reactos/sdk/lib/ucrt/conio/getch.cpp
2025-01-16 14:18:53 +02:00

574 lines
19 KiB
C++

//
// getch.cpp
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//
// Defines _getch(), _getche(), and _ungetch(), which get and unget
// characters directly from the console.
//
#include <conio.h>
#include <corecrt_internal_lowio.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
namespace
{
struct CharPair
{
unsigned char LeadChar;
unsigned char SecondChar;
};
struct EnhKeyVals
{
unsigned short ScanCode;
CharPair RegChars;
CharPair ShiftChars;
CharPair CtrlChars;
CharPair AltChars;
};
struct NormKeyVals
{
CharPair RegChars;
CharPair ShiftChars;
CharPair CtrlChars;
CharPair AltChars;
};
}
// Table of enhanced key values:
static EnhKeyVals const EnhancedKeys[] =
{
{ 28, { 13, 0 }, { 13, 0 }, { 10, 0 }, { 0, 166 } },
{ 53, { 47, 0 }, { 63, 0 }, { 0, 149 }, { 0, 164 } },
{ 71, { 224, 71 }, { 224, 71 }, { 224, 119 }, { 0, 151 } },
{ 72, { 224, 72 }, { 224, 72 }, { 224, 141 }, { 0, 152 } },
{ 73, { 224, 73 }, { 224, 73 }, { 224, 134 }, { 0, 153 } },
{ 75, { 224, 75 }, { 224, 75 }, { 224, 115 }, { 0, 155 } },
{ 77, { 224, 77 }, { 224, 77 }, { 224, 116 }, { 0, 157 } },
{ 79, { 224, 79 }, { 224, 79 }, { 224, 117 }, { 0, 159 } },
{ 80, { 224, 80 }, { 224, 80 }, { 224, 145 }, { 0, 160 } },
{ 81, { 224, 81 }, { 224, 81 }, { 224, 118 }, { 0, 161 } },
{ 82, { 224, 82 }, { 224, 82 }, { 224, 146 }, { 0, 162 } },
{ 83, { 224, 83 }, { 224, 83 }, { 224, 147 }, { 0, 163 } }
};
// The number of elements in EnhancedKeys:
#define NUM_EKA_ELTS (sizeof(EnhancedKeys) / sizeof(EnhKeyVals))
// Table of key values for normal keys. Note that the table is padded so that
// the key scan code serves as an index into the table.
static NormKeyVals const NormalKeys[] =
{
/* padding */
{ /* 0 */ { 0, 0 }, { 0, 0 }, { 0, 0 }, { 0, 0 } },
{ /* 1 */ { 27, 0 }, { 27, 0 }, { 27, 0 }, { 0, 1 } },
{ /* 2 */ { 49, 0 }, { 33, 0 }, { 0, 0 }, { 0, 120 } },
{ /* 3 */ { 50, 0 }, { 64, 0 }, { 0, 3 }, { 0, 121 } },
{ /* 4 */ { 51, 0 }, { 35, 0 }, { 0, 0 }, { 0, 122 } },
{ /* 5 */ { 52, 0 }, { 36, 0 }, { 0, 0 }, { 0, 123 } },
{ /* 6 */ { 53, 0 }, { 37, 0 }, { 0, 0 }, { 0, 124 } },
{ /* 7 */ { 54, 0 }, { 94, 0 }, { 30, 0 }, { 0, 125 } },
{ /* 8 */ { 55, 0 }, { 38, 0 }, { 0, 0 }, { 0, 126 } },
{ /* 9 */ { 56, 0 }, { 42, 0 }, { 0, 0 }, { 0, 127 } },
{ /* 10 */ { 57, 0 }, { 40, 0 }, { 0, 0 }, { 0, 128 } },
{ /* 11 */ { 48, 0 }, { 41, 0 }, { 0, 0 }, { 0, 129 } },
{ /* 12 */ { 45, 0 }, { 95, 0 }, { 31, 0 }, { 0, 130 } },
{ /* 13 */ { 61, 0 }, { 43, 0 }, { 0, 0 }, { 0, 131 } },
{ /* 14 */ { 8, 0 }, { 8, 0 }, { 127, 0 }, { 0, 14 } },
{ /* 15 */ { 9, 0 }, { 0, 15 }, { 0, 148 }, { 0, 15 } },
{ /* 16 */ { 113, 0 }, { 81, 0 }, { 17, 0 }, { 0, 16 } },
{ /* 17 */ { 119, 0 }, { 87, 0 }, { 23, 0 }, { 0, 17 } },
{ /* 18 */ { 101, 0 }, { 69, 0 }, { 5, 0 }, { 0, 18 } },
{ /* 19 */ { 114, 0 }, { 82, 0 }, { 18, 0 }, { 0, 19 } },
{ /* 20 */ { 116, 0 }, { 84, 0 }, { 20, 0 }, { 0, 20 } },
{ /* 21 */ { 121, 0 }, { 89, 0 }, { 25, 0 }, { 0, 21 } },
{ /* 22 */ { 117, 0 }, { 85, 0 }, { 21, 0 }, { 0, 22 } },
{ /* 23 */ { 105, 0 }, { 73, 0 }, { 9, 0 }, { 0, 23 } },
{ /* 24 */ { 111, 0 }, { 79, 0 }, { 15, 0 }, { 0, 24 } },
{ /* 25 */ { 112, 0 }, { 80, 0 }, { 16, 0 }, { 0, 25 } },
{ /* 26 */ { 91, 0 }, { 123, 0 }, { 27, 0 }, { 0, 26 } },
{ /* 27 */ { 93, 0 }, { 125, 0 }, { 29, 0 }, { 0, 27 } },
{ /* 28 */ { 13, 0 }, { 13, 0 }, { 10, 0 }, { 0, 28 } },
/* padding */
{ /* 29 */ { 0, 0 }, { 0, 0 }, { 0, 0 }, { 0, 0 } },
{ /* 30 */ { 97, 0 }, { 65, 0 }, { 1, 0 }, { 0, 30 } },
{ /* 31 */ { 115, 0 }, { 83, 0 }, { 19, 0 }, { 0, 31 } },
{ /* 32 */ { 100, 0 }, { 68, 0 }, { 4, 0 }, { 0, 32 } },
{ /* 33 */ { 102, 0 }, { 70, 0 }, { 6, 0 }, { 0, 33 } },
{ /* 34 */ { 103, 0 }, { 71, 0 }, { 7, 0 }, { 0, 34 } },
{ /* 35 */ { 104, 0 }, { 72, 0 }, { 8, 0 }, { 0, 35 } },
{ /* 36 */ { 106, 0 }, { 74, 0 }, { 10, 0 }, { 0, 36 } },
{ /* 37 */ { 107, 0 }, { 75, 0 }, { 11, 0 }, { 0, 37 } },
{ /* 38 */ { 108, 0 }, { 76, 0 }, { 12, 0 }, { 0, 38 } },
{ /* 39 */ { 59, 0 }, { 58, 0 }, { 0, 0 }, { 0, 39 } },
{ /* 40 */ { 39, 0 }, { 34, 0 }, { 0, 0 }, { 0, 40 } },
{ /* 41 */ { 96, 0 }, { 126, 0 }, { 0, 0 }, { 0, 41 } },
/* padding */
{ /* 42 */ { 0, 0 }, { 0, 0 }, { 0, 0 }, { 0, 0 } },
{ /* 43 */ { 92, 0 }, { 124, 0 }, { 28, 0 }, { 0, 0 } },
{ /* 44 */ { 122, 0 }, { 90, 0 }, { 26, 0 }, { 0, 44 } },
{ /* 45 */ { 120, 0 }, { 88, 0 }, { 24, 0 }, { 0, 45 } },
{ /* 46 */ { 99, 0 }, { 67, 0 }, { 3, 0 }, { 0, 46 } },
{ /* 47 */ { 118, 0 }, { 86, 0 }, { 22, 0 }, { 0, 47 } },
{ /* 48 */ { 98, 0 }, { 66, 0 }, { 2, 0 }, { 0, 48 } },
{ /* 49 */ { 110, 0 }, { 78, 0 }, { 14, 0 }, { 0, 49 } },
{ /* 50 */ { 109, 0 }, { 77, 0 }, { 13, 0 }, { 0, 50 } },
{ /* 51 */ { 44, 0 }, { 60, 0 }, { 0, 0 }, { 0, 51 } },
{ /* 52 */ { 46, 0 }, { 62, 0 }, { 0, 0 }, { 0, 52 } },
{ /* 53 */ { 47, 0 }, { 63, 0 }, { 0, 0 }, { 0, 53 } },
/* padding */
{ /* 54 */ { 0, 0 }, { 0, 0 }, { 0, 0 }, { 0, 0 } },
{ /* 55 */ { 42, 0 }, { 0, 0 }, { 114, 0 }, { 0, 0 } },
/* padding */
{ /* 56 */ { 0, 0 }, { 0, 0 }, { 0, 0 }, { 0, 0 } },
{ /* 57 */ { 32, 0 }, { 32, 0 }, { 32, 0 }, { 32, 0 } },
/* padding */
{ /* 58 */ { 0, 0 }, { 0, 0 }, { 0, 0 }, { 0, 0 } },
{ /* 59 */ { 0, 59 }, { 0, 84 }, { 0, 94 }, { 0, 104 } },
{ /* 60 */ { 0, 60 }, { 0, 85 }, { 0, 95 }, { 0, 105 } },
{ /* 61 */ { 0, 61 }, { 0, 86 }, { 0, 96 }, { 0, 106 } },
{ /* 62 */ { 0, 62 }, { 0, 87 }, { 0, 97 }, { 0, 107 } },
{ /* 63 */ { 0, 63 }, { 0, 88 }, { 0, 98 }, { 0, 108 } },
{ /* 64 */ { 0, 64 }, { 0, 89 }, { 0, 99 }, { 0, 109 } },
{ /* 65 */ { 0, 65 }, { 0, 90 }, { 0, 100 }, { 0, 110 } },
{ /* 66 */ { 0, 66 }, { 0, 91 }, { 0, 101 }, { 0, 111 } },
{ /* 67 */ { 0, 67 }, { 0, 92 }, { 0, 102 }, { 0, 112 } },
{ /* 68 */ { 0, 68 }, { 0, 93 }, { 0, 103 }, { 0, 113 } },
/* padding */
{ /* 69 */ { 0, 0 }, { 0, 0 }, { 0, 0 }, { 0, 0 } },
{ /* 70 */ { 0, 0 }, { 0, 0 }, { 0, 0 }, { 0, 0 } },
{ /* 71 */ { 0, 71 }, { 55, 0 }, { 0, 119 }, { 0, 0 } },
{ /* 72 */ { 0, 72 }, { 56, 0 }, { 0, 141 }, { 0, 0 } },
{ /* 73 */ { 0, 73 }, { 57, 0 }, { 0, 132 }, { 0, 0 } },
{ /* 74 */ { 0, 0 }, { 45, 0 }, { 0, 0 }, { 0, 0 } },
{ /* 75 */ { 0, 75 }, { 52, 0 }, { 0, 115 }, { 0, 0 } },
{ /* 76 */ { 0, 0 }, { 53, 0 }, { 0, 0 }, { 0, 0 } },
{ /* 77 */ { 0, 77 }, { 54, 0 }, { 0, 116 }, { 0, 0 } },
{ /* 78 */ { 0, 0 }, { 43, 0 }, { 0, 0 }, { 0, 0 } },
{ /* 79 */ { 0, 79 }, { 49, 0 }, { 0, 117 }, { 0, 0 } },
{ /* 80 */ { 0, 80 }, { 50, 0 }, { 0, 145 }, { 0, 0 } },
{ /* 81 */ { 0, 81 }, { 51, 0 }, { 0, 118 }, { 0, 0 } },
{ /* 82 */ { 0, 82 }, { 48, 0 }, { 0, 146 }, { 0, 0 } },
{ /* 83 */ { 0, 83 }, { 46, 0 }, { 0, 147 }, { 0, 0 } },
/* padding */
{ /* 84 */ { 0, 0 }, { 0, 0 }, { 0, 0 }, { 0, 0 } },
{ /* 85 */ { 0, 0 }, { 0, 0 }, { 0, 0 }, { 0, 0 } },
{ /* 86 */ { 0, 0 }, { 0, 0 }, { 0, 0 }, { 0, 0 } },
{ /* 87 */ { 224, 133 }, { 224, 135 }, { 224, 137 }, { 224, 139 } },
{ /* 88 */ { 224, 134 }, { 224, 136 }, { 224, 138 }, { 224, 140 } }
};
// The primary purpose of the pushback buffer is so that if a
// multi-byte character or extended key code is read, we can return
// the first byte and store the rest of the data in the buffer for
// subsequent calls. UTF-8 characters can be up to 4 bytes long, so
// the pushback buffer must be able to store the 3 remaining bytes.
size_t const getch_pushback_buffer_capacity = 3;
static int getch_pushback_buffer[getch_pushback_buffer_capacity];
static int getch_pushback_buffer_index = 0;
static int getch_pushback_buffer_current_size = 0;
static bool is_getch_pushback_buffer_full()
{
return getch_pushback_buffer_current_size >= getch_pushback_buffer_capacity;
}
static void add_to_getch_pushback_buffer(int const c)
{
_ASSERTE(!is_getch_pushback_buffer_full());
getch_pushback_buffer[getch_pushback_buffer_current_size++] = c;
}
static int peek_next_getch_pushback_buffer()
{
if (getch_pushback_buffer_current_size == 0) {
return EOF;
}
return getch_pushback_buffer[getch_pushback_buffer_index];
}
static int get_next_getch_pushback_buffer()
{
if (getch_pushback_buffer_current_size == 0) {
return EOF;
}
int const ret_val = getch_pushback_buffer[getch_pushback_buffer_index++];
if (getch_pushback_buffer_index == getch_pushback_buffer_current_size) {
getch_pushback_buffer_index = 0;
getch_pushback_buffer_current_size = 0;
}
return ret_val;
}
extern "C" intptr_t __dcrt_lowio_console_input_handle;
extern "C" CharPair const* __cdecl _getextendedkeycode(KEY_EVENT_RECORD*);
extern "C" int __cdecl _kbhit_nolock();
// These functions read a single character from the console. _getch() does not
// echo the character; _getche() does echo the character. If the push-back
// buffer is nonempty, the buffered character is returned immediately, without
// being echoed.
//
// On success, the read character is returned; on failure, EOF is returned.
extern "C" int __cdecl _getch()
{
__acrt_lock(__acrt_conio_lock);
int result = 0;
__try
{
result = _getch_nolock();
}
__finally
{
__acrt_unlock(__acrt_conio_lock);
}
__endtry
return result;
}
extern "C" int __cdecl _getche()
{
__acrt_lock(__acrt_conio_lock);
int result = 0;
__try
{
result = _getche_nolock();
}
__finally
{
__acrt_unlock(__acrt_conio_lock);
}
__endtry
return result;
}
extern "C" int __cdecl _getch_nolock()
{
// Check the pushback buffer for a character. If one is present, return it:
int const pushback = get_next_getch_pushback_buffer();
if (pushback != EOF)
{
return pushback;
}
if (__dcrt_lowio_ensure_console_input_initialized() == FALSE) {
return EOF;
}
// Switch console to raw mode:
DWORD old_console_mode;
__dcrt_get_input_console_mode(&old_console_mode);
__dcrt_set_input_console_mode(0);
int result = 0;
__try
{
for ( ; ; )
{
// Get a console input event:
INPUT_RECORD input_record;
DWORD num_read;
if (__dcrt_read_console_input(&input_record, 1, &num_read) == FALSE || num_read == 0)
{
result = EOF;
__leave;
}
// Look for, and decipher, key events.
if (input_record.EventType == KEY_EVENT && input_record.Event.KeyEvent.bKeyDown)
{
// Simple case: if UnicodeChar is non-zero, we can convert it to char and return it.
wchar_t const c = input_record.Event.KeyEvent.uChar.UnicodeChar;
if (c != 0)
{
wchar_t const c_buffer[2] = {c, L'\0'};
char mb_chars[4];
size_t const amount_written = __acrt_wcs_to_mbs_cp_array(
c_buffer,
mb_chars,
GetConsoleCP()
);
// Mask with 0xFF to just get lowest byte
if (amount_written >= 1) {
result = mb_chars[0] & 0xFF;
}
if (amount_written >= 2) {
for (size_t i = 1; i < amount_written; ++i) {
add_to_getch_pushback_buffer(mb_chars[i] & 0xFF);
}
}
__leave;
}
// Hard case: either it is an extended code or an event which
// should not be recognized. Let _getextendedkeycode do the work:
CharPair const* const cp = _getextendedkeycode(&input_record.Event.KeyEvent);
if (cp != nullptr)
{
// Mask with 0xFF to just get lowest byte
add_to_getch_pushback_buffer(cp->SecondChar & 0xFF);
result = cp->LeadChar & 0xFF;
__leave;
}
}
}
}
__finally
{
// Restore the previous console mode:
__dcrt_set_input_console_mode(old_console_mode);
}
__endtry
return result;
}
extern "C" int __cdecl _getche_nolock()
{
// Check the pushback buffer for a character. If one is present, return
// it without echoing:
int const pushback = get_next_getch_pushback_buffer();
if (pushback != EOF)
{
return pushback;
}
// Otherwise, read the next character from the console and echo it:
int const c = _getch_nolock();
if (c == EOF)
return EOF;
if (_putch_nolock(c) == EOF)
return EOF;
return c;
}
// Returns nonzero if a keystroke is waiting to be read; otherwise returns zero.
extern "C" int __cdecl _kbhit()
{
__acrt_lock(__acrt_conio_lock);
int result = 0;
__try
{
result = _kbhit_nolock();
}
__finally
{
__acrt_unlock(__acrt_conio_lock);
}
__endtry
return result;
}
extern "C" int __cdecl _kbhit_nolock()
{
// If a character has been pushed back, return TRUE:
if (peek_next_getch_pushback_buffer() != EOF) {
return TRUE;
}
if (__dcrt_lowio_ensure_console_input_initialized() == FALSE) {
return FALSE;
}
// Peek at all pending console events:
DWORD num_pending;
if (__dcrt_get_number_of_console_input_events(&num_pending) == FALSE) {
return FALSE;
}
if (num_pending == 0) {
return FALSE;
}
__crt_scoped_stack_ptr<INPUT_RECORD> const input_buffer(_malloca_crt_t(INPUT_RECORD, num_pending));
if (input_buffer.get() == nullptr) {
return FALSE;
}
DWORD num_peeked;
// AsciiChar is not read, so using the narrow Win32 API is permitted.
if (__dcrt_peek_console_input_a(input_buffer.get(), num_pending, &num_peeked) == FALSE) {
return FALSE;
}
if (num_peeked == 0 || num_peeked > num_pending) {
return FALSE;
}
// Scan all of the peeked events to determine if any is a key event
// that should be recognized:
for (INPUT_RECORD* p = input_buffer.get(); num_peeked > 0; --num_peeked, ++p)
{
if (p->EventType != KEY_EVENT)
continue;
if (!p->Event.KeyEvent.bKeyDown)
continue;
if (p->Event.KeyEvent.uChar.AsciiChar == 0 &&
_getextendedkeycode(&p->Event.KeyEvent) == nullptr)
continue;
return TRUE;
}
return FALSE;
}
// Pushes back ("ungets") one character to be read next by _getwch() or
// _getwche(). On success, returns the character that was pushed back; on
// failure, returns EOF.
extern "C" int __cdecl _ungetch(int const c)
{
__acrt_lock(__acrt_conio_lock);
int result = 0;
__try
{
result = _ungetch_nolock(c);
}
__finally
{
__acrt_unlock(__acrt_conio_lock);
}
__endtry
return result;
}
extern "C" int __cdecl _ungetch_nolock(int const c)
{
// Fail if the character is EOF or the pusback buffer is nonempty:
if (c == EOF || is_getch_pushback_buffer_full()) {
return EOF;
}
add_to_getch_pushback_buffer(c);
return c;
}
// Returns the extended code (if there is one) for a key event. This is the
// core function for the _getch() and _getche() functions and their wide
// character equivalents, and is essential to _kbhit(). This is the function
// that determines whether or not a key event NOT accompanied by an ASCII
// character has an extended code and returns that code.
//
// On success, a pointer to a CharPair value holding the lead and second
// characters of the extended code is returned. On failure, nullptr is returned.
extern "C" CharPair const* __cdecl _getextendedkeycode(KEY_EVENT_RECORD* const pKE)
{
DWORD const CKS = pKE->dwControlKeyState;
if (CKS & ENHANCED_KEY)
{
// Find the appropriate entry in EnhancedKeys[]:
for (int i = 0 ; i < NUM_EKA_ELTS; ++i)
{
if (EnhancedKeys[i].ScanCode != pKE->wVirtualScanCode)
{
continue;
}
// We found a match! Determine which pair to return:
if (CKS & (LEFT_ALT_PRESSED | RIGHT_ALT_PRESSED))
{
return &EnhancedKeys[i].AltChars;
}
else if (CKS & (LEFT_CTRL_PRESSED | RIGHT_CTRL_PRESSED))
{
return &EnhancedKeys[i].CtrlChars;
}
else if (CKS & SHIFT_PRESSED)
{
return &EnhancedKeys[i].ShiftChars;
}
else
{
return &EnhancedKeys[i].RegChars;
}
}
return nullptr;
}
else
{
// Regular key or keyboard event which shouldn't be recognized.
// Determine which by getting the proper field of the proper entry in
// NormalKeys[] and examining the extended code.
CharPair const* pCP;
if (CKS & (LEFT_ALT_PRESSED | RIGHT_ALT_PRESSED))
{
pCP = &NormalKeys[pKE->wVirtualScanCode].AltChars;
}
else if (CKS & (LEFT_CTRL_PRESSED | RIGHT_CTRL_PRESSED))
{
pCP = &NormalKeys[pKE->wVirtualScanCode].CtrlChars;
}
else if (CKS & SHIFT_PRESSED)
{
pCP = &NormalKeys[pKE->wVirtualScanCode].ShiftChars;
}
else
{
pCP = &NormalKeys[pKE->wVirtualScanCode].RegChars;
}
// Make sure it wasn't a keyboard event which should not be recognized
// (e.g. the shift key was pressed):
if ((pCP->LeadChar != 0 && pCP->LeadChar != 224) || pCP->SecondChar == 0)
{
return nullptr;
}
return pCP;
}
}