Initial commit

.gitignore

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+.idea/

CMakeLists.txt

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+cmake_minimum_required(VERSION 3.16)
+project(getch C)
+
+set(CMAKE_C_STANDARD 11)
+
+add_library(getch SHARED getch.c getch.h)
+add_executable(test test.c )
+
+target_link_libraries(test -L./build getch)

getch.c

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+#include <stdio.h>
+#include <termios.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+#include <linux/input.h>
+#include <glob.h>
+#include "getch.h"
+
+// #define FKEY(k) ((k) >= KEY_F1 && (k) <= KEY_F10) || (k) == KEY_F12 || (k) == KEY_F11
+#define NOTNUMPAD(k) ((k) >= KEY_HOME && (k) <= KEY_DELETE)
+
+#define EVENT_DEVICE_GLOB "/dev/input/by-path/*-event-kbd"
+
+static struct termios oldTermAttributes;
+
+static void setRawMode(void);
+static void setNormalMode(void);
+
+inline static int discardRead(unsigned int length)
+{
+    char buffer[length];
+    ssize_t bytes_read;
+
+    int flags = fcntl(STDIN_FILENO, F_GETFL);
+    fcntl(STDIN_FILENO, F_SETFL, flags|O_NONBLOCK);
+
+    if( (bytes_read = fread(buffer, sizeof(char), length, stdin)) == -1) {
+        perror("discardRead");
+    }
+
+    fcntl(STDIN_FILENO, F_SETFL, flags);
+
+    return (int)bytes_read;
+}
+
+int getEventDevice(const char * device)
+{
+    glob_t search;
+
+    int globResult = glob(
+            EVENT_DEVICE_GLOB,
+            GLOB_NOSORT,
+            NULL,
+            &search
+        );
+
+    if(0 != globResult) {
+        globfree(&search);
+        return -1;
+    }
+
+    if(search.gl_pathc == 0) {
+        globfree(&search);
+        return -1;
+    }
+
+    size_t pathLength;
+
+    for(int i = 0; i<search.gl_pathc;i++) {
+        if(access(search.gl_pathv[i], F_OK) == 0) {
+            pathLength = strlen(search.gl_pathv[i]) + 1;
+            strncpy((char *)device, search.gl_pathv[i], pathLength);
+            globfree(&search);
+            return 1;
+        }
+    }
+
+    globfree(&search);
+    return -1;
+}
+
+unsigned short getScanCode()
+{
+    struct input_event inputEvent[5];
+    int fd;
+
+    const char device[FILENAME_MAX];
+    if(-1 == getEventDevice(device)) {
+        return KEY_RESERVED;
+    }
+
+    if( (fd = open(device, O_RDONLY)) == -1 ) {
+        return KEY_RESERVED;
+    };
+
+    if( read(fd, &inputEvent, sizeof (inputEvent)) == -1 ) {
+        return KEY_RESERVED;
+    }
+
+    close(fd);
+
+    for(int i = 0; i<=5; i++) {
+        if(inputEvent[i].type == EV_KEY) {
+            return inputEvent[i].code;
+        }
+    }
+
+    return KEY_RESERVED;
+}
+
+#pragma clang diagnostic push
+#pragma ide diagnostic ignored "cppcoreguidelines-narrowing-conversions"
+inline static char *reverseString(char *str)
+{
+      char *p1, *p2;
+
+      if (! str || ! *str)
+            return str;
+      for (p1 = str, p2 = str + strlen(str) - 1; p2 > p1; ++p1, --p2)
+      {
+            *p1 ^= *p2;
+            *p2 ^= *p1;
+            *p1 ^= *p2;
+      }
+      return str;
+}
+#pragma clang diagnostic pop
+
+#pragma clang diagnostic push
+#pragma ide diagnostic ignored "bugprone-reserved-identifier"
+inline static void pushStdin(int c) {
+    ungetc(c, stdin);
+}
+#pragma clang diagnostic pop
+
+inline static void setNormalMode(void)
+{
+    tcsetattr(STDIN_FILENO, TCSANOW, &oldTermAttributes);
+}
+
+inline static void setRawMode(void)
+{
+    tcgetattr(STDIN_FILENO, &oldTermAttributes);
+
+    struct termios raw = oldTermAttributes;
+
+    cfmakeraw(&raw);
+    tcsetattr(STDIN_FILENO, TCSANOW, &raw);
+
+}
+
+unsigned short resolveScanCode(unsigned short key)
+{
+    switch(key) {
+        case KEY_DOWN: return KEY_KP2;
+        case KEY_LEFT: return KEY_KP4;
+        case KEY_RIGHT: return KEY_KP6;
+        case KEY_UP: return KEY_KP8;
+        case KEY_HOME: return KEY_KP7;
+        case KEY_END: return KEY_KP1;
+        case KEY_INSERT: return KEY_KP0;
+        case KEY_DELETE: return KEY_KPDOT;
+        case KEY_PAGEUP: return KEY_KP9;
+        case KEY_PAGEDOWN: return KEY_KP3;
+        default: return key;
+    };
+}
+
+int readKey(void) {
+
+    unsigned short scanCode;
+    int key = getchar();
+
+    if (key == 27) {
+
+        scanCode = getScanCode();
+
+        if (scanCode == KEY_ESC) {
+            return 27;
+        }
+
+        int returnResult = 0;
+
+        if (NOTNUMPAD(scanCode)) {
+            scanCode = resolveScanCode(scanCode);
+            returnResult = 224;
+        }
+
+        u_short discardBytes;
+
+        switch (scanCode) {
+            case KEY_F1:
+            case KEY_F2:
+            case KEY_F3:
+            case KEY_F4:
+
+            case KEY_KP1: // END
+            case KEY_KP2: // DOWN
+            case KEY_KP4: // LEFT
+            case KEY_KP6: // RIGHT
+            case KEY_KP7: // HOME
+            case KEY_KP8: // UP
+                discardBytes = 2;
+                break;
+            case KEY_KP0: // INSERT
+            case KEY_KPDOT: // DELETE
+            case KEY_KP9: // PAGEUP
+            case KEY_KP3: // PAGEDOWN
+                discardBytes = 3;
+                break;
+            case KEY_F5:
+            case KEY_F6:
+            case KEY_F7:
+            case KEY_F8:
+            case KEY_F9:
+            case KEY_F10:
+            case KEY_F11:
+            case KEY_F12:
+                discardBytes = 4;
+                break;
+
+            default:
+                discardBytes = 0;
+        }
+
+        if (discardBytes != 0) {
+            discardRead(discardBytes);
+        }
+
+        pushStdin(scanCode);
+        return returnResult;
+    }
+
+    return key;
+}
+
+int _getch(void) {
+
+    atexit(setNormalMode);
+    setRawMode();
+
+    int key = readKey();
+
+    setNormalMode();
+
+    return key;
+}
+
+int _ungetch(int ch)
+{
+    return ungetc(ch, stdin);
+}

getch.h

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+
+#ifndef GETCH_H
+#define GETCH_H
+
+int _getch(void);
+int _ungetch(int ch);
+
+#endif //GETCH_H

test.c

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+#include <stdio.h>
+#include "getch.h"
+
+int main() {
+
+   int key = _getch();
+
+   printf("Key %d\n", key);
+
+   if (key == 0 || key == 224) {
+        key = _getch();
+        printf("Special Key : %d\n", key);
+    }
+
+    key = _getch();
+    printf("Anything left? : %d\n", key);
+
+    return 0;
+}