Add more layouts to HID

[anarchyysm]

HID Keyboard Layouts

How layouts work

The device sends HID keycodes — physical key positions, not characters. The host OS driver decides what character appears on screen based on its configured keyboard layout. This means the device must know: "to type @ on a host configured with layout X, which physical key do I press?"

That mapping is different for every layout, and must be implemented manually.

Current implementation

Each layout is a dedicated function with a switch over every character:

void hid_layouts_type_string_us(const char *str);
void hid_layouts_type_string_abnt2(const char *str);

Adding a new layout requires writing a new function with its own switch block — code is duplicated across layouts.

Proposed approach: ASCII lookup table

Each layout becomes a 128-entry array indexed directly by the character value. A single generic function handles all layouts.

typedef struct {
    uint8_t keycode;
    uint8_t modifier;
} hid_key_entry_t;

// One array per layout — pure data, no code duplication
static const hid_key_entry_t s_layout_us[128]   = { ... };
static const hid_key_entry_t s_layout_de[128]   = { ... };
static const hid_key_entry_t s_layout_fr[128]   = { ... };

// Single generic function handles all layouts
void hid_layouts_type_string(const hid_key_entry_t *layout, const char *str);

Lookup is a direct array index (layout[(uint8_t)c]): O(1), branch-free. Each layout costs 256 bytes in flash.

Extended characters outside ASCII (e.g. UTF-8 accented sequences for ABNT2) stay as a small supplemental table searched linearly, since they are few in number.

Registering a new layout

1. Add the enum value to ducky_layout_t in ducky_parser.h.
2. Declare the 128-entry hid_key_entry_t array in hid_layouts.c.
3. Add a supplemental table for characters outside ASCII if needed.
4. Add the dispatch case in ducky_parser.c → process_line().

Supported layouts

Layout	Enum	Notes
US (QWERTY)	DUCKY_LAYOUT_US	Default. Standard ASCII mapping.
ABNT2 (Brazil)	DUCKY_LAYOUT_ABNT2	Dead-key accent support, remapped punctuation.