terminal input tester, including mouse support - find out your key code

terminput.c

// compile: gcc -O2 terminput.c -o terminput
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

int main(int argc, char* argv[]) {
	system("/bin/stty raw -echo");
	int optCnt  = argc > 4 ? argc - 1 : 4;
	char** opts = malloc(optCnt * sizeof(char*));
	opts[0]     = ">1u"; // kitty keyboard protocol
	// see https://invisible-island.net/xterm/ctlseqs/ctlseqs.html#h2-Mouse-Tracking
	opts[1] = "1006";
	opts[2] = "1003";
	opts[3] = ">4;2m"; // get all modifiers in the same format
	for (int i = 1; i < argc; i++) opts[i - 1] = argv[i];
	for (int i = 0; i < optCnt; i++)
		fprintf(stderr, *opts[i] == '>' ? "\033[%s" : "\033[?%sh", opts[i]);

	char seq[20];
	int len, leftOver = 0;
	while (1) {
		int i = 0;
		if (!(len = read(0, seq + leftOver, sizeof(seq) - 1 - leftOver) + leftOver)) continue;
		leftOver = 0;
		seq[len] = 0;
		printf("I(");
		if (*seq < 0) printf("%s", seq); // not handling utf-8
		else do {
				if (seq[i] > 31) {
					if (seq[i] == 127) printf("\\b");
					else printf("%c", seq[i]);
				} else printf("^%c", seq[i] + 64);
				i++;
			} while (i < len && seq[i]);
		printf("):");
		i = 0;
		do {
			printf(" %d", seq[i]);
			i++;
		} while (i < len && seq[i]);
		printf("\r\n");
		if (*seq == 'q' && len == 1) break;
		while (i < len) seq[leftOver++] = seq[i++];
	}

	for (int i = 0; i < optCnt; i++)
		if (*opts[i] != '>') fprintf(stderr, "\033[?%sl", opts[i]);
	free(opts);
	fprintf(stderr, "\033[>4m\033[<u");
	system("/bin/stty sane");
	return 0;
}