Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 1 | #LyX 1.3 created this file. For more info see http://www.lyx.org/ |
| 2 | \lyxformat 221 |
| 3 | \textclass book |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 4 | \begin_preamble |
| 5 | %\fancyhf{} |
| 6 | %\renewcommand{\chaptermark}[1]{\markboth{\thechapter.\ #1\ sdf}{}} |
| 7 | %\renewcommand{\sectionmark}[1]{\markright{\MakeUppercase{\thesection.\ #1}}} |
| 8 | %\fancyhead[LE,RO]{\thepage} |
| 9 | %\fancyhead[LO]{\rightmark} |
| 10 | %\fancyhead[RE]]{\leftmark} |
| 11 | \usepackage{extramarks} |
| 12 | \lhead{\firstxmark} |
| 13 | \rfoot{\lastxmark} |
| 14 | \end_preamble |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 15 | \language english |
| 16 | \inputencoding latin1 |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 17 | \fontscheme times |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 18 | \graphics default |
| 19 | \paperfontsize default |
| 20 | \spacing single |
| 21 | \papersize Default |
| 22 | \paperpackage a4 |
| 23 | \use_geometry 0 |
| 24 | \use_amsmath 0 |
| 25 | \use_natbib 0 |
| 26 | \use_numerical_citations 0 |
| 27 | \paperorientation portrait |
| 28 | \secnumdepth 3 |
| 29 | \tocdepth 3 |
| 30 | \paragraph_separation indent |
| 31 | \defskip medskip |
| 32 | \quotes_language swedish |
| 33 | \quotes_times 2 |
| 34 | \papercolumns 1 |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 35 | \papersides 2 |
| 36 | \paperpagestyle fancy |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 37 | |
| 38 | \layout Title |
| 39 | |
Lev Walkin | 26871b5 | 2004-09-08 03:01:06 +0000 | [diff] [blame] | 40 | Using the Open ASN.1 Compiler |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 41 | \layout Author |
| 42 | |
| 43 | Lev Walkin < |
| 44 | \begin_inset LatexCommand \url{vlm@lionet.info} |
| 45 | |
| 46 | \end_inset |
| 47 | |
| 48 | > |
| 49 | \layout Standard |
| 50 | |
| 51 | |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 52 | \begin_inset ERT |
| 53 | status Open |
| 54 | |
| 55 | \layout Standard |
| 56 | |
| 57 | \backslash |
Lev Walkin | 35d446b | 2004-09-24 20:56:07 +0000 | [diff] [blame] | 58 | extramarks{$Revision$ -- describes asn1c-0.9.6}{} |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 59 | \end_inset |
| 60 | |
| 61 | |
| 62 | \layout Standard |
| 63 | |
| 64 | |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 65 | \begin_inset LatexCommand \tableofcontents{} |
| 66 | |
| 67 | \end_inset |
| 68 | |
| 69 | |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 70 | \layout Standard |
| 71 | |
| 72 | |
| 73 | \begin_inset ERT |
| 74 | status Collapsed |
| 75 | |
| 76 | \layout Standard |
| 77 | |
| 78 | \backslash |
| 79 | pagestyle{headings} |
| 80 | \end_inset |
| 81 | |
| 82 | |
Lev Walkin | 4a83dd5 | 2004-08-07 05:00:07 +0000 | [diff] [blame] | 83 | \layout Part |
| 84 | |
| 85 | ASN.1 Basics |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 86 | \layout Chapter |
| 87 | |
Lev Walkin | 4a83dd5 | 2004-08-07 05:00:07 +0000 | [diff] [blame] | 88 | Abstract Syntax Notation: ASN.1 |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 89 | \layout Standard |
| 90 | |
| 91 | |
| 92 | \emph on |
| 93 | This chapter defines some basic ASN.1 concepts and describes several most |
| 94 | widely used types. |
| 95 | It is by no means an authoritative or complete reference. |
| 96 | For more complete ASN.1 description, please refer to Olivier Dubuisson's |
| 97 | book |
| 98 | \begin_inset LatexCommand \cite{Dub00} |
| 99 | |
| 100 | \end_inset |
| 101 | |
Lev Walkin | 4a83dd5 | 2004-08-07 05:00:07 +0000 | [diff] [blame] | 102 | or the ASN.1 body of standards itself |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 103 | \begin_inset LatexCommand \cite{ITU-T/ASN.1} |
| 104 | |
| 105 | \end_inset |
| 106 | |
| 107 | . |
| 108 | \layout Standard |
| 109 | |
| 110 | The Abstract Syntax Notation One is used to formally describe the semantics |
| 111 | of data transmitted across the network. |
| 112 | Two communicating parties may have different formats of their native data |
| 113 | types (i.e. |
| 114 | number of bits in the integer type), thus it is important to have a way |
| 115 | to describe the data in a manner which is independent from the particular |
| 116 | machine's representation. |
| 117 | The ASN.1 specifications is used to achieve one or more of the following: |
| 118 | \layout Itemize |
| 119 | |
| 120 | The specification expressed in the ASN.1 notation is a formal and precise |
| 121 | way to communicate the data semantics to human readers; |
| 122 | \layout Itemize |
| 123 | |
| 124 | The ASN.1 specifications may be used as input for automatic compilers which |
| 125 | produce the code for some target language (C, C++, Java, etc) to encode |
| 126 | and decode the data according to some encoding rules (which are also defined |
| 127 | by the ASN.1 standard). |
| 128 | \layout Standard |
| 129 | |
| 130 | Consider the following example: |
| 131 | \layout LyX-Code |
| 132 | |
| 133 | Rectangle ::= SEQUENCE { |
| 134 | \layout LyX-Code |
| 135 | |
| 136 | height INTEGER, |
| 137 | \layout LyX-Code |
| 138 | |
| 139 | width INTEGER |
| 140 | \layout LyX-Code |
| 141 | |
| 142 | } |
| 143 | \layout Standard |
| 144 | |
| 145 | This ASN.1 specification describes a constructed type, |
| 146 | \emph on |
| 147 | Rectangle |
| 148 | \emph default |
| 149 | , containing two integer fields. |
| 150 | This specification may tell the reader that there is this kind of data |
| 151 | structure and that some entity may be prepared to send or receive it. |
| 152 | The question on |
| 153 | \emph on |
| 154 | how |
| 155 | \emph default |
| 156 | that entity is going to send or receive the |
| 157 | \emph on |
| 158 | encoded data |
| 159 | \emph default |
| 160 | is outside the scope of ASN.1. |
| 161 | For example, this data structure may be encoded according to some encoding |
| 162 | rules and sent to the destination using the TCP protocol. |
| 163 | The ASN.1 specifies several ways of encoding (or |
| 164 | \begin_inset Quotes sld |
| 165 | \end_inset |
| 166 | |
| 167 | serializing |
| 168 | \begin_inset Quotes srd |
| 169 | \end_inset |
| 170 | |
| 171 | , or |
| 172 | \begin_inset Quotes sld |
| 173 | \end_inset |
| 174 | |
| 175 | marshaling |
| 176 | \begin_inset Quotes srd |
| 177 | \end_inset |
| 178 | |
| 179 | ) the data: BER, CER, DER and XER, some of them which will be described |
| 180 | later. |
| 181 | \layout Standard |
| 182 | |
| 183 | The complete specification must be wrapped in a module, which looks like |
| 184 | this: |
| 185 | \layout LyX-Code |
| 186 | |
| 187 | UsageExampleModule1 |
| 188 | \layout LyX-Code |
| 189 | |
| 190 | { iso org(3) dod(6) internet(1) private(4) |
| 191 | \layout LyX-Code |
| 192 | |
| 193 | enterprise(1) spelio(9363) software(1) |
| 194 | \layout LyX-Code |
| 195 | |
| 196 | asn1c(5) docs(2) usage(1) 1 } |
| 197 | \layout LyX-Code |
| 198 | |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 199 | DEFINITIONS AUTOMATIC TAGS ::= |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 200 | \layout LyX-Code |
| 201 | |
| 202 | BEGIN |
| 203 | \layout LyX-Code |
| 204 | |
| 205 | |
| 206 | \layout LyX-Code |
| 207 | |
| 208 | -- This is a comment which describes nothing. |
| 209 | \layout LyX-Code |
| 210 | |
| 211 | Rectangle ::= SEQUENCE { |
| 212 | \layout LyX-Code |
| 213 | |
| 214 | height INTEGER, -- Height of the rectangle |
| 215 | \layout LyX-Code |
| 216 | |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 217 | width INTEGER -- Width of the rectangle |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 218 | \layout LyX-Code |
| 219 | |
| 220 | } |
| 221 | \layout LyX-Code |
| 222 | |
| 223 | |
| 224 | \layout LyX-Code |
| 225 | |
| 226 | END |
| 227 | \layout Standard |
| 228 | |
| 229 | The module header consists of module name (UsageExampleModule1), the module |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 230 | object identifier ({...}), a keyword |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 231 | \begin_inset Quotes sld |
| 232 | \end_inset |
| 233 | |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 234 | DEFINITIONS |
| 235 | \begin_inset Quotes srd |
| 236 | \end_inset |
| 237 | |
| 238 | , a set of module flags (AUTOMATIC TAGS) and |
| 239 | \begin_inset Quotes sld |
| 240 | \end_inset |
| 241 | |
| 242 | ::= BEGIN |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 243 | \begin_inset Quotes srd |
| 244 | \end_inset |
| 245 | |
| 246 | . |
| 247 | The module ends with an |
| 248 | \begin_inset Quotes sld |
| 249 | \end_inset |
| 250 | |
| 251 | END |
| 252 | \begin_inset Quotes srd |
| 253 | \end_inset |
| 254 | |
| 255 | statement. |
| 256 | \layout Section |
| 257 | |
| 258 | Some of the ASN.1 Basic Types |
| 259 | \layout Subsection |
| 260 | |
| 261 | The BOOLEAN type |
| 262 | \layout Standard |
| 263 | |
| 264 | The BOOLEAN type models the simple binary TRUE/FALSE, YES/NO, ON/OFF or |
| 265 | a similar kind of two-way choice. |
| 266 | \layout Subsection |
| 267 | |
| 268 | The INTEGER type |
| 269 | \layout Standard |
| 270 | |
| 271 | The INTEGER type is a signed natural number type without any restrictions |
| 272 | on its size. |
| 273 | If the automatic checking on INTEGER value bounds are necessary, the subtype |
| 274 | constraints must be used. |
| 275 | \layout LyX-Code |
| 276 | |
| 277 | SimpleInteger ::= INTEGER |
| 278 | \layout LyX-Code |
| 279 | |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 280 | |
| 281 | \layout LyX-Code |
| 282 | |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 283 | -- An integer with a very limited range |
| 284 | \layout LyX-Code |
| 285 | |
| 286 | SmallInt ::= INTEGER (0..127) |
| 287 | \layout LyX-Code |
| 288 | |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 289 | |
| 290 | \layout LyX-Code |
| 291 | |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 292 | -- Integer, negative |
| 293 | \layout LyX-Code |
| 294 | |
| 295 | NegativeInt ::= INTEGER (MIN..0) |
| 296 | \layout Subsection |
| 297 | |
| 298 | The ENUMERATED type |
| 299 | \layout Standard |
| 300 | |
| 301 | The ENUMERATED type is semantically equivalent to the INTEGER type with |
| 302 | some integer values explicitly named. |
| 303 | \layout LyX-Code |
| 304 | |
| 305 | FruitId ::= ENUMERATED { apple(1), orange(2) } |
| 306 | \layout LyX-Code |
| 307 | |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 308 | |
| 309 | \layout LyX-Code |
| 310 | |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 311 | -- The numbers in braces are optional, |
| 312 | \layout LyX-Code |
| 313 | |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 314 | -- the enumeration can be performed |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 315 | \layout LyX-Code |
| 316 | |
| 317 | -- automatically by the compiler |
| 318 | \layout LyX-Code |
| 319 | |
| 320 | ComputerOSType ::= ENUMERATED { |
| 321 | \layout LyX-Code |
| 322 | |
| 323 | FreeBSD, -- will be 0 |
| 324 | \layout LyX-Code |
| 325 | |
| 326 | Windows, -- will be 1 |
| 327 | \layout LyX-Code |
| 328 | |
| 329 | Solaris(5), -- will remain 5 |
| 330 | \layout LyX-Code |
| 331 | |
| 332 | Linux, -- will be 6 |
| 333 | \layout LyX-Code |
| 334 | |
| 335 | MacOS -- will be 7 |
| 336 | \layout LyX-Code |
| 337 | |
| 338 | } |
| 339 | \layout Subsection |
| 340 | |
| 341 | The OCTET STRING type |
| 342 | \layout Standard |
| 343 | |
| 344 | This type models the sequence of 8-bit bytes. |
| 345 | This may be used to transmit some opaque data or data serialized by other |
| 346 | types of encoders (i.e. |
| 347 | video file, photo picture, etc). |
| 348 | \layout Subsection |
| 349 | |
| 350 | The OBJECT IDENTIFIER type |
| 351 | \layout Standard |
| 352 | |
| 353 | The OBJECT IDENTIFIER is used to represent the unique identifier of any |
| 354 | object, starting from the very root of the registration tree. |
| 355 | If your organization needs to uniquely identify something (a router, a |
| 356 | room, a person, a standard, or whatever), you are encouraged to get your |
| 357 | own identification subtree at |
| 358 | \begin_inset LatexCommand \htmlurl{http://www.iana.org/protocols/forms.htm} |
| 359 | |
| 360 | \end_inset |
| 361 | |
| 362 | . |
| 363 | \layout Standard |
| 364 | |
| 365 | For example, the very first ASN.1 module in this document has the following |
| 366 | OBJECT IDENTIFIER: 1 3 6 1 4 1 9363 1 5 2 1 1. |
| 367 | \layout LyX-Code |
| 368 | |
| 369 | ExampleOID ::= OBJECT IDENTIFIER |
| 370 | \layout LyX-Code |
| 371 | |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 372 | |
| 373 | \layout LyX-Code |
| 374 | |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 375 | usageExampleModule1-oid ExampleOID |
| 376 | \layout LyX-Code |
| 377 | |
| 378 | ::= { 1 3 6 1 4 1 9363 1 5 2 1 1 } |
| 379 | \layout LyX-Code |
| 380 | |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 381 | |
| 382 | \layout LyX-Code |
| 383 | |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 384 | -- An identifier of the Internet. |
| 385 | \layout LyX-Code |
| 386 | |
| 387 | internet-id OBJECT IDENTIFIER |
| 388 | \layout LyX-Code |
| 389 | |
| 390 | ::= { iso(1) identified-organization(3) |
| 391 | \layout LyX-Code |
| 392 | |
| 393 | dod(6) internet(1) } |
| 394 | \layout Standard |
| 395 | |
| 396 | As you see, names are optional. |
| 397 | \layout Subsection |
| 398 | |
| 399 | The RELATIVE-OID type |
| 400 | \layout Standard |
| 401 | |
| 402 | The RELATIVE-OID type has the semantics of a subtree of an OBJECT IDENTIFIER. |
| 403 | There may be no need to repeat the whole sequence of numbers from the root |
| 404 | of the registration tree where the only thing of interest is some of the |
| 405 | tree's subsequence. |
| 406 | \layout LyX-Code |
| 407 | |
| 408 | this-document RELATIVE-OID ::= { docs(2) usage(1) } |
| 409 | \layout LyX-Code |
| 410 | |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 411 | |
| 412 | \layout LyX-Code |
| 413 | |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 414 | this-example RELATIVE-OID ::= { |
| 415 | \layout LyX-Code |
| 416 | |
| 417 | this-document assorted-examples(0) this-example(1) } |
| 418 | \layout Section |
| 419 | |
| 420 | Some of the ASN.1 String Types |
| 421 | \layout Subsection |
| 422 | |
| 423 | The IA5String type |
| 424 | \layout Standard |
| 425 | |
| 426 | This is essentially the ASCII, with 128 character codes available (7 lower |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 427 | bits of an 8-bit byte). |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 428 | \layout Subsection |
| 429 | |
| 430 | The UTF8String type |
| 431 | \layout Standard |
| 432 | |
| 433 | This is the character string which encodes the full Unicode range (4 bytes) |
| 434 | using multibyte character sequences. |
| 435 | \layout Subsection |
| 436 | |
| 437 | The NumericString type |
| 438 | \layout Standard |
| 439 | |
| 440 | This type represents the character string with the alphabet consisting of |
| 441 | numbers ( |
| 442 | \begin_inset Quotes sld |
| 443 | \end_inset |
| 444 | |
| 445 | 0 |
| 446 | \begin_inset Quotes srd |
| 447 | \end_inset |
| 448 | |
| 449 | to |
| 450 | \begin_inset Quotes sld |
| 451 | \end_inset |
| 452 | |
| 453 | 9 |
| 454 | \begin_inset Quotes srd |
| 455 | \end_inset |
| 456 | |
| 457 | ) and a space. |
| 458 | \layout Subsection |
| 459 | |
| 460 | The PrintableString type |
| 461 | \layout Standard |
| 462 | |
| 463 | The character string with the following alphabet: space, |
| 464 | \begin_inset Quotes sld |
| 465 | \end_inset |
| 466 | |
| 467 | |
| 468 | \series bold |
| 469 | ' |
| 470 | \series default |
| 471 | |
| 472 | \begin_inset Quotes srd |
| 473 | \end_inset |
| 474 | |
| 475 | (single quote), |
| 476 | \begin_inset Quotes sld |
| 477 | \end_inset |
| 478 | |
| 479 | |
| 480 | \series bold |
| 481 | ( |
| 482 | \series default |
| 483 | |
| 484 | \begin_inset Quotes sld |
| 485 | \end_inset |
| 486 | |
| 487 | , |
| 488 | \begin_inset Quotes sld |
| 489 | \end_inset |
| 490 | |
| 491 | |
| 492 | \series bold |
| 493 | ) |
| 494 | \series default |
| 495 | |
| 496 | \begin_inset Quotes srd |
| 497 | \end_inset |
| 498 | |
| 499 | , |
| 500 | \begin_inset Quotes sld |
| 501 | \end_inset |
| 502 | |
| 503 | |
| 504 | \series bold |
| 505 | + |
| 506 | \series default |
| 507 | |
| 508 | \begin_inset Quotes srd |
| 509 | \end_inset |
| 510 | |
| 511 | , |
| 512 | \begin_inset Quotes sld |
| 513 | \end_inset |
| 514 | |
| 515 | , |
| 516 | \begin_inset Quotes srd |
| 517 | \end_inset |
| 518 | |
| 519 | (comma), |
| 520 | \begin_inset Quotes sld |
| 521 | \end_inset |
| 522 | |
| 523 | |
| 524 | \series bold |
| 525 | - |
| 526 | \series default |
| 527 | |
| 528 | \begin_inset Quotes srd |
| 529 | \end_inset |
| 530 | |
| 531 | , |
| 532 | \begin_inset Quotes sld |
| 533 | \end_inset |
| 534 | |
| 535 | |
| 536 | \series bold |
| 537 | . |
| 538 | \series default |
| 539 | |
| 540 | \begin_inset Quotes srd |
| 541 | \end_inset |
| 542 | |
| 543 | , |
| 544 | \begin_inset Quotes sld |
| 545 | \end_inset |
| 546 | |
| 547 | |
| 548 | \series bold |
| 549 | / |
| 550 | \series default |
| 551 | |
| 552 | \begin_inset Quotes srd |
| 553 | \end_inset |
| 554 | |
| 555 | , digits ( |
| 556 | \begin_inset Quotes sld |
| 557 | \end_inset |
| 558 | |
| 559 | 0 |
| 560 | \begin_inset Quotes srd |
| 561 | \end_inset |
| 562 | |
| 563 | to |
| 564 | \begin_inset Quotes sld |
| 565 | \end_inset |
| 566 | |
| 567 | 9 |
| 568 | \begin_inset Quotes srd |
| 569 | \end_inset |
| 570 | |
| 571 | ), |
| 572 | \begin_inset Quotes sld |
| 573 | \end_inset |
| 574 | |
| 575 | |
| 576 | \series bold |
| 577 | : |
| 578 | \series default |
| 579 | |
| 580 | \begin_inset Quotes srd |
| 581 | \end_inset |
| 582 | |
| 583 | , |
| 584 | \begin_inset Quotes sld |
| 585 | \end_inset |
| 586 | |
| 587 | |
| 588 | \series bold |
| 589 | = |
| 590 | \series default |
| 591 | |
| 592 | \begin_inset Quotes srd |
| 593 | \end_inset |
| 594 | |
| 595 | , |
| 596 | \begin_inset Quotes sld |
| 597 | \end_inset |
| 598 | |
| 599 | |
| 600 | \series bold |
| 601 | ? |
| 602 | \series default |
| 603 | |
| 604 | \begin_inset Quotes srd |
| 605 | \end_inset |
| 606 | |
| 607 | , upper-case and lower-case letters ( |
| 608 | \begin_inset Quotes sld |
| 609 | \end_inset |
| 610 | |
| 611 | A |
| 612 | \begin_inset Quotes srd |
| 613 | \end_inset |
| 614 | |
| 615 | to |
| 616 | \begin_inset Quotes sld |
| 617 | \end_inset |
| 618 | |
| 619 | Z |
| 620 | \begin_inset Quotes srd |
| 621 | \end_inset |
| 622 | |
| 623 | and |
| 624 | \begin_inset Quotes sld |
| 625 | \end_inset |
| 626 | |
| 627 | a |
| 628 | \begin_inset Quotes srd |
| 629 | \end_inset |
| 630 | |
| 631 | to |
| 632 | \begin_inset Quotes sld |
| 633 | \end_inset |
| 634 | |
| 635 | z |
| 636 | \begin_inset Quotes srd |
| 637 | \end_inset |
| 638 | |
| 639 | ) |
| 640 | \layout Subsection |
| 641 | |
| 642 | The VisibleString type |
| 643 | \layout Standard |
| 644 | |
| 645 | The character string with the alphabet which is more or less a subset of |
| 646 | ASCII between space and |
| 647 | \begin_inset Quotes sld |
| 648 | \end_inset |
| 649 | |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 650 | |
| 651 | \series bold |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 652 | ~ |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 653 | \series default |
| 654 | |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 655 | \begin_inset Quotes srd |
| 656 | \end_inset |
| 657 | |
| 658 | (tilde). |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 659 | Alternatively, the alphabet may be described as the PrintableString alphabet |
| 660 | presented earlier, plus the following characters: |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 661 | \begin_inset Quotes sld |
| 662 | \end_inset |
| 663 | |
| 664 | |
| 665 | \series bold |
| 666 | ! |
| 667 | \series default |
| 668 | |
| 669 | \begin_inset Quotes srd |
| 670 | \end_inset |
| 671 | |
| 672 | , |
| 673 | \begin_inset Quotes sld |
| 674 | \end_inset |
| 675 | |
| 676 | |
| 677 | \series bold |
| 678 | |
| 679 | \begin_inset Quotes srd |
| 680 | \end_inset |
| 681 | |
| 682 | |
| 683 | \series default |
| 684 | |
| 685 | \begin_inset Quotes srd |
| 686 | \end_inset |
| 687 | |
| 688 | , |
| 689 | \begin_inset Quotes sld |
| 690 | \end_inset |
| 691 | |
| 692 | |
| 693 | \series bold |
| 694 | # |
| 695 | \series default |
| 696 | |
| 697 | \begin_inset Quotes srd |
| 698 | \end_inset |
| 699 | |
| 700 | , |
| 701 | \begin_inset Quotes sld |
| 702 | \end_inset |
| 703 | |
| 704 | |
| 705 | \series bold |
| 706 | $ |
| 707 | \series default |
| 708 | |
| 709 | \begin_inset Quotes srd |
| 710 | \end_inset |
| 711 | |
| 712 | , |
| 713 | \begin_inset Quotes sld |
| 714 | \end_inset |
| 715 | |
| 716 | |
| 717 | \series bold |
| 718 | % |
| 719 | \series default |
| 720 | |
| 721 | \begin_inset Quotes srd |
| 722 | \end_inset |
| 723 | |
| 724 | , |
| 725 | \begin_inset Quotes sld |
| 726 | \end_inset |
| 727 | |
| 728 | |
| 729 | \series bold |
| 730 | & |
| 731 | \series default |
| 732 | |
| 733 | \begin_inset Quotes srd |
| 734 | \end_inset |
| 735 | |
| 736 | , |
| 737 | \begin_inset Quotes sld |
| 738 | \end_inset |
| 739 | |
| 740 | |
| 741 | \series bold |
| 742 | * |
| 743 | \series default |
| 744 | |
| 745 | \begin_inset Quotes srd |
| 746 | \end_inset |
| 747 | |
| 748 | , |
| 749 | \begin_inset Quotes sld |
| 750 | \end_inset |
| 751 | |
| 752 | |
| 753 | \series bold |
| 754 | ; |
| 755 | \series default |
| 756 | |
| 757 | \begin_inset Quotes srd |
| 758 | \end_inset |
| 759 | |
| 760 | , |
| 761 | \begin_inset Quotes sld |
| 762 | \end_inset |
| 763 | |
| 764 | |
| 765 | \series bold |
| 766 | < |
| 767 | \series default |
| 768 | |
| 769 | \begin_inset Quotes srd |
| 770 | \end_inset |
| 771 | |
| 772 | , |
| 773 | \begin_inset Quotes sld |
| 774 | \end_inset |
| 775 | |
| 776 | |
| 777 | \series bold |
| 778 | > |
| 779 | \series default |
| 780 | |
| 781 | \begin_inset Quotes srd |
| 782 | \end_inset |
| 783 | |
| 784 | , |
| 785 | \begin_inset Quotes sld |
| 786 | \end_inset |
| 787 | |
| 788 | |
| 789 | \series bold |
| 790 | [ |
| 791 | \series default |
| 792 | |
| 793 | \begin_inset Quotes srd |
| 794 | \end_inset |
| 795 | |
| 796 | , |
| 797 | \begin_inset Quotes sld |
| 798 | \end_inset |
| 799 | |
| 800 | |
| 801 | \series bold |
| 802 | |
| 803 | \backslash |
| 804 | |
| 805 | \series default |
| 806 | |
| 807 | \begin_inset Quotes srd |
| 808 | \end_inset |
| 809 | |
| 810 | , |
| 811 | \begin_inset Quotes sld |
| 812 | \end_inset |
| 813 | |
| 814 | |
| 815 | \series bold |
| 816 | ] |
| 817 | \series default |
| 818 | |
| 819 | \begin_inset Quotes srd |
| 820 | \end_inset |
| 821 | |
| 822 | , |
| 823 | \begin_inset Quotes sld |
| 824 | \end_inset |
| 825 | |
| 826 | |
| 827 | \series bold |
| 828 | ^ |
| 829 | \series default |
| 830 | |
| 831 | \begin_inset Quotes srd |
| 832 | \end_inset |
| 833 | |
| 834 | , |
| 835 | \begin_inset Quotes sld |
| 836 | \end_inset |
| 837 | |
| 838 | |
| 839 | \series bold |
| 840 | _ |
| 841 | \series default |
| 842 | |
| 843 | \begin_inset Quotes srd |
| 844 | \end_inset |
| 845 | |
| 846 | , |
| 847 | \begin_inset Quotes sld |
| 848 | \end_inset |
| 849 | |
| 850 | |
| 851 | \series bold |
| 852 | ` |
| 853 | \series default |
| 854 | |
| 855 | \begin_inset Quotes srd |
| 856 | \end_inset |
| 857 | |
| 858 | (single left quote), |
| 859 | \begin_inset Quotes sld |
| 860 | \end_inset |
| 861 | |
| 862 | |
| 863 | \series bold |
| 864 | { |
| 865 | \series default |
| 866 | |
| 867 | \begin_inset Quotes srd |
| 868 | \end_inset |
| 869 | |
| 870 | , |
| 871 | \begin_inset Quotes sld |
| 872 | \end_inset |
| 873 | |
| 874 | |
| 875 | \series bold |
| 876 | | |
| 877 | \series default |
| 878 | |
| 879 | \begin_inset Quotes srd |
| 880 | \end_inset |
| 881 | |
| 882 | , |
| 883 | \begin_inset Quotes sld |
| 884 | \end_inset |
| 885 | |
| 886 | |
| 887 | \series bold |
| 888 | } |
| 889 | \series default |
| 890 | |
| 891 | \begin_inset Quotes srd |
| 892 | \end_inset |
| 893 | |
| 894 | , |
| 895 | \begin_inset Quotes sld |
| 896 | \end_inset |
| 897 | |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 898 | |
| 899 | \series bold |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 900 | ~ |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 901 | \series default |
| 902 | |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 903 | \begin_inset Quotes srd |
| 904 | \end_inset |
| 905 | |
| 906 | . |
| 907 | \layout Section |
| 908 | |
| 909 | ASN.1 Constructed Types |
| 910 | \layout Subsection |
| 911 | |
| 912 | The SEQUENCE type |
| 913 | \layout Standard |
| 914 | |
| 915 | This is an ordered collection of other simple or constructed types. |
| 916 | The SEQUENCE constructed type resembles the C |
| 917 | \begin_inset Quotes sld |
| 918 | \end_inset |
| 919 | |
| 920 | struct |
| 921 | \begin_inset Quotes srd |
| 922 | \end_inset |
| 923 | |
| 924 | statement. |
| 925 | \layout LyX-Code |
| 926 | |
| 927 | Address ::= SEQUENCE { |
| 928 | \layout LyX-Code |
| 929 | |
| 930 | -- The apartment number may be omitted |
| 931 | \layout LyX-Code |
| 932 | |
| 933 | apartmentNumber NumericString OPTIONAL, |
| 934 | \layout LyX-Code |
| 935 | |
| 936 | streetName PrintableString, |
| 937 | \layout LyX-Code |
| 938 | |
| 939 | cityName PrintableString, |
| 940 | \layout LyX-Code |
| 941 | |
| 942 | stateName PrintableString, |
| 943 | \layout LyX-Code |
| 944 | |
| 945 | -- This one may be omitted too |
| 946 | \layout LyX-Code |
| 947 | |
| 948 | zipNo NumericString OPTIONAL |
| 949 | \layout LyX-Code |
| 950 | |
| 951 | } |
| 952 | \layout Subsection |
| 953 | |
| 954 | The SET type |
| 955 | \layout Standard |
| 956 | |
| 957 | This is a collection of other simple or constructed types. |
| 958 | Ordering is not important. |
| 959 | The data may arrive in the order which is different from the order of specifica |
| 960 | tion. |
| 961 | Data is encoded in the order not necessarily corresponding to the order |
| 962 | of specification. |
| 963 | \layout Subsection |
| 964 | |
| 965 | The CHOICE type |
| 966 | \layout Standard |
| 967 | |
| 968 | This type is just a choice between the subtypes specified in it. |
| 969 | The CHOICE type contains at most one of the subtypes specified, and it |
| 970 | is always implicitly known which choice is being decoded or encoded. |
| 971 | This one resembles the C |
| 972 | \begin_inset Quotes sld |
| 973 | \end_inset |
| 974 | |
| 975 | union |
| 976 | \begin_inset Quotes srd |
| 977 | \end_inset |
| 978 | |
| 979 | statement. |
| 980 | \layout Standard |
| 981 | |
| 982 | The following type defines a response code, which may be either an integer |
| 983 | code or a boolean |
| 984 | \begin_inset Quotes sld |
| 985 | \end_inset |
| 986 | |
| 987 | true |
| 988 | \begin_inset Quotes srd |
| 989 | \end_inset |
| 990 | |
| 991 | / |
| 992 | \begin_inset Quotes srd |
| 993 | \end_inset |
| 994 | |
| 995 | false |
| 996 | \begin_inset Quotes srd |
| 997 | \end_inset |
| 998 | |
| 999 | code. |
| 1000 | \layout LyX-Code |
| 1001 | |
| 1002 | ResponseCode ::= CHOICE { |
| 1003 | \layout LyX-Code |
| 1004 | |
| 1005 | intCode INTEGER, |
| 1006 | \layout LyX-Code |
| 1007 | |
| 1008 | boolCode BOOLEAN |
| 1009 | \layout LyX-Code |
| 1010 | |
| 1011 | } |
| 1012 | \layout LyX-Code |
| 1013 | |
| 1014 | \layout Subsection |
| 1015 | |
| 1016 | The SEQUENCE OF type |
| 1017 | \layout Standard |
| 1018 | |
| 1019 | This one is the list (array) of simple or constructed types: |
| 1020 | \layout LyX-Code |
| 1021 | |
| 1022 | -- Example 1 |
| 1023 | \layout LyX-Code |
| 1024 | |
| 1025 | ManyIntegers ::= SEQUENCE OF INTEGER |
| 1026 | \layout LyX-Code |
| 1027 | |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 1028 | |
| 1029 | \layout LyX-Code |
| 1030 | |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 1031 | -- Example 2 |
| 1032 | \layout LyX-Code |
| 1033 | |
| 1034 | ManyRectangles ::= SEQUENCE OF Rectangle |
| 1035 | \layout LyX-Code |
| 1036 | |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 1037 | |
| 1038 | \layout LyX-Code |
| 1039 | |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 1040 | -- More complex example: |
| 1041 | \layout LyX-Code |
| 1042 | |
| 1043 | -- an array of structures defined in place. |
| 1044 | \layout LyX-Code |
| 1045 | |
| 1046 | ManyCircles ::= SEQUENCE OF SEQUENCE { |
| 1047 | \layout LyX-Code |
| 1048 | |
| 1049 | radius INTEGER |
| 1050 | \layout LyX-Code |
| 1051 | |
| 1052 | } |
| 1053 | \layout Subsection |
| 1054 | |
| 1055 | The SET OF type |
| 1056 | \layout Standard |
| 1057 | |
| 1058 | The SET OF type models the bag of structures. |
| 1059 | It resembles the SEQUENCE OF type, but the order is not important: i.e. |
| 1060 | the elements may arrive in the order which is not necessarily the same |
| 1061 | as the in-memory order on the remote machines. |
| 1062 | \layout LyX-Code |
| 1063 | |
| 1064 | -- A set of structures defined elsewhere |
| 1065 | \layout LyX-Code |
| 1066 | |
| 1067 | SetOfApples :: SET OF Apple |
| 1068 | \layout LyX-Code |
| 1069 | |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 1070 | |
| 1071 | \layout LyX-Code |
| 1072 | |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 1073 | -- Set of integers encoding the kind of a fruit |
| 1074 | \layout LyX-Code |
| 1075 | |
| 1076 | FruitBag ::= SET OF ENUMERATED { apple, orange } |
Lev Walkin | 4a83dd5 | 2004-08-07 05:00:07 +0000 | [diff] [blame] | 1077 | \layout Part |
| 1078 | |
| 1079 | Using the ASN.1 Compiler |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 1080 | \layout Chapter |
| 1081 | |
Lev Walkin | 4a83dd5 | 2004-08-07 05:00:07 +0000 | [diff] [blame] | 1082 | Introduction to the ASN.1 Compiler |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 1083 | \layout Standard |
| 1084 | |
| 1085 | The purpose of the ASN.1 compiler, of which this document is part, is to |
| 1086 | convert the ASN.1 specifications to some other target language (currently, |
| 1087 | only C is supported |
| 1088 | \begin_inset Foot |
| 1089 | collapsed false |
| 1090 | |
| 1091 | \layout Standard |
| 1092 | |
| 1093 | C++ is |
| 1094 | \begin_inset Quotes sld |
| 1095 | \end_inset |
| 1096 | |
| 1097 | supported |
| 1098 | \begin_inset Quotes srd |
| 1099 | \end_inset |
| 1100 | |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 1101 | too, as long as an class-based approach is not a definitive factor. |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 1102 | \end_inset |
| 1103 | |
| 1104 | ). |
| 1105 | The compiler reads the specification and emits a series of target language |
| 1106 | structures and surrounding maintenance code. |
| 1107 | For example, the C structure which may be created by compiler to represent |
| 1108 | the simple |
| 1109 | \emph on |
| 1110 | Rectangle |
| 1111 | \emph default |
| 1112 | specification defined earlier in this document, may look like this |
| 1113 | \begin_inset Foot |
| 1114 | collapsed false |
| 1115 | |
| 1116 | \layout Standard |
| 1117 | |
| 1118 | |
| 1119 | \emph on |
Lev Walkin | 9930189 | 2004-09-14 12:48:17 +0000 | [diff] [blame] | 1120 | -fnative-types |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 1121 | \emph default |
| 1122 | compiler option is used to produce basic C |
| 1123 | \emph on |
| 1124 | int |
| 1125 | \emph default |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 1126 | types instead of infinite width INTEGER_t structures. |
| 1127 | See Table |
| 1128 | \begin_inset LatexCommand \vref{cap:asn1c-cmdopts} |
| 1129 | |
| 1130 | \end_inset |
| 1131 | |
| 1132 | . |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 1133 | \end_inset |
| 1134 | |
| 1135 | : |
| 1136 | \layout LyX-Code |
| 1137 | |
| 1138 | typedef struct Rectangle_s { |
| 1139 | \layout LyX-Code |
| 1140 | |
| 1141 | int height; |
| 1142 | \layout LyX-Code |
| 1143 | |
| 1144 | int width; |
| 1145 | \layout LyX-Code |
| 1146 | |
| 1147 | } Rectangle_t; |
| 1148 | \layout Standard |
| 1149 | |
| 1150 | This would not be of much value for such a simple specification, so the |
| 1151 | compiler goes further and actually produces the code which fills in this |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 1152 | structure by parsing the opaque binary |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 1153 | \begin_inset Foot |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 1154 | collapsed true |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 1155 | |
| 1156 | \layout Standard |
| 1157 | |
| 1158 | BER, CER and DER encodings are binary. |
| 1159 | However, the XER encoding is text (XML) based. |
| 1160 | \end_inset |
| 1161 | |
| 1162 | data provided in some buffer. |
| 1163 | It also produces the code that takes this structure as an argument and |
| 1164 | performs structure serialization by emitting a series of bytes. |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 1165 | \layout Chapter |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 1166 | |
| 1167 | Quick start |
| 1168 | \layout Standard |
| 1169 | |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 1170 | After building and installing the compiler, the |
| 1171 | \emph on |
| 1172 | asn1c |
| 1173 | \begin_inset Foot |
| 1174 | collapsed false |
| 1175 | |
| 1176 | \layout Standard |
| 1177 | |
| 1178 | The 1 symbol in asn |
| 1179 | \series bold |
| 1180 | 1 |
| 1181 | \series default |
| 1182 | c is a digit, not an |
| 1183 | \begin_inset Quotes sld |
| 1184 | \end_inset |
| 1185 | |
| 1186 | ell |
| 1187 | \begin_inset Quotes srd |
| 1188 | \end_inset |
| 1189 | |
| 1190 | letter. |
| 1191 | \end_inset |
| 1192 | |
| 1193 | |
| 1194 | \emph default |
| 1195 | command may be used to compile the ASN.1 specification |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 1196 | \begin_inset Foot |
| 1197 | collapsed false |
| 1198 | |
| 1199 | \layout Standard |
| 1200 | |
| 1201 | This is probably |
| 1202 | \series bold |
| 1203 | not |
| 1204 | \series default |
| 1205 | what you want to try out right now -- read through the rest of this chapter |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 1206 | to find out about |
| 1207 | \series bold |
| 1208 | -P |
| 1209 | \series default |
| 1210 | and |
| 1211 | \series bold |
| 1212 | -R |
| 1213 | \series default |
| 1214 | options. |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 1215 | \end_inset |
| 1216 | |
| 1217 | : |
| 1218 | \layout LyX-Code |
| 1219 | |
| 1220 | asn1c |
| 1221 | \emph on |
| 1222 | <spec.asn1> |
| 1223 | \layout Standard |
| 1224 | |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 1225 | If several specifications contain interdependencies, all of the files must |
| 1226 | be specified altogether: |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 1227 | \layout LyX-Code |
| 1228 | |
| 1229 | asn1c |
| 1230 | \emph on |
| 1231 | <spec1.asn1> <spec2.asn1> ... |
| 1232 | \layout Standard |
| 1233 | |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 1234 | The compiler |
| 1235 | \series bold |
| 1236 | -E |
| 1237 | \series default |
| 1238 | and |
| 1239 | \series bold |
| 1240 | -EF |
| 1241 | \series default |
| 1242 | options are used for testing the parser and the semantic fixer, respectively. |
| 1243 | These options will instruct the compiler to dump out the parsed (and fixed, |
| 1244 | if |
| 1245 | \series bold |
| 1246 | -F |
| 1247 | \series default |
| 1248 | is involved) ASN.1 specification as it was "understood" by the compiler. |
| 1249 | It might be useful to check whether a particular syntactic construction |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 1250 | is properly supported by the compiler. |
| 1251 | \layout LyX-Code |
| 1252 | |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 1253 | asn1c |
| 1254 | \series bold |
| 1255 | -EF |
| 1256 | \series default |
| 1257 | |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 1258 | \emph on |
| 1259 | <spec-to-test.asn1> |
| 1260 | \layout Standard |
| 1261 | |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 1262 | The |
| 1263 | \series bold |
| 1264 | -P |
| 1265 | \series default |
| 1266 | option is used to dump the compiled output on the screen instead of creating |
| 1267 | a bunch of .c and .h files on disk in the current directory. |
| 1268 | You would probably want to start with |
| 1269 | \series bold |
| 1270 | -P |
| 1271 | \series default |
| 1272 | option instead of creating a mess in your current directory. |
| 1273 | Another option, |
| 1274 | \series bold |
| 1275 | -R |
| 1276 | \series default |
| 1277 | , asks compiler to only generate the files which need to be generated, and |
| 1278 | supress linking in the numerous support files. |
| 1279 | \layout Standard |
| 1280 | |
| 1281 | Print the compiled output instead of creating multiple source files: |
| 1282 | \layout LyX-Code |
| 1283 | |
| 1284 | asn1c |
| 1285 | \series bold |
| 1286 | -P |
| 1287 | \series default |
| 1288 | |
| 1289 | \emph on |
| 1290 | <spec-to-compile-and-print.asn1> |
| 1291 | \layout LyX-Code |
| 1292 | |
| 1293 | \layout Chapter |
| 1294 | |
| 1295 | Using the ASN.1 Compiler |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 1296 | \layout Section |
| 1297 | |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 1298 | Command-line options |
| 1299 | \layout Standard |
| 1300 | |
| 1301 | The Table |
| 1302 | \begin_inset LatexCommand \vref{cap:asn1c-cmdopts} |
| 1303 | |
| 1304 | \end_inset |
| 1305 | |
| 1306 | summarizes various options affecting the compiler's behavior. |
| 1307 | \layout Standard |
| 1308 | |
| 1309 | |
| 1310 | \begin_inset Float table |
| 1311 | wide false |
Lev Walkin | dd32b59 | 2004-09-06 08:07:29 +0000 | [diff] [blame] | 1312 | collapsed false |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 1313 | |
| 1314 | \layout Standard |
| 1315 | |
| 1316 | |
| 1317 | \begin_inset Tabular |
Lev Walkin | 35d446b | 2004-09-24 20:56:07 +0000 | [diff] [blame] | 1318 | <lyxtabular version="3" rows="20" columns="2"> |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 1319 | <features> |
| 1320 | <column alignment="left" valignment="top" leftline="true" width="0"> |
| 1321 | <column alignment="block" valignment="top" leftline="true" rightline="true" width="3in"> |
| 1322 | <row topline="true" bottomline="true"> |
| 1323 | <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
| 1324 | \begin_inset Text |
| 1325 | |
| 1326 | \layout Standard |
| 1327 | |
| 1328 | |
| 1329 | \series bold |
| 1330 | Overall Options |
| 1331 | \end_inset |
| 1332 | </cell> |
| 1333 | <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> |
| 1334 | \begin_inset Text |
| 1335 | |
| 1336 | \layout Standard |
| 1337 | |
| 1338 | |
| 1339 | \series bold |
| 1340 | Description |
| 1341 | \end_inset |
| 1342 | </cell> |
| 1343 | </row> |
| 1344 | <row topline="true"> |
| 1345 | <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
| 1346 | \begin_inset Text |
| 1347 | |
| 1348 | \layout Standard |
| 1349 | |
| 1350 | -E |
| 1351 | \end_inset |
| 1352 | </cell> |
| 1353 | <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> |
| 1354 | \begin_inset Text |
| 1355 | |
| 1356 | \layout Standard |
| 1357 | |
| 1358 | |
| 1359 | \size small |
| 1360 | Stop after the parsing stage and print the reconstructed ASN.1 specification |
| 1361 | code to the standard output. |
| 1362 | \end_inset |
| 1363 | </cell> |
| 1364 | </row> |
| 1365 | <row topline="true"> |
| 1366 | <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
| 1367 | \begin_inset Text |
| 1368 | |
| 1369 | \layout Standard |
| 1370 | |
| 1371 | -F |
| 1372 | \end_inset |
| 1373 | </cell> |
| 1374 | <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> |
| 1375 | \begin_inset Text |
| 1376 | |
| 1377 | \layout Standard |
| 1378 | |
| 1379 | |
| 1380 | \size small |
| 1381 | Used together with -E, instructs the compiler to stop after the ASN.1 syntax |
| 1382 | tree fixing stage and dump the reconstructed ASN.1 specification to the |
| 1383 | standard output. |
| 1384 | \end_inset |
| 1385 | </cell> |
| 1386 | </row> |
| 1387 | <row topline="true"> |
| 1388 | <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
| 1389 | \begin_inset Text |
| 1390 | |
| 1391 | \layout Standard |
| 1392 | |
| 1393 | -P |
| 1394 | \end_inset |
| 1395 | </cell> |
| 1396 | <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> |
| 1397 | \begin_inset Text |
| 1398 | |
| 1399 | \layout Standard |
| 1400 | |
| 1401 | |
| 1402 | \size small |
| 1403 | Dump the compiled output to the standard output instead of cre- ating the |
| 1404 | target language files on disk. |
| 1405 | \end_inset |
| 1406 | </cell> |
| 1407 | </row> |
| 1408 | <row topline="true"> |
| 1409 | <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
| 1410 | \begin_inset Text |
| 1411 | |
| 1412 | \layout Standard |
| 1413 | |
| 1414 | -R |
| 1415 | \end_inset |
| 1416 | </cell> |
| 1417 | <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> |
| 1418 | \begin_inset Text |
| 1419 | |
| 1420 | \layout Standard |
| 1421 | |
| 1422 | |
| 1423 | \size small |
| 1424 | Restrict the compiler to generate only the ASN.1 tables, omit- ting the usual |
| 1425 | support code. |
| 1426 | \end_inset |
| 1427 | </cell> |
| 1428 | </row> |
Lev Walkin | 35d446b | 2004-09-24 20:56:07 +0000 | [diff] [blame] | 1429 | <row topline="true" bottomline="true"> |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 1430 | <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
| 1431 | \begin_inset Text |
| 1432 | |
| 1433 | \layout Standard |
| 1434 | |
| 1435 | -S |
| 1436 | \emph on |
| 1437 | <directory> |
| 1438 | \end_inset |
| 1439 | </cell> |
| 1440 | <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> |
| 1441 | \begin_inset Text |
| 1442 | |
| 1443 | \layout Standard |
| 1444 | |
| 1445 | |
| 1446 | \size small |
| 1447 | Use the specified directory with ASN.1 skeleton files. |
| 1448 | \end_inset |
| 1449 | </cell> |
| 1450 | </row> |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 1451 | <row topline="true"> |
| 1452 | <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
| 1453 | \begin_inset Text |
| 1454 | |
| 1455 | \layout Standard |
| 1456 | |
| 1457 | |
| 1458 | \series bold |
| 1459 | Warning Options |
| 1460 | \end_inset |
| 1461 | </cell> |
| 1462 | <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> |
| 1463 | \begin_inset Text |
| 1464 | |
| 1465 | \layout Standard |
| 1466 | |
| 1467 | |
| 1468 | \series bold |
| 1469 | Description |
| 1470 | \end_inset |
| 1471 | </cell> |
| 1472 | </row> |
| 1473 | <row topline="true"> |
| 1474 | <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
| 1475 | \begin_inset Text |
| 1476 | |
| 1477 | \layout Standard |
| 1478 | |
| 1479 | -Werror |
| 1480 | \end_inset |
| 1481 | </cell> |
| 1482 | <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> |
| 1483 | \begin_inset Text |
| 1484 | |
| 1485 | \layout Standard |
| 1486 | |
| 1487 | |
| 1488 | \size small |
| 1489 | Treat warnings as errors; abort if any warning is produced. |
| 1490 | \end_inset |
| 1491 | </cell> |
| 1492 | </row> |
| 1493 | <row topline="true"> |
| 1494 | <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
| 1495 | \begin_inset Text |
| 1496 | |
| 1497 | \layout Standard |
| 1498 | |
| 1499 | -Wdebug-lexer |
| 1500 | \end_inset |
| 1501 | </cell> |
| 1502 | <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> |
| 1503 | \begin_inset Text |
| 1504 | |
| 1505 | \layout Standard |
| 1506 | |
| 1507 | |
| 1508 | \size small |
| 1509 | Enable lexer debugging during the ASN.1 parsing stage. |
| 1510 | \end_inset |
| 1511 | </cell> |
| 1512 | </row> |
| 1513 | <row topline="true"> |
| 1514 | <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
| 1515 | \begin_inset Text |
| 1516 | |
| 1517 | \layout Standard |
| 1518 | |
| 1519 | -Wdebug-fixer |
| 1520 | \end_inset |
| 1521 | </cell> |
| 1522 | <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> |
| 1523 | \begin_inset Text |
| 1524 | |
| 1525 | \layout Standard |
| 1526 | |
| 1527 | |
| 1528 | \size small |
| 1529 | Enable ASN.1 syntax tree fixer debugging during the fixing stage. |
| 1530 | \end_inset |
| 1531 | </cell> |
| 1532 | </row> |
| 1533 | <row topline="true" bottomline="true"> |
| 1534 | <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
| 1535 | \begin_inset Text |
| 1536 | |
| 1537 | \layout Standard |
| 1538 | |
| 1539 | -Wdebug-compiler |
| 1540 | \end_inset |
| 1541 | </cell> |
| 1542 | <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> |
| 1543 | \begin_inset Text |
| 1544 | |
| 1545 | \layout Standard |
| 1546 | |
| 1547 | |
| 1548 | \size small |
| 1549 | Enable debugging during the actual compile time. |
| 1550 | \end_inset |
| 1551 | </cell> |
| 1552 | </row> |
| 1553 | <row topline="true"> |
| 1554 | <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
| 1555 | \begin_inset Text |
| 1556 | |
| 1557 | \layout Standard |
| 1558 | |
| 1559 | |
| 1560 | \series bold |
| 1561 | Language Options |
| 1562 | \end_inset |
| 1563 | </cell> |
| 1564 | <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> |
| 1565 | \begin_inset Text |
| 1566 | |
| 1567 | \layout Standard |
| 1568 | |
| 1569 | |
| 1570 | \series bold |
| 1571 | Description |
| 1572 | \end_inset |
| 1573 | </cell> |
| 1574 | </row> |
| 1575 | <row topline="true"> |
| 1576 | <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
| 1577 | \begin_inset Text |
| 1578 | |
| 1579 | \layout Standard |
| 1580 | |
Lev Walkin | dd32b59 | 2004-09-06 08:07:29 +0000 | [diff] [blame] | 1581 | -fall-defs-global |
| 1582 | \end_inset |
| 1583 | </cell> |
| 1584 | <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> |
| 1585 | \begin_inset Text |
| 1586 | |
| 1587 | \layout Standard |
| 1588 | |
| 1589 | Normally the compiler hides the definitions (asn1_DEF_xxx) of the inner |
| 1590 | structure elements (members of SEQUENCE, SET and other types). |
| 1591 | This option makes all such definitions global. |
| 1592 | Enabling this option may pollute the namespace by making lots of asn1_DEF_xxx |
| 1593 | structures globally visible, but will allow you to manipulate (encode and |
| 1594 | decode) the individual members of any complex ASN.1 structure. |
| 1595 | \end_inset |
| 1596 | </cell> |
| 1597 | </row> |
| 1598 | <row topline="true"> |
| 1599 | <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
| 1600 | \begin_inset Text |
| 1601 | |
| 1602 | \layout Standard |
| 1603 | |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 1604 | -fbless-SIZE |
| 1605 | \end_inset |
| 1606 | </cell> |
| 1607 | <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> |
| 1608 | \begin_inset Text |
| 1609 | |
| 1610 | \layout Standard |
| 1611 | |
| 1612 | |
| 1613 | \size small |
| 1614 | Allow SIZE() constraint for INTEGER, ENUMERATED, and other types for which |
| 1615 | this constraint is normally prohibited by the standard. |
| 1616 | This is a violation of an ASN.1 standard and compiler may fail to produce |
| 1617 | the meaningful code. |
| 1618 | \end_inset |
| 1619 | </cell> |
| 1620 | </row> |
| 1621 | <row topline="true"> |
| 1622 | <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
| 1623 | \begin_inset Text |
| 1624 | |
| 1625 | \layout Standard |
| 1626 | |
Lev Walkin | 9930189 | 2004-09-14 12:48:17 +0000 | [diff] [blame] | 1627 | -fnative-types |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 1628 | \end_inset |
| 1629 | </cell> |
| 1630 | <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> |
| 1631 | \begin_inset Text |
| 1632 | |
| 1633 | \layout Standard |
| 1634 | |
| 1635 | |
| 1636 | \size small |
Lev Walkin | 9930189 | 2004-09-14 12:48:17 +0000 | [diff] [blame] | 1637 | Use the native machine's data types (int, double) whenever possible, instead |
| 1638 | of the compound ASN.1 INTEGER_t, ENUMERATED_t and REAL_t types. |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 1639 | |
| 1640 | \end_inset |
| 1641 | </cell> |
| 1642 | </row> |
| 1643 | <row topline="true"> |
| 1644 | <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
| 1645 | \begin_inset Text |
| 1646 | |
| 1647 | \layout Standard |
| 1648 | |
| 1649 | -funnamed-unions |
| 1650 | \end_inset |
| 1651 | </cell> |
| 1652 | <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> |
| 1653 | \begin_inset Text |
| 1654 | |
| 1655 | \layout Standard |
| 1656 | |
| 1657 | |
| 1658 | \size small |
| 1659 | Enable unnamed unions in the definitions of target language's structures. |
| 1660 | \end_inset |
| 1661 | </cell> |
| 1662 | </row> |
| 1663 | <row topline="true" bottomline="true"> |
| 1664 | <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
| 1665 | \begin_inset Text |
| 1666 | |
| 1667 | \layout Standard |
| 1668 | |
| 1669 | -ftypes88 |
| 1670 | \end_inset |
| 1671 | </cell> |
| 1672 | <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> |
| 1673 | \begin_inset Text |
| 1674 | |
| 1675 | \layout Standard |
| 1676 | |
| 1677 | |
| 1678 | \size small |
| 1679 | Use only ASN.1:1988 embedded types. |
| 1680 | \end_inset |
| 1681 | </cell> |
| 1682 | </row> |
| 1683 | <row topline="true"> |
| 1684 | <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
| 1685 | \begin_inset Text |
| 1686 | |
| 1687 | \layout Standard |
| 1688 | |
| 1689 | |
| 1690 | \series bold |
| 1691 | Output Options |
| 1692 | \end_inset |
| 1693 | </cell> |
| 1694 | <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> |
| 1695 | \begin_inset Text |
| 1696 | |
| 1697 | \layout Standard |
| 1698 | |
| 1699 | |
| 1700 | \series bold |
| 1701 | Description |
| 1702 | \end_inset |
| 1703 | </cell> |
| 1704 | </row> |
| 1705 | <row topline="true"> |
| 1706 | <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
| 1707 | \begin_inset Text |
| 1708 | |
| 1709 | \layout Standard |
| 1710 | |
| 1711 | -print-constraints |
| 1712 | \end_inset |
| 1713 | </cell> |
| 1714 | <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> |
| 1715 | \begin_inset Text |
| 1716 | |
| 1717 | \layout Standard |
| 1718 | |
| 1719 | |
| 1720 | \size small |
| 1721 | When -EF are also specified, this option forces the compiler to explain |
| 1722 | its internal understanding of subtype constraints. |
| 1723 | \end_inset |
| 1724 | </cell> |
| 1725 | </row> |
| 1726 | <row topline="true" bottomline="true"> |
| 1727 | <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> |
| 1728 | \begin_inset Text |
| 1729 | |
| 1730 | \layout Standard |
| 1731 | |
| 1732 | -print-lines |
| 1733 | \end_inset |
| 1734 | </cell> |
| 1735 | <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> |
| 1736 | \begin_inset Text |
| 1737 | |
| 1738 | \layout Standard |
| 1739 | |
| 1740 | |
| 1741 | \size small |
| 1742 | Generate "-- #line" comments in -E output. |
| 1743 | \end_inset |
| 1744 | </cell> |
| 1745 | </row> |
| 1746 | </lyxtabular> |
| 1747 | |
| 1748 | \end_inset |
| 1749 | |
| 1750 | |
| 1751 | \layout Caption |
| 1752 | |
| 1753 | |
| 1754 | \begin_inset LatexCommand \label{cap:asn1c-cmdopts} |
| 1755 | |
| 1756 | \end_inset |
| 1757 | |
| 1758 | The list of asn1c command line options |
| 1759 | \end_inset |
| 1760 | |
| 1761 | |
| 1762 | \layout Section |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 1763 | |
| 1764 | Recognizing compiler output |
| 1765 | \layout Standard |
| 1766 | |
| 1767 | After compiling, the following entities will be created in your current |
| 1768 | directory: |
| 1769 | \layout Itemize |
| 1770 | |
| 1771 | A set of .c and .h files, generally a single pair for each type defined in |
| 1772 | the ASN.1 specifications. |
| 1773 | These files will be named similarly to the ASN.1 types ( |
| 1774 | \emph on |
| 1775 | Rectangle.c |
| 1776 | \emph default |
| 1777 | and |
| 1778 | \emph on |
| 1779 | Rectangle.h |
| 1780 | \emph default |
| 1781 | for the specification defined in the beginning of this document). |
| 1782 | \layout Itemize |
| 1783 | |
| 1784 | A set of helper .c and .h files which contain generic encoders, decoders and |
| 1785 | other useful routines. |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 1786 | There will be quite a few of them, some of them even are not always necessary, |
| 1787 | but the overall amount of code after compiling will be rather small anyway. |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 1788 | \layout Standard |
| 1789 | |
| 1790 | It is your responsibility to create .c file with the |
| 1791 | \emph on |
| 1792 | int main() |
| 1793 | \emph default |
| 1794 | routine and the Makefile (if needed). |
| 1795 | Compiler helps you with the latter by creating the Makefile.am.sample, containing |
| 1796 | the skeleton definition for the automake, should you want to use autotools. |
| 1797 | \layout Standard |
| 1798 | |
| 1799 | In other words, after compiling the Rectangle module, you have the following |
| 1800 | set of files: { Makefile.am.sample, Rectangle.c, Rectangle.h, |
| 1801 | \series bold |
| 1802 | \SpecialChar \ldots{} |
| 1803 | |
| 1804 | \series default |
| 1805 | }, where |
| 1806 | \series bold |
| 1807 | |
| 1808 | \begin_inset Quotes sld |
| 1809 | \end_inset |
| 1810 | |
| 1811 | \SpecialChar \ldots{} |
| 1812 | |
| 1813 | \begin_inset Quotes srd |
| 1814 | \end_inset |
| 1815 | |
| 1816 | |
| 1817 | \series default |
| 1818 | stands for the set of additional |
| 1819 | \begin_inset Quotes sld |
| 1820 | \end_inset |
| 1821 | |
| 1822 | helper |
| 1823 | \begin_inset Quotes srd |
| 1824 | \end_inset |
| 1825 | |
| 1826 | files created by the compiler. |
| 1827 | If you add the simple file with the |
| 1828 | \emph on |
| 1829 | int main() |
| 1830 | \emph default |
| 1831 | routine, it would even be possible to compile everything with the single |
| 1832 | instruction: |
| 1833 | \layout LyX-Code |
| 1834 | |
| 1835 | cc -o rectangle *.c # It could be |
| 1836 | \emph on |
| 1837 | that |
| 1838 | \emph default |
| 1839 | simple |
| 1840 | \begin_inset Foot |
| 1841 | collapsed false |
| 1842 | |
| 1843 | \layout Standard |
| 1844 | |
| 1845 | Provided that you've also created a .c file with the |
| 1846 | \emph on |
| 1847 | int main() |
| 1848 | \emph default |
| 1849 | routine. |
| 1850 | \end_inset |
| 1851 | |
| 1852 | |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 1853 | \layout Section |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 1854 | |
| 1855 | Invoking the ASN.1 helper code from the application |
| 1856 | \layout Standard |
| 1857 | |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 1858 | First of all, you should to include one or more header files into your applicati |
| 1859 | on. |
| 1860 | For our Rectangle module, including the Rectangle.h file is enough: |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 1861 | \layout LyX-Code |
| 1862 | |
| 1863 | #include <Rectangle.h> |
| 1864 | \layout Standard |
| 1865 | |
| 1866 | The header files defines the C structure corresponding to the ASN.1 definition |
| 1867 | of a rectangle and the declaration of the ASN.1 type descriptor, which is |
| 1868 | used as an argument to most of the functions provided by the ASN.1 module. |
| 1869 | For example, here is the code which frees the Rectangle_t structure: |
| 1870 | \layout LyX-Code |
| 1871 | |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 1872 | Rectangle_t *rect = ...; |
| 1873 | \layout LyX-Code |
| 1874 | |
| 1875 | |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 1876 | \layout LyX-Code |
| 1877 | |
| 1878 | asn1_DEF_Rectangle->free_struct(&asn1_DEF_Rectangle, |
| 1879 | \layout LyX-Code |
| 1880 | |
| 1881 | rect, 0); |
| 1882 | \layout Standard |
| 1883 | |
| 1884 | This code defines a |
| 1885 | \emph on |
| 1886 | rect |
| 1887 | \emph default |
| 1888 | pointer which points to the Rectangle_t structure which needs to be freed. |
| 1889 | The second line invokes the generic free_struct routine created specifically |
| 1890 | for this Rectangle_t structure. |
| 1891 | The |
| 1892 | \emph on |
| 1893 | asn1_DEF_Rectangle |
| 1894 | \emph default |
| 1895 | is the type descriptor, which holds a collection of generic routines to |
| 1896 | deal with the Rectangle_t structure. |
| 1897 | \layout Standard |
| 1898 | |
| 1899 | There are several generic functions available: |
| 1900 | \layout Description |
| 1901 | |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 1902 | ber_decoder This is the generic |
| 1903 | \emph on |
| 1904 | restartable |
| 1905 | \begin_inset Foot |
| 1906 | collapsed false |
| 1907 | |
| 1908 | \layout Standard |
| 1909 | |
| 1910 | Restartable means that if the decoder encounters the end of the buffer, |
| 1911 | it will fail, but may later be invoked again with the rest of the buffer |
| 1912 | to continue decoding. |
| 1913 | \end_inset |
| 1914 | |
| 1915 | |
| 1916 | \emph default |
| 1917 | BER decoder (Basic Encoding Rules). |
| 1918 | This decoder would create and/or fill the target structure for you. |
| 1919 | Please refer to Section |
| 1920 | \begin_inset LatexCommand \ref{sub:Decoding-BER} |
| 1921 | |
| 1922 | \end_inset |
| 1923 | |
| 1924 | . |
| 1925 | \layout Description |
| 1926 | |
| 1927 | der_encoder This is the generic DER encoder (Distinguished Encoding Rules). |
Lev Walkin | 35d446b | 2004-09-24 20:56:07 +0000 | [diff] [blame] | 1928 | This encoder will take the target structure and encode it into a series |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 1929 | of bytes. |
| 1930 | Please refer to Section |
| 1931 | \begin_inset LatexCommand \ref{sub:Encoding-DER} |
| 1932 | |
| 1933 | \end_inset |
| 1934 | |
| 1935 | . |
| 1936 | \layout Description |
| 1937 | |
Lev Walkin | 35d446b | 2004-09-24 20:56:07 +0000 | [diff] [blame] | 1938 | xer_encoder This is the generic XER encoder (XML Encoding Rules). |
| 1939 | This encoder will take the target structure and represent it as an XML |
| 1940 | (text) document. |
| 1941 | Please refer to Section |
| 1942 | \begin_inset LatexCommand \ref{sub:Encoding-XER} |
| 1943 | |
| 1944 | \end_inset |
| 1945 | |
| 1946 | . |
| 1947 | \layout Description |
| 1948 | |
| 1949 | check_constraints Check that the contents of the target structure are semantical |
| 1950 | ly valid and constrained to appropriate implicit or explicit subtype constraints. |
| 1951 | Please refer to Section |
| 1952 | \begin_inset LatexCommand \vref{sub:Validating-the-target} |
| 1953 | |
| 1954 | \end_inset |
| 1955 | |
| 1956 | . |
| 1957 | \layout Description |
| 1958 | |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 1959 | print_struct This function convert the contents of the passed target structure |
| 1960 | into human readable form. |
| 1961 | This form is not formal and cannot be converted back into the structure, |
| 1962 | but it may turn out to be useful for debugging or quick-n-dirty printing. |
| 1963 | Please refer to Section |
| 1964 | \begin_inset LatexCommand \ref{sub:Printing-the-target} |
| 1965 | |
| 1966 | \end_inset |
| 1967 | |
| 1968 | . |
| 1969 | \layout Description |
| 1970 | |
| 1971 | free_struct This is a generic disposal which frees the target structure. |
| 1972 | Please refer to Section |
| 1973 | \begin_inset LatexCommand \ref{sub:Freeing-the-target} |
| 1974 | |
| 1975 | \end_inset |
| 1976 | |
| 1977 | . |
| 1978 | \layout Standard |
| 1979 | |
Lev Walkin | 35d446b | 2004-09-24 20:56:07 +0000 | [diff] [blame] | 1980 | check_constraints Check that the contents of the target structure are semantical |
| 1981 | ly valid and constrained to appropriate implicit or explicit subtype constraints. |
| 1982 | Please refer to Section |
| 1983 | \begin_inset LatexCommand \vref{sub:Validating-the-target} |
| 1984 | |
| 1985 | \end_inset |
| 1986 | |
| 1987 | . |
| 1988 | \layout Standard |
| 1989 | |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 1990 | Each of the above function takes the type descriptor ( |
| 1991 | \emph on |
| 1992 | asn1_DEF_\SpecialChar \ldots{} |
| 1993 | |
| 1994 | \emph default |
| 1995 | ) and the target structure ( |
| 1996 | \emph on |
| 1997 | rect |
| 1998 | \emph default |
| 1999 | , in the above example). |
| 2000 | The target structure is typically created by the generic BER decoder or |
| 2001 | by the application itself. |
| 2002 | \layout Standard |
| 2003 | |
| 2004 | Here is how the buffer can be deserialized into the structure: |
| 2005 | \layout LyX-Code |
| 2006 | |
| 2007 | Rectangle_t * |
| 2008 | \layout LyX-Code |
| 2009 | |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 2010 | simple_deserializer(const void *buffer, size_t buf_size) { |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 2011 | \layout LyX-Code |
| 2012 | |
| 2013 | Rectangle_t *rect = 0; /* Note this 0! */ |
| 2014 | \layout LyX-Code |
| 2015 | |
| 2016 | ber_dec_rval_t rval; |
| 2017 | \layout LyX-Code |
| 2018 | |
| 2019 | |
| 2020 | \layout LyX-Code |
| 2021 | |
| 2022 | rval = asn1_DEF_Rectangle->ber_decoder( |
| 2023 | \layout LyX-Code |
| 2024 | |
| 2025 | &asn1_DEF_Rectangle, |
| 2026 | \layout LyX-Code |
| 2027 | |
| 2028 | (void **)&rect, |
| 2029 | \layout LyX-Code |
| 2030 | |
| 2031 | buffer, buf_size, |
| 2032 | \layout LyX-Code |
| 2033 | |
| 2034 | 0); |
| 2035 | \layout LyX-Code |
| 2036 | |
| 2037 | |
| 2038 | \layout LyX-Code |
| 2039 | |
| 2040 | if(rval |
| 2041 | \series bold |
| 2042 | .code |
| 2043 | \series default |
| 2044 | == RC_OK) { |
| 2045 | \layout LyX-Code |
| 2046 | |
| 2047 | return rect; /* Decoding succeeded */ |
| 2048 | \layout LyX-Code |
| 2049 | |
| 2050 | } else { |
| 2051 | \layout LyX-Code |
| 2052 | |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 2053 | /* Free partially decoded rect */ |
| 2054 | \layout LyX-Code |
| 2055 | |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 2056 | asn1_DEF_Rectangle->free_struct( |
| 2057 | \layout LyX-Code |
| 2058 | |
| 2059 | &asn1_DEF_Rectangle, rect, 0); |
| 2060 | \layout LyX-Code |
| 2061 | |
| 2062 | return 0; |
| 2063 | \layout LyX-Code |
| 2064 | |
| 2065 | } |
| 2066 | \layout LyX-Code |
| 2067 | |
| 2068 | } |
| 2069 | \layout Standard |
| 2070 | |
| 2071 | The code above defines a function, |
| 2072 | \emph on |
| 2073 | simple_deserializer |
| 2074 | \emph default |
| 2075 | , which takes a buffer and its length and expected to return a pointer to |
| 2076 | the Rectangle_t structure. |
| 2077 | Inside, it tries to convert the bytes passed into the target structure |
| 2078 | (rect) using the generic BER decoder and returns the rect pointer afterwards. |
| 2079 | If the structure cannot be deserialized, it frees the memory which might |
| 2080 | be left allocated by the unfinished |
| 2081 | \emph on |
| 2082 | ber_decoder |
| 2083 | \emph default |
| 2084 | routine and returns NULL. |
| 2085 | |
| 2086 | \series bold |
| 2087 | This freeing is necessary |
| 2088 | \series default |
| 2089 | because the ber_decoder is a restartable procedure, and may fail just because |
| 2090 | there is more data needs to be provided before decoding could be finalized. |
| 2091 | The code above obviously does not take into account the way the |
| 2092 | \emph on |
| 2093 | ber_decoder |
| 2094 | \emph default |
| 2095 | failed, so the freeing is necessary because the part of the buffer may |
| 2096 | already be decoded into the structure by the time something goes wrong. |
| 2097 | \layout Standard |
| 2098 | |
| 2099 | Restartable decoding is a little bit trickier: you need to provide the old |
| 2100 | target structure pointer (which might be already half-decoded) and react |
| 2101 | on RC_WMORE return code. |
| 2102 | This will be explained later in Section |
| 2103 | \begin_inset LatexCommand \vref{sub:Decoding-BER} |
| 2104 | |
| 2105 | \end_inset |
| 2106 | |
| 2107 | |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 2108 | \layout Subsection |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 2109 | |
| 2110 | |
| 2111 | \begin_inset LatexCommand \label{sub:Decoding-BER} |
| 2112 | |
| 2113 | \end_inset |
| 2114 | |
| 2115 | Decoding BER |
| 2116 | \layout Standard |
| 2117 | |
| 2118 | The Basic Encoding Rules describe the basic way how the structure can be |
| 2119 | encoded and decoded. |
| 2120 | Several other encoding rules (CER, DER) define a more restrictive versions |
| 2121 | of BER, so the generic BER parser is also capable of decoding the data |
| 2122 | encoded by CER and DER encoders. |
| 2123 | The opposite is not true. |
| 2124 | \layout Standard |
| 2125 | |
| 2126 | The ASN.1 compiler provides the generic BER decoder which is implicitly capable |
| 2127 | of decoding BER, CER and DER encoded data. |
| 2128 | \layout Standard |
| 2129 | |
| 2130 | The decoder is restartable (stream-oriented), which means that in case the |
| 2131 | buffer has less data than it is expected, the decoder will process whatever |
| 2132 | it is available and ask for more data to be provided. |
| 2133 | Please note that the decoder may actually process less data than it is |
| 2134 | given in the buffer, which means that you should be able to make the next |
| 2135 | buffer contain the unprocessed part of the previous buffer. |
| 2136 | \layout Standard |
| 2137 | |
| 2138 | Suppose, you have two buffers of encoded data: 100 bytes and 200 bytes. |
| 2139 | \layout Itemize |
| 2140 | |
| 2141 | You may concatenate these buffers and feed the BER decoder with 300 bytes |
| 2142 | of data, or |
| 2143 | \layout Itemize |
| 2144 | |
| 2145 | You may feed it the first buffer of 100 bytes of data, realize that the |
| 2146 | ber_decoder consumed only 95 bytes from it and later feed the decoder with |
| 2147 | 205 bytes buffer which consists of 5 unprocessed bytes from the first buffer |
| 2148 | and the latter 200 bytes from the second buffer. |
| 2149 | \layout Standard |
| 2150 | |
| 2151 | This is not as convenient as it could be (like, the BER encoder would consume |
| 2152 | the whole 100 bytes and keep these 5 bytes in some temporary storage), |
| 2153 | but in case of stream-based processing it might actually be OK. |
| 2154 | Suggestions are welcome. |
| 2155 | \layout Standard |
| 2156 | |
| 2157 | There are two ways to invoke a BER decoder. |
| 2158 | The first one is a direct reference of the type-specific decoder. |
| 2159 | This way was shown in the previous example of |
| 2160 | \emph on |
| 2161 | simple_deserializer |
| 2162 | \emph default |
| 2163 | function. |
| 2164 | The second way is to invoke a |
| 2165 | \emph on |
| 2166 | ber_decode |
| 2167 | \emph default |
| 2168 | function, which is just a simple wrapper of the former approach into a |
| 2169 | less wordy notation: |
| 2170 | \layout LyX-Code |
| 2171 | |
| 2172 | rval = ber_decode(&asn1_DEF_Rectangle, (void **)&rect, |
| 2173 | \layout LyX-Code |
| 2174 | |
| 2175 | buffer, buf_size); |
| 2176 | \layout Standard |
| 2177 | |
| 2178 | Note that the initial (asn1_DEF_Rectangle->ber_decoder) reference is gone, |
| 2179 | and also the last argument (0) is no longer necessary. |
| 2180 | \layout Standard |
| 2181 | |
| 2182 | These two ways of invocations are fully equivalent. |
| 2183 | \layout Standard |
| 2184 | |
| 2185 | The BER de |
| 2186 | \emph on |
| 2187 | coder |
| 2188 | \emph default |
| 2189 | may fail because ( |
| 2190 | \emph on |
| 2191 | the following RC_\SpecialChar \ldots{} |
| 2192 | codes are defined in ber_decoder.h |
| 2193 | \emph default |
| 2194 | ): |
| 2195 | \layout Itemize |
| 2196 | |
| 2197 | RC_WMORE: There is more data expected than it is provided (stream mode continuat |
| 2198 | ion feature); |
| 2199 | \layout Itemize |
| 2200 | |
| 2201 | RC_FAIL: General failure to decode the buffer; |
| 2202 | \layout Itemize |
| 2203 | |
| 2204 | \SpecialChar \ldots{} |
| 2205 | other codes may be defined as well. |
| 2206 | \layout Standard |
| 2207 | |
| 2208 | Together with the return code (.code) the ber_dec_rval_t type contains the |
| 2209 | number of bytes which is consumed from the buffer. |
| 2210 | In the previous hypothetical example of two buffers (of 100 and 200 bytes), |
| 2211 | the first call to ber_decode() would return with .code = RC_WMORE and .consumed |
| 2212 | = 95. |
| 2213 | The .consumed field of the BER decoder return value is |
| 2214 | \series bold |
| 2215 | always |
| 2216 | \series default |
| 2217 | valid, even if the decoder succeeds or fails with any other return code. |
| 2218 | \layout Standard |
| 2219 | |
| 2220 | Please look into ber_decoder.h for the precise definition of ber_decode() |
| 2221 | and related types. |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 2222 | \layout Subsection |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 2223 | |
| 2224 | |
| 2225 | \begin_inset LatexCommand \label{sub:Encoding-DER} |
| 2226 | |
| 2227 | \end_inset |
| 2228 | |
| 2229 | Encoding DER |
| 2230 | \layout Standard |
| 2231 | |
Lev Walkin | 35d446b | 2004-09-24 20:56:07 +0000 | [diff] [blame] | 2232 | The Distinguished Encoding Rules is the |
| 2233 | \emph on |
| 2234 | canonical |
| 2235 | \emph default |
| 2236 | variant of BER encoding rules. |
| 2237 | The DER is best suited to encode the structures where all the lengths are |
| 2238 | known beforehand. |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 2239 | This is probably exactly how you want to encode: either after a BER decoding |
| 2240 | or after a manual fill-up, the target structure contains the data which |
| 2241 | size is implicitly known before encoding. |
| 2242 | The DER encoding is used, for example, to encode X.509 certificates. |
| 2243 | \layout Standard |
| 2244 | |
| 2245 | As with BER decoder, the DER encoder may be invoked either directly from |
| 2246 | the ASN.1 type descriptor (asn1_DEF_Rectangle) or from the stand-alone function, |
| 2247 | which is somewhat simpler: |
| 2248 | \layout LyX-Code |
| 2249 | |
| 2250 | /* |
| 2251 | \layout LyX-Code |
| 2252 | |
| 2253 | * This is a custom function which writes the |
| 2254 | \layout LyX-Code |
| 2255 | |
| 2256 | * encoded output into some FILE stream. |
| 2257 | \layout LyX-Code |
| 2258 | |
| 2259 | */ |
| 2260 | \layout LyX-Code |
| 2261 | |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 2262 | static int |
| 2263 | \layout LyX-Code |
| 2264 | |
| 2265 | write_stream(const void *buffer, size_t size, void *app_key) { |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 2266 | \layout LyX-Code |
| 2267 | |
| 2268 | FILE *ostream = app_key; |
| 2269 | \layout LyX-Code |
| 2270 | |
| 2271 | size_t wrote; |
| 2272 | \layout LyX-Code |
| 2273 | |
| 2274 | |
| 2275 | \layout LyX-Code |
| 2276 | |
| 2277 | wrote = fwrite(buffer, 1, size, ostream); |
| 2278 | \layout LyX-Code |
| 2279 | |
| 2280 | |
| 2281 | \layout LyX-Code |
| 2282 | |
| 2283 | return (wrote == size) ? 0 : -1; |
| 2284 | \layout LyX-Code |
| 2285 | |
| 2286 | } |
| 2287 | \layout LyX-Code |
| 2288 | |
| 2289 | |
| 2290 | \layout LyX-Code |
| 2291 | |
| 2292 | /* |
| 2293 | \layout LyX-Code |
| 2294 | |
| 2295 | * This is the serializer itself, |
| 2296 | \layout LyX-Code |
| 2297 | |
| 2298 | * it supplies the DER encoder with the |
| 2299 | \layout LyX-Code |
| 2300 | |
| 2301 | * pointer to the custom output function. |
| 2302 | \layout LyX-Code |
| 2303 | |
| 2304 | */ |
| 2305 | \layout LyX-Code |
| 2306 | |
| 2307 | ssize_t |
| 2308 | \layout LyX-Code |
| 2309 | |
| 2310 | simple_serializer(FILE *ostream, Rectangle_t *rect) { |
| 2311 | \layout LyX-Code |
| 2312 | |
Lev Walkin | 35d446b | 2004-09-24 20:56:07 +0000 | [diff] [blame] | 2313 | asn_enc_rval_t er; /* Encoder return value */ |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 2314 | \layout LyX-Code |
| 2315 | |
| 2316 | |
| 2317 | \layout LyX-Code |
| 2318 | |
Lev Walkin | 35d446b | 2004-09-24 20:56:07 +0000 | [diff] [blame] | 2319 | er = der_encode(&asn1_DEF_Rect, rect, |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 2320 | \layout LyX-Code |
| 2321 | |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 2322 | write_stream, ostream); |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 2323 | \layout LyX-Code |
| 2324 | |
Lev Walkin | 35d446b | 2004-09-24 20:56:07 +0000 | [diff] [blame] | 2325 | if(er. |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 2326 | \series bold |
Lev Walkin | 35d446b | 2004-09-24 20:56:07 +0000 | [diff] [blame] | 2327 | encoded |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 2328 | \series default |
| 2329 | == -1) { |
| 2330 | \layout LyX-Code |
| 2331 | |
| 2332 | /* |
| 2333 | \layout LyX-Code |
| 2334 | |
Lev Walkin | 35d446b | 2004-09-24 20:56:07 +0000 | [diff] [blame] | 2335 | * Failed to encode the rectangle data. |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 2336 | \layout LyX-Code |
| 2337 | |
| 2338 | */ |
| 2339 | \layout LyX-Code |
| 2340 | |
| 2341 | fprintf(stderr, |
| 2342 | \begin_inset Quotes sld |
| 2343 | \end_inset |
| 2344 | |
| 2345 | Cannot encode %s: %s |
| 2346 | \backslash |
| 2347 | n |
| 2348 | \begin_inset Quotes srd |
| 2349 | \end_inset |
| 2350 | |
| 2351 | , |
| 2352 | \layout LyX-Code |
| 2353 | |
Lev Walkin | 35d446b | 2004-09-24 20:56:07 +0000 | [diff] [blame] | 2354 | er. |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 2355 | \series bold |
Lev Walkin | 35d446b | 2004-09-24 20:56:07 +0000 | [diff] [blame] | 2356 | failed_type |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 2357 | \series default |
| 2358 | ->name, |
| 2359 | \layout LyX-Code |
| 2360 | |
| 2361 | strerror(errno)); |
| 2362 | \layout LyX-Code |
| 2363 | |
| 2364 | return -1; |
| 2365 | \layout LyX-Code |
| 2366 | |
| 2367 | } else { |
| 2368 | \layout LyX-Code |
| 2369 | |
| 2370 | /* Return the number of bytes */ |
| 2371 | \layout LyX-Code |
| 2372 | |
Lev Walkin | 35d446b | 2004-09-24 20:56:07 +0000 | [diff] [blame] | 2373 | return er.encoded; |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 2374 | \layout LyX-Code |
| 2375 | |
| 2376 | } |
| 2377 | \layout LyX-Code |
| 2378 | |
| 2379 | } |
| 2380 | \layout Standard |
| 2381 | |
| 2382 | As you see, the DER encoder does not write into some sort of buffer or something. |
| 2383 | It just invokes the custom function (possible, multiple times) which would |
| 2384 | save the data into appropriate storage. |
| 2385 | The optional argument |
| 2386 | \emph on |
| 2387 | app_key |
| 2388 | \emph default |
| 2389 | is opaque for the DER encoder code and just used by |
| 2390 | \emph on |
| 2391 | _write_stream() |
| 2392 | \emph default |
| 2393 | as the pointer to the appropriate output stream to be used. |
| 2394 | \layout Standard |
| 2395 | |
| 2396 | If the custom write function is not given (passed as 0), then the DER encoder |
| 2397 | will essentially do the same thing (i.e., encode the data) but no callbacks |
| 2398 | will be invoked (so the data goes nowhere). |
| 2399 | It may prove useful to determine the size of the structure's encoding before |
| 2400 | actually doing the encoding |
| 2401 | \begin_inset Foot |
| 2402 | collapsed false |
| 2403 | |
| 2404 | \layout Standard |
| 2405 | |
| 2406 | It is actually faster too: the encoder might skip over some computations |
| 2407 | which aren't important for the size determination. |
| 2408 | \end_inset |
| 2409 | |
| 2410 | . |
| 2411 | \layout Standard |
| 2412 | |
| 2413 | Please look into der_encoder.h for the precise definition of der_encode() |
| 2414 | and related types. |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 2415 | \layout Subsection |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 2416 | |
| 2417 | |
Lev Walkin | 35d446b | 2004-09-24 20:56:07 +0000 | [diff] [blame] | 2418 | \begin_inset LatexCommand \label{sub:Encoding-XER} |
| 2419 | |
| 2420 | \end_inset |
| 2421 | |
| 2422 | Encoding XER |
| 2423 | \layout Standard |
| 2424 | |
| 2425 | The XER stands for XML Encoding Rules, where XML, in turn, is eXtensible |
| 2426 | Markup Language, a text-based format for information exchange. |
| 2427 | The encoder routine API comes in two flavors: stdio-based and callback-based. |
| 2428 | With the callback-based encoder, the encoding process is very similar to |
| 2429 | the DER one, described in Section |
| 2430 | \begin_inset LatexCommand \vref{sub:Encoding-DER} |
| 2431 | |
| 2432 | \end_inset |
| 2433 | |
| 2434 | . |
| 2435 | The following example uses the definition of write_stream() from up there. |
| 2436 | \layout LyX-Code |
| 2437 | |
| 2438 | /* |
| 2439 | \layout LyX-Code |
| 2440 | |
| 2441 | * This procedure generates the XML document |
| 2442 | \layout LyX-Code |
| 2443 | |
| 2444 | * by invoking the XER encoder. |
| 2445 | \layout LyX-Code |
| 2446 | |
| 2447 | * NOTE: Do not copy this code verbatim! |
| 2448 | \layout LyX-Code |
| 2449 | |
| 2450 | * If the stdio output is necessary, |
| 2451 | \layout LyX-Code |
| 2452 | |
| 2453 | * use the xer_fprint() procedure instead. |
| 2454 | \layout LyX-Code |
| 2455 | |
| 2456 | * See Section |
| 2457 | \begin_inset LatexCommand \vref{sub:Printing-the-target} |
| 2458 | |
| 2459 | \end_inset |
| 2460 | |
| 2461 | . |
| 2462 | \layout LyX-Code |
| 2463 | |
| 2464 | */ |
| 2465 | \layout LyX-Code |
| 2466 | |
| 2467 | int |
| 2468 | \layout LyX-Code |
| 2469 | |
| 2470 | print_as_XML(FILE *ostream, Rectangle_t *rect) { |
| 2471 | \layout LyX-Code |
| 2472 | |
| 2473 | asn_enc_rval_t er; /* Encoder return value */ |
| 2474 | \layout LyX-Code |
| 2475 | |
| 2476 | |
| 2477 | \layout LyX-Code |
| 2478 | |
| 2479 | er = xer_encode(&asn1_DEF_Rect, rect, |
| 2480 | \layout LyX-Code |
| 2481 | |
| 2482 | XER_F_BASIC, /* BASIC-XER or CANONICAL-XER */ |
| 2483 | \layout LyX-Code |
| 2484 | |
| 2485 | write_stream, ostream); |
| 2486 | \layout LyX-Code |
| 2487 | |
| 2488 | |
| 2489 | \layout LyX-Code |
| 2490 | |
| 2491 | return (er.encoded == -1) ? -1 : 0; |
| 2492 | \layout LyX-Code |
| 2493 | |
| 2494 | } |
| 2495 | \layout Standard |
| 2496 | |
| 2497 | Please look into xer_encoder.h for the precise definition of xer_encode() |
| 2498 | and related types. |
| 2499 | \layout Standard |
| 2500 | |
| 2501 | See Section |
| 2502 | \begin_inset LatexCommand \ref{sub:Printing-the-target} |
| 2503 | |
| 2504 | \end_inset |
| 2505 | |
| 2506 | for the example of stdio-based XML encoder and other pretty-printing suggestion |
| 2507 | s. |
| 2508 | \layout Subsection |
| 2509 | |
| 2510 | |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 2511 | \begin_inset LatexCommand \label{sub:Validating-the-target} |
| 2512 | |
| 2513 | \end_inset |
| 2514 | |
| 2515 | Validating the target structure |
| 2516 | \layout Standard |
| 2517 | |
| 2518 | Sometimes the target structure needs to be validated. |
| 2519 | For example, if the structure was created by the application (as opposed |
| 2520 | to being decoded from some external source), some important information |
| 2521 | required by the ASN.1 specification might be missing. |
| 2522 | On the other hand, the successful decoding of the data from some external |
| 2523 | source does not necessarily mean that the data is fully valid either. |
| 2524 | It might well be the case that the specification describes some subtype |
| 2525 | constraints that were not taken into account during decoding, and it would |
| 2526 | actually be useful to perform the last check when the data is ready to |
| 2527 | be encoded or when the data has just been decoded to ensure its validity |
| 2528 | according to some stricter rules. |
| 2529 | \layout Standard |
| 2530 | |
| 2531 | The asn_check_constraints() function checks the type for various implicit |
| 2532 | and explicit constraints. |
| 2533 | It is recommended to use asn_check_constraints() function after each decoding |
| 2534 | and before each encoding. |
| 2535 | \layout Standard |
| 2536 | |
| 2537 | Please look into constraints.h for the precise definition of asn_check_constraint |
| 2538 | s() and related types. |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 2539 | \layout Subsection |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 2540 | |
| 2541 | |
| 2542 | \begin_inset LatexCommand \label{sub:Printing-the-target} |
| 2543 | |
| 2544 | \end_inset |
| 2545 | |
| 2546 | Printing the target structure |
| 2547 | \layout Standard |
| 2548 | |
| 2549 | There are two ways to print the target structure: either invoke the print_struct |
| 2550 | member of the ASN.1 type descriptor, or using the asn_fprint() function, |
| 2551 | which is a simpler wrapper of the former: |
| 2552 | \layout LyX-Code |
| 2553 | |
| 2554 | asn_fprint(stdout, &asn1_DEF_Rectangle, rect); |
| 2555 | \layout Standard |
| 2556 | |
| 2557 | Please look into constr_TYPE.h for the precise definition of asn_fprint() |
| 2558 | and related types. |
Lev Walkin | 35d446b | 2004-09-24 20:56:07 +0000 | [diff] [blame] | 2559 | \layout Standard |
| 2560 | |
| 2561 | Another practical alternative to this custom format printing would be to |
| 2562 | invoke XER encoder. |
| 2563 | The default BASIC-XER encoder performs reasonable formatting for the output |
| 2564 | to be useful and human readable. |
| 2565 | To invoke the XER decoder in a manner similar to asn_fprint(), use the |
| 2566 | xer_fprint() call: |
| 2567 | \layout LyX-Code |
| 2568 | |
| 2569 | xer_fprint(stdout, &asn1_DEF_Rectangle, rect); |
| 2570 | \layout Standard |
| 2571 | |
| 2572 | See Section |
| 2573 | \begin_inset LatexCommand \vref{sub:Encoding-XER} |
| 2574 | |
| 2575 | \end_inset |
| 2576 | |
| 2577 | for XML-related details. |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 2578 | \layout Subsection |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 2579 | |
| 2580 | |
| 2581 | \begin_inset LatexCommand \label{sub:Freeing-the-target} |
| 2582 | |
| 2583 | \end_inset |
| 2584 | |
| 2585 | Freeing the target structure |
| 2586 | \layout Standard |
| 2587 | |
| 2588 | Freeing the structure is slightly more complex than it may seem to. |
| 2589 | When the ASN.1 structure is freed, all the members of the structure and |
| 2590 | their submembers etc etc are recursively freed too. |
| 2591 | But it might not be feasible to free the structure itself. |
| 2592 | Consider the following case: |
| 2593 | \layout LyX-Code |
| 2594 | |
| 2595 | struct my_figure { /* The custom structure */ |
| 2596 | \layout LyX-Code |
| 2597 | |
| 2598 | int flags; /* <some custom member> */ |
| 2599 | \layout LyX-Code |
| 2600 | |
| 2601 | /* The type is generated by the ASN.1 compiler */ |
| 2602 | \layout LyX-Code |
| 2603 | |
| 2604 | |
| 2605 | \emph on |
| 2606 | Rectangle_t rect; |
| 2607 | \layout LyX-Code |
| 2608 | |
| 2609 | /* other members of the structure */ |
| 2610 | \layout LyX-Code |
| 2611 | |
| 2612 | }; |
| 2613 | \layout Standard |
| 2614 | |
| 2615 | In this example, the application programmer defined a custom structure with |
| 2616 | one ASN.1-derived member (rect). |
| 2617 | This member is not a reference to the Rectangle_t, but an in-place inclusion |
| 2618 | of the Rectangle_t structure. |
| 2619 | If the freeing is necessary, the usual procedure of freeing everything |
| 2620 | must not be applied to the &rect pointer itself, because it does not point |
| 2621 | to the memory block directly allocated by memory allocation routine, but |
| 2622 | instead lies within such a block allocated for my_figure structure. |
| 2623 | \layout Standard |
| 2624 | |
| 2625 | To solve this problem, the free_struct routine has the additional argument |
| 2626 | (besides the intuitive type descriptor and target structure pointers), |
| 2627 | which is the flag specifying whether the outer pointer itself must be freed |
| 2628 | (0, default) or it should be left intact (non-zero value). |
| 2629 | \layout LyX-Code |
| 2630 | |
| 2631 | /* Rectangle_t is defined within my_figure */ |
| 2632 | \layout LyX-Code |
| 2633 | |
| 2634 | struct my_figure *mf = |
| 2635 | \series bold |
| 2636 | ... |
| 2637 | \series default |
| 2638 | ; |
| 2639 | \layout LyX-Code |
| 2640 | |
| 2641 | /* |
| 2642 | \layout LyX-Code |
| 2643 | |
| 2644 | * Freeing the Rectangle_td |
| 2645 | \layout LyX-Code |
| 2646 | |
| 2647 | * without freeing the mf->rect pointer |
| 2648 | \layout LyX-Code |
| 2649 | |
| 2650 | */ |
| 2651 | \layout LyX-Code |
| 2652 | |
| 2653 | asn1_DEF_Rectangle->free_struct( |
| 2654 | \layout LyX-Code |
| 2655 | |
| 2656 | &asn1_DEF_Rectangle, &mf->rect, |
| 2657 | \emph on |
| 2658 | 1 |
| 2659 | \emph default |
| 2660 | /* !free */); |
| 2661 | \layout LyX-Code |
| 2662 | |
| 2663 | |
| 2664 | \layout LyX-Code |
| 2665 | |
| 2666 | /* Rectangle_t is a stand-alone pointer */ |
| 2667 | \layout LyX-Code |
| 2668 | |
| 2669 | Rectangle_t *rect = |
| 2670 | \series bold |
| 2671 | ... |
| 2672 | \series default |
| 2673 | ; |
| 2674 | \layout LyX-Code |
| 2675 | |
| 2676 | /* |
| 2677 | \layout LyX-Code |
| 2678 | |
| 2679 | * Freeing the Rectangle_t |
| 2680 | \layout LyX-Code |
| 2681 | |
| 2682 | * and freeing the rect pointer |
| 2683 | \layout LyX-Code |
| 2684 | |
| 2685 | */ |
| 2686 | \layout LyX-Code |
| 2687 | |
| 2688 | asn1_DEF_Rectangle->free_struct( |
| 2689 | \layout LyX-Code |
| 2690 | |
| 2691 | &asn1_DEF_Rectangle, rect, |
| 2692 | \emph on |
| 2693 | 0 |
| 2694 | \emph default |
| 2695 | /* free the pointer too */); |
| 2696 | \layout Standard |
| 2697 | |
| 2698 | It is safe to invoke the |
| 2699 | \emph on |
| 2700 | free_struct |
| 2701 | \emph default |
| 2702 | function with the target structure pointer set to 0 (NULL), the function |
| 2703 | will do nothing. |
| 2704 | \layout Bibliography |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 2705 | \bibitem [ASN1C]{ASN1C} |
| 2706 | |
Lev Walkin | 26871b5 | 2004-09-08 03:01:06 +0000 | [diff] [blame] | 2707 | The OpenSource ASN.1 Compiler. |
Lev Walkin | 26587ab | 2004-08-23 15:12:04 +0000 | [diff] [blame] | 2708 | |
| 2709 | \begin_inset LatexCommand \htmlurl{http://lionet.info/asn1/} |
| 2710 | |
| 2711 | \end_inset |
| 2712 | |
| 2713 | |
| 2714 | \layout Bibliography |
Lev Walkin | 84291e0 | 2004-06-03 03:49:45 +0000 | [diff] [blame] | 2715 | \bibitem [Dub00]{Dub00} |
| 2716 | |
| 2717 | Olivier Dubuisson -- |
| 2718 | \emph on |
| 2719 | ASN.1 Communication between heterogeneous systems |
| 2720 | \emph default |
| 2721 | -- Morgan Kaufmann Publishers, 2000. |
| 2722 | |
| 2723 | \begin_inset LatexCommand \htmlurl{http://asn1.elibel.tm.fr/en/book/} |
| 2724 | |
| 2725 | \end_inset |
| 2726 | |
| 2727 | . |
| 2728 | ISBN:0-12-6333361-0. |
| 2729 | \layout Bibliography |
| 2730 | \bibitem [ITU-T/ASN.1]{ITU-T/ASN.1} |
| 2731 | |
| 2732 | ITU-T Study Group 17 -- Languages for Telecommunication Systems |
| 2733 | \begin_inset LatexCommand \url{http://www.itu.int/ITU-T/studygroups/com17/languages/} |
| 2734 | |
| 2735 | \end_inset |
| 2736 | |
| 2737 | |
| 2738 | \the_end |