
1108 | ==== | |
1109 | ||
2adf4336 PP |
1110 | ==== |
1111 | Input: | |
1112 | ||
1113 | ---- | |
1114 | {times = 1} | |
e57a18e1 | 1115 | |
2adf4336 | 1116 | aa bb cc dd |
e57a18e1 PP |
1117 | |
1118 | !repeat 3 | |
2adf4336 | 1119 | <here> |
e57a18e1 PP |
1120 | |
1121 | !repeat {here + 1} | |
1122 | ee ff | |
1123 | !end | |
1124 | ||
1125 | 11 22 !repeat times 33 !end | |
1126 | ||
2adf4336 | 1127 | {times = times + 1} |
e57a18e1 PP |
1128 | !end |
1129 | ||
2adf4336 PP |
1130 | "coucou!" |
1131 | ---- | |
1132 | ||
1133 | Output: | |
1134 | ||
1135 | ---- | |
1136 | aa bb cc dd ee ff ee ff ee ff ee ff ee ff 11 22 ┆ •••••••••••••••" | |
1137 | 33 ee ff ee ff ee ff ee ff ee ff ee ff ee ff ee ┆ 3••••••••••••••• | |
1138 | ff ee ff ee ff ee ff ee ff ee ff ee ff ee ff ee ┆ •••••••••••••••• | |
1139 | ff ee ff ee ff 11 22 33 33 ee ff ee ff ee ff ee ┆ ••••••"33••••••• | |
1140 | ff ee ff ee ff ee ff ee ff ee ff ee ff ee ff ee ┆ •••••••••••••••• | |
1141 | ff ee ff ee ff ee ff ee ff ee ff ee ff ee ff ee ┆ •••••••••••••••• | |
1142 | ff ee ff ee ff ee ff ee ff ee ff ee ff ee ff ee ┆ •••••••••••••••• | |
1143 | ff ee ff ee ff ee ff ee ff ee ff ee ff ee ff ee ┆ •••••••••••••••• | |
1144 | ff ee ff ee ff ee ff ee ff ee ff ee ff ee ff ee ┆ •••••••••••••••• | |
1145 | ff ee ff ee ff ee ff ee ff ee ff ee ff ee ff ee ┆ •••••••••••••••• | |
1146 | ff ee ff ee ff ee ff ee ff ee ff ee ff 11 22 33 ┆ ••••••••••••••"3 | |
1147 | 33 33 63 6f 75 63 6f 75 21 ┆ 33coucou! | |
1148 | ---- | |
1149 | ==== | |
1150 | ||
1151 | ==== | |
e57a18e1 PP |
1152 | This example shows how to use a repetition block as a conditional |
1153 | section depending on some predefined variable. | |
2adf4336 PP |
1154 | |
1155 | Input: | |
1156 | ||
1157 | ---- | |
1158 | aa bb cc dd | |
e57a18e1 PP |
1159 | |
1160 | !repeat cond | |
1161 | ee ff "meow mix" 00 | |
1162 | !end | |
1163 | ||
2adf4336 PP |
1164 | {be} {-1993:16} |
1165 | ---- | |
1166 | ||
1167 | Output (`cond` is 0): | |
1168 | ||
1169 | ---- | |
1170 | aa bb cc dd f8 37 | |
1171 | ---- | |
1172 | ||
1173 | Output (`cond` is 1): | |
1174 | ||
1175 | ---- | |
1176 | aa bb cc dd ee ff 6d 65 6f 77 20 6d 69 78 00 f8 ┆ ••••••meow mix•• | |
1177 | 37 ┆ 7 | |
1178 | ---- | |
1179 | ==== | |
1180 | ||
e57a18e1 PP |
1181 | === Post-item repetition |
1182 | ||
1183 | A _post-item repetition_ represents the bytes of an item repeated a | |
1184 | given number of times. | |
1185 | ||
1186 | A post-item repetition is: | |
1187 | ||
1188 | . Any item except: | |
1189 | ||
1190 | ** A <<current-byte-order-setting,current byte order setting>>. | |
1191 | ** A <<current-offset-setting,current offset setting>>. | |
1192 | ** A <<label,label>>. | |
1193 | ** A <<offset-alignment,offset alignment>>. | |
1194 | ** A <<variable-assignment,variable assignment>>. | |
1195 | ** A <<repetition-block,repetition block>>. | |
1196 | ||
1197 | . The ``pass:[*]`` character. | |
1198 | ||
1199 | . One of: | |
1200 | ||
1201 | ** A positive integer (hexadecimal starting with `0x` or `0X` accepted) | |
1202 | which is the number of times to repeat the previous item. | |
1203 | ||
1204 | ** The ``pass:[{]`` prefix, a valid {py3} expression, and the | |
1205 | ``pass:[}]`` suffix. | |
1206 | + | |
1207 | For a repetition at some source location{nbsp}__**L**__, this expression | |
1208 | may contain: | |
1209 | + | |
1210 | -- | |
1211 | * The name of any <<label,label>> defined before{nbsp}__**L**__ and | |
1212 | which isn't part of its repeated item. | |
1213 | * The name of any <<variable-assignment,variable>> known | |
1214 | at{nbsp}__**L**__, which isn't part of its repeated item, and which | |
1215 | doesn't, directly or indirectly, refer to a label defined | |
1216 | after{nbsp}__**L**__. | |
1217 | -- | |
1218 | + | |
1219 | The value of the special name `ICITTE` (`int` type) in this expression | |
1220 | is the <<cur-offset,current offset>> (before handling the items to | |
1221 | repeat). | |
1222 | ||
1223 | ** A valid {py3} name. | |
1224 | + | |
1225 | For the name `__NAME__`, this is equivalent to the | |
1226 | `pass:[{]__NAME__pass:[}]` form above. | |
1227 | ||
1228 | You may also use a <<repetition-block,repetition block>>. The form | |
1229 | ``__ITEM__{nbsp}pass:[*]{nbsp}__X__`` is equivalent to | |
1230 | ``!repeat{nbsp}__X__{nbsp}__ITEM__{nbsp}!end``. | |
1231 | ||
1232 | ==== | |
1233 | Input: | |
1234 | ||
1235 | ---- | |
1236 | {end - ICITTE - 1 : 8} * 0x100 <end> | |
1237 | ---- | |
1238 | ||
1239 | Output: | |
1240 | ||
1241 | ---- | |
1242 | ff fe fd fc fb fa f9 f8 f7 f6 f5 f4 f3 f2 f1 f0 ┆ •••••••••••••••• | |
1243 | ef ee ed ec eb ea e9 e8 e7 e6 e5 e4 e3 e2 e1 e0 ┆ •••••••••••••••• | |
1244 | df de dd dc db da d9 d8 d7 d6 d5 d4 d3 d2 d1 d0 ┆ •••••••••••••••• | |
1245 | cf ce cd cc cb ca c9 c8 c7 c6 c5 c4 c3 c2 c1 c0 ┆ •••••••••••••••• | |
1246 | bf be bd bc bb ba b9 b8 b7 b6 b5 b4 b3 b2 b1 b0 ┆ •••••••••••••••• | |
1247 | af ae ad ac ab aa a9 a8 a7 a6 a5 a4 a3 a2 a1 a0 ┆ •••••••••••••••• | |
1248 | 9f 9e 9d 9c 9b 9a 99 98 97 96 95 94 93 92 91 90 ┆ •••••••••••••••• | |
1249 | 8f 8e 8d 8c 8b 8a 89 88 87 86 85 84 83 82 81 80 ┆ •••••••••••••••• | |
1250 | 7f 7e 7d 7c 7b 7a 79 78 77 76 75 74 73 72 71 70 ┆ •~}|{zyxwvutsrqp | |
1251 | 6f 6e 6d 6c 6b 6a 69 68 67 66 65 64 63 62 61 60 ┆ onmlkjihgfedcba` | |
1252 | 5f 5e 5d 5c 5b 5a 59 58 57 56 55 54 53 52 51 50 ┆ _^]\[ZYXWVUTSRQP | |
1253 | 4f 4e 4d 4c 4b 4a 49 48 47 46 45 44 43 42 41 40 ┆ ONMLKJIHGFEDCBA@ | |
1254 | 3f 3e 3d 3c 3b 3a 39 38 37 36 35 34 33 32 31 30 ┆ ?>=<;:9876543210 | |
1255 | 2f 2e 2d 2c 2b 2a 29 28 27 26 25 24 23 22 21 20 ┆ /.-,+*)('&%$#"! | |
1256 | 1f 1e 1d 1c 1b 1a 19 18 17 16 15 14 13 12 11 10 ┆ •••••••••••••••• | |
1257 | 0f 0e 0d 0c 0b 0a 09 08 07 06 05 04 03 02 01 00 ┆ •••••••••••••••• | |
1258 | ---- | |
1259 | ==== | |
1260 | ||
1261 | ==== | |
1262 | Input: | |
1263 | ||
1264 | ---- | |
1265 | {times = 1} | |
1266 | aa bb cc dd | |
1267 | ( | |
1268 | <here> | |
1269 | (ee ff) * {here + 1} | |
1270 | 11 22 33 * {times} | |
1271 | {times = times + 1} | |
1272 | ) * 3 | |
1273 | "coucou!" | |
1274 | ---- | |
1275 | ||
1276 | Output: | |
1277 | ||
1278 | ---- | |
1279 | aa bb cc dd ee ff ee ff ee ff ee ff ee ff 11 22 ┆ •••••••••••••••" | |
1280 | 33 ee ff ee ff ee ff ee ff ee ff ee ff ee ff ee ┆ 3••••••••••••••• | |
1281 | ff ee ff ee ff ee ff ee ff ee ff ee ff ee ff ee ┆ •••••••••••••••• | |
1282 | ff ee ff ee ff 11 22 33 33 ee ff ee ff ee ff ee ┆ ••••••"33••••••• | |
1283 | ff ee ff ee ff ee ff ee ff ee ff ee ff ee ff ee ┆ •••••••••••••••• | |
1284 | ff ee ff ee ff ee ff ee ff ee ff ee ff ee ff ee ┆ •••••••••••••••• | |
1285 | ff ee ff ee ff ee ff ee ff ee ff ee ff ee ff ee ┆ •••••••••••••••• | |
1286 | ff ee ff ee ff ee ff ee ff ee ff ee ff ee ff ee ┆ •••••••••••••••• | |
1287 | ff ee ff ee ff ee ff ee ff ee ff ee ff ee ff ee ┆ •••••••••••••••• | |
1288 | ff ee ff ee ff ee ff ee ff ee ff ee ff ee ff ee ┆ •••••••••••••••• | |
1289 | ff ee ff ee ff ee ff ee ff ee ff ee ff 11 22 33 ┆ ••••••••••••••"3 | |
1290 | 33 33 63 6f 75 63 6f 75 21 ┆ 33coucou! | |
1291 | ---- | |
1292 | ==== | |
1293 | ||
71aaa3f7 PP |
1294 | == Command-line tool |
1295 | ||
1296 | If you <<install-normand,installed>> the `normand` package, then you | |
1297 | can use the `normand` command-line tool: | |
1298 | ||
1299 | ---- | |
1300 | $ normand <<< '"ma gang de malades"' | hexdump -C | |
1301 | ---- | |
1302 | ||
1303 | ---- | |
1304 | 00000000 6d 61 20 67 61 6e 67 20 64 65 20 6d 61 6c 61 64 |ma gang de malad| | |
1305 | 00000010 65 73 |es| | |
1306 | ---- | |
1307 | ||
1308 | If you copy the `normand.py` module to your own project, then you can | |
1309 | run the module itself: | |
1310 | ||
1311 | ---- | |
1312 | $ python3 -m normand <<< '"ma gang de malades"' | hexdump -C | |
1313 | ---- | |
1314 | ||
1315 | ---- | |
1316 | 00000000 6d 61 20 67 61 6e 67 20 64 65 20 6d 61 6c 61 64 |ma gang de malad| | |
1317 | 00000010 65 73 |es| | |
1318 | ---- | |
1319 | ||
1320 | Without a path argument, the `normand` tool reads from the standard | |
1321 | input. | |
1322 | ||
1323 | The `normand` tool prints the generated binary data to the standard | |
1324 | output. | |
1325 | ||
1326 | Various options control the initial <<state,state>> of the processor: | |
1327 | use the `--help` option to learn more. | |
1328 | ||
1329 | == {py3} API | |
1330 | ||
e57a18e1 | 1331 | The whole `normand` package/module public API is: |
71aaa3f7 PP |
1332 | |
1333 | [source,python] | |
1334 | ---- | |
e57a18e1 | 1335 | # Byte order. |
71aaa3f7 PP |
1336 | class ByteOrder(enum.Enum): |
1337 | # Big endian. | |
1338 | BE = ... | |
1339 | ||
1340 | # Little endian. | |
1341 | LE = ... | |
1342 | ||
1343 | ||
e57a18e1 PP |
1344 | # Text location. |
1345 | class TextLocation: | |
71aaa3f7 PP |
1346 | # Line number. |
1347 | @property | |
1348 | def line_no(self) -> int: | |
1349 | ... | |
1350 | ||
1351 | # Column number. | |
1352 | @property | |
1353 | def col_no(self) -> int: | |
1354 | ... | |
1355 | ||
1356 | ||
e57a18e1 | 1357 | # Parsing error. |
71aaa3f7 PP |
1358 | class ParseError(RuntimeError): |
1359 | # Source text location. | |
1360 | @property | |
e57a18e1 | 1361 | def text_loc(self) -> TextLocation: |
71aaa3f7 PP |
1362 | ... |
1363 | ||
1364 | ||
e57a18e1 PP |
1365 | # Variables dictionary type (for type hints). |
1366 | VariablesT = typing.Dict[str, typing.Union[int, float]] | |
1367 | ||
1368 | ||
1369 | # Labels dictionary type (for type hints). | |
1370 | LabelsT = typing.Dict[str, int] | |
1b8aa84a PP |
1371 | |
1372 | ||
e57a18e1 | 1373 | # Parsing result. |
71aaa3f7 PP |
1374 | class ParseResult: |
1375 | # Generated data. | |
1376 | @property | |
1377 | def data(self) -> bytearray: | |
1378 | ... | |
1379 | ||
1380 | # Updated variable values. | |
1381 | @property | |
1b8aa84a | 1382 | def variables(self) -> SymbolsT: |
71aaa3f7 PP |
1383 | ... |
1384 | ||
1385 | # Updated main group label values. | |
1386 | @property | |
1b8aa84a | 1387 | def labels(self) -> SymbolsT: |
71aaa3f7 PP |
1388 | ... |
1389 | ||
1390 | # Final offset. | |
1391 | @property | |
1392 | def offset(self) -> int: | |
1393 | ... | |
1394 | ||
1395 | # Final byte order. | |
1396 | @property | |
1b8aa84a | 1397 | def byte_order(self) -> typing.Optional[ByteOrder]: |
71aaa3f7 PP |
1398 | ... |
1399 | ||
1b8aa84a | 1400 | |
e57a18e1 PP |
1401 | # Parses the `normand` input using the initial state defined by |
1402 | # `init_variables`, `init_labels`, `init_offset`, and `init_byte_order`, | |
1403 | # and returns the corresponding parsing result. | |
71aaa3f7 | 1404 | def parse(normand: str, |
1b8aa84a PP |
1405 | init_variables: typing.Optional[SymbolsT] = None, |
1406 | init_labels: typing.Optional[SymbolsT] = None, | |
71aaa3f7 PP |
1407 | init_offset: int = 0, |
1408 | init_byte_order: typing.Optional[ByteOrder] = None) -> ParseResult: | |
1409 | ... | |
1410 | ---- | |
1411 | ||
1412 | The `normand` parameter is the actual <<learn-normand,Normand input>> | |
1413 | while the other parameters control the initial <<state,state>>. | |
1414 | ||
1415 | The `parse()` function raises a `ParseError` instance should it fail to | |
1416 | parse the `normand` string for any reason. | |
bf8f3b38 PP |
1417 | |
1418 | == Development | |
1419 | ||
1420 | Normand is a https://python-poetry.org/[Poetry] project. | |
1421 | ||
1422 | To develop it, install it through Poetry and enter the virtual | |
1423 | environment: | |
1424 | ||
1425 | ---- | |
1426 | $ poetry install | |
1427 | $ poetry shell | |
1428 | $ normand <<< '"lol" * 10 0a' | |
1429 | ---- | |
1430 | ||
1431 | `normand.py` is processed by: | |
1432 | ||
1433 | * https://microsoft.github.io/pyright/[Pyright] | |
1434 | * https://github.com/psf/black[Black] | |
1435 | * https://pycqa.github.io/isort/[isort] | |
1436 | ||
1437 | === Testing | |
1438 | ||
1439 | Use https://docs.pytest.org/[pytest] to test Normand once the package is | |
1440 | part of your virtual environment, for example: | |
1441 | ||
1442 | ---- | |
1443 | $ poetry install | |
1444 | $ poetry run pip3 install pytest | |
1445 | $ poetry run pytest | |
1446 | ---- | |
1447 | ||
1448 | The `pytest` project is currently not a development dependency in | |
1449 | `pyproject.toml` due to backward compatibiliy issues with | |
1450 | Python{nbsp}3.4. | |
1451 | ||
1452 | In the `tests` directory, each `*.nt` file is a test. The file name | |
1453 | prefix indicates what it's meant to test: | |
1454 | ||
1455 | `pass-`:: | |
1456 | Everything above the `---` line is the valid Normand input | |
1457 | to test. | |
1458 | + | |
1459 | Everything below the `---` line is the expected data | |
1460 | (whitespace-separated hexadecimal bytes). | |
1461 | ||
1462 | `fail-`:: | |
1463 | Everything above the `---` line is the invalid Normand input | |
1464 | to test. | |
1465 | + | |
1466 | Everything below the `---` line is the expected error message having | |
1467 | this form: | |
1468 | + | |
1469 | ---- | |
1470 | LINE:COL - MESSAGE | |
1471 | ---- | |
1472 | ||
1473 | === Contributing | |
1474 | ||
1475 | Normand uses https://review.lttng.org/admin/repos/normand,general[Gerrit] | |
1476 | for code review. | |
1477 | ||
1478 | To report a bug, https://github.com/efficios/normand/issues/new[create a | |
1479 | GitHub issue]. |