I'm working with a Windows virtual keyboard driver to generate keystrokes, and it requires specifying keys using the USB keyboard usage index. (See "Windows Platform Design Notes - Keyboard Scan Code Specification" appendix C for a list of usage indices and corresponding keys.) However, the keys I need to type will be specified by virtual key code.
Windows provides functions for converting between virtual key codes and scan codes, but I haven't found any way of converting between scan codes and these usage indices. Other than writing my own function that converts the hundred-and-change possible scan codes that my virtual keyboard driver may need to type, does Microsoft provide a function for doing this?
The following hash table will convert from scan code to USB usage ID. Note that it only includes page IDs with a corresponding usage page of 7.
The translations were acquired from the Microsoft document USB HID to PS/2 Scan Code Translation Table and from this pastebin that conveniently already has all that information formatted into a Python data structure.
std::unordered_map<WORD, BYTE> scanCodeToUSBUsageIndex({
{0x00FF, 0x01}, // Overrun Error
{0x00FC, 0x02}, // POST Fail
{0x001E, 0x04}, // a A
{0x0030, 0x05}, // b B
{0x002E, 0x06}, // c C
{0x0020, 0x07}, // d D
{0x0012, 0x08}, // e E
{0x0021, 0x09}, // f F
{0x0022, 0x0A}, // g G
{0x0023, 0x0B}, // h H
{0x0017, 0x0C}, // i I
{0x0024, 0x0D}, // j J
{0x0025, 0x0E}, // k K
{0x0026, 0x0F}, // l L
{0x0032, 0x10}, // m M
{0x0031, 0x11}, // n N
{0x0018, 0x12}, // o O
{0x0019, 0x13}, // p P
{0x0010, 0x14}, // q Q
{0x0013, 0x15}, // r R
{0x001F, 0x16}, // s S
{0x0014, 0x17}, // t T
{0x0016, 0x18}, // u U
{0x002F, 0x19}, // v V
{0x0011, 0x1A}, // w W
{0x002D, 0x1B}, // x X
{0x0015, 0x1C}, // y Y
{0x002C, 0x1D}, // z Z
{0x0002, 0x1E}, // 1 !
{0x0003, 0x1F}, // 2 @
{0x0004, 0x20}, // 3 #
{0x0005, 0x21}, // 4 $
{0x0006, 0x22}, // 5 %
{0x0007, 0x23}, // 6 ^
{0x0008, 0x24}, // 7 &
{0x0009, 0x25}, // 8 *
{0x000A, 0x26}, // 9 (
{0x000B, 0x27}, // 0 )
{0x001C, 0x28}, // Return
{0x0001, 0x29}, // Escape
{0x000E, 0x2A}, // Backspace
{0x000F, 0x2B}, // Tab
{0x0039, 0x2C}, // Space
{0x000C, 0x2D}, // - _
{0x000D, 0x2E}, // = +
{0x001A, 0x2F}, // [ {
{0x001B, 0x30}, // ] }
{0x002B, 0x31}, // \ |
{0x002B, 0x32}, // Europe 1 (Note 2)
{0x0027, 0x33}, // ; :
{0x0028, 0x34}, // ' "
{0x0029, 0x35}, // ` ~
{0x0033, 0x36}, // , <
{0x0034, 0x37}, // . >
{0x0035, 0x38}, // / ?
{0x003A, 0x39}, // Caps Lock
{0x003B, 0x3A}, // F1
{0x003C, 0x3B}, // F2
{0x003D, 0x3C}, // F3
{0x003E, 0x3D}, // F4
{0x003F, 0x3E}, // F5
{0x0040, 0x3F}, // F6
{0x0041, 0x40}, // F7
{0x0042, 0x41}, // F8
{0x0043, 0x42}, // F9
{0x0044, 0x43}, // F10
{0x0057, 0x44}, // F11
{0x0058, 0x45}, // F12
{0xE037, 0x46}, // Print Screen (Note 1)
{0x0046, 0x47}, // Scroll Lock
{0xE052, 0x49}, // Insert (Note 1)
{0xE047, 0x4A}, // Home (Note 1)
{0xE049, 0x4B}, // Page Up (Note 1)
{0xE053, 0x4C}, // Delete (Note 1)
{0xE04F, 0x4D}, // End (Note 1)
{0xE051, 0x4E}, // Page Down (Note 1)
{0xE04D, 0x4F}, // Right Arrow (Note 1)
{0xE04B, 0x50}, // Left Arrow (Note 1)
{0xE050, 0x51}, // Down Arrow (Note 1)
{0xE048, 0x52}, // Up Arrow (Note 1)
{0x0045, 0x53}, // Num Lock
{0xE035, 0x54}, // Keypad / (Note 1)
{0x0037, 0x55}, // Keypad *
{0x004A, 0x56}, // Keypad -
{0x004E, 0x57}, // Keypad +
{0xE01C, 0x58}, // Keypad Enter
{0x004F, 0x59}, // Keypad 1 End
{0x0050, 0x5A}, // Keypad 2 Down
{0x0051, 0x5B}, // Keypad 3 PageDn
{0x004B, 0x5C}, // Keypad 4 Left
{0x004C, 0x5D}, // Keypad 5
{0x004D, 0x5E}, // Keypad 6 Right
{0x0047, 0x5F}, // Keypad 7 Home
{0x0048, 0x60}, // Keypad 8 Up
{0x0049, 0x61}, // Keypad 9 PageUp
{0x0052, 0x62}, // Keypad 0 Insert
{0x0053, 0x63}, // Keypad . Delete
{0x0056, 0x64}, // Europe 2 (Note 2)
{0xE05D, 0x65}, // App
{0x0059, 0x67}, // Keypad =
{0x005D, 0x68}, // F13
{0x005E, 0x69}, // F14
{0x005F, 0x6A}, // F15
{0x007E, 0x85}, // Keypad , (Brazilian Keypad .)
{0x0073, 0x87}, // Keyboard Int'l 1 ろ (Ro)
{0x0070, 0x88}, // Keyboard Int'l 2 かたかな ひらがな ローマ字 (Katakana/Hiragana)
{0x007D, 0x89}, // Keyboard Int'l 3 ￥ (Yen)
{0x0079, 0x8A}, // Keyboard Int'l 4 前候補 変換 (次候補) 全候補 (Henkan)
{0x007B, 0x8B}, // Keyboard Int'l 5 無変換 (Muhenkan)
{0x005C, 0x8C}, // Keyboard Int'l 6 (PC9800 Keypad , )
{0x00F2, 0x90}, // Keyboard Lang 1 한/영 (Hanguel/English)
{0x00F1, 0x91}, // Keyboard Lang 2 한자 (Hanja)
{0x0078, 0x92}, // Keyboard Lang 3 かたかな (Katakana)
{0x0077, 0x93}, // Keyboard Lang 4 ひらがな (Hiragana)
{0x0076, 0x94}, // Keyboard Lang 5 半角/全角 (Zenkaku/Hankaku)
{0x001D, 0xE0}, // Left Control
{0x002A, 0xE1}, // Left Shift
{0x0038, 0xE2}, // Left Alt
{0xE05B, 0xE3}, // Left GUI
{0xE01D, 0xE4}, // Right Control
{0x0036, 0xE5}, // Right Shift
{0xE038, 0xE6}, // Right Alt
{0xE05C, 0xE7} // Right GUI
});