Commit 95ee49d9 authored by Alan Coopersmith's avatar Alan Coopersmith
Browse files

Add comments about sizes of dynamically allocated arrays

Many arrays have sz_* or size_* fields to list the number of entries
allocated, and num_* fields to record the number of entries used.

Others use num_* for the number allocated, or size based on max_key_code.

And a few are just plain trying to mess with your head.  (I'm looking at
you XkbNamesRec & XkbKeyTypeRec.)

It sure would have been nice if all the XKB authors could have picked
a single convention and stuck to it, but we're 20 years too late for
that now, so just document it so I can stop reverse engineering from
the code every time I need to see if we got a bounds check right or not.
Signed-off-by: Alan Coopersmith's avatarAlan Coopersmith <>
parent db07706c
......@@ -95,6 +95,11 @@ typedef struct _XkbBounds {
#define XkbBoundsWidth(b) (((b)->x2)-((b)->x1))
#define XkbBoundsHeight(b) (((b)->y2)-((b)->y1))
* In the following structs, this pattern is used for dynamically sized arrays:
* foo is an array for which sz_foo entries are allocated & num_foo are used
typedef struct _XkbOutline {
unsigned short num_points;
unsigned short sz_points;
......@@ -92,9 +92,12 @@ typedef struct _XkbKeyType {
XkbModsRec mods;
unsigned char num_levels;
unsigned char map_count;
/* map is an array of map_count XkbKTMapEntryRec structs */
XkbKTMapEntryPtr map;
/* preserve is an array of map_count XkbModsRec structs */
XkbModsPtr preserve;
Atom name;
/* level_names is an array of num_levels Atoms */
Atom * level_names;
} XkbKeyTypeRec, *XkbKeyTypePtr;
......@@ -298,10 +301,14 @@ typedef struct _XkbControls {
#define XkbAX_NeedFeedback(c,w) (XkbAX_AnyFeedback(c)&&XkbAX_NeedOption(c,w))
typedef struct _XkbServerMapRec {
/* acts is an array of XkbActions structs, with size_acts entries
allocated, and num_acts entries used. */
unsigned short num_acts;
unsigned short size_acts;
XkbAction *acts;
/* behaviors, key_acts, explicit, & vmodmap are all arrays with
(xkb->max_key_code + 1) entries allocated for each. */
XkbBehavior *behaviors;
unsigned short *key_acts;
#if defined(__cplusplus) || defined(c_plusplus)
......@@ -328,15 +335,20 @@ typedef struct _XkbSymMapRec {
} XkbSymMapRec, *XkbSymMapPtr;
typedef struct _XkbClientMapRec {
/* types is an array of XkbKeyTypeRec structs, with size_types entries
allocated, and num_types entries used. */
unsigned char size_types;
unsigned char num_types;
XkbKeyTypePtr types;
/* syms is an array of size_syms KeySyms, in which num_syms are used */
unsigned short size_syms;
unsigned short num_syms;
KeySym *syms;
/* key_sym_map is an array of (max_key_code + 1) XkbSymMapRec structs */
XkbSymMapPtr key_sym_map;
/* modmap is an array of (max_key_code + 1) unsigned chars */
unsigned char *modmap;
} XkbClientMapRec, *XkbClientMapPtr;
......@@ -364,6 +376,8 @@ typedef struct _XkbSymInterpretRec {
} XkbSymInterpretRec,*XkbSymInterpretPtr;
typedef struct _XkbCompatMapRec {
/* sym_interpret is an array of XkbSymInterpretRec structs,
in which size_si are allocated & num_si are used. */
XkbSymInterpretPtr sym_interpret;
XkbModsRec groups[XkbNumKbdGroups];
unsigned short num_si;
......@@ -413,11 +427,15 @@ typedef struct _XkbNamesRec {
Atom vmods[XkbNumVirtualMods];
Atom indicators[XkbNumIndicators];
Atom groups[XkbNumKbdGroups];
/* keys is an array of (xkb->max_key_code + 1) XkbKeyNameRec entries */
XkbKeyNamePtr keys;
/* key_aliases is an array of num_key_aliases XkbKeyAliasRec entries */
XkbKeyAliasPtr key_aliases;
/* radio_groups is an array of num_rg Atoms */
Atom *radio_groups;
Atom phys_symbols;
/* num_keys seems to be unused in libX11 */
unsigned char num_keys;
unsigned char num_key_aliases;
unsigned short num_rg;
......@@ -592,6 +610,7 @@ typedef struct _XkbDeviceInfo {
unsigned short supported;
unsigned short unsupported;
/* btn_acts is an array of num_btn XkbAction entries */
unsigned short num_btns;
XkbAction * btn_acts;
......@@ -599,6 +618,8 @@ typedef struct _XkbDeviceInfo {
unsigned short num_leds;
unsigned short dflt_kbd_fb;
unsigned short dflt_led_fb;
/* leds is an array of XkbDeviceLedInfoRec in which
sz_leds entries are allocated and num_leds entries are used */
XkbDeviceLedInfoPtr leds;
} XkbDeviceInfoRec,*XkbDeviceInfoPtr;
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