diff options
Diffstat (limited to 'libxcb/doc/xkb_internals')
-rw-r--r-- | libxcb/doc/xkb_internals | 98 |
1 files changed, 49 insertions, 49 deletions
diff --git a/libxcb/doc/xkb_internals b/libxcb/doc/xkb_internals index 3e103910c..93c6d0170 100644 --- a/libxcb/doc/xkb_internals +++ b/libxcb/doc/xkb_internals @@ -1,49 +1,49 @@ -
-XKB introduces several uncommon data structures:
- - switch allows conditional inclusion of fields
- - several complex objects intermix variable and fixed size fields
- - lists with a variable number of variable size objects
-
-To handle these objects, a number of new functions is generated:
- - _serialize() turns a structured object into a byte stream,
- (re)ordering or including fields according to the protocol
- - _unserialize() rewrites data from a buffer into a structured object
- - _unpack() expands a buffer representing a switch object into
- a special structured type, all flags needed to resolve the switch
- expression have to given as parameters
- - _sizeof() calculates the size of a serialized object, often by calling
- _unserialize()/_unpack() internally
-
-The new structured data type for switch is special as it contains fixed
-and variable size fields. Variable size fields can be accessed via pointers.
-
-If switch appears in a request, an additional set of request helpers is
-generated with the suffix _aux or _aux_(un)checked. While the 'common'
-request functions require that switch has been serialized before, the _aux
-variants take the structured data type. They are especially designed to
-replace certain functions in xcb-util/aux.
-
-Accessors for switch members need two parameters, where the first is usually
-a pointer to the respective request or reply structure, while the second
-is a pointer to the unpacked switch data structure.
-
-Functions from the serialize family that take a double pointer can allocate
-memory on their own, which is useful if the size of a buffer has to be
-calculated depending on the data within. These functions call malloc() when
-the double pointer is given as the address of a pointer that has been
-initialized to 0. It is the responsibility of the user to free any allocated
-memory.
-
-Intermixed variable and fixed size fields are an important special case in XKB.
-The current implementation resolves the issue by reordering the fields before
-sending them on the wire as well as before returning a reply. That means that
-these objects look like 'common' XCB data types and they can be accessed as such
-(i.e. fixed size fields directly via the structured type and variable size fields
-via accessors/iterators).
-
-In case a list with variable size elements needs to be accessed, it is necessary
-to use iterators. The iterator functions take care of determining the actual
-object size for each element automatically.
-
-A small and preliminary set of auxiliary functions is available in xkb_util.c
-in the check_xkb module.
+ +XKB introduces several uncommon data structures: + - switch allows conditional inclusion of fields + - several complex objects intermix variable and fixed size fields + - lists with a variable number of variable size objects + +To handle these objects, a number of new functions is generated: + - _serialize() turns a structured object into a byte stream, + (re)ordering or including fields according to the protocol + - _unserialize() rewrites data from a buffer into a structured object + - _unpack() expands a buffer representing a switch object into + a special structured type, all flags needed to resolve the switch + expression have to given as parameters + - _sizeof() calculates the size of a serialized object, often by calling + _unserialize()/_unpack() internally + +The new structured data type for switch is special as it contains fixed +and variable size fields. Variable size fields can be accessed via pointers. + +If switch appears in a request, an additional set of request helpers is +generated with the suffix _aux or _aux_(un)checked. While the 'common' +request functions require that switch has been serialized before, the _aux +variants take the structured data type. They are especially designed to +replace certain functions in xcb-util/aux. + +Accessors for switch members need two parameters, where the first is usually +a pointer to the respective request or reply structure, while the second +is a pointer to the unpacked switch data structure. + +Functions from the serialize family that take a double pointer can allocate +memory on their own, which is useful if the size of a buffer has to be +calculated depending on the data within. These functions call malloc() when +the double pointer is given as the address of a pointer that has been +initialized to 0. It is the responsibility of the user to free any allocated +memory. + +Intermixed variable and fixed size fields are an important special case in XKB. +The current implementation resolves the issue by reordering the fields before +sending them on the wire as well as before returning a reply. That means that +these objects look like 'common' XCB data types and they can be accessed as such +(i.e. fixed size fields directly via the structured type and variable size fields +via accessors/iterators). + +In case a list with variable size elements needs to be accessed, it is necessary +to use iterators. The iterator functions take care of determining the actual +object size for each element automatically. + +A small and preliminary set of auxiliary functions is available in xkb_util.c +in the check_xkb module. |