XKM_file_format.txt 15 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684
                        XKM File Format Description
                                Version 15

1. Introduction

The XKM file format is the exchange format for XKB keyboard descriptions
between the server and xkbcomp. Usually, the server forks off xkbcomp,
xkbcomp compiles the XKM format from the given parameters.
The resulting XKM file is put into a directory readable by the server and
then parsed.

The XKM format is little more than a binary dump of various XKB-specific
structures and hence tied to the ABI of the server.

                              ❧❧❧❧❧❧❧❧❧❧❧

1.1 About this file format description

This description was produced by analyzing the XKM parsing code. Parts of
the file description present in the original format specification may be
missing. This description thus cannot be a reference document for XKM
implementations.

No description of the meaning of the various fields is given here. Refer to
the XKB protocol specification for more details.
                              ❧❧❧❧❧❧❧❧❧❧❧

2. Notations used in this document

Notation for structures:

┌───
  Name of struct
	name of field:		type or fixed value of field
	name of field:		type or fixed value of field
└───

Data types are identical to those used in the X Protocol specification
except where noted otherwise. Structs specific to XKM are prefixed with XKM,
defines specific to the XKB protocol specification are prefixed with Xkb and
their value is equivalent to that in the protocol specification.

Multiple instances of a given type are denoted in the following form:
	name of field:		LISTofFIELDTYPE

Length specifiers for such fields are usually prefixed with num_. For
example, a struct containing a num_foo of 8 and a 'foo' field contains 8
structures of type 'foo'.

Variable length padding is specified as pad(x), where x is the length of the
data to be padded out to a multiple of 4 bytes. For example, given an x of
10, pad(x) would be the remaining 2 bytes to pad the whole struct to 12
bytes.

A special notation is a variable content struct. In this case, the contents
of the struct depend on the value of one or more specific fields.
┌───
  Name of struct
	field:			type or fixed value of field
	field:			type or fixed value of field
	───
	field ⇒ value 1

		specific field:		type
		specific field:		type
	───
        field ⇒ value 2

		specific field:		type
		specific field:		type
└───
This notation denotes that if field is of value 1, this struct contains the
specific fields listed underneath value 1.

                              ❧❧❧❧❧❧❧❧❧❧❧

3. XKM Format

The XKM format is a binary format with structs usually being padded to a
multiple of 4 bytes. No provisions for endianess are provided, the parser is
left to guess the endianess of the XKM file.

                              ❧❧❧❧❧❧❧❧❧❧❧
3.1 Common data types

┌───
  XKMCountedString
	count:			CARD16
	string:			count * CHAR
	pad:			pad(count + 2)
└───

XKMCountedString is used for user-readable identifiers. Prime example are
the level names and the section names ("complete", "evdev(inet)", etc.)

┌───
  XKMGroupBits:		CARD8
	group1			0x1
	group2			0x2
	group3			0x4
	group4			0x8
└───

                              ❧❧❧❧❧❧❧❧❧❧❧

3.2 Header and Table of Contents

┌───
  XKMHeader
	version:		CARD8
	identifier1:		'm'
	identifier2:		'k'
	idenfifier3:		'x'
└───

The XKM file format has a 4 byte header identifying the file and the XKM
version. The header is followed by the table of contents indicating the
sections present in this file.

┌───
  XKMFileInfo
	type:			CARD8
	min_keycode:		CARD8
	max_keycode:		CARD8
	num_sectioninfo:	CARD8
	present:		CARD16
	pad:			CARD16
	sectioninfo:		LISTofXKMSectionInfo
└───

min_keycode and max_keycode specify the keycode range for this keyboard
descriptions. The core protocol requires min_keycode always be equal to or
greater than 8.

┌───
  XKMSectionInfo
	type:			CARD16
		XkmTypesIndex		0
		XkmCompatMapIndex	1
		XkmSymbolsIndex		2
		XkmIndicatorsIndex	3
		XkmKeyNamesIndex	4
		XkmGeometryIndex	5
		XkmVirtualModsIndex	6
	format:			CARD16
	size:			CARD16
	offset:			CARD16
└───

Describes the section found in a chunk of a file. This struct is found
_twice_ in the file per section, once as part of the XKMFileInfo, once at
the beginning of the actual section (see offset).
The type specifies the type of the section, the section is to be parsed
according to this type.
Size and offset specify the size in bytes and the offset into the file in
bytes, respectively.

3.3 Sections

Each section resides at the offset specified in the XKMFileInfo sectioninfo.

                              ❧❧❧❧❧❧❧❧❧❧❧

3.3.1 XKMTypes

An XKMTypes section describes the key types defined in a layout. Roughly
speaking, a key type defines how many levels a given key has and which
modifiers change to a particular level.

┌───
  XKMTypesSection
	section_info:		XKMSectionInfo
	name:			XKMCountedString
	num_types:		CARD16
	pad:			CARD16
	types:			LISTofXKMKeyType
└───

┌───
  XKMKeyType
	real_mods:		CARD8
	num_levels:		CARD8
	virt_mods:		CARD16
	num_map_entries: 	CARD8
	num_level_names: 	CARD8
	perserve:	 	CARD8
	pad:			CARD8
	map_entries:		LISTofXKMKTMapEntry
	name:			XKMCountedString
	mods:			LISTofXKMModsDesc
	level_names:		LISXTofXKMCountedString
└───

The num_map_entries specifies the number of structs in both map_entries and mods. mods is only present if preserve is TRUE.

┌───
  XKMKTMapEntry
	level:			CARD8
	real_mods:		CARD8
	virt_mods:		CARD16
└───

┌───
  XKMModsDesc
	real_mods:		CARD8
	pad:			CARD8
	virt_mods:		CARD16
└───

                              ❧❧❧❧❧❧❧❧❧❧❧
3.3.2 XKMCompatMap

An XKMCompatMap section describes the actions a keyboard may trigger. This
ranges from the TerminateServer action to simple modifier bits.

┌───
  XKMCompatMap
	section_info:		XKMSectionInfo
	name:			XKMCountedString
	num_si:			CARD16
	group_mask:		XKMGroupBits
	pad:			CARD8
	si:			LISTofXKMSymInterpreterDesc
	groups:			LISTofXKMModsDesc
└───

One XKMModsDesc is present for each bit set in group_mask.

┌───
  XKMSymInterpretDesc
	sym:			CARD32
	mods:			CARD8
	match:			CARD8
	virtual_mod:		CARD8
	flags:			CARD8
	action_type:		CARD8
	action_data:		XKMActionData
└───

Where the action is 7 bytes of CARD8 whose content is determined by
action_type.

┌───
  XKMActionData:
	pad0:			CARD8
	pad1:			CARD16
	pad2:			CARD32
	───
        action_type ⇒ XkbSA_SetMods ||
        action_type ⇒ XkbSA_LatchMods ||
        action_type ⇒ XkbSA_LockMods

		flags:			CARD8
		mask:			CARD8
		real_mods:		CARD8
		vmods1:			CARD8
		vmods2:			CARD8
		pad:			CARD16
	───
        action_type ⇒ XkbSA_SetGroup ||
        action_type ⇒ XkbSA_LatchGroup ||
        action_type ⇒ XkbSA_LockGroup

		flags:			CARD8
		group_XXX:		CARD8
		pad0:			CARD8
		pad1:			CARD32
	───
        action_type ⇒ XkbSA_MovePtr

		flags:			CARD8
		high_XXX:		CARD8
		low_XXX:		CARD8
		high_YYY:		CARD8
		low_YYY:		CARD8
		pad:			CARD16
	───
        action_type ⇒ XkbSA_PtrBtn ||
        action_type ⇒ XkbSA_LockPtrBtn

		flags:			CARD8
		count:			CARD8
		button:			CARD8
		pad:			CARD32
	───
        action_type ⇒ XkbSA_DeviceBtn ||
        action_type ⇒ XkbSA_LockLockPtrBtn

		flags:			CARD8
		count:			CARD8
		button:			CARD8
		device:			CARD8
		pad0:			CARD8
		pad1:			CARD16
	───
        action_type ⇒ XkbSA_SetPtrDflt

		flags:			CARD8
		affect:			CARD8
		valueXXX:		CARD8
		pad0:			CARD32
	───
        action_type ⇒ XkbSA_ISOLock

		flags:			CARD8
		mask:			CARD8
		real_mods:		CARD8
		group_XXX:		CARD8
		affect:			CARD8
		vmods1:			CARD8
		vmods1:			CARD8
	───
        action_type ⇒ XkbSA_SwitchScreen

		flags:			CARD8
		screenXXX:		CARD8
		pad0:			CARD8
		pad1:			CARD32
	───
        action_type ⇒ XkbSA_SetControls ||
        action_type ⇒ XkbSA_LockControls

		flags:			CARD8
		ctrls3:			CARD8
		ctrls2:			CARD8
		ctrls1:			CARD8
		ctrls0:			CARD8
		pad:			CARD16
	───
        action_type ⇒ XkbSA_RedirectKey

		new_key:		CARD8
		mods_mask:		CARD8
		mods:			CARD8
		vmods_mask0:		CARD8
		vmods_mask1:		CARD8
		vmods0:			CARD8
		vmods1:			CARD8
	───
        action_type ⇒ XkbSA_DeviceValuator

		device:		CARD8
		v1_what:		CARD8
		v1_idx:			CARD8
		v1_value:		CARD8
		v2_what:		CARD8
		v2_idx:			CARD8
		v2_value:		CARD8
		pad:			CARD8
	───
        action_type ⇒ XkbSA_XFree86Private ||
        action_type ⇒ XkbSA_Terminate

		pad0:			CARD8
		pad1:			CARD16
		pad2:			CARD32
	───
        action_type ⇒ XkbSA_ActionMessage

		press_msg:		BOOL
		release_msg:		BOOL
		gen_event:		BOOL
		message:		4 * CHAR
└───

Note: XkbSA_ActionMessage is currently unsupported and the contents are
ignored.

                              ❧❧❧❧❧❧❧❧❧❧❧
3.3.3 XkmSymbols

The symbols in a keymap define the actual keysyms each key may produce.

┌───
  XKMSymbols
	section_info:		XKMSectionInfo
	name:			XKMCountedString
	min_keycode:		CARD8
	max_keycode:		CARD8
	group_names_mask:	XKMGroupBits
	num_vmod_maps:		CARD8
	group_names:		LISTofXKMCountedString
	keysyms:		XKMKeysymMapDesc
	vmod_maps:		XKMVModMapDesc
└───
One group_name is present for each bit set in group_names_mask.
The number of keysyms present is max_keycode - min_keycode + 1.

┌───
  XKMKeysymMapDesc
	width:			CARD8
	num_groups:		CARD8
	modifier_map:		CARD8
	flags:			CARD8
	names:			LISTofXKMCountedString
	syms:			LISTofCARD32
	behavior:		XKMBehaviorDesc
└───

Presence of names is conditional on the XkmKeyHasTypes flag. The number of
strings is equal to the number of group bits in group_names_mask in the
preceeding XKMSymbols section.
The number of elements in syms is equal to width * num_groups.
Presence of behavior is conditional on the XkmKeyHasBehavior flag.

┌───
  XKMKeyBehaviorDesc
	type:			CARD8
	data:			CARD8
	pad:			CARD16
└───

┌───
  XKMVModMapDesc
	key:			CARD8
	pad:			CARD8
	vmods:			CARD16
└───

                              ❧❧❧❧❧❧❧❧❧❧❧

3.3.4 XKMIndicators

┌───
  XKMIndicators
	section_info:		XKMSectionInfo
	name:			XKMCountedString
	num_indicators:		CARD8
	pad0:			CARD8
	pad1:			CARD16
	indicators:		LISTofXKMIndicatorMapDesc
└───

┌───
  XKMIndicatorMapDesc
	name:			XKMCountedString
	indicator:		CARD8
	flags:			CARD8
	which_mods:		CARD8
	real_mods:		CARD8
	vmods:			CARD16
	which_groups:		CARD8
	groups:			CARD8
	ctrls:			CARD32
└───
                              ❧❧❧❧❧❧❧❧❧❧❧

3.3.5 XKMKeyNames

┌───
  XKMKeyNames
	section_info:		XKMSectionInfo
	name:			XKMCountedString
	min_keycode:		CARD8
	max_keycode:		CARD8
	num_aliases:		CARD8
	pad:			CARD8
	keynames:		LISTofXKMKeyname
	aliases:		LISTofXKMKeyAlias
└───

keynames contains max_keycode - min_keycode + 1 entries.

┌───
  XkmKeyname
	name:			4 * CHAR8
└───

┌───
  XkmKeyAlias
	real:			XkmKeyname
	alias:			XkmKeyname
└───

                              ❧❧❧❧❧❧❧❧❧❧❧

3.3.5 XKMGeometry

┌───
  XKMGeometry
	section_info:		XKMSectionInfo
	name:			XKMCountedString
	width_mm:		CARD16
	height_mm:		CARD16
	base_color_ndx:		CARD8
	label_color_ndx:	CARD8
	num_properties:		CARD16
	num_colors:		CARD16
	num_shapes:		CARD16
	num_sections:		CARD16
	num_doodads:		CARD16
	num_key_aliases:	CARD16
	pad:			CARD16
	label_font:		XKMCountedString
	properties:		LISTofXKMGeomProperty
	colors:			LISTofXKMCountedString
	shapes:			LISTofXKMGeomShape
	sections:		LISTofXKMGeomSection
	doodads:		LISTofXKMGeomDoodad
	key_aliases:		LISTofXKMKeyAlias
└───

┌───
  XKMGeomProperty
	name:			XKMCountedString
	value:			XKMCountedString

└───

┌───
  XKMGeomShape
	name:			XKMCountedString
	num_outlines:		CARD8
	primary_idx:		CARD8
	approx_idx:		CARD8
	pad:			CARD8
	outlines:		LISTofXKMOutlineDesc
└───

┌───
  XKMOutlineDesc
	num_points:		CARD8
	corner_radius:		CARD8
	pad:			CARD16
	points:			LISTofXKMPointDesc
└───

┌───
  XKMPointDesc
	x:			INT16
	y:			INT16
└───

┌───
  XKMGeomSection
	name:			XKMCountedString
	top:			INT16
	left:			INT16
	width:			CARD16
	height:			CARD16
	angle:			INT16
	priority:		CARD8
	num_rows:		CARD8
	num_doodads:		CARD8
	num_overlays:		CARD8
	pad:			CARD16
	rows:			LISTofXKMRowDesc
	doodads:		LISTofXKMGeomDoodad
	overlays:		LISTofXKMGeomOverlay
└───

┌───
  XKMRowDesc
	top:			INT16
	left:			INT16
	num_keys:		CARD8
	vertical:		BOOL
	pad:			CARD16
	keys:			XKMKeyDesc
└───

┌───
  XKMKeyDesc
	name:			XKMKeyname
	gap:			INT16
	shape_idx:		CARD8
	color_idx:		CARD8
└───

┌───
  XKMGeomDoodad
	name:			XKMCountedString
	type:			CARD8
	priority:		CARD8
	top:			INT16
	left:			INT16
	pad1:			CARD16
	pad2:			CARD32
	pad3:			CARD32
	───
        type ⇒ XkbOutlineDoodad ||
        type ⇒ XkbSolideDoodad

		type:			CARD8
		priority:		CARD8
		top:			INT16
		left:			INT16
		angle:			INT16
		color_idx:		CARD8
		shape_idx:		CARD8
		pad0:			CARD16
		pad1:			CARD32
	───
        type ⇒ XkbTextDoodad

		type:			CARD8
		priority:		CARD8
		top:			INT16
		left:			INT16
		angle:			INT16
		width:			CARD16
		height:			CARD16
		color_idx:		CARD8
		pad0:			CARD8
		pad1:			CARD16
		text:			XKMCountedString
		font:			XKMCountedString
	───
        type ⇒ XkbIndicatorDoodad

		type:			CARD8
		priority:		CARD8
		top:			INT16
		left:			INT16
		shape_idx:		CARD8
		on_color_idx:		CARD8
		off_color_idx:		CARD8
		pad0:			CARD8
		pad1:			CARD16
		pad2:			CARD32
	───
        type ⇒ XkbLogoDoodad

		type:			CARD8
		priority:		CARD8
		top:			INT16
		left:			INT16
		angle:			INT16
		color_idx:		CARD8
		shape_idx:		CARD8
		pad0:			CARD16
		pad1:			CARD32
		logo_name:		XKMCountedString
└───

WARNING: XKMGeomDoodad has variable length depending on the type.
NOTE: The current server implementation does not use all fields of all
structures.

┌───
  XKMOverlayDesc
	name:			XKMCountedString
	num_rows:		CARD8
	pad0:			CARD8
	pad1:			CARD16
	rows:			LISTofXKMOverlayRowDesc
└───

┌───
  XKMOverlayRowDesc
	name:			XKMCountedString
	row_under:		CARD8
	num_keys:		CARD8
	pad:			CARD16
	keys:			LISTofXKMOverlayKeyDesc
└───

┌───
  XKMOverlayKeyDesc
	over:			XKMKeyname
	under:			XKMKeyname
└───

                              ❧❧❧❧❧❧❧❧❧❧❧

3.3.6 XKMVirtualMods

┌───
  XKMOverlayRowDesc
	section_info:		XKMSectionInfo
	name:			XKMCountedString
	bound_mask:		SETofVMODBITS
	named_mask:		SETofVMODBITS
	vmods:			LISTofCARD8
	pad:			pad(vmods)
	names:			LISTofXKMCountedString
└───

	VMODBITS:		CARD16

Number of elements in vmods is equal to the number of bits set in
bound_mask. The padding completes vmods to a multiple of 4 byte units.
Number of elements in names is equal to the number of bits set in
named_mask.