| 1 | '\" |
| 2 | '\" Copyright (c) 1997 by Sun Microsystems, Inc. |
| 3 | '\" |
| 4 | '\" See the file "license.terms" for information on usage and redistribution |
| 5 | '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. |
| 6 | '\" |
| 7 | '\" RCS: @(#) $Id: binary.n,v 1.11.2.8 2005/02/10 10:28:21 dkf Exp $ |
| 8 | '\" |
| 9 | '\" The definitions below are for supplemental macros used in Tcl/Tk |
| 10 | '\" manual entries. |
| 11 | '\" |
| 12 | '\" .AP type name in/out ?indent? |
| 13 | '\" Start paragraph describing an argument to a library procedure. |
| 14 | '\" type is type of argument (int, etc.), in/out is either "in", "out", |
| 15 | '\" or "in/out" to describe whether procedure reads or modifies arg, |
| 16 | '\" and indent is equivalent to second arg of .IP (shouldn't ever be |
| 17 | '\" needed; use .AS below instead) |
| 18 | '\" |
| 19 | '\" .AS ?type? ?name? |
| 20 | '\" Give maximum sizes of arguments for setting tab stops. Type and |
| 21 | '\" name are examples of largest possible arguments that will be passed |
| 22 | '\" to .AP later. If args are omitted, default tab stops are used. |
| 23 | '\" |
| 24 | '\" .BS |
| 25 | '\" Start box enclosure. From here until next .BE, everything will be |
| 26 | '\" enclosed in one large box. |
| 27 | '\" |
| 28 | '\" .BE |
| 29 | '\" End of box enclosure. |
| 30 | '\" |
| 31 | '\" .CS |
| 32 | '\" Begin code excerpt. |
| 33 | '\" |
| 34 | '\" .CE |
| 35 | '\" End code excerpt. |
| 36 | '\" |
| 37 | '\" .VS ?version? ?br? |
| 38 | '\" Begin vertical sidebar, for use in marking newly-changed parts |
| 39 | '\" of man pages. The first argument is ignored and used for recording |
| 40 | '\" the version when the .VS was added, so that the sidebars can be |
| 41 | '\" found and removed when they reach a certain age. If another argument |
| 42 | '\" is present, then a line break is forced before starting the sidebar. |
| 43 | '\" |
| 44 | '\" .VE |
| 45 | '\" End of vertical sidebar. |
| 46 | '\" |
| 47 | '\" .DS |
| 48 | '\" Begin an indented unfilled display. |
| 49 | '\" |
| 50 | '\" .DE |
| 51 | '\" End of indented unfilled display. |
| 52 | '\" |
| 53 | '\" .SO |
| 54 | '\" Start of list of standard options for a Tk widget. The |
| 55 | '\" options follow on successive lines, in four columns separated |
| 56 | '\" by tabs. |
| 57 | '\" |
| 58 | '\" .SE |
| 59 | '\" End of list of standard options for a Tk widget. |
| 60 | '\" |
| 61 | '\" .OP cmdName dbName dbClass |
| 62 | '\" Start of description of a specific option. cmdName gives the |
| 63 | '\" option's name as specified in the class command, dbName gives |
| 64 | '\" the option's name in the option database, and dbClass gives |
| 65 | '\" the option's class in the option database. |
| 66 | '\" |
| 67 | '\" .UL arg1 arg2 |
| 68 | '\" Print arg1 underlined, then print arg2 normally. |
| 69 | '\" |
| 70 | '\" RCS: @(#) $Id: man.macros,v 1.4 2000/08/25 06:18:32 ericm Exp $ |
| 71 | '\" |
| 72 | '\" # Set up traps and other miscellaneous stuff for Tcl/Tk man pages. |
| 73 | .if t .wh -1.3i ^B |
| 74 | .nr ^l \n(.l |
| 75 | .ad b |
| 76 | '\" # Start an argument description |
| 77 | .de AP |
| 78 | .ie !"\\$4"" .TP \\$4 |
| 79 | .el \{\ |
| 80 | . ie !"\\$2"" .TP \\n()Cu |
| 81 | . el .TP 15 |
| 82 | .\} |
| 83 | .ta \\n()Au \\n()Bu |
| 84 | .ie !"\\$3"" \{\ |
| 85 | \&\\$1 \\fI\\$2\\fP (\\$3) |
| 86 | .\".b |
| 87 | .\} |
| 88 | .el \{\ |
| 89 | .br |
| 90 | .ie !"\\$2"" \{\ |
| 91 | \&\\$1 \\fI\\$2\\fP |
| 92 | .\} |
| 93 | .el \{\ |
| 94 | \&\\fI\\$1\\fP |
| 95 | .\} |
| 96 | .\} |
| 97 | .. |
| 98 | '\" # define tabbing values for .AP |
| 99 | .de AS |
| 100 | .nr )A 10n |
| 101 | .if !"\\$1"" .nr )A \\w'\\$1'u+3n |
| 102 | .nr )B \\n()Au+15n |
| 103 | .\" |
| 104 | .if !"\\$2"" .nr )B \\w'\\$2'u+\\n()Au+3n |
| 105 | .nr )C \\n()Bu+\\w'(in/out)'u+2n |
| 106 | .. |
| 107 | .AS Tcl_Interp Tcl_CreateInterp in/out |
| 108 | '\" # BS - start boxed text |
| 109 | '\" # ^y = starting y location |
| 110 | '\" # ^b = 1 |
| 111 | .de BS |
| 112 | .br |
| 113 | .mk ^y |
| 114 | .nr ^b 1u |
| 115 | .if n .nf |
| 116 | .if n .ti 0 |
| 117 | .if n \l'\\n(.lu\(ul' |
| 118 | .if n .fi |
| 119 | .. |
| 120 | '\" # BE - end boxed text (draw box now) |
| 121 | .de BE |
| 122 | .nf |
| 123 | .ti 0 |
| 124 | .mk ^t |
| 125 | .ie n \l'\\n(^lu\(ul' |
| 126 | .el \{\ |
| 127 | .\" Draw four-sided box normally, but don't draw top of |
| 128 | .\" box if the box started on an earlier page. |
| 129 | .ie !\\n(^b-1 \{\ |
| 130 | \h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' |
| 131 | .\} |
| 132 | .el \}\ |
| 133 | \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' |
| 134 | .\} |
| 135 | .\} |
| 136 | .fi |
| 137 | .br |
| 138 | .nr ^b 0 |
| 139 | .. |
| 140 | '\" # VS - start vertical sidebar |
| 141 | '\" # ^Y = starting y location |
| 142 | '\" # ^v = 1 (for troff; for nroff this doesn't matter) |
| 143 | .de VS |
| 144 | .if !"\\$2"" .br |
| 145 | .mk ^Y |
| 146 | .ie n 'mc \s12\(br\s0 |
| 147 | .el .nr ^v 1u |
| 148 | .. |
| 149 | '\" # VE - end of vertical sidebar |
| 150 | .de VE |
| 151 | .ie n 'mc |
| 152 | .el \{\ |
| 153 | .ev 2 |
| 154 | .nf |
| 155 | .ti 0 |
| 156 | .mk ^t |
| 157 | \h'|\\n(^lu+3n'\L'|\\n(^Yu-1v\(bv'\v'\\n(^tu+1v-\\n(^Yu'\h'-|\\n(^lu+3n' |
| 158 | .sp -1 |
| 159 | .fi |
| 160 | .ev |
| 161 | .\} |
| 162 | .nr ^v 0 |
| 163 | .. |
| 164 | '\" # Special macro to handle page bottom: finish off current |
| 165 | '\" # box/sidebar if in box/sidebar mode, then invoked standard |
| 166 | '\" # page bottom macro. |
| 167 | .de ^B |
| 168 | .ev 2 |
| 169 | 'ti 0 |
| 170 | 'nf |
| 171 | .mk ^t |
| 172 | .if \\n(^b \{\ |
| 173 | .\" Draw three-sided box if this is the box's first page, |
| 174 | .\" draw two sides but no top otherwise. |
| 175 | .ie !\\n(^b-1 \h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c |
| 176 | .el \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c |
| 177 | .\} |
| 178 | .if \\n(^v \{\ |
| 179 | .nr ^x \\n(^tu+1v-\\n(^Yu |
| 180 | \kx\h'-\\nxu'\h'|\\n(^lu+3n'\ky\L'-\\n(^xu'\v'\\n(^xu'\h'|0u'\c |
| 181 | .\} |
| 182 | .bp |
| 183 | 'fi |
| 184 | .ev |
| 185 | .if \\n(^b \{\ |
| 186 | .mk ^y |
| 187 | .nr ^b 2 |
| 188 | .\} |
| 189 | .if \\n(^v \{\ |
| 190 | .mk ^Y |
| 191 | .\} |
| 192 | .. |
| 193 | '\" # DS - begin display |
| 194 | .de DS |
| 195 | .RS |
| 196 | .nf |
| 197 | .sp |
| 198 | .. |
| 199 | '\" # DE - end display |
| 200 | .de DE |
| 201 | .fi |
| 202 | .RE |
| 203 | .sp |
| 204 | .. |
| 205 | '\" # SO - start of list of standard options |
| 206 | .de SO |
| 207 | .SH "STANDARD OPTIONS" |
| 208 | .LP |
| 209 | .nf |
| 210 | .ta 5.5c 11c |
| 211 | .ft B |
| 212 | .. |
| 213 | '\" # SE - end of list of standard options |
| 214 | .de SE |
| 215 | .fi |
| 216 | .ft R |
| 217 | .LP |
| 218 | See the \\fBoptions\\fR manual entry for details on the standard options. |
| 219 | .. |
| 220 | '\" # OP - start of full description for a single option |
| 221 | .de OP |
| 222 | .LP |
| 223 | .nf |
| 224 | .ta 4c |
| 225 | Command-Line Name: \\fB\\$1\\fR |
| 226 | Database Name: \\fB\\$2\\fR |
| 227 | Database Class: \\fB\\$3\\fR |
| 228 | .fi |
| 229 | .IP |
| 230 | .. |
| 231 | '\" # CS - begin code excerpt |
| 232 | .de CS |
| 233 | .RS |
| 234 | .nf |
| 235 | .ta .25i .5i .75i 1i |
| 236 | .. |
| 237 | '\" # CE - end code excerpt |
| 238 | .de CE |
| 239 | .fi |
| 240 | .RE |
| 241 | .. |
| 242 | .de UL |
| 243 | \\$1\l'|0\(ul'\\$2 |
| 244 | .. |
| 245 | .TH binary n 8.0 Tcl "Tcl Built-In Commands" |
| 246 | .BS |
| 247 | '\" Note: do not modify the .SH NAME line immediately below! |
| 248 | .SH NAME |
| 249 | binary \- Insert and extract fields from binary strings |
| 250 | .SH SYNOPSIS |
| 251 | \fBbinary format \fIformatString \fR?\fIarg arg ...\fR? |
| 252 | .br |
| 253 | \fBbinary scan \fIstring formatString \fR?\fIvarName varName ...\fR? |
| 254 | .BE |
| 255 | |
| 256 | .SH DESCRIPTION |
| 257 | .PP |
| 258 | This command provides facilities for manipulating binary data. The |
| 259 | first form, \fBbinary format\fR, creates a binary string from normal |
| 260 | Tcl values. For example, given the values 16 and 22, on a 32 bit |
| 261 | architecture, it might produce an 8-byte binary string consisting of |
| 262 | two 4-byte integers, one for each of the numbers. The second form of |
| 263 | the command, \fBbinary scan\fR, does the opposite: it extracts data |
| 264 | from a binary string and returns it as ordinary Tcl string values. |
| 265 | |
| 266 | .SH "BINARY FORMAT" |
| 267 | .PP |
| 268 | The \fBbinary format\fR command generates a binary string whose layout |
| 269 | is specified by the \fIformatString\fR and whose contents come from |
| 270 | the additional arguments. The resulting binary value is returned. |
| 271 | .PP |
| 272 | The \fIformatString\fR consists of a sequence of zero or more field |
| 273 | specifiers separated by zero or more spaces. Each field specifier is |
| 274 | a single type character followed by an optional numeric \fIcount\fR. |
| 275 | Most field specifiers consume one argument to obtain the value to be |
| 276 | formatted. The type character specifies how the value is to be |
| 277 | formatted. The \fIcount\fR typically indicates how many items of the |
| 278 | specified type are taken from the value. If present, the \fIcount\fR |
| 279 | is a non-negative decimal integer or \fB*\fR, which normally indicates |
| 280 | that all of the items in the value are to be used. If the number of |
| 281 | arguments does not match the number of fields in the format string |
| 282 | that consume arguments, then an error is generated. |
| 283 | .PP |
| 284 | Here is a small example to clarify the relation between the field |
| 285 | specifiers and the arguments: |
| 286 | .CS |
| 287 | \fBbinary format d3d {1.0 2.0 3.0 4.0} 0.1\fR |
| 288 | .CE |
| 289 | .PP |
| 290 | The first argument is a list of four numbers, but because of the count |
| 291 | of 3 for the associated field specifier, only the first three will be |
| 292 | used. The second argument is associated with the second field |
| 293 | specifier. The resulting binary string contains the four numbers 1.0, |
| 294 | 2.0, 3.0 and 0.1. |
| 295 | .PP |
| 296 | Each type-count pair moves an imaginary cursor through the binary |
| 297 | data, storing bytes at the current position and advancing the cursor |
| 298 | to just after the last byte stored. The cursor is initially at |
| 299 | position 0 at the beginning of the data. The type may be any one of |
| 300 | the following characters: |
| 301 | .IP \fBa\fR 5 |
| 302 | Stores a character string of length \fIcount\fR in the output string. |
| 303 | Every character is taken as modulo 256 (i.e. the low byte of every |
| 304 | character is used, and the high byte discarded) so when storing |
| 305 | character strings not wholly expressible using the characters \\u0000-\\u00ff, |
| 306 | the \fBencoding convertto\fR command should be used |
| 307 | first if this truncation is not desired (i.e. if the characters are |
| 308 | not part of the ISO 8859-1 character set.) |
| 309 | If \fIarg\fR has fewer than \fIcount\fR bytes, then additional zero |
| 310 | bytes are used to pad out the field. If \fIarg\fR is longer than the |
| 311 | specified length, the extra characters will be ignored. If |
| 312 | \fIcount\fR is \fB*\fR, then all of the bytes in \fIarg\fR will be |
| 313 | formatted. If \fIcount\fR is omitted, then one character will be |
| 314 | formatted. For example, |
| 315 | .RS |
| 316 | .CS |
| 317 | \fBbinary format a7a*a alpha bravo charlie\fR |
| 318 | .CE |
| 319 | will return a string equivalent to \fBalpha\\000\\000bravoc\fR. |
| 320 | .RE |
| 321 | .IP \fBA\fR 5 |
| 322 | This form is the same as \fBa\fR except that spaces are used for |
| 323 | padding instead of nulls. For example, |
| 324 | .RS |
| 325 | .CS |
| 326 | \fBbinary format A6A*A alpha bravo charlie\fR |
| 327 | .CE |
| 328 | will return \fBalpha bravoc\fR. |
| 329 | .RE |
| 330 | .IP \fBb\fR 5 |
| 331 | Stores a string of \fIcount\fR binary digits in low-to-high order |
| 332 | within each byte in the output string. \fIArg\fR must contain a |
| 333 | sequence of \fB1\fR and \fB0\fR characters. The resulting bytes are |
| 334 | emitted in first to last order with the bits being formatted in |
| 335 | low-to-high order within each byte. If \fIarg\fR has fewer than |
| 336 | \fIcount\fR digits, then zeros will be used for the remaining bits. |
| 337 | If \fIarg\fR has more than the specified number of digits, the extra |
| 338 | digits will be ignored. If \fIcount\fR is \fB*\fR, then all of the |
| 339 | digits in \fIarg\fR will be formatted. If \fIcount\fR is omitted, |
| 340 | then one digit will be formatted. If the number of bits formatted |
| 341 | does not end at a byte boundary, the remaining bits of the last byte |
| 342 | will be zeros. For example, |
| 343 | .RS |
| 344 | .CS |
| 345 | \fBbinary format b5b* 11100 111000011010\fR |
| 346 | .CE |
| 347 | will return a string equivalent to \fB\\x07\\x87\\x05\fR. |
| 348 | .RE |
| 349 | .IP \fBB\fR 5 |
| 350 | This form is the same as \fBb\fR except that the bits are stored in |
| 351 | high-to-low order within each byte. For example, |
| 352 | .RS |
| 353 | .CS |
| 354 | \fBbinary format B5B* 11100 111000011010\fR |
| 355 | .CE |
| 356 | will return a string equivalent to \fB\\xe0\\xe1\\xa0\fR. |
| 357 | .RE |
| 358 | .IP \fBh\fR 5 |
| 359 | Stores a string of \fIcount\fR hexadecimal digits in low-to-high |
| 360 | within each byte in the output string. \fIArg\fR must contain a |
| 361 | sequence of characters in the set ``0123456789abcdefABCDEF''. The |
| 362 | resulting bytes are emitted in first to last order with the hex digits |
| 363 | being formatted in low-to-high order within each byte. If \fIarg\fR |
| 364 | has fewer than \fIcount\fR digits, then zeros will be used for the |
| 365 | remaining digits. If \fIarg\fR has more than the specified number of |
| 366 | digits, the extra digits will be ignored. If \fIcount\fR is |
| 367 | \fB*\fR, then all of the digits in \fIarg\fR will be formatted. If |
| 368 | \fIcount\fR is omitted, then one digit will be formatted. If the |
| 369 | number of digits formatted does not end at a byte boundary, the |
| 370 | remaining bits of the last byte will be zeros. For example, |
| 371 | .RS |
| 372 | .CS |
| 373 | \fBbinary format h3h* AB def\fR |
| 374 | .CE |
| 375 | will return a string equivalent to \fB\\xba\\x00\\xed\\x0f\fR. |
| 376 | .RE |
| 377 | .IP \fBH\fR 5 |
| 378 | This form is the same as \fBh\fR except that the digits are stored in |
| 379 | high-to-low order within each byte. For example, |
| 380 | .RS |
| 381 | .CS |
| 382 | \fBbinary format H3H* ab DEF\fR |
| 383 | .CE |
| 384 | will return a string equivalent to \fB\\xab\\x00\\xde\\xf0\fR. |
| 385 | .RE |
| 386 | .IP \fBc\fR 5 |
| 387 | Stores one or more 8-bit integer values in the output string. If no |
| 388 | \fIcount\fR is specified, then \fIarg\fR must consist of an integer |
| 389 | value; otherwise \fIarg\fR must consist of a list containing at least |
| 390 | \fIcount\fR integer elements. The low-order 8 bits of each integer |
| 391 | are stored as a one-byte value at the cursor position. If \fIcount\fR |
| 392 | is \fB*\fR, then all of the integers in the list are formatted. If |
| 393 | the number of elements in the list is fewer than \fIcount\fR, then an |
| 394 | error is generated. If the number of elements in the list is greater |
| 395 | than \fIcount\fR, then the extra elements are ignored. For example, |
| 396 | .RS |
| 397 | .CS |
| 398 | \fBbinary format c3cc* {3 -3 128 1} 260 {2 5}\fR |
| 399 | .CE |
| 400 | will return a string equivalent to |
| 401 | \fB\\x03\\xfd\\x80\\x04\\x02\\x05\fR, whereas |
| 402 | .CS |
| 403 | \fBbinary format c {2 5}\fR |
| 404 | .CE |
| 405 | will generate an error. |
| 406 | .RE |
| 407 | .IP \fBs\fR 5 |
| 408 | This form is the same as \fBc\fR except that it stores one or more |
| 409 | 16-bit integers in little-endian byte order in the output string. The |
| 410 | low-order 16-bits of each integer are stored as a two-byte value at |
| 411 | the cursor position with the least significant byte stored first. For |
| 412 | example, |
| 413 | .RS |
| 414 | .CS |
| 415 | \fBbinary format s3 {3 -3 258 1}\fR |
| 416 | .CE |
| 417 | will return a string equivalent to |
| 418 | \fB\\x03\\x00\\xfd\\xff\\x02\\x01\fR. |
| 419 | .RE |
| 420 | .IP \fBS\fR 5 |
| 421 | This form is the same as \fBs\fR except that it stores one or more |
| 422 | 16-bit integers in big-endian byte order in the output string. For |
| 423 | example, |
| 424 | .RS |
| 425 | .CS |
| 426 | \fBbinary format S3 {3 -3 258 1}\fR |
| 427 | .CE |
| 428 | will return a string equivalent to |
| 429 | \fB\\x00\\x03\\xff\\xfd\\x01\\x02\fR. |
| 430 | .RE |
| 431 | .IP \fBi\fR 5 |
| 432 | This form is the same as \fBc\fR except that it stores one or more |
| 433 | 32-bit integers in little-endian byte order in the output string. The |
| 434 | low-order 32-bits of each integer are stored as a four-byte value at |
| 435 | the cursor position with the least significant byte stored first. For |
| 436 | example, |
| 437 | .RS |
| 438 | .CS |
| 439 | \fBbinary format i3 {3 -3 65536 1}\fR |
| 440 | .CE |
| 441 | will return a string equivalent to |
| 442 | \fB\\x03\\x00\\x00\\x00\\xfd\\xff\\xff\\xff\\x00\\x00\\x01\\x00\fR |
| 443 | .RE |
| 444 | .IP \fBI\fR 5 |
| 445 | This form is the same as \fBi\fR except that it stores one or more one |
| 446 | or more 32-bit integers in big-endian byte order in the output string. |
| 447 | For example, |
| 448 | .RS |
| 449 | .CS |
| 450 | \fBbinary format I3 {3 -3 65536 1}\fR |
| 451 | .CE |
| 452 | will return a string equivalent to |
| 453 | \fB\\x00\\x00\\x00\\x03\\xff\\xff\\xff\\xfd\\x00\\x01\\x00\\x00\fR |
| 454 | .RE |
| 455 | .IP \fBw\fR 5 |
| 456 | .VS 8.4 |
| 457 | This form is the same as \fBc\fR except that it stores one or more |
| 458 | 64-bit integers in little-endian byte order in the output string. The |
| 459 | low-order 64-bits of each integer are stored as an eight-byte value at |
| 460 | the cursor position with the least significant byte stored first. For |
| 461 | example, |
| 462 | .RS |
| 463 | .CS |
| 464 | \fBbinary format w 7810179016327718216\fR |
| 465 | .CE |
| 466 | will return the string \fBHelloTcl\fR |
| 467 | .RE |
| 468 | .IP \fBW\fR 5 |
| 469 | This form is the same as \fBw\fR except that it stores one or more one |
| 470 | or more 64-bit integers in big-endian byte order in the output string. |
| 471 | For example, |
| 472 | .RS |
| 473 | .CS |
| 474 | \fBbinary format Wc 4785469626960341345 110\fR |
| 475 | .CE |
| 476 | will return the string \fBBigEndian\fR |
| 477 | .VE |
| 478 | .RE |
| 479 | .IP \fBf\fR 5 |
| 480 | This form is the same as \fBc\fR except that it stores one or more one |
| 481 | or more single-precision floating in the machine's native |
| 482 | representation in the output string. This representation is not |
| 483 | portable across architectures, so it should not be used to communicate |
| 484 | floating point numbers across the network. The size of a floating |
| 485 | point number may vary across architectures, so the number of bytes |
| 486 | that are generated may vary. If the value overflows the |
| 487 | machine's native representation, then the value of FLT_MAX |
| 488 | as defined by the system will be used instead. Because Tcl uses |
| 489 | double-precision floating-point numbers internally, there may be some |
| 490 | loss of precision in the conversion to single-precision. For example, |
| 491 | on a Windows system running on an Intel Pentium processor, |
| 492 | .RS |
| 493 | .CS |
| 494 | \fBbinary format f2 {1.6 3.4}\fR |
| 495 | .CE |
| 496 | will return a string equivalent to |
| 497 | \fB\\xcd\\xcc\\xcc\\x3f\\x9a\\x99\\x59\\x40\fR. |
| 498 | .RE |
| 499 | .IP \fBd\fR 5 |
| 500 | This form is the same as \fBf\fR except that it stores one or more one |
| 501 | or more double-precision floating in the machine's native |
| 502 | representation in the output string. For example, on a |
| 503 | Windows system running on an Intel Pentium processor, |
| 504 | .RS |
| 505 | .CS |
| 506 | \fBbinary format d1 {1.6}\fR |
| 507 | .CE |
| 508 | will return a string equivalent to |
| 509 | \fB\\x9a\\x99\\x99\\x99\\x99\\x99\\xf9\\x3f\fR. |
| 510 | .RE |
| 511 | .IP \fBx\fR 5 |
| 512 | Stores \fIcount\fR null bytes in the output string. If \fIcount\fR is |
| 513 | not specified, stores one null byte. If \fIcount\fR is \fB*\fR, |
| 514 | generates an error. This type does not consume an argument. For |
| 515 | example, |
| 516 | .RS |
| 517 | .CS |
| 518 | \fBbinary format a3xa3x2a3 abc def ghi\fR |
| 519 | .CE |
| 520 | will return a string equivalent to \fBabc\\000def\\000\\000ghi\fR. |
| 521 | .RE |
| 522 | .IP \fBX\fR 5 |
| 523 | Moves the cursor back \fIcount\fR bytes in the output string. If |
| 524 | \fIcount\fR is \fB*\fR or is larger than the current cursor position, |
| 525 | then the cursor is positioned at location 0 so that the next byte |
| 526 | stored will be the first byte in the result string. If \fIcount\fR is |
| 527 | omitted then the cursor is moved back one byte. This type does not |
| 528 | consume an argument. For example, |
| 529 | .RS |
| 530 | .CS |
| 531 | \fBbinary format a3X*a3X2a3 abc def ghi\fR |
| 532 | .CE |
| 533 | will return \fBdghi\fR. |
| 534 | .RE |
| 535 | .IP \fB@\fR 5 |
| 536 | Moves the cursor to the absolute location in the output string |
| 537 | specified by \fIcount\fR. Position 0 refers to the first byte in the |
| 538 | output string. If \fIcount\fR refers to a position beyond the last |
| 539 | byte stored so far, then null bytes will be placed in the uninitialized |
| 540 | locations and the cursor will be placed at the specified location. If |
| 541 | \fIcount\fR is \fB*\fR, then the cursor is moved to the current end of |
| 542 | the output string. If \fIcount\fR is omitted, then an error will be |
| 543 | generated. This type does not consume an argument. For example, |
| 544 | .RS |
| 545 | .CS |
| 546 | \fBbinary format a5@2a1@*a3@10a1 abcde f ghi j\fR |
| 547 | .CE |
| 548 | will return \fBabfdeghi\\000\\000j\fR. |
| 549 | .RE |
| 550 | |
| 551 | .SH "BINARY SCAN" |
| 552 | .PP |
| 553 | The \fBbinary scan\fR command parses fields from a binary string, |
| 554 | returning the number of conversions performed. \fIString\fR gives the |
| 555 | input to be parsed and \fIformatString\fR indicates how to parse it. |
| 556 | Each \fIvarName\fR gives the name of a variable; when a field is |
| 557 | scanned from \fIstring\fR the result is assigned to the corresponding |
| 558 | variable. |
| 559 | .PP |
| 560 | As with \fBbinary format\fR, the \fIformatString\fR consists of a |
| 561 | sequence of zero or more field specifiers separated by zero or more |
| 562 | spaces. Each field specifier is a single type character followed by |
| 563 | an optional numeric \fIcount\fR. Most field specifiers consume one |
| 564 | argument to obtain the variable into which the scanned values should |
| 565 | be placed. The type character specifies how the binary data is to be |
| 566 | interpreted. The \fIcount\fR typically indicates how many items of |
| 567 | the specified type are taken from the data. If present, the |
| 568 | \fIcount\fR is a non-negative decimal integer or \fB*\fR, which |
| 569 | normally indicates that all of the remaining items in the data are to |
| 570 | be used. If there are not enough bytes left after the current cursor |
| 571 | position to satisfy the current field specifier, then the |
| 572 | corresponding variable is left untouched and \fBbinary scan\fR returns |
| 573 | immediately with the number of variables that were set. If there are |
| 574 | not enough arguments for all of the fields in the format string that |
| 575 | consume arguments, then an error is generated. |
| 576 | .PP |
| 577 | A similar example as with \fBbinary format\fR should explain the |
| 578 | relation between field specifiers and arguments in case of the binary |
| 579 | scan subcommand: |
| 580 | .CS |
| 581 | \fBbinary scan $bytes s3s first second\fR |
| 582 | .CE |
| 583 | .PP |
| 584 | This command (provided the binary string in the variable \fIbytes\fR |
| 585 | is long enough) assigns a list of three integers to the variable |
| 586 | \fIfirst\fR and assigns a single value to the variable \fIsecond\fR. |
| 587 | If \fIbytes\fR contains fewer than 8 bytes (i.e. four 2-byte |
| 588 | integers), no assignment to \fIsecond\fR will be made, and if |
| 589 | \fIbytes\fR contains fewer than 6 bytes (i.e. three 2-byte integers), |
| 590 | no assignment to \fIfirst\fR will be made. Hence: |
| 591 | .CS |
| 592 | \fBputs [binary scan abcdefg s3s first second]\fR |
| 593 | \fBputs $first\fR |
| 594 | \fBputs $second\fR |
| 595 | .CE |
| 596 | will print (assuming neither variable is set previously): |
| 597 | .CS |
| 598 | \fB1\fR |
| 599 | \fB25185 25699 26213\fR |
| 600 | \fIcan't read "second": no such variable\fR |
| 601 | .CE |
| 602 | .PP |
| 603 | It is \fBimportant\fR to note that the \fBc\fR, \fBs\fR, and \fBS\fR |
| 604 | (and \fBi\fR and \fBI\fR on 64bit systems) will be scanned into |
| 605 | long data size values. In doing this, values that have their high |
| 606 | bit set (0x80 for chars, 0x8000 for shorts, 0x80000000 for ints), |
| 607 | will be sign extended. Thus the following will occur: |
| 608 | .CS |
| 609 | \fBset signShort [binary format s1 0x8000]\fR |
| 610 | \fBbinary scan $signShort s1 val; \fI# val == 0xFFFF8000\fR |
| 611 | .CE |
| 612 | If you want to produce an unsigned value, then you can mask the return |
| 613 | value to the desired size. For example, to produce an unsigned short |
| 614 | value: |
| 615 | .CS |
| 616 | \fBset val [expr {$val & 0xFFFF}]; \fI# val == 0x8000\fR |
| 617 | .CE |
| 618 | .PP |
| 619 | Each type-count pair moves an imaginary cursor through the binary data, |
| 620 | reading bytes from the current position. The cursor is initially |
| 621 | at position 0 at the beginning of the data. The type may be any one of |
| 622 | the following characters: |
| 623 | .IP \fBa\fR 5 |
| 624 | The data is a character string of length \fIcount\fR. If \fIcount\fR |
| 625 | is \fB*\fR, then all of the remaining bytes in \fIstring\fR will be |
| 626 | scanned into the variable. If \fIcount\fR is omitted, then one |
| 627 | character will be scanned. |
| 628 | All characters scanned will be interpreted as being in the |
| 629 | range \\u0000-\\u00ff so the \fBencoding convertfrom\fR command might be |
| 630 | needed if the string is not an ISO 8859\-1 string. |
| 631 | For example, |
| 632 | .RS |
| 633 | .CS |
| 634 | \fBbinary scan abcde\\000fghi a6a10 var1 var2\fR |
| 635 | .CE |
| 636 | will return \fB1\fR with the string equivalent to \fBabcde\\000\fR |
| 637 | stored in \fBvar1\fR and \fBvar2\fR left unmodified. |
| 638 | .RE |
| 639 | .IP \fBA\fR 5 |
| 640 | This form is the same as \fBa\fR, except trailing blanks and nulls are stripped from |
| 641 | the scanned value before it is stored in the variable. For example, |
| 642 | .RS |
| 643 | .CS |
| 644 | \fBbinary scan "abc efghi \\000" A* var1\fR |
| 645 | .CE |
| 646 | will return \fB1\fR with \fBabc efghi\fR stored in \fBvar1\fR. |
| 647 | .RE |
| 648 | .IP \fBb\fR 5 |
| 649 | The data is turned into a string of \fIcount\fR binary digits in |
| 650 | low-to-high order represented as a sequence of ``1'' and ``0'' |
| 651 | characters. The data bytes are scanned in first to last order with |
| 652 | the bits being taken in low-to-high order within each byte. Any extra |
| 653 | bits in the last byte are ignored. If \fIcount\fR is \fB*\fR, then |
| 654 | all of the remaining bits in \fBstring\fR will be scanned. If |
| 655 | \fIcount\fR is omitted, then one bit will be scanned. For example, |
| 656 | .RS |
| 657 | .CS |
| 658 | \fBbinary scan \\x07\\x87\\x05 b5b* var1 var2\fR |
| 659 | .CE |
| 660 | will return \fB2\fR with \fB11100\fR stored in \fBvar1\fR and |
| 661 | \fB1110000110100000\fR stored in \fBvar2\fR. |
| 662 | .RE |
| 663 | .IP \fBB\fR 5 |
| 664 | This form is the same as \fBb\fR, except the bits are taken in |
| 665 | high-to-low order within each byte. For example, |
| 666 | .RS |
| 667 | .CS |
| 668 | \fBbinary scan \\x70\\x87\\x05 B5B* var1 var2\fR |
| 669 | .CE |
| 670 | will return \fB2\fR with \fB01110\fR stored in \fBvar1\fR and |
| 671 | \fB1000011100000101\fR stored in \fBvar2\fR. |
| 672 | .RE |
| 673 | .IP \fBh\fR 5 |
| 674 | The data is turned into a string of \fIcount\fR hexadecimal digits in |
| 675 | low-to-high order represented as a sequence of characters in the set |
| 676 | ``0123456789abcdef''. The data bytes are scanned in first to last |
| 677 | order with the hex digits being taken in low-to-high order within each |
| 678 | byte. Any extra bits in the last byte are ignored. If \fIcount\fR |
| 679 | is \fB*\fR, then all of the remaining hex digits in \fBstring\fR will be |
| 680 | scanned. If \fIcount\fR is omitted, then one hex digit will be |
| 681 | scanned. For example, |
| 682 | .RS |
| 683 | .CS |
| 684 | \fBbinary scan \\x07\\x86\\x05 h3h* var1 var2\fR |
| 685 | .CE |
| 686 | will return \fB2\fR with \fB706\fR stored in \fBvar1\fR and |
| 687 | \fB50\fR stored in \fBvar2\fR. |
| 688 | .RE |
| 689 | .IP \fBH\fR 5 |
| 690 | This form is the same as \fBh\fR, except the digits are taken in |
| 691 | high-to-low order within each byte. For example, |
| 692 | .RS |
| 693 | .CS |
| 694 | \fBbinary scan \\x07\\x86\\x05 H3H* var1 var2\fR |
| 695 | .CE |
| 696 | will return \fB2\fR with \fB078\fR stored in \fBvar1\fR and |
| 697 | \fB05\fR stored in \fBvar2\fR. |
| 698 | .RE |
| 699 | .IP \fBc\fR 5 |
| 700 | The data is turned into \fIcount\fR 8-bit signed integers and stored |
| 701 | in the corresponding variable as a list. If \fIcount\fR is \fB*\fR, |
| 702 | then all of the remaining bytes in \fBstring\fR will be scanned. If |
| 703 | \fIcount\fR is omitted, then one 8-bit integer will be scanned. For |
| 704 | example, |
| 705 | .RS |
| 706 | .CS |
| 707 | \fBbinary scan \\x07\\x86\\x05 c2c* var1 var2\fR |
| 708 | .CE |
| 709 | will return \fB2\fR with \fB7 -122\fR stored in \fBvar1\fR and \fB5\fR |
| 710 | stored in \fBvar2\fR. Note that the integers returned are signed, but |
| 711 | they can be converted to unsigned 8-bit quantities using an expression |
| 712 | like: |
| 713 | .CS |
| 714 | \fBexpr { $num & 0xff }\fR |
| 715 | .CE |
| 716 | .RE |
| 717 | .IP \fBs\fR 5 |
| 718 | The data is interpreted as \fIcount\fR 16-bit signed integers |
| 719 | represented in little-endian byte order. The integers are stored in |
| 720 | the corresponding variable as a list. If \fIcount\fR is \fB*\fR, then |
| 721 | all of the remaining bytes in \fBstring\fR will be scanned. If |
| 722 | \fIcount\fR is omitted, then one 16-bit integer will be scanned. For |
| 723 | example, |
| 724 | .RS |
| 725 | .CS |
| 726 | \fBbinary scan \\x05\\x00\\x07\\x00\\xf0\\xff s2s* var1 var2\fR |
| 727 | .CE |
| 728 | will return \fB2\fR with \fB5 7\fR stored in \fBvar1\fR and \fB-16\fR |
| 729 | stored in \fBvar2\fR. Note that the integers returned are signed, but |
| 730 | they can be converted to unsigned 16-bit quantities using an expression |
| 731 | like: |
| 732 | .CS |
| 733 | \fBexpr { $num & 0xffff }\fR |
| 734 | .CE |
| 735 | .RE |
| 736 | .IP \fBS\fR 5 |
| 737 | This form is the same as \fBs\fR except that the data is interpreted |
| 738 | as \fIcount\fR 16-bit signed integers represented in big-endian byte |
| 739 | order. For example, |
| 740 | .RS |
| 741 | .CS |
| 742 | \fBbinary scan \\x00\\x05\\x00\\x07\\xff\\xf0 S2S* var1 var2\fR |
| 743 | .CE |
| 744 | will return \fB2\fR with \fB5 7\fR stored in \fBvar1\fR and \fB-16\fR |
| 745 | stored in \fBvar2\fR. |
| 746 | .RE |
| 747 | .IP \fBi\fR 5 |
| 748 | The data is interpreted as \fIcount\fR 32-bit signed integers |
| 749 | represented in little-endian byte order. The integers are stored in |
| 750 | the corresponding variable as a list. If \fIcount\fR is \fB*\fR, then |
| 751 | all of the remaining bytes in \fBstring\fR will be scanned. If |
| 752 | \fIcount\fR is omitted, then one 32-bit integer will be scanned. For |
| 753 | example, |
| 754 | .RS |
| 755 | .CS |
| 756 | \fBbinary scan \\x05\\x00\\x00\\x00\\x07\\x00\\x00\\x00\\xf0\\xff\\xff\\xff i2i* var1 var2\fR |
| 757 | .CE |
| 758 | will return \fB2\fR with \fB5 7\fR stored in \fBvar1\fR and \fB-16\fR |
| 759 | stored in \fBvar2\fR. Note that the integers returned are signed, but |
| 760 | they can be converted to unsigned 32-bit quantities using an expression |
| 761 | like: |
| 762 | .CS |
| 763 | \fBexpr { $num & 0xffffffff }\fR |
| 764 | .CE |
| 765 | .RE |
| 766 | .IP \fBI\fR 5 |
| 767 | This form is the same as \fBI\fR except that the data is interpreted |
| 768 | as \fIcount\fR 32-bit signed integers represented in big-endian byte |
| 769 | order. For example, |
| 770 | .RS |
| 771 | .CS |
| 772 | \fBbinary scan \\x00\\x00\\x00\\x05\\x00\\x00\\x00\\x07\\xff\\xff\\xff\\xf0 I2I* var1 var2\fR |
| 773 | .CE |
| 774 | will return \fB2\fR with \fB5 7\fR stored in \fBvar1\fR and \fB-16\fR |
| 775 | stored in \fBvar2\fR. |
| 776 | .RE |
| 777 | .IP \fBw\fR 5 |
| 778 | .VS 8.4 |
| 779 | The data is interpreted as \fIcount\fR 64-bit signed integers |
| 780 | represented in little-endian byte order. The integers are stored in |
| 781 | the corresponding variable as a list. If \fIcount\fR is \fB*\fR, then |
| 782 | all of the remaining bytes in \fBstring\fR will be scanned. If |
| 783 | \fIcount\fR is omitted, then one 64-bit integer will be scanned. For |
| 784 | example, |
| 785 | .RS |
| 786 | .CS |
| 787 | \fBbinary scan \\x05\\x00\\x00\\x00\\x07\\x00\\x00\\x00\\xf0\\xff\\xff\\xff wi* var1 var2\fR |
| 788 | .CE |
| 789 | will return \fB2\fR with \fB30064771077\fR stored in \fBvar1\fR and |
| 790 | \fB-16\fR stored in \fBvar2\fR. Note that the integers returned are |
| 791 | signed and cannot be represented by Tcl as unsigned values. |
| 792 | .RE |
| 793 | .IP \fBW\fR 5 |
| 794 | This form is the same as \fBw\fR except that the data is interpreted |
| 795 | as \fIcount\fR 64-bit signed integers represented in big-endian byte |
| 796 | order. For example, |
| 797 | .RS |
| 798 | .CS |
| 799 | \fBbinary scan \\x00\\x00\\x00\\x05\\x00\\x00\\x00\\x07\\xff\\xff\\xff\\xf0 WI* var1 var2\fR |
| 800 | .CE |
| 801 | will return \fB2\fR with \fB21474836487\fR stored in \fBvar1\fR and \fB-16\fR |
| 802 | stored in \fBvar2\fR. |
| 803 | .VE |
| 804 | .RE |
| 805 | .IP \fBf\fR 5 |
| 806 | The data is interpreted as \fIcount\fR single-precision floating point |
| 807 | numbers in the machine's native representation. The floating point |
| 808 | numbers are stored in the corresponding variable as a list. If |
| 809 | \fIcount\fR is \fB*\fR, then all of the remaining bytes in |
| 810 | \fBstring\fR will be scanned. If \fIcount\fR is omitted, then one |
| 811 | single-precision floating point number will be scanned. The size of a |
| 812 | floating point number may vary across architectures, so the number of |
| 813 | bytes that are scanned may vary. If the data does not represent a |
| 814 | valid floating point number, the resulting value is undefined and |
| 815 | compiler dependent. For example, on a Windows system running on an |
| 816 | Intel Pentium processor, |
| 817 | .RS |
| 818 | .CS |
| 819 | \fBbinary scan \\x3f\\xcc\\xcc\\xcd f var1\fR |
| 820 | .CE |
| 821 | will return \fB1\fR with \fB1.6000000238418579\fR stored in |
| 822 | \fBvar1\fR. |
| 823 | .RE |
| 824 | .IP \fBd\fR 5 |
| 825 | This form is the same as \fBf\fR except that the data is interpreted |
| 826 | as \fIcount\fR double-precision floating point numbers in the |
| 827 | machine's native representation. For example, on a Windows system |
| 828 | running on an Intel Pentium processor, |
| 829 | .RS |
| 830 | .CS |
| 831 | \fBbinary scan \\x9a\\x99\\x99\\x99\\x99\\x99\\xf9\\x3f d var1\fR |
| 832 | .CE |
| 833 | will return \fB1\fR with \fB1.6000000000000001\fR |
| 834 | stored in \fBvar1\fR. |
| 835 | .RE |
| 836 | .IP \fBx\fR 5 |
| 837 | Moves the cursor forward \fIcount\fR bytes in \fIstring\fR. If |
| 838 | \fIcount\fR is \fB*\fR or is larger than the number of bytes after the |
| 839 | current cursor cursor position, then the cursor is positioned after |
| 840 | the last byte in \fIstring\fR. If \fIcount\fR is omitted, then the |
| 841 | cursor is moved forward one byte. Note that this type does not |
| 842 | consume an argument. For example, |
| 843 | .RS |
| 844 | .CS |
| 845 | \fBbinary scan \\x01\\x02\\x03\\x04 x2H* var1\fR |
| 846 | .CE |
| 847 | will return \fB1\fR with \fB0304\fR stored in \fBvar1\fR. |
| 848 | .RE |
| 849 | .IP \fBX\fR 5 |
| 850 | Moves the cursor back \fIcount\fR bytes in \fIstring\fR. If |
| 851 | \fIcount\fR is \fB*\fR or is larger than the current cursor position, |
| 852 | then the cursor is positioned at location 0 so that the next byte |
| 853 | scanned will be the first byte in \fIstring\fR. If \fIcount\fR |
| 854 | is omitted then the cursor is moved back one byte. Note that this |
| 855 | type does not consume an argument. For example, |
| 856 | .RS |
| 857 | .CS |
| 858 | \fBbinary scan \\x01\\x02\\x03\\x04 c2XH* var1 var2\fR |
| 859 | .CE |
| 860 | will return \fB2\fR with \fB1 2\fR stored in \fBvar1\fR and \fB020304\fR |
| 861 | stored in \fBvar2\fR. |
| 862 | .RE |
| 863 | .IP \fB@\fR 5 |
| 864 | Moves the cursor to the absolute location in the data string specified |
| 865 | by \fIcount\fR. Note that position 0 refers to the first byte in |
| 866 | \fIstring\fR. If \fIcount\fR refers to a position beyond the end of |
| 867 | \fIstring\fR, then the cursor is positioned after the last byte. If |
| 868 | \fIcount\fR is omitted, then an error will be generated. For example, |
| 869 | .RS |
| 870 | .CS |
| 871 | \fBbinary scan \\x01\\x02\\x03\\x04 c2@1H* var1 var2\fR |
| 872 | .CE |
| 873 | will return \fB2\fR with \fB1 2\fR stored in \fBvar1\fR and \fB020304\fR |
| 874 | stored in \fBvar2\fR. |
| 875 | .RE |
| 876 | .SH "PLATFORM ISSUES" |
| 877 | Sometimes it is desirable to format or scan integer values in the |
| 878 | native byte order for the machine. Refer to the \fBbyteOrder\fR |
| 879 | element of the \fBtcl_platform\fR array to decide which type character |
| 880 | to use when formatting or scanning integers. |
| 881 | .SH EXAMPLES |
| 882 | This is a procedure to write a Tcl string to a binary-encoded channel as |
| 883 | UTF-8 data preceded by a length word: |
| 884 | .CS |
| 885 | proc writeString {channel string} { |
| 886 | set data [encoding convertto utf-8 $string] |
| 887 | puts -nonewline [\fBbinary format\fR Ia* \e |
| 888 | [string length $data] $data] |
| 889 | } |
| 890 | .CE |
| 891 | .PP |
| 892 | This procedure reads a string from a channel that was written by the |
| 893 | previously presented \fBwriteString\fR procedure: |
| 894 | .CS |
| 895 | proc readString {channel} { |
| 896 | if {![\fBbinary scan\fR [read $channel 4] I length]} { |
| 897 | error "missing length" |
| 898 | } |
| 899 | set data [read $channel $length] |
| 900 | return [encoding convertfrom utf-8 $data] |
| 901 | } |
| 902 | .CE |
| 903 | |
| 904 | .SH "SEE ALSO" |
| 905 | format(n), scan(n), tclvars(n) |
| 906 | |
| 907 | .SH KEYWORDS |
| 908 | binary, format, scan |